Microbiology Chapter 10 - Host-Microbe Interactions

<p>Group B streptococci causing infections in newborns (A)</p> Signup and view all the answers

<p>Tropism (D)</p> Signup and view all the answers

<p>Pathogenicity (C)</p> Signup and view all the answers

<p>By directly damaging host cells and provoking immune responses (D)</p> Signup and view all the answers

<p>Pathogen transmissibility or contagiousness (C)</p> Signup and view all the answers

<p>Cellular response (D)</p> Signup and view all the answers

<p>Require linkage to a larger molecule for immune activation (A)</p> Signup and view all the answers

<p>Dendritic cells and macrophages (B)</p> Signup and view all the answers

<p>T helper 1 cells (A)</p> Signup and view all the answers

<p>Gene rearrangement (C)</p> Signup and view all the answers

<p>Thymus (A)</p> Signup and view all the answers

<p>Regulate the functions of other immune cells (C)</p> Signup and view all the answers

<p>MHC I (B)</p> Signup and view all the answers

<p>Humoral response (B)</p> Signup and view all the answers

<p>They undergo apoptosis (C)</p> Signup and view all the answers

<p>MHC II presents intracellular antigens (A)</p> Signup and view all the answers

<p>T cytotoxic cells (B)</p> Signup and view all the answers

<p>Antigen presentation and lymphocyte activation (A)</p> Signup and view all the answers

<p>Dangerous, incurable agents that are not vaccine preventable (A)</p> Signup and view all the answers

<p>Innate immunity (C)</p> Signup and view all the answers

<p>Treatment of agents with vaccines (D)</p> Signup and view all the answers

<p>Filtering and circulating fluid in the body (D)</p> Signup and view all the answers

<p>Fluid circulation and screening (A)</p> Signup and view all the answers

<p>They contain granules that are visible when stained (B)</p> Signup and view all the answers

<p>They target and disrupt the plasma membrane of pathogens (B)</p> Signup and view all the answers

<p>Presence of epithelial tissue (D)</p> Signup and view all the answers

<p>Increased microbial diversity strengthens immune health (D)</p> Signup and view all the answers

<p>All are primarily involved in phagocytosis (B)</p> Signup and view all the answers

<p>Infection causing rapid leukocyte production (B)</p> Signup and view all the answers

<p>Dedicated for single-patient use (C)</p> Signup and view all the answers

<p>Ability to exhibit memory after exposure (D)</p> Signup and view all the answers

<p>Recruiting other leukocytes and restricting pathogen growth (C)</p> Signup and view all the answers

<p>It remains infectious but has reduced virulence. (D)</p> Signup and view all the answers

<p>The infectious dose needed to infect 50% of exposed hosts. (C)</p> Signup and view all the answers

<p>Endotoxins originate from lipid A of Gram-negative bacteria. (D)</p> Signup and view all the answers

<p>Respiratory mucous membranes. (D)</p> Signup and view all the answers

<p>Dendritic cells (D)</p> Signup and view all the answers

<p>By disguising itself with host molecules. (C)</p> Signup and view all the answers

<p>Attract white blood cells to specific locations (B)</p> Signup and view all the answers

<p>To snatch iron from transferrin for survival. (A)</p> Signup and view all the answers

<p>Classical complement cascade (A)</p> Signup and view all the answers

<p>Redness, pain, localized heat, swelling (D)</p> Signup and view all the answers

<p>They bind to receptors and alter gene expression. (D)</p> Signup and view all the answers

<p>An exaggerated cytokine response (B)</p> Signup and view all the answers

<p>LD50 measures the amount of toxin required to kill 50% of hosts. (D)</p> Signup and view all the answers

<p>They help pull iron from iron-binding proteins (A)</p> Signup and view all the answers

<p>By forming protective capsules. (D)</p> Signup and view all the answers

<p>NK cells (D)</p> Signup and view all the answers

<p>Enter, adhere, invade, replicate, transmit. (D)</p> Signup and view all the answers

<p>Vasodilation and increased vessel permeability (B)</p> Signup and view all the answers

<p>They can lead to cell death or damage. (A)</p> Signup and view all the answers

<p>By passing through the epidermis. (A)</p> Signup and view all the answers

<p>Increases the efficiency of phagocytes (D)</p> Signup and view all the answers

<p>Bind to and neutralize specific antigens (C)</p> Signup and view all the answers

<p>They break down host tissues and induce uptake of the pathogen. (B)</p> Signup and view all the answers

<p>They can induce toxic shock and immune suppression. (D)</p> Signup and view all the answers

<p>Exacerbation of tissue injury (B)</p> Signup and view all the answers

<p>To build new blood vessels during healing (B)</p> Signup and view all the answers

<p>It activates a large number of T cells non-specifically (C)</p> Signup and view all the answers

<p>Breaking down red blood cells (C)</p> Signup and view all the answers

<p>They activate other immune cells and provide support. (C)</p> Signup and view all the answers

<p>Involves cross-linking of B cell receptors by non-protein antigen epitopes. (A)</p> Signup and view all the answers

<p>It requires primary and secondary signals including MHC interaction and co-stimulatory proteins. (B)</p> Signup and view all the answers

<p>They lead to a lack of affinity maturation. (D)</p> Signup and view all the answers

<p>T cells proliferate and differentiate into effector and memory cells. (A)</p> Signup and view all the answers

<p>Cytotoxic T cells, which use perforins and granzymes. (B)</p> Signup and view all the answers

<p>The capacity to generate a stronger and faster immune response upon re-exposure to the same pathogen. (C)</p> Signup and view all the answers

<p>TH1, which promotes T cytotoxic cell activation, and TH2, which promotes B cell maturation. (D)</p> Signup and view all the answers

<p>IgM (D)</p> Signup and view all the answers

<p>To measure a patient's antibody response to determine past exposure or vaccination status. (C)</p> Signup and view all the answers

<p>Memory B cells remain in the body for a longer duration and provide faster responses upon re-exposure. (C)</p> Signup and view all the answers

<p>They neutralize pathogens and enhance phagocytosis through opsonization. (A)</p> Signup and view all the answers

<p>IgG (D)</p> Signup and view all the answers

<p>It contains antibodies from recovered patients and is used to provide passive immunity to current patients. (B)</p> Signup and view all the answers

<p>They help in manufacturing vitamins and compete with potential pathogens. (C)</p> Signup and view all the answers

<p>By allowing opportunistic pathogens to flourish and cause disease. (A)</p> Signup and view all the answers

<p>Pathogenicity describes the ability to cause disease while virulence describes the extent of that disease. (D)</p> Signup and view all the answers

<p>Disruption of normal microbiota leading to opportunistic infection. (A)</p> Signup and view all the answers

<p>They enable pathogens to adhere to and invade host tissues. (C)</p> Signup and view all the answers

<p>By undergoing random mutations and natural selection. (A)</p> Signup and view all the answers

<p>The actual number of secondary infections generated by an infected individual. (A)</p> Signup and view all the answers

<p>It shapes the host and tissue range that pathogens can infect. (B)</p> Signup and view all the answers

<p>The number of pathogens required to cause an infection in 50% of hosts (A)</p> Signup and view all the answers

<p>They are used by pathogens to adhere to host tissues. (A)</p> Signup and view all the answers

<p>Type I exotoxins (D)</p> Signup and view all the answers

<p>They periodically alter their surface molecules. (B)</p> Signup and view all the answers

<p>They can cause toxic shock. (C)</p> Signup and view all the answers

<p>Latency (C)</p> Signup and view all the answers

<p>They snatch iron from host proteins. (B)</p> Signup and view all the answers

<p>Skin abrasions (C)</p> Signup and view all the answers

<p>They cause lysis of host cells. (C)</p> Signup and view all the answers

<p>Via the same route used as their portal of entry (D)</p> Signup and view all the answers

<p>To break down lipids for nutrient acquisition (A)</p> Signup and view all the answers

<p>Humoral response (A)</p> Signup and view all the answers

<p>They block protein synthesis. (B)</p> Signup and view all the answers

<p>Acting as antigen-presenting cells (D)</p> Signup and view all the answers

<p>Utilizing toxins to kill phagocytes (D)</p> Signup and view all the answers

<p>Intracellular antigens (D)</p> Signup and view all the answers

<p>It varies based on host-pathogen interactions. (A)</p> Signup and view all the answers

<p>Activate cytotoxic T cells and macrophages (A)</p> Signup and view all the answers

<p>Bone marrow (C)</p> Signup and view all the answers

<p>To attract immune cells to sites of infection (C)</p> Signup and view all the answers

<p>Natural Killer (NK) cells (B)</p> Signup and view all the answers

<p>Present antigens to T cells for recognition (A)</p> Signup and view all the answers

<p>An exaggerated cytokine response (B)</p> Signup and view all the answers

<p>T cytotoxic cells (A)</p> Signup and view all the answers

<p>Apoptosis (B)</p> Signup and view all the answers

<p>Enhance inflammation and activate immune responses (C)</p> Signup and view all the answers

<p>MHC proteins (A)</p> Signup and view all the answers

<p>Lymphocyte activation (A)</p> Signup and view all the answers

<p>Antigen-presenting cells (APCs) (D)</p> Signup and view all the answers

<p>Vascular changes phase (B)</p> Signup and view all the answers

<p>They help maintain iron levels crucial for oxygen delivery (A)</p> Signup and view all the answers

<p>Suppress immune responses to maintain homeostasis (B)</p> Signup and view all the answers

<p>Breaking down red blood cells (A)</p> Signup and view all the answers

<p>Somatic recombination of gene segments (B)</p> Signup and view all the answers

<p>They act as phagocytes and antigen-presenting cells. (D)</p> Signup and view all the answers

<p>Intracellular antigens (D)</p> Signup and view all the answers

<p>Producing siderophores (B)</p> Signup and view all the answers

<p>Promote B cell antibody production (A)</p> Signup and view all the answers

<p>Boost immune defenses against invaders (A)</p> Signup and view all the answers

<p>Classical complement cascade (C)</p> Signup and view all the answers

<p>A highly immunogenic toxin that activates many T cells (D)</p> Signup and view all the answers

<p>BSL-2 agents are not vaccine preventable. (C)</p> Signup and view all the answers

<p>They are designed to prevent pathogen entry. (B)</p> Signup and view all the answers

<p>They disrupt pathogen membranes and stimulate leukocytes. (D)</p> Signup and view all the answers

<p>It filters lymph and detects pathogens. (A)</p> Signup and view all the answers

<p>Granulocytes contain granules that can be seen when stained. (D)</p> Signup and view all the answers

<p>They have no known cures or treatments. (B)</p> Signup and view all the answers

<p>It includes barriers like skin and mucous membranes. (B)</p> Signup and view all the answers

<p>To reduce direct contact with patients. (B)</p> Signup and view all the answers

<p>An increase in white blood cells. (B)</p> Signup and view all the answers

<p>Presenting antigens to T cells. (C)</p> Signup and view all the answers

<p>Dangerous and incurable with no vaccines. (A)</p> Signup and view all the answers

<p>Recruit other leukocytes to infection sites. (A)</p> Signup and view all the answers

<p>Decreased diversity negatively affects immune responses. (A)</p> Signup and view all the answers

<p>They enhance the activation of other immune cells. (A)</p> Signup and view all the answers

<p>They lack the ability to form memory B cells. (D)</p> Signup and view all the answers

<p>T cell receptor interaction with MHC-antigen and co-stimulatory proteins. (C)</p> Signup and view all the answers

<p>By using perforins to lyse the target membrane. (C)</p> Signup and view all the answers

<p>They differentiate into plasma cells and memory B cells. (D)</p> Signup and view all the answers

<p>The primary response generates IgM first and then IgG. (C)</p> Signup and view all the answers

<p>They tag antigens for phagocytosis and neutralize toxins. (B)</p> Signup and view all the answers

<p>IgM (C)</p> Signup and view all the answers

<p>The generation of memory cells that enable rapid reactivation of the immune response. (A)</p> Signup and view all the answers

<p>To assess a patient's antibody titers to determine exposure to a disease. (D)</p> Signup and view all the answers

<p>They provide necessary signals to complete B cell activation. (C)</p> Signup and view all the answers

<p>T cells multiply and differentiate based on cytokine signals. (C)</p> Signup and view all the answers

<p>T cell-dependent B cell activation requires cytokines released by T helper cells. (D)</p> Signup and view all the answers

<p>They manufacture vitamins, compete with pathogens, and promote immune system maturation. (B)</p> Signup and view all the answers

<p>Dysbiosis (B)</p> Signup and view all the answers

<p>Virulence factors (C)</p> Signup and view all the answers

<p>Due to differences in host immunity and microbiota composition (C)</p> Signup and view all the answers

<p>The preference of a pathogen for a specific host or tissue (C)</p> Signup and view all the answers

<p>It typically causes severe disease (C)</p> Signup and view all the answers

<p>A measure of the average number of secondary cases produced by one infected individual in a population (B)</p> Signup and view all the answers

<p>The transmissibility of a pathogen (A)</p> Signup and view all the answers

<p>To provide help and support to other immune cells (B)</p> Signup and view all the answers

<p>It has limited capacity for memory formation (C)</p> Signup and view all the answers

<p>Primary and secondary signals involving receptor interactions (C)</p> Signup and view all the answers

<p>Cytokines released from other immune cells (D)</p> Signup and view all the answers

<p>By releasing granzymes and perforins (C)</p> Signup and view all the answers

<p>They enhance phagocytosis and neutralize toxins (B)</p> Signup and view all the answers

<p>IgM (C)</p> Signup and view all the answers

<p>To provide passive immunity to newly infected individuals (B)</p> Signup and view all the answers

<p>Secondary responses produce a higher concentration of IgG with limited IgM (D)</p> Signup and view all the answers

<p>They differentiate into plasma cells that secrete antibodies (C)</p> Signup and view all the answers

<p>Repetitive non-protein polysaccharide epitopes (A)</p> Signup and view all the answers

<p>Dendritic cells (A)</p> Signup and view all the answers

<p>By acting on the hypothalamus. (A)</p> Signup and view all the answers

<p>Chemokines (D)</p> Signup and view all the answers

<p>White blood cells undergo apoptosis. (B), New blood vessels are formed. (D)</p> Signup and view all the answers

<p>The number of virions needed to infect 50% of exposed hosts (C)</p> Signup and view all the answers

<p>They are soluble proteins that can cause cytopathic effects. (A)</p> Signup and view all the answers

<p>Alternative pathway (B)</p> Signup and view all the answers

<p>Exploiting iron-binding proteins. (A)</p> Signup and view all the answers

<p>Altering surface antigens periodically. (B)</p> Signup and view all the answers

<p>Endotoxins from E. coli (A)</p> Signup and view all the answers

<p>Exaggerated immune response. (C)</p> Signup and view all the answers

<p>Innate immune cells (C)</p> Signup and view all the answers

<p>Invading host immune cells (B)</p> Signup and view all the answers

<p>Dead tissue cells and bacteria. (B)</p> Signup and view all the answers

<p>They bind and sequester iron from the host. (D)</p> Signup and view all the answers

<p>Plasma membrane (C)</p> Signup and view all the answers

<p>Humoral immunity (B)</p> Signup and view all the answers

<p>T cytotoxic cells destroy infected cells, whereas T helper cells coordinate the immune response. (B)</p> Signup and view all the answers

<p>Respiratory droplets (D)</p> Signup and view all the answers

<p>Act as signaling molecules to mediate inflammation. (A)</p> Signup and view all the answers

<p>They maintain infectious potential but are weakened. (B)</p> Signup and view all the answers

<p>Inhibit mediators of inflammation. (A)</p> Signup and view all the answers

<p>They need to be linked to proteins or polysaccharides to stimulate an immune response. (A)</p> Signup and view all the answers

<p>Signal the presence of pathogens. (A)</p> Signup and view all the answers

<p>By releasing toxins and disrupting normal cell functions. (D)</p> Signup and view all the answers

<p>MHC II (B)</p> Signup and view all the answers

<p>A capsule resembling host carbohydrates. (B)</p> Signup and view all the answers

<p>To eliminate the risk of autoimmune reactions. (B)</p> Signup and view all the answers

<p>Lymphocyte proliferation and differentiation (C)</p> Signup and view all the answers

<p>To facilitate attachment to host cells. (C)</p> Signup and view all the answers

<p>They can decrease based on route of exposure. (A)</p> Signup and view all the answers

<p>They control the functions of other immune cells. (A)</p> Signup and view all the answers

<p>Antigen recognition receptors (C)</p> Signup and view all the answers

<p>T cells are tested for self-MHC recognition. (B)</p> Signup and view all the answers

<p>From intracellular pathogens. (D)</p> Signup and view all the answers

<p>T helper 1 cells activate macrophages and cytotoxic T cells, whereas T helper 2 cells stimulate B cells to produce antibodies. (A)</p> Signup and view all the answers

<p>Lymphocyte activation and cytokine release. (D)</p> Signup and view all the answers

<p>CD4 interacts with MHC II, and CD8 interacts with MHC I. (C)</p> Signup and view all the answers

<p>TCRs can recognize a vast variety of antigens due to the large number of T cells produced. (B)</p> Signup and view all the answers

<p>BSL-1 (B)</p> Signup and view all the answers

<p>Bone marrow (C)</p> Signup and view all the answers

<p>Contain highly effective vaccines (B)</p> Signup and view all the answers

<p>Generalized responses (C)</p> Signup and view all the answers

<p>Screen and filter body fluid for pathogens (D)</p> Signup and view all the answers

<p>Physical and chemical barriers preventing entry (B)</p> Signup and view all the answers

<p>Have no cures or treatments available (A)</p> Signup and view all the answers

<p>To destroy a broad range of pathogens (D)</p> Signup and view all the answers

<p>Presence of foreign pathogens or invaders (C)</p> Signup and view all the answers

<p>Physically block pathogen entry into the body (C)</p> Signup and view all the answers

<p>Increase in leukocyte levels in the blood (D)</p> Signup and view all the answers

<p>Physical, chemical, and mechanical strategies (A)</p> Signup and view all the answers

<p>Contain visible granules when stained (D)</p> Signup and view all the answers

<p>To prevent specific disease transmissions (D)</p> Signup and view all the answers

<p>By fine-tuning immune responses to pathogens (A)</p> Signup and view all the answers

Produce vitamins, compete with pathogens, and help immune system develop.

Pathogen = disease-causing microbe; Normal microbiota are microbes that usually don't cause disease and reside in the body.

Disruption of the normal microbiota.

A microbe that is usually harmless may cause disease in a different host. Example: Group B Strep (GBS) in newborns.

Preference of a pathogen for a specific host (or tissue).

Ability of a microbe to cause disease.

Extent of disease caused by a pathogen.

Measure of a pathogen’s contagiousness.

A pathogen's average number of secondary infections produced by an infected individual in a fully susceptible population, useful during epidemics and pandemics.

A weakened but still infectious pathogen used in vaccines, often created by growing the pathogen in cell cultures.

Infectious Dose-50; the amount of pathogen needed to establish an infection in 50% of exposed hosts.

Lethal Dose-50; amount of a toxin needed to kill 50% of affected and untreated hosts.

Molecules causing adverse host effects like tissue damage or immune suppression.

Lipid A component of Gram-negative bacteria's LPS, triggering septic shock; Often with a lower LD50.

Soluble protein toxins from Gram-positive and Gram-negative bacteria, capable of causing various effects.

Binds to host cell surface receptors, altering gene expression.

Disrupts cell membranes, causing lysis.

Enters host cells after binding to receptors.

The route a pathogen uses to enter the host.

Virulence factor that allows a pathogen to attach to host cells.

Community of microorganisms attached to a surface, often formed by adhesins.

Route a pathogen takes to leave the host.

Molecule that helps pathogens obtain iron from the host.

A metric classifying agents by risk level based on infectivity, disease severity, and transmission.

Agents posing limited risk of infection.

Infectious agents, not typically airborne.

Dangerous and incurable pathogens, not airborne or vaccine preventable.

Serious or lethal human diseases, often transmitted through the air.

Dangerous exotic pathogens, with no known cure or treatment, potentially airborne.

Procedures to minimize the spread of bloodborne pathogens, treating all patients as potential carriers.

Measures to prevent direct contact, droplet, and airborne transmission of diseases.

Generalized, non-specific immune response, a quick reaction.

Vertebrate-specific, targeted immune response, slower, and with memory.

Prevent pathogen entry; mechanical, chemical, and physical barriers.

Natural bacteria that helps optimize immune responses to pathogens.

Destroy pathogens by disrupting their plasma membranes or cell walls.

Collection of tissues filtering body fluids.

The ability of a molecule to trigger an immune response, from strongest to weakest: Proteins > Polysaccharides > Lipids > Small Molecules (Haptens).

A small molecule that cannot trigger an immune response on its own but can do so when attached to a larger carrier molecule (like a protein).

Potent T helper cell activators; they can bind to many different T cells, leading to an overactive immune response.

Immune response mediated by T cells, particularly T cytotoxic cells, to target intracellular pathogens and cancer cells.

Immune response mediated by B cells and antibodies, primarily targeting extracellular pathogens and toxins.

Process by which antigen-presenting cells (APCs) display antigens to T cells, initiating an adaptive immune response.

Engagement of T and B cell receptors by antigens, leading to cell signaling and cytokine release, initiating clonal expansion.

Rapid division and specialization of activated T and B cells into effector cells and memory cells.

The destruction of pathogens or infected cells by effector cells and the generation of memory cells for long-term immunity.

T cells develop in the bone marrow and mature in the thymus, where they undergo selection and differentiation into various subtypes.

B cells are produced and mature in the bone marrow, later differentiating into plasma cells which produce antibodies.

Directly destroys infected or cancerous cells, recognizing intracellular antigens presented by MHC I.

Coordinates the adaptive immune response by stimulating other immune cells, recognizing extracellular antigens presented by MHC II.

MHC I presents intracellular antigens to T cytotoxic cells, while MHC II presents extracellular antigens to T helper cells.

Controls the function of other immune cells, preventing excessive immune responses and autoimmune reactions.

T helper cells are essential for activating both branches of the adaptive immune system. They provide crucial support to other immune cells, leading to a robust response.

Some B cells can be activated directly by antigens without T cell help. This usually involves repetitive, non-protein antigens, such as bacterial capsule polysaccharides. However, this activation is limited in its capacity for memory.

T cells require two signals for activation: 1) interaction of the T cell receptor with the MHC-antigen complex and 2) co-stimulatory protein interactions.

When a T cell recognizes its specific antigen, it undergoes rapid proliferation, creating many identical copies of itself.

Activated T cells differentiate into various types, including memory T cells (long-term protection) and effector T cells (immediate action). T helper cells can further differentiate to become TH1 or TH2, depending on the cytokines present. These cells perform different tasks in the immune response.

T cytotoxic cells recognize infected cells by binding to MHC-I antigen complexes. They release perforins (to create pores) and granzymes (to induce apoptosis) which lead to the infected cell's death.

B cell activation in a T cell-dependent manner requires two signals: 1) the B cell receptor binding to extracellular antigen and 2) co-stimulatory proteins interacting, often involving cytokine release from a T helper cell.

Activated B cells proliferate into numerous clones, all recognizing the same epitope. These clones differentiate into plasma cells (antibody production) and memory B cells (long-term immunity).

Antibodies are proteins secreted by plasma cells. They bind to specific antigens that triggered the B cell's activation.

There are five major antibody isotypes: IgG, IgA, IgM, IgE, and IgD, each with unique characteristics and functions. IgG is the most abundant, crosses the placenta, and provides long-lasting immunity. IgM is produced early in infection.

The ability of the immune system to mount a faster and more effective response to pathogens encountered before.

During primary exposure, IgM is produced first, followed by IgG. In a secondary response, memory cells quickly produce high levels of high-affinity IgG, with only a small amount of IgM.

Serological testing measures antibody titers in a person's blood to determine if they have been exposed to a specific pathogen or have been vaccinated.

Convalescent plasma is plasma from recovered patients. It contains antibodies against a specific pathogen and can be used to provide passive immunity for currently infected individuals.

Humoral immunity refers to immunity mediated by antibodies in the bloodstream. The four types are: natural active, artificial active, natural passive, and artificial passive immunity.

Cells that engulf and destroy foreign invaders, such as bacteria and viruses. These include macrophages, neutrophils, and dendritic cells.

Cells that capture and present antigens to T cells, initiating an adaptive immune response. Dendritic cells are the most important type.

The first leukocytes to arrive at a site of injury. They release antimicrobial peptides (AMPs) to fight infection.

Granulocytes that target parasites. They release enzymes and toxins stored in their granules.

Granulocytes packed with defense molecules, including histamine, which contribute to allergies and fighting parasites.

Similar to basophils, they play a role in allergies and fighting parasites, releasing histamine and other inflammatory mediators.

Large, circulating leukocytes that mature into macrophages once they enter tissues.

Large phagocytic cells that can be fixed (residing in specific tissues) or wandering (roaming around) to engulf and destroy invaders.

White blood cells responsible for adaptive immunity. They recognize specific antigens and coordinate a tailored immune response.

Lymphocytes that provide innate immune protection against viruses, bacteria, parasites, and even tumor cells.

Signaling proteins that allow cells to communicate with each other. They regulate and coordinate immune responses.

A type of cytokine that attracts white blood cells to areas where they are needed, like a battleground.

Proteins like transferrin and lactoferrin that bind iron, making it unavailable to pathogens, which need iron for growth.

Organic molecules produced by some pathogens to snatch iron from our iron-binding proteins, allowing them to thrive.

Bacteria that break down red blood cells (RBCs) to access the iron-rich hemoglobin within, overcoming our iron-binding defenses.

A complex system of over 30 proteins that work together in a cascade to enhance the immune response.

There are three pathways: the classical (triggered by antibodies), alternative (activated directly by pathogens), and lectin pathway (activated by mannose-binding lectin).

The complement system is tightly regulated to prevent self-damage. This is achieved through self-destruct mechanisms and regulators that shut down the cascade after a threat passes.

The localized response to tissue injury, characterized by redness, pain, heat, and swelling. It serves to protect, fight infection, and initiate tissue repair.

The first stage, characterized by vasodilation (blood vessel widening) and increased vessel permeability, allowing fluid to leak into the tissues.

Molecules released during inflammation that contribute to vasodilation, increased vessel permeability, and attracting immune cells.

The second stage, where white blood cells are recruited to the site of injury by chemoattractants.

The final stage, where inflammation subsides, swelling decreases, and tissue repair begins.

The formation of new blood vessels, which occurs during the resolution phase of inflammation to provide nutrients and oxygen for tissue repair.

A collection of dead tissue cells and white blood cells that accumulates in the resolution phase of inflammation at a wound.

An abnormally high systemic body temperature triggered by pyrogens (fever-inducing substances), which act on the hypothalamus.

Substances like bacterial endotoxins that trigger fever by acting on the hypothalamus.

Fever increases antiviral effects of interferons, enhances phagocyte efficiency, promotes leukocyte production, limits microbial growth, and can promote tissue repair.

Any substance that is foreign to the body and can trigger an immune response. Most antigens are proteins or polysaccharides from bacteria, viruses, fungi, protists, or cancer cells.

The specific part of an antigen that is recognized by antibodies or T cell receptors.

Proteins produced by B cells that specifically bind to antigens, neutralizing their effects and marking them for destruction.

A small molecule that is not immunogenic on its own but can become immunogenic when bound to a larger carrier molecule.

A type of antigen that activates a large number of T cells, leading to a massive immune response that can be harmful.

A microbe capable of causing disease.

A specific mechanism used by a pathogen to overcome host defenses.

A pathogen's preference for a specific host or tissue within a host.

Virulence factors harm the host directly by damaging cells or indirectly by provoking dangerous immune responses.

Previously unknown or rare pathogens that have recently begun to cause disease.

An enzyme secreted by pathogens to break down host tissues and invade deeper.

The damage caused by pathogens to host cells, ranging from mild to severe.

A strategy used by pathogens to evade the immune system by altering their surface molecules.

A system classifying infectious agents based on their risk to humans, ranging from BSL-1 (minimal risk) to BSL-4 (highly dangerous).

Proteins that directly target pathogens to disrupt their cell membranes or walls.

White blood cells with granules in their cytoplasm that are visible under a microscope.

White blood cells that lack granules in their cytoplasm.

A test that measures the different types of white blood cells in the blood, which can indicate a disease.

Lymphocytes are white blood cells involved in adaptive immunity. The main types are B cells, T cells, and NK cells.

B cells and T cells are the only lymphocytes involved in adaptive immunity.

Signaling proteins that allow cells to communicate with each other. They regulate and coordinate immune responses.

An exaggerated, overactive response by the immune system involving excessive cytokine production. It can be dangerous, leading to tissue damage.

Cytokines that attract white blood cells to areas where they are needed, like a battleground.

Iron-binding proteins like transferrin and lactoferrin bind iron, making it unavailable to pathogens that need iron for their growth.

Some pathogens produce siderophores, molecules that snatch iron from our iron-binding proteins, or they break down red blood cells to access the iron-rich hemoglobin.

A complex system of over 30 proteins that work together in a cascade to enhance the immune response.

The classical pathway is triggered by antibodies, the alternative pathway activates directly by interacting with the invading agent, and the lectin pathway is activated when mannose-binding lectin binds to sugars on the microbe's surface.

Regulating the complement system is crucial to prevent self-damage. Without regulation, the cascade could continue unchecked, leading to harmful inflammation.

The cardinal signs of inflammation are redness, pain, localized heat, and swelling.

A collection of dead tissue cells and white blood cells that forms in the late resolution phase of inflammation.

An abnormally high systemic body temperature triggered by pyrogens (fever-inducing substances), which act on the hypothalamus.

Some B cells can be activated directly by antigens without T cell help. This is usually limited to repetitive non-protein antigens, like bacterial capsule polysaccharides.

T cells require two signals for activation: 1) interaction of the T cell receptor with the MHC-antigen complex, and 2) co-stimulatory protein interactions.

Activated T cells differentiate into memory T cells for long-term protection, and effector T cells for immediate action.

T cytotoxic cells kill infected or cancerous cells by recognizing intracellular antigens presented by MHC I.

T cytotoxic cells release perforins to create pores in target cells and granzymes to induce apoptosis.

B cells require two signals for activation in a T cell-dependent manner: 1) the B cell receptor binding to extracellular antigen and 2) co-stimulatory proteins interacting, often involving cytokine release from a T helper cell.

B cell clones differentiate into plasma cells (antibody production) and memory B cells (long-term immunity).

Antibodies are proteins secreted by plasma cells. They bind to specific antigens that triggered the B cell's activation, neutralizing them and marking them for destruction.

IgM is produced early in infection, while IgG is the most abundant and provides longer-lasting immunity.

Convalescent plasma is plasma from recovered patients, containing antibodies against a specific pathogen. This is a passive immunity treatment for infected individuals.

Many emerging pathogens have expanded their host or tissue range, meaning they can now infect humans, sometimes even targeting specific tissues within the body.

Normal microbiota are microbes that usually don't cause disease and reside in our body, while pathogens are disease-causing microbes.

Pathogenicity is the ability of a microbe to cause disease, while virulence measures the degree or extent of disease caused by a pathogen.

The amount of pathogen needed to establish an infection in 50% of exposed hosts.

The amount of toxin needed to kill 50% of affected and untreated hosts.

The complement system is powerful but needs to be tightly regulated to prevent damage to our own tissues. Uncontrolled activation can lead to inflammation and autoimmune diseases.

Redness (rubor), swelling (tumor), heat (calor), and pain (dolor). These are caused by the body's response to injury or infection, involving vasodilation, increased vessel permeability, and the recruitment of immune cells.

Angiogenesis is the formation of new blood vessels. It occurs in the resolution phase of inflammation to provide nutrients and oxygen for tissue repair.

Pus is a yellowish-white fluid that accumulates in the resolution phase of inflammation. It consists mainly of dead white blood cells, bacteria, and other debris.

Fever is an abnormally high systemic body temperature triggered by pyrogens (fever-inducing substances). It is a systemic response to infection and can enhance the immune system's ability to fight pathogens by increasing antiviral effects, enhancing phagocyte efficiency, promoting leukocyte production, and limiting the growth of some pathogens.