Immunology: Defense Against Infection

<p>Severe tissue destruction (B)</p> Signup and view all the answers

<p>Killing infected cells (B)</p> Signup and view all the answers

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

<p>They determine the severity of certain diseases (B)</p> Signup and view all the answers

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

<p>Bacteria, Fungi, Viruses, and Parasites (B)</p> Signup and view all the answers

<p>Characteristics of both the host and the microbe (A)</p> Signup and view all the answers

<p>Under-reaction and excessive response (D)</p> Signup and view all the answers

<p>Anti-viral immune response (B)</p> Signup and view all the answers

<p>Duration of symptoms (D)</p> Signup and view all the answers

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

<p>Pathogens can hide from immune detection (B)</p> Signup and view all the answers

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

<p>They neutralize viruses and prevent attachment to target cells. (B)</p> Signup and view all the answers

<p>Cytotoxic T-cells (CTLs) (C)</p> Signup and view all the answers

<p>By inhibiting intracellular replication of viruses. (D)</p> Signup and view all the answers

<p>To attract and activate macrophages. (B)</p> Signup and view all the answers

<p>Antibodies bind to virus-infected cells which are then lysed by immune cells. (D)</p> Signup and view all the answers

<p>They act early in viral diseases before antibodies are produced. (B)</p> Signup and view all the answers

<p>They block the transport of viral nucleoproteins into the nucleus. (B)</p> Signup and view all the answers

<p>Cell-mediated immunity (B)</p> Signup and view all the answers

<p>Production of VA RNA that binds PKR without activating it (D)</p> Signup and view all the answers

<p>Sequesters p300/CPB co-factors to block interferon expression (B)</p> Signup and view all the answers

<p>Cell-mediated response involving effector T lymphocytes (C)</p> Signup and view all the answers

<p>The cytokine signals at initial antigen contact (B)</p> Signup and view all the answers

<p>Recovery from infection that promotes long-term immunity to re-infection (B)</p> Signup and view all the answers

<p>IL-4, IL-5, IL-10, and IL-13 (C)</p> Signup and view all the answers

<p>Strong production of immunoglobulin E (IgE) (D)</p> Signup and view all the answers

<p>Virulence mechanisms employed by pathogens (B)</p> Signup and view all the answers

<p>A highly inflammatory form of programmed cell death. (C)</p> Signup and view all the answers

<p>It results from sensing DNA fragments produced during reverse transcription. (C)</p> Signup and view all the answers

<p>They can impair B and T cell function. (D)</p> Signup and view all the answers

<p>They trigger the release of mediators that inhibit lymphocyte function. (A)</p> Signup and view all the answers

<p>Igniting inflammation for non-dangerous stimuli. (C)</p> Signup and view all the answers

<p>A.actinomycetemcomitans (D)</p> Signup and view all the answers

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

<p>They inhibit lymphocyte function. (C)</p> Signup and view all the answers

<p>A few flat lesions, some large and numb (B)</p> Signup and view all the answers

<p>It may persist, regress, or progress to other forms. (B)</p> Signup and view all the answers

<p>Presence of bacteria and severe nerve involvement (B)</p> Signup and view all the answers

<p>Can persist, revert to tuberculoid, or advance (D)</p> Signup and view all the answers

<p>Lesions include reddish plaques with moderate numbness (D)</p> Signup and view all the answers

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

<p>Tuberculoid may heal on its own; Lepromatous does not (B)</p> Signup and view all the answers

<p>It presents many lesions, including nodules and flat lesions. (B)</p> Signup and view all the answers

<p>Severe nerve involvement and limb weakness (B)</p> Signup and view all the answers

<p>Borderline tuberculoid leprosy (C)</p> Signup and view all the answers

Microbial infectious agents that cause diseases and epidemics.

The characteristics of a disease caused by a pathogen: the type of pathogen, the affected body part, the location of the pathogen (inside or outside cells), and the immune response triggered.

Interactions between a host and a pathogen vary depending on the individual host's characteristics and the pathogen's properties. This dynamic relationship influences the outcome of infection.

Extreme immune reactions, whether overactive or insufficient, can both be detrimental to the host. This highlights the delicate balance needed for a healthy immune response.

Both hosts and pathogens continuously evolve and adapt to each other, resulting in a dynamic race for survival, where each tries to outsmart the other.

The location of infectious agents within host tissues can influence how the immune system responds. Extracellular pathogens are found outside cells, while intracellular pathogens reside within cells.

The response of the immune system to pathogens can be influenced by various factors, including the type of pathogen, the location of infection, and the individual's immune status.

Because pathogens differ in their properties and mechanisms of infection, the immune system has evolved varying strategies to combat each type of pathogen effectively.

Innate immunity is the body's first line of defense against pathogens. It's non-specific, meaning it targets a wide range of invaders. This includes mechanisms like complement activation, phagocytosis, and the inflammatory response.

Acquired immunity is a specific defense system that targets particular pathogens. It involves memory cells that recognize and eliminate the same pathogen upon re-exposure. It mainly includes humoral immunity (antibodies) and cell-mediated immunity (T cells).

Humoral immunity, a part of acquired immunity, involves antibodies produced by B cells. These antibodies bind to and neutralize specific pathogens. It's dominant in defending against extracellular bacteria, such as those causing pneumonia or urinary tract infections.

Cell-mediated immunity relies on T cells that directly attack infected cells or activate other immune cells. It's crucial for combating intracellular bacteria such as Mycobacterium tuberculosis, which reside inside macrophages.

Natural Killer (NK) cells are part of the innate immune system. They detect and kill infected cells, preventing the spread of infection. They also produce IFN-gamma to enhance phagocytosis (cell-eating) by macrophages.

Macrophages are essential phagocytic cells that engulf and destroy pathogens. In the context of intracellular bacteria, they are activated by T cells and release antimicrobial substances to kill the bacteria inside.

Cytotoxic T lymphocytes (CTLs) are a type of T cell that directly kills infected cells. They recognize and destroy infected cells, preventing them from spreading the pathogen further.

Granuloma formation is a characteristic response to intracellular bacterial infection. It's a localized area of immune cells surrounding the bacteria, forming a walled-off area to contain the infection. Often seen in diseases like tuberculosis.

Antibodies bind to viruses, preventing them from attaching to cells and causing infection.

A type of immunity that involves cells, primarily T cells, directly attacking infected cells.

Specialized immune cells that directly kill virus-infected cells by recognizing viral antigens on their surface.

Proteins produced by virus-infected cells that help fight viral infection by interfering with viral replication.

A specialized protein that helps break down viral RNA, preventing the virus from replicating inside cells.

An enzyme activated by double-stranded RNA (dsRNA) that is involved in degrading viral RNA.

A protein kinase activated by double-stranded RNA (dsRNA) that plays a role in inhibiting viral protein synthesis.

A viral protein that binds to p300/CPB, preventing interferon expression and inhibiting the host's immune response.

A type of leprosy characterized by a few, flat, and often numb lesions. It can heal on its own, persist, or progress to a more severe form.

A type of leprosy characterized by a mix of symptoms. It can persist, revert to a more mild form (tuberculoid), or advance to a more severe form.

A double-stranded RNA molecule produced by adenoviruses that binds to PKR but does not trigger its activation, allowing viral translation to proceed.

A leprosy type with more numerous lesions, more nerve involvement, and reddish plaques. It can regress, persist, or progress to other forms.

A key signaling molecule that plays a critical role in the host's response to viral infections and activates the transcription of interferon genes.

The most severe form of leprosy, characterized by numerous, diverse lesions, significant numbness, and widespread nerve involvement. It can persist, regress, or progress to other forms.

The most severe form of leprosy characterized by many lesions, hair loss, significant nerve involvement, limb weakness, and disfigurement. It doesn't regress.

A cellular process that involves the phosphorylation of the translation initiation factor eIF2α, effectively halting protein synthesis and preventing viral replication.

A type of immune response characterized by the production of antibodies and the activation of B cells, which are primarily responsible for recognizing and neutralizing extracellular pathogens.

The immune response to leprosy can range from healing on its own to a more severe form of the disease. The specific immune response and the severity of the disease depend on the balance of two immune system subsets.

A type of immune response mediated by T cells, responsible for targeting and eliminating intracellular pathogens, as well as infected cells.

A type of immune response characterized by a strong cellular immune response, leading to fewer, but larger lesions.

The ability of the immune system to mount a more rapid and effective response to a previously encountered pathogen.

A type of immune response characterized by a weaker cellular immune response, leading to more numerous and varied lesions.

The balance of the immune response determines the severity of leprosy. A strong cellular response leads to milder forms like tuberculoid leprosy, while a weak cellular response leads to more severe forms like lepromatous leprosy.

A type of white blood cell that plays a crucial role in the immune system and primarily targets intracellular pathogens such as bacteria, viruses, and parasites. They're vital in recognizing and eliminating these intruders.

A type of programmed cell death that involves the release of inflammatory substances, potentially contributing to chronic inflammation and immune activation.

The immune system's ability to distinguish between the body's own cells and foreign invaders. This prevents harmful attacks on healthy tissues.

The ability of the immune system to identify and eliminate harmful substances, like infectious agents, while ignoring safe substances like food.

Oral bacteria can suppress the immune system by impairing B and T cell function, producing toxins that kill monocytes, and releasing substances that inhibit lymphocyte activity.

Signaling molecules produced by cells of the immune system to communicate and coordinate immune responses. They play a crucial role in regulating immune function.

Lipopolysaccharide (LPS) from various periodontopathogens (bacteria that cause gum disease) can trigger the production of cytokines by host cells, indicating an immune response to these bacterial components.

Gram-positive bacteria, with thick peptidoglycan layers, and Gram-negative bacteria, with thin peptidoglycan layers and outer membranes, can both trigger cytokine production through distinct mechanisms.