Immunology Chapter Overview

The ability of the immune system to remember a specific pathogen and mount a more rapid and effective response upon re-exposure.

A type of immunity that is non-specific and responds rapidly to a wide range of pathogens. It involves cells like macrophages and neutrophils.

A highly specific type of immunity that develops after exposure to a specific pathogen. It involves cells like B and T lymphocytes.

A protein produced by B lymphocytes that binds to specific antigens, leading to pathogen neutralization or destruction.

A substance that triggers an immune response. It can be a protein, carbohydrate, or other molecule found on the surface of pathogens.

The site where white blood cells are produced, including B lymphocytes. It's important for antibody production.

A small gland located behind the breastbone. It's the site where T lymphocytes mature.

Small, bean-shaped organs that filter lymph and allow immune cells to interact with antigens. Key points of immune response activation.

Specialized cells that recognize and attack specific pathogens. They are responsible for the adaptive immune response's memory function.

The ability of the adaptive immune system to remember past encounters with pathogens and mount a faster and stronger response upon reinfection.

The ability of the immune system to defend the body from infection and disease.

A process that weakens the immune system, making the body more susceptible to infections.

A study of how the immune system functions by observing an organism's reaction to an introduced pathogen.

A study of how the immune system functions by examining genetic mutations causing immune deficiencies.

The body's response to harmful stimuli, such as pathogens or tissue damage.

The entry of harmful pathogens into the body, leading to infection.

A short-term response of the immune system to infection or injury, characterized by redness, swelling, pain, and heat. It aims to eliminate the harmful stimulus and promote healing.

A prolonged inflammatory response that persists for weeks, months, or even years, leading to tissue damage and loss of function.

Increased blood flow to the affected area, resulting in redness and warmth.

Increased permeability of blood vessels, leading to fluid leakage into the tissues and causing swelling.

The process by which the body returns to its normal state after injury or infection, involving tissue repair and restoration of function.

The recruitment of immune cells to the site of infection or injury, helping combat the pathogen and promote healing.

A rare genetic disorder that prevents the immune system from functioning properly, making individuals susceptible to even mild infections.

A sterile environment designed to protect individuals with compromised immune systems from external pathogens, like in the case of "Bubble Boy."

A state where the immune system is excessively active, potentially leading to harmful immune reactions against the body's own tissues.

The first line of defense against pathogens, including physical barriers like skin and mucous membranes, and chemical defenses like lysozyme and defensins.

The outermost layer of skin, acting as a physical barrier against pathogens.

Tight junctions between cells of the epithelium, forming a barrier that prevents pathogens from penetrating.

An enzyme found in tears and mucous membranes, breaking down the peptidoglycan cell wall of bacteria.

Peptides produced by epithelial cells, directly killing or inhibiting bacterial growth.

Receptors of the innate immune system that recognize molecular patterns specific to pathogens (PAMPs) or cellular damage (DAMPs). Upon detection, they trigger immune responses such as inflammation, phagocytosis and activation of adaptive cells, playing a key role in defense against infections.

A molecule present in the wall of Gram-negative bacteria (lipopolysaccharides), which remains active after the death of the bacteria and causes severe inflammatory responses.

Components of the external membrane of Gram-negative bacteria that trigger an inflammatory response in the host.

A type of receptor on macrophages that recognizes LPS and activates the transcription factor NF-κB.

A transcription factor activated by TLR4 that leads to the release of pro-inflammatory cytokines, triggering an immune response.

These are crucial for innate immunity and detect pathogen-specific motifs (PAMPs), such as lipopolysaccharides (LPS) from Gram-negative bacteria, single-stranded RNA (ssRNA) from viruses, or fungal compounds.

Located on the membrane or inside cells, TLRs activate signalling pathways via adaptors such as MyD88, leading to the expression of inflammatory cytokines (e.g., TNF-α) to fight infection.

A type of inflammatory cytokine released in response to TLR activation, amplifying the immune response to fight infection.

Toll-like receptors (TLRs) are transmembrane proteins that play a crucial role in innate immunity by recognizing pathogen-associated molecular patterns (PAMPs) and activating immune responses. They have two main parts: the extracellular LRR domain which binds to PAMPs and the intracellular TIR domain which transmits signals into the cell.

TLR7 and TLR8 are specialized TLRs that recognize single-stranded RNA (ssRNA) found in pathogens, like viruses, within endosomes. These TLRs distinguish pathogenic ssRNAs from host mRNA based on specific motifs, such as uridine-rich sequences or secondary structures, which are often present in viral RNAs.

Leucine-Rich Repeats (LRRs) are protein motifs that form horseshoe-shaped structures, creating binding sites for specific ligands, like PAMPs. These motifs are found in many proteins, including TLRs, and play a crucial role in pathogen recognition and immune activation.

TLR-2 and TLR-1 form a heterodimer, meaning they are composed of two different receptors. Together they create a complex structure that binds to lipopeptide lipid chains, commonly found on bacterial pathogens.

TLRs are expressed on almost every cell in the body, highlighting their critical role in recognizing pathogens throughout the organism. This emphasizes the importance of innate immunity in protecting the body from a wide range of infections.