Introduction to Immunology Lecture Notes

Flashcards covering the fundamentals of the immune system, including innate and adaptive responses, barrier functions, cell types, and antibody subtypes.

Innate Immune System

A system of defense based on pattern recognition that includes barrier functions, cytolytic chemicals, and phagocytic or secretory cells.

Adaptive Immune System

A branch of the immune system coordinated by $CD4+$ T cells that utilizes B cells and $CD8+$ T cells for specific pathogen responses.

Tight Junctions

Mechanical barrier structures that join epithelial cells together to prevent infection.

Lysozyme

A chemical salivary enzyme found in the eyes and nose that acts as a barrier defense.

Normal Flora

The microbiological component of the body's barrier defenses composed of native microorganisms.

Pattern Recognition Receptors (PRRs)

Receptors, such as Toll-like receptors ($TLRs$), that recognize non-mammalian patterns and trigger inflammation.

Complement

A key antimicrobial killer chemical dissolved in the blood that marks intruders for phagocytosis and activates inflammation.

Phagocytes

Immune effector cells, including neutrophils, monocytes, and myeloid dendritic cells, that literally "eat" pathogens.

Cytokines

Chemical messengers (literally "cell movers") that serve as master coordinators to stimulate inflammation and guide the immune response.

Major Histocompatibility Antigens ($MHC$)

Also known as Human Leukocyte Antigens ($HLA$), these are receptors where amino acids from digested pathogens are loaded.

Immunological Synapse

The interaction site where the innate immune system (e.g., Dendritic cells) communicates with the adaptive immune system (e.g., $CD4$ T cells).

CD4+ T cells

The chief co-ordinators of the immune response, also known as "T(op) cells," that provide a helping hand to other immune cells.

Th1 Cytokines

Specific chemical messengers used by $CD4+$ T cells to arm $CD8+$ T cells.

Th2 Cytokines

Specific chemical messengers used by $CD4+$ T cells to help B cells.

Lymphocyte Education

A process ensuring that B-cell or T-cell receptors bind correctly to protein and do not react to "self."

Antibody

The secreted form of the B-cell receptor, also referred to as Immunoglobulin ($Ig$).

IgM

The first antibody subtype secreted during an immune response.

IgA

The antibody subtype secreted at mucosal surfaces.

IgG

The major antibody subtype associated with immunological memory.

IgE

The antibody subtype specifically utilized against parasites.

O CAN (Antibody Functions)

An acronym for the four functions of antibodies: Opsonisation, Complement fixation, Antibody-dependent cellular cytotoxicity, and Neutralization.

CD8+ T cells

Killer cells that destroy target cells expressing proteins in the context of $MHC\,1$, such as cells infected by viruses or malignant cells.

Primary Immunodeficiency

A genetic condition, typically presenting in children, characterized by a lack of adequate inflammation.

Secondary Immunodeficiency

A lack of adequate inflammation caused by external factors such as infections, drugs, or malnutrition.