Untitled Flashcards Set

Immunity

Specific (adaptive) defense against infection by lymphocytes in response to antigens.

Humoral Immunity

An immune response that takes place in bodily fluids and is mediated by antibodies.

Cellular Immunity

Mediated by T Lymphocytes (T cells) that protect against intracellular organisms.

Antigen

Any substance that provokes the production of antibodies.

Antibodies

Proteins that recognize and bind to specific foreign antigens.

Valence

The number of epitopes on an antigen.

IgG

The most abundant antibody in serum that protects against circulating antigens.

IgA

Antibody found in serum and body fluids, primarily protecting mucosal surfaces.

IgM

The first antibody produced during an immune response, consisting of five antibody units.

T Cells

A type of lymphocyte that plays a central role in cell-mediated immunity.

B Cells

Lymphocytes that produce antibodies and mediate humoral immunity.

MHC (Major Histocompatibility Complex)

Glycoproteins that help the immune system distinguish between self and nonself.

Cytokines

Chemical messengers secreted by T cells that regulate the immune response.

Primary Response

The immune response following the first exposure to an antigen characterized by a lag period.

Secondary Response

The immune response upon subsequent exposure to an antigen, typically faster and stronger than the primary response.

Hypersensitivity

An abnormal physiological state resulting from the combination of antigen with an immune effector.

Type I Hypersensitivity

Immediate hypersensitivity reaction, including allergies and anaphylaxis.

Type II Hypersensitivity

Cytotoxic hypersensitivity involving IgG and IgM antibodies.

Type III Hypersensitivity

Immune complex-mediated hypersensitivity associated with autoimmune diseases.

Type IV Hypersensitivity

Delayed hypersensitivity involving T cells and macrophages.

Autoimmune Diseases

Conditions where the immune system mistakenly attacks the body's own tissues.

Clonal Selection Theory

The theory that each antigen-reactive B or T cell has a specific receptor that allows for targeted immune responses.

Memory B Cells

Cells that retain the memory of antigens and can mount a rapid response upon re-exposure.

Plasma Cells

Activated B cells that rapidly produce and secrete antibodies.

Natural Killer (NK) Cells

A type of lymphocyte that can kill infected host cells without prior sensitization.

Monoclonal Antibodies

Antibodies that are identical and produced from a single clone of cells that recognize specific antigens.