Immune System & The Body's Defense

Flashcards for reviewing the immune system and body defense mechanisms.

Prions

Infectious agents that are misfolded proteins capable of causing disease.

Prion disease

A disease caused by prions.

Leukocytes

Cells of the immune system.

Cytokines

Small signaling proteins that affect the behavior of other cells.

Innate Immunity

Immunity present from birth; rapid response.

Adaptive Immunity

Immunity that develops over time with exposure to antigens; slower response.

Granzymes

Enzymes that induce apoptosis (cell death).

Interferons

Proteins that interfere with viral replication.

Complement System

A system of proteins that enhance the ability of antibodies and phagocytic cells to clear microbes and damaged cells.

Membrane Attack Complex (MAC)

A structure formed on the surface of pathogen cells that disrupts the cell membrane, leading to cell lysis.

Inflammation

A localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

Diapedesis

The passage of blood cells through the intact walls of the capillaries, typically accompanying inflammation.

Chemotaxis

Movement of an organism in response to a chemical stimulus.

Margination

Process where leukocytes adhere to the endothelial cells of blood vessels at the site of inflammation.

Fever

A raised body temperature.

Antigen

A substance that triggers an immune response.

Antigenic Determinant

The specific part of an antigen that is recognized by the immune system.

Immunogenicity

The ability of an antigen to provoke an immune response.

Hapten

Small molecule that can elicit an immune response only when attached to a large carrier such as a protein.

Antigen Presentation

Process where an antigen is taken up and processed by an antigen-presenting cell to be presented to T-cells.

Antigen-Presenting Cells (APCs)

Cells that display antigen complexed with major histocompatibility complexes (MHC) on their surfaces.

Major Histocompatibility Complex (MHC)

A set of cell surface proteins essential for the acquired immune system to recognize foreign cells.

CD4 proteins

Helper T-cells express these on their surface.

CD8 proteins

Cytotoxic T-cells express these on their surface.

Negative Selection

Process in the thymus where T-cells that recognize self-antigens are eliminated.

Positive Selection

Process in the thymus where T-cells that can bind to MHC molecules are allowed to mature.

Regulatory T-lymphocytes

T-cells that suppress the immune system.

Antibody Titer

A measure of how much antibody is present in the blood.

Plasma cells

Antibody-producing cells.

Antigen-binding site

The region of an antibody that binds to an antigen.

Fc region

Region of an antibody that interacts with effector molecules and cells.

Opsonization

Enhancement of phagocytosis by coating with antibodies or complement.

IgG: Immunoglobulin G

The most abundant type of antibody, found in all body fluids and protects against bacterial and viral infections.

Immunologic Memory

The ability of the immune system to respond more quickly and effectively to pathogens that it has encountered previously.

Primary Response

The initial immune response to an antigen.

Secondary Response

The rapid and enhanced immune response to a previously encountered antigen.

Active Immunity

A type of immunity where the body actively produces antibodies.

Passive Immunity

A type of immunity where antibodies are acquired from an external source.