Active and Specific Immunity Practice Flashcards

A set of vocabulary flashcards covering the concepts of active and specific immunity, MHC molecules, antibody structures, and immunization methods based on the lecture transcript.

Active and Specific Immunity

The third line of defense comprising B and T cells that protect against various pathogens and cancer.

Antigens

Molecules that stimulate a response from T cells and B cells.

MHC Class I

Molecules possessed by all cells except red blood cells that present endogenous self-antigens and intracellular foreign antigens.

MHC Class II

Regulatory receptors restricted to immune cells like B cells, macrophages, and dendritic cells that present extracellularly derived antigens.

Human Leukocyte Antigen (HLA)

The specific MHC molecule in humans used for HLA typing before donor transplants.

Epitope

A distinct identifier or bacterial component that is processed and loaded into an MHC molecule for antigen presentation.

Clonal Selection Theory

The concept that distinct genes are used to possess specific receptors that interact with antigens through a lock and key mechanism.

Naive T cell

A mature T cell that has completed maturation in the thymus and expresses either a $CD4$ or $CD8$ co-receptor.

Plasma Cells

Activated B cells that differentiate and secrete specific antibodies into the blood.

Capping

The aggregation of antigen-antibody complexes on the surface of a B cell following interaction.

Immunoglobulins

Globular proteins in the blood plasma that serve as both B cell receptors and free-floating antibodies.

Affinity Maturation

The process where the individual variable region of an antibody modifies and changes after antigen binding to increase specificity.

Isotype Switching

A process in the Fc region of the antibody chain where heavy chains are modified to change the antibody class.

Regulatory T Cells

Cells essential for maintaining immune homeostasis and preventing autoimmunity by modulating the immune response at the end of an infection.

Perforins

Molecules produced by cytotoxic $CD8$ killer T cells that poke holes in target cells to cause osmolaric dysregulation.

Granzymes

Molecules secreted by killer T cells that enter through perforin holes to induce apoptosis in infected or cancer cells.

Haptens

Molecules that are too small to be immunogenic on their own and must be complexed with a carrier molecule to elicit an immune response.

Super Antigens

Potent T cell stimulators that bind inappropriately to MHC class II and T cell receptors, causing an overwhelming, nonspecific release of cytokines such as $IL-2$.

Opsonization

The coating of a microbe with antibodies or complement proteins to increase the rate of phagocytosis.

Neutralization

A process where antibodies coat the microbial surface to prevent the pathogen from attaching to its host cell.

IgM

The first antibody produced during an immune response; it is a pentamer with $10$ binding sites.

IgG

A class of antibody produced by plasma cells found in both primary and secondary immune responses.

IgA

An antibody that can exist as a dimer and is predominantly found in mucus and serous secretions of the gastrointestinal and respiratory tracts.

IgE

An antibody class involved in allergic reactions and the defense against parasitic worms.

Lag Period

A timeframe of nearly $10-12$ days during the first encounter with a microbe before antibodies are produced.

Active Immunity

A long-lasting form of immunity where the body's own immune cells produce antibodies and memory cells in response to an antigen.

Passive Immunity

Immediate, short-term protection provided by preformed antibodies, such as those transferred from mother to child or through immunotherapy.

Natural Immunity

Immunity acquired through normal life experiences, such as falling ill with a virus.

Artificial Immunity

Immunity obtained through medical procedures, such as vaccinations or the administration of immunoglobulins.

Live Attenuated Vaccine

Vaccines prepared using live microbes that can replicate and stimulate robust immunity but have had their virulence factors removed.