Antigen Presentation and Immune Memory Lecture Flashcards

A set of vocabulary flashcards covering the concepts of antigen presentation, MHC classes, B and T cell receptors, and immune responses based on the lecture transcript.

Antigen

Anything that is recognized by a $B$ or $T$ cell.

Epitope

Smaller portions of an antigen that are broken down for presentation.

Lipopolysaccharide (LPS)

An antigen found on a gram negative cell wall.

Memory cells

Long lasting cells that can be recalled later to mount a more robust response, preventing infections.

Tuberculoid leprosy

A type of leprosy outcome associated with $T_H 1$ responses that results in shallow lesions.

Lepromatous leprosy

A type of leprosy outcome associated with $T_H 2$ responses that results in nodules.

Pattern recognition receptors (PRRs)

Receptors important for recognizing foreign molecules, including fragments of DNA, in the second line of defense.

Opsonization

A process where complement proteins coat the surface of a microbe to increase the likelihood of it getting phagocytosed.

Complement

Proteins found in the bloodstream and produced by the liver that bind to microbes to increase inflammation and rates of phagocytosis.

Major Histocompatibility Complex (MHC)

Receptors used to process and load epitopes for recognition by $T$ cells.

MHC Class I

Receptors located on all cells within the body except red blood cells, used to recognize self and process intracellular microbes or cancer.

MHC Class II

Receptors found only on immune cells like dendritic cells, macrophages, $B$ cells, and monocytes to process extracellular microbes.

Human Leukocyte Antigen (HLA)

The specific name for the major histocompatibility complex in humans.

Autoimmunity

A condition where $MHC$ receptors present self proteins, causing the body's immune system to attack itself.

Natural killer cells

Innate immune cells that recognize the absence of $MHC$ on cells, often used to fight cancer cells that suppress $MHC$ expression.

CD8 killer T cells

Also known as cytolytic $T$ cells, these communicate with $MHC$ Class $I$ receptors.

CD4 T cells

Also known as helper $T$ cells, these communicate with $MHC$ Class $II$ receptors and secrete cytokines.

Alpha beta (\alpha\beta) T cell receptor

The most commonly expressed type of receptor found on $T$ cells.

B cell receptor

A receptor bound to $B$ cells that can interact with microbes directly and has the same structure as antibodies.

Clonal selection

The maturation process, occurring in the thymus for $T$ cells and bone marrow for $B$ cells, where cells are given a single unique receptor specificity.

Clonal expansion

The process of proliferation where a lymphocyte makes copies of itself after an effective antigen presentation takes place.

Naive T cell

A $T$ cell that has left the thymus but has not yet experienced antigen presentation within the body.

Light chains

The two smaller protein chains in the structure of an antibody or immunoglobulin.

Heavy chains

The two larger protein chains in the structure of an antibody or immunoglobulin.

Variable region

The section of the antibody protein that forms the antigen binding site and is specific to a particular molecule or epitope.

Fc region

Standing for fragment crystallized, this is the conserved region of the antibody that determines its class, such as $IgM$ or $IgG$.

Class switching

A genetic process that allows $B$ cells to change the conserved structures of their antibodies, such as transitioning from $IgM$ to $IgA$.

Natural immunity

Immunity developed by being naturally infected by a microbe.

Artificial immunity

Immunity developed through vaccines by inserting a piece of a microbe to create plasma $B$ cells and memory cells.