FINAL IMMUNO STUDY GUIDE

A comprehensive set of flashcards covering key concepts in immunology related to T and B lymphocytes, antigen recognition, and immune responses.

Antigen presentation

The process where antigen-presenting cells (APCs) display peptide antigens on major histocompatibility complex (MHC) molecules to T lymphocytes.

T-cell receptors (TCRs)

Proteins on T cells that recognize and bind to specific antigens presented by MHC.

Major histocompatibility complex (MHC)

Molecules that present peptide antigens on the surface of APCs to TCRs.

Antigen-presenting cells (APCs)

Cells that process and present antigens to T cells; includes B cells, macrophages, and dendritic cells.

Proteasome

A protein complex that degrades other proteins into peptide fragments.

Immunoproteasome

A modified proteasome that produces peptides favoring binding to MHC class I.

TAP (Transporter-associated with Antigen Processing)

A protein that transports peptides from the immunoproteasome to the endoplasmic reticulum.

CD8+ T cells

Cytotoxic T lymphocytes that recognize MHC class I-peptide complexes.

CD4+ T cells

Helper T lymphocytes that recognize MHC class II-peptide complexes.

Invariant chain

A protein that prevents MHC class II molecules from binding peptides in the ER.

HLA-DM

A molecule that aids in loading peptides onto MHC class II proteins.

HLA-DO

A molecule that antagonizes HLA-DM function in MHC class II compartments.

Positive selection

The process where thymocytes that bind MHC peptides with moderate affinity survive to mature T cells.

Negative selection

The elimination of autoreactive T cells that bind self-antigens too tightly.

Thymocytes

Immature T cells that develop in the thymus.

Double-negative thymocytes (DN)

Thymocytes that do not express CD4 or CD8 markers.

Double-positive thymocytes (DP)

Thymocytes that express both CD4 and CD8 markers.

Pre-TCR (T-cell receptor)

A signaling complex expressing the beta chain of TCR that directs thymocyte development.

Cognate pair

A T cell and its specific antigen-presenting B cell or dendritic cell that interact during activation.

Central tolerance

The process by which B cells that react to self-antigens undergo apoptosis or receptor editing.

Peripheral tolerance

Mechanisms that prevent autoreactive B and T cells from responding to self-antigens outside the thymus.

Affinity maturation

The process that enables B cells to produce high-affinity antibodies against specific antigens.

Clonal deletion

The process by which B cells that fail to rearrange their receptor genes die.

Somatic hypermutation

The process that introduces mutations into the variable regions of B cell receptors to increase affinity.

Germinal center

A site within secondary lymphoid tissues where B cells proliferate and undergo affinity maturation.

Isotype switching

The process by which a B cell changes the antibody class it produces without altering the specificity.

CD28

A co-stimulatory receptor on T cells that provides necessary signals for T cell activation.

B7

A class of co-stimulatory molecules expressed on professional APCs that interact with CD28 on T cells.

IL-2

A key cytokine secreted by T cells that promotes T cell proliferation and differentiation.

Nuclear factor of activated T cells (NFAT)

A transcription factor that regulates IL-2 production in activated T cells.

Effector T cells

Differentiated T cells that perform direct functions such as killing infected cells or helping other immune cells.

naïve T cells

T cells that have not yet encountered their specific antigen.

Folicular dendritic cells

Specialized cells that present antigens to B cells in lymphoid tissues.

Memory B cells

Long-lived B cells that provide rapid response upon re-exposure to an antigen.

Memory T cells

Long-lived T cells that remember previous infections and mount quick responses upon re-encountering an antigen.

Chemokines

Cytokines that signal the movement of immune cells to sites of infection or inflammation.

CCR7

A chemokine receptor expressed by T cells that helps guide them to lymphoid tissues.

C3d

A fragment of the complement system that enhances B cell response when bound to pathogens.

Co-stimulatory signals

Additional signals required alongside TCR signaling for T cell activation.

CD81

A tetraspanin that organizes the B cell receptor (BCR) and co-receptor complexes.

IL-12

A cytokine produced by APCs that drives T cell differentiation into TH1 cells.

TH1 cells

A subset of CD4+ T helper cells that enhance cellular immunity.

TH2 cells

A subset of CD4+ T helper cells that enhance humoral immunity.

TH17 cells

A subset of CD4+ T helper cells associated with inflammation and the defense against extracellular pathogens.

Treg cells

Regulatory T cells that help maintain immune tolerance and prevent autoimmunity.

Natural Killer T (NKT) cells

A subset of T cells that possess features of both T cells and NK cells.

Affinity maturation

The process by which B cells produce antibodies of increased affinity for their specific antigen.

Professional APCs

APCs that can provide necessary co-stimulatory signals to T cells.

BCR (B cell receptor)

A membrane-bound immunoglobulin molecule that functions as an antigen receptor on B cells.

Pre-BCR

A receptor that tests the heavy chain during B cell development.

Surface IgM and IgD

Antibodies that newly formed B cells express on their surface.

Cytokine signaling

Cell signaling mediated by cytokines that directs cell differentiation and function.

Memory T cells

T cells that persist long-term after infection and respond faster when the same antigen is encountered.

Antigen specificity

The ability of an antibody or T cell receptor to recognize a specific epitope on an antigen.

Dendritic cells

APCs that capture antigens from pathogens and present them to T cells.

Secondary lymphoid tissue

Tissue where immune responses are initiated; includes lymph nodes and the spleen.

Clonal expansion

The rapid proliferation of B or T cells upon activation by antigen.

Antibody-dependent cell-mediated cytotoxicity (ADCC)

A mechanism by which antibodies mark infected cells for destruction by immune cells.

Extravasation

The process of immune cells migrating out of blood vessels and into tissues.

Chemokine gradients

Concentration gradients of chemokines that guide immune cell movement.

CD4

A co-receptor on helper T cells that enhances TCR signaling.

CD8

A co-receptor on cytotoxic T cells that enhances TCR signaling.

V(D)J recombination

The process of rearranging variable (V), diversity (D), and joining (J) gene segments in TCR and BCR development.

Antigenic diversity

The wide variety of antigens that antibodies and TCRs can recognize.

Somatic hypermutation

The process by which B cells mutate their antibody genes to increase affinity for an antigen.

Low-affinity antibodies

Antibodies produced during the early stages of B cell activation before affinity maturation.

High-affinity antibodies

Antibodies generated after somatic hypermutation and selection in germinal centers.

Isotope switching

The process by which B cells change the class of antibody they produce.

AID (Activation-induced cytidine deaminase)

An enzyme involved in somatic hypermutation and isotype switching in B cells.

Affinity for self-antigens

Binding strength of antibodies or T cells to body's own molecules.

T follicular helper (TFH) cells

A specialized subset of CD4+ T cells that provide help to B cells in germinal centers.

Primary response

The initial immune response that occurs the first time an antigen is encountered.

Secondary response

The immune response elicited upon subsequent exposure to the same antigen, typically faster and more robust.

Cytokine-rich environment

Condition that stimulates T and B cells to proliferate and differentiate during immune responses.

Clonal selection

The process by which specific B or T cells are activated by their corresponding antigens.

Autoimmune diseases

Diseases that arise from an immune response against the body’s own tissues.

APCs (Antigen Presenting Cells)

Cells like dendritic cells, B cells, and macrophages that display antigens and provide signals to T cells.

Cross-presentation

The ability of some APCs to present extracellular antigens on MHC class I molecules.

Phagocytosis

The process by which cells engulf and digest large particles or pathogens.

Extracellular pathogens

Pathogens that exist outside of host cells, typically targeted by antibody-mediated immunity.

Intracellular pathogens

Pathogens that invade and replicate within host cells, typically targeted by CD8+ T cells.

Genetic rearrangement

The process of changing the genetic sequence of TCR and BCR during immune cell development.

In vitro

Experiments conducted in a controlled environment outside of a living organism.

In vivo

Experiments conducted in or on living organisms.

CLIP (Class II-associated invariant chain peptide)

A peptide that blocks MHC class II binding sites until degradation of the invariant chain allows peptide loading.

Sensitivity to infection

The degree to which the immune system can effectively recognize and respond to pathogens.

Antibody functions

Mechanisms by which antibodies neutralize pathogens and mark them for elimination by immune cells.

Immune evasion

Strategies utilized by pathogens to escape detection and destruction by the immune system.

Lymphatic system

A network of vessels that transports lymph fluid, immune cells, and pathogens.

Antigen diversity mechanism

Processes such as V(D)J recombination that generate a diverse array of TCRs and BCRs.

B cell activation signals

Signals required for B cell activation including BCR binding and co-stimulatory signals.

Proliferative response

The rapid increase in cell numbers following activation by antigen.

Chemoattractant molecules

Substances that attract immune cells to sites of infection.

Endocytic pathways

Mechanisms that cells use to internalize extracellular material like antigens.

Cellular immunity

The aspect of immunity that involves T cells directly attacking infected or cancerous cells.

Humoral immunity

The aspect of immunity that involves the production of antibodies by B cells.

Helper T cells

CD4+ T cells that assist other immune cells in mounting an effective immune response.

Cytotoxic T cells

CD8+ T cells that kill infected or cancerous cells directly.

Immune system memory

The lasting ability of the immune system to respond more rapidly and effectively upon re-exposure to a previously encountered antigen.