Helper T Cells and Their Response to Antigens

Flashcards covering key vocabulary and concepts related to Helper T cells and their immune responses. Each term includes a definition to aid in understanding important terms in immunology.

Antigen-Presenting Cell (APC)

A cell that displays antigen on its surface to T cells via MHC molecules.

MHC Class II

A class of molecules on APCs that presents antigens to CD4+ T cells.

T Cell Receptor (TCR)

The molecule on T cells that recognizes specific antigens.

Costimulation

Secondary signals required for T cell activation in addition to TCR signaling.

Cytokines

Small proteins produced by cells that have a specific effect on the interactions and communications between cells of the immune system.

TH1 Cells

A subset of helper T cells that secrete interferon-γ (IFN-γ) and mainly respond to intracellular pathogens.

TH2 Cells

A subset of helper T cells that secrete IL-4, IL-5, IL-10, and promote antibody responses.

TH17 Cells

A subset of helper T cells that secrete IL-17 and play a role in neutrophil-mediated inflammation.

Cytotoxic T Cell

T cells that kill cancerous or infected cells, identified by CD8 markers.

Regulatory T Cells (Treg)

A subset of T cells that modulate the immune response, maintaining tolerance to self-antigens.

Immunological Synapse

The interface between T cells and APCs where signaling occurs for T cell activation.

Peptide Antigen

Short chains of amino acids that are presented on MHC molecules to T cells.

Interleukin-2 (IL-2)

A cytokine that promotes T cell proliferation and is critical for T cell activation.

Supramolecular Activation Clusters (SMAC)

Structures formed at the immunological synapse that organize signaling molecules.

T Cell Activation

The process by which T cells are stimulated to proliferate and differentiate in response to antigen.

Transcription Factors

Proteins that help turn specific genes on or off by binding to nearby DNA.

Helper T Cell Types

Different subsets of T helper cells including TH1, TH2, TH17, each with distinct functions.

Central SMAC (cSMAC)

The core region of the SMAC that contains TCRs and MHC-peptide complexes.

Peripheral SMAC (pSMAC)

The outer region of SMAC that includes adhesion molecules.