Glossary Patho exam 2

Cytokines

Proteins that act as immune-system messengers, helping immune cells communicate.

IL-2

Cytokine made mainly by activated CD4 T cells; promotes T cell survival and proliferation.

Transient

Cytokines are produced for a short time and then go away.

Autocrine signaling

Cytokine acts on the same cell that secreted it.

Paracrine signaling

Cytokine acts on nearby cells.

Pleiotropic

One cytokine can have many effects.

Redundant

Different cytokines can produce overlapping effects.

Effector T cell

Activated, differentiated T cell capable of performing immune functions.

Clonal expansion

Rapid increase in antigen-specific T cell clones after activation.

CD4 helper T cells

Activate other immune cells by secreting cytokines.

CD8 cytotoxic T cells

Kill infected cells expressing microbial proteins.

IFN-γ

activates macrophages and promotes cell-mediated immunity. (CD4, CD8, NK CELLS)

TH1 cells

Helper T cells that activate macrophages through IFN-γ production.

TH2 cells

Helper T cells that are important for defense against helminth parasites.

TGF-β

Cytokine that inhibits T cell activation and helps with regulatory T cell development.

Memory T cells

Long-lived T cells formed after antigen activation that respond faster upon re-exposure.

Central memory T cells

Respond more slowly to re-exposure.

Effector memory T cells

Respond more quickly to re-exposure.

S1P (sphingosine 1-phosphate)

Lipid signaling molecule that directs T cells to exit lymph nodes.

Homeostasis

Return to a steady state after the immune response, removing survival signals.

IL−7 and IL−15

Memory T cells require for long-term survival and homeostatic maintenance in the absence of antigen.

IL-17

Promotes actue inflammation (CD4 TCELLS)

IL-4

B cell switching to IgE (From CD4+ , MAST CELLS) also drive Th2 differentiation and promotes allergic responses.

IL-5

Activation of eosinophils (From CD4+ , MAST CELLS) also drives Th2 response

TGF BETA

Inhibits inflammation and promotes tissue repair, produced by various immune cells. (CD4 TCELL)

IL-13

Drives Th2 response

Th17

driven by IL-17 and IL-22 these are inflammatory cytokines that promote neutrophil responses and are associated with autoimmune diseases.

ICAM 1

adhesion molecule is expressed on High Endothelial Venules (HEVs) and binds to LFA−1 on naïve T cells to facilitate their migration into lymphoid tissues.

IL-22

Promotes Th17 differentiation and is involved in mucosal immunity.

inhibits macrophage activity “Alternative macrophage activity”

IL-4, IL-10, IL-13

Immunosuppressors

IL-10, IL35, TGF beta

Central tolerance

occurs in bone marrow/ thymus

apoptosis

change in receptors in b cells

development of regulatory t lymphocytes

Peripheral tolerance

anergy=unresponsiveness

apoptosis

suppression

AIRE

is a transcription factor critical for the establishment of central tolerance by promoting the expression of tissue-specific antigens in the thymus.

Many auto reactive lymphocytes removed in thymus

FoxP3

For the development and function of regulatory T cells