Immunology Protein cell surface markers

markers associated with B cells

B cell receptor

Ig alpha

Ig beta

CD40/CD40L

ICOS/ICOSL

where is BCR expressed on

B cells

where is CD40 expressed on

B cells

where is CD40L expressed on

Tfh cells (follicular helper T cells)

where is ICOS expressed on

Th cells

where is ICOS-L expressed on

activated B cells

what is the function of BCR

when cognate antigen binds to it, it starts chain reaction that will ultimately active the B cell

they are antibodies in the secreted form

what is the function of Ig alpha and beta

signaling protein for BCR

helps signal to the nucleus when there is sufficient BCR clustering/cross linking to activate the B cell

signals to the nucleus when there is CD40/CD40L coupling to activate the B cell

what its the target cell of CD40

Tfh

what is the target cell of CD40L

B cells

what is the target cell of ICOS

Activated B cells

what is the target cell of ICOS-L

Th

what its he function of CD40

costimulatory protein to activate B cells in T dependent B cell activation

what is the function of CD40L

costimulatory proteins needed to activate B cells in T cell dependent B activation

what is the function of ICOS

Binds to ICOSL in secondary lymphoid organs to cause activated Th to become Tfh cells

what is the function of ICOSL

bind to ICOS on activated Th cells in secondary lymphoid organs to cause them to become Tfh cells

cell surface markers for T cells

TCR

CD3 complex

CD4+

2CD8+

MHC I

HLA I

MHC II

B7

CD28

Fas protein

FasL

TCR function

scans MHC/antigen complex

finds cognate antigen and start chain reaction to ultimately activate T cell

TCR and CD3 are expressed where

T cells

function of CD3

signaling protein for TCRs

signal nucleus when antigen MHC complex bind to TCR and transport TCR to the cell surface

CD4 is expressed where

Th cells and tregs

target cell of CD4

MHC II

function of CD4

coreceptor for MHC II

promote adhesion to APC and target cells

ensure correct T cell is activated

CD8 expressed on

CTLs

CD8 target cell

MHC I

CD8 function

coreceptor for MHC I

promotes adhesion to APC and infected target cells

ensures correct T cells is activated

MHC I expressed on

almost all body cells

MHC I target cell

CTLs

MHC I function

displays endogenous (8-11aa) proteins from cellular, viral, and parasitic proteins

Uses proteosomes TAP 1 and 2

MHC II expressed on

APCs (macrophages, dendritic cells, B cells)

MHC II target cell

Th cells

MHC II function

displays (13-25aa) exogenous protein from pathogen or antigenic proteins in the tissue

an invariant chain is used in the processing of it

B7 expressed on

APCs

B7 target cell

T cells

B7 function

costimulatory coupling with CD28 to activate the T cell

CD28 expressed on

T cells

CD28 target cell

APCs

CD28 function

costimulatory coupling with B7 to activate T cell

Fas protein expressed on

Effector cells

Fas protein target cell

CTLs

Fas protein function

on almost all body cells as a checks and balance in the event the body becomes infected

FasL expressed on

CTLs

FasL target cell

effector cells

FasL function

used by CTLs to ligate with fas protein after the TCR recognizes the antigen on MHC I

induces cell apoptosis for the infected cell

Cell surface markers with negative regulators

CTLA-4

PD-1

PD1-L

Fas and FasL

CTLA-4 expressed on

very experienced T cells

CTLA-4 target cell

B7

CTLA-4 function

unregulated with the more a T cell is activated

competitively competes with CD28 to bind with B7 on the APC

prevents CD28 from binding to B7 (anergy)

PD-1 expressed on

T cells

PD-1 target cell

T, B, and APCs

PD-1 function

increasingly unregulated on the T cell with each reactivation

more reactivation, more sensitive it is to ligation of PD1 by PD1L to cause apoptosis of experienced T cell

Reduce T cell response after infection has been cleared

PD1L expressed on

T, B, APCs

PD1L target cell

T cells

PD1L function

any cell with it can ligate with a T cell expressing PD1 to cause apoptosis of that T cell

Fas protein expressed on -

CTLs and Th cells

Fas protein target cells -

other WBCs and body cells

Fas protein function -

T cells get reactivated it becomes sensitive to ligation from FasL

any cell with FasL can kill a T cell that has been reactivated too much

FasL expressed on -

other WBCs and body cells

FasL target cell -

CTLs and Th cells

FasL function -

if they have both fas protein and fasL, they can be killed when infected or can kill when threatened by very active T cells

cell surface markers associated with extravasation and cell trafficking

INT

ICAM

SEL

SLIG

INT expressed on

neutrophils, eosinophils, basophils, monocytes, NK cells

INT target cell

surface of endothelial blood vessel cells

INT function

coupling of INT with ICAM causes WBC to stop rolling for diapedesis

premade and stored in the WBC and expressed on the surface of the WBC when exposed to cytokines

ICAM expressed on

surface of endothelial blood vessel cells after receiving TNF and IL-1

ICAM target cell

neutrophils, eosinophils, basophils, monocytes, NK cells

ICAM function

coupling of INT with ICAM causes WBC to stop rolling for diapedesis

Always expressed on the lumen surface/endothelial cells of the blood vessels

SEL expressed on

surface of endothelial blood vessels after receiving TNF and IL1

SEL target cell

neutrophils, eosinophils, basophils, monocytes, NK cells

SEL function

coupling of SEL with SLIG causes WBC to slow down by rolling along endothelial surfaces

is not expressed until after receiving cytokine chemicals

SLIG expressed on

neutrophils, eosinophils, basophils, monocytes, NK cells

SLIG target cell

surface of endothelial blood vessel cells

SLIG function

coupling of SEL with SLIG causes the WBC to slow down by rolling along the endothelial surface

always expressed on the endothelial surface of blood vessels