Cluster of Differentiation (CD) Molecules

Question 1

CD3

Answer 1

Location: T cells assoc. w/TCR; a group of four transmembrane polypeptides

Function: initiates cytoplasmic signal transduction, used to identify T cells

Question 2

CD4

Answer 2

Location: T helper cells (MHC II restricted)

Function: enhance TCR signaling by stabilizing interaction between TCR/MCH II

Question 3

CD8

Answer 3

Location: Cytotoxic T cells (MHC I restricted)

Function: enhance TCR signaling by stabilizing TCR/MHC I interaction

Question 4

CD19

Answer 4

Location: B cells

Function: BCR coreceptor

Question 5

CD28

Answer 5

Location: T cells

Function: delivers major co-stimulatory to T cells by binding CD80 (B7.1) or CD86 (B7.2) on APCs

Question 6

CD40

Answer 6

Location: APCs (B cells, monocytes, MPs, DCs)

Function: co-stimulatory, binds to CD40L (CD154) on T cells

Question 7

CD79a,B (Iga, IgB)

Answer 7

Location: B cells assoc. w/BCR (cell surface Ig)

Function: initiates activation process triggered by antigen recognition by BCR

Question 8

CD80 (B7.1) & CD86 (B7.2)

Answer 8

Location: Activated APCs (B cells, DCs)

Function: co-stimulatory molecule found on APCs, binds to CD28 and provides signal to T cells

Question 9

CD95 (Fas)

Answer 9

Location: Many cell types

Function: signaling molecule bound by FasL on T cells, induces programmed cell death

Question 10

CD154 (CD40L)

Answer 10

Location: Activated T cells

Function: costimulatory signal to APCs