Cell surface proteins

Question 1

Present on all nucleated cells

Answer 1

• MHC I

- Remember not RBCs! (no nucleus!)

Question 2

T cells

Answer 2

• TCR (binds antigen-MHC complex)
• CD3 (associated with TCR for signal transduction)
• CD28 (binds B7 on APC)
• CCR5/CXCR4 (co-receptors for HIV)

Question 3

Helper T cells

Answer 3

• CD4
• CD40L
• TCR (binds antigen-MHC complex)
• CD3 (associated with TCR for signal transduction)
• CD28 (binds B7 on APC)
• CCR5/CXCR4 (co-receptors for HIV)

Question 4

Cytotoxic T cells

Answer 4

• CD8
• CXCR4/CCR5
• TCR (binds antigen-MHC complex)
• CD3 (associated with TCR for signal transduction)
• CD28 (binds B7 on APC)
• CCR5/CXCR4 (co-receptors for HIV)

Question 5

Regulatory T cells

Answer 5

• CD4
• CD25
• FOXP3
• TCR (binds antigen-MHC complex)
• CD3 (associated with TCR for signal transduction)
• CD28 (binds B7 on APC)
• CCR5/CXCR4 (co-receptors for HIV)

Question 6

B cells

Answer 6

• Ig (binds antigen)
• CD19
• CD20
• CD21 (EBV receptor)
• CD40
• MHC II
• B7

Question 7

Macrophages

Answer 7

• CD14 (receptor for PAMPs like LPS)
• CD40
• CCR5
• MHC II
• B7
• Fc and C3b receptors (enhanced phagocytosis)

Question 8

NK cells

Answer 8

• CD16 (binds Fc region of IgG)

- CD56 (unique marker for NK)

Question 9

Hematopoietic stem cells

Answer 9

CD34