Cell surface Proteins

Question 1

T cell cell-surface proteins?

Answer 1

TCR (binds antigen-MHC complex)
CD3 (associated with TCR for signal transduction)
CD28 (binds B7 on APC)

Helper T cells
CD4, CD40L, CXCR4/CCR5 (HIV co-receptors)

Cytotoxic T cells
CD8

Regulatory T cells
CD4, CD25

Question 2

B cell cell-surface proteins?

Answer 2

Ig (binds antigen)

CD19, CD20, CD21 (receptor for Epstein-Barr virus)

CD40

MHC II, B7

Question 3

Helper T cells cell-surface proteins?

Answer 3

CD4, CD40L, CXCR4/CCR5 (HIV co-receptors)

Question 4

Cytotoxic T cells cell-surface proteins?

Answer 4

CD8

Question 5

Regulatory T cells cell-surface proteins?

Answer 5

CD4, CD25

Question 6

Macrophages cell-surface proteins?

Answer 6

CD14 (receptor for PAMPs, eg, LPS)

CD40

CCR5

MHC II, B7 (CD80/86)

Fc and C3b receptors (enhanced phagocytosis)

Question 7

NK cells cell-surface proteins?

Answer 7

CD16 (binds Fc of IgG)

CD56 (suggestive marker for NK)

Question 8

Hematopoietic stem cells cell-surface proteins?

Answer 8

CD34

Question 9

CD28 known function?

Answer 9

binds B7 on APC

T cell receptor for costimulation signal

Question 10

CD3 known function?

Answer 10

associated with TCR for signal transduction

activates both T cytotoxic cells (CD8+ naïve T cells
& T helper cells (CD4+ naïve T cells)

Question 11

TCR known function?

Answer 11

binds antigen-MHC complex on T cells

Question 12

CD4 & CD40L are receptors on which cells?

Answer 12

Helper T cells

Question 13

CD25 is receptor on which cells?

Answer 13

Regulatory T cells (T reg cells)

Activated Th cells

Question 14

CD8 is receptor on which cells?

Answer 14

Cytotoxic T cells (CTLs)

Question 15

CD3 & CD28 are receptors on which cells?

Answer 15

T cells

Question 16

CD19, CD20, CD21 are receptors on which cells?

Answer 16

B cells

Question 17

CD40 is receptor on which cells?

Answer 17

B cells

Macrophages

Dendritic cells

Endothelial cells

Question 18

CD14 known function?

Answer 18

receptor for PAMPs (eg LPS lipopolysaccharide) on macrophages

Question 19

CD16 known function?

Answer 19

Opsonization ADCC

Fc receptor: binds Fc of IgG

Question 20

CD16 is receptor on which cells?

Answer 20

NK cells

Monocytes/ macrophages

Neutrophils

Question 21

What is the receptor for Epstein-Barr virus?

Answer 21

CD21

Question 22

What are HIV co-receptors?

Answer 22

CXCR4/CCR5

Question 23

CD18 known function?

Answer 23

Integrin molecule on leukocytes that causes cell adhesion (migration into sites of inflammation during immune response) & cell surface signaling

Question 24

Leukocyte adhesion deficiency is due to lack of which CD molecule?

Answer 24

CD18

Question 25

CD18 deficiency causes which disorder?

Answer 25

Leukocyte adhesion deficiency

Question 26

What is the first indication of LAD leukocyte adhesion deficiency?

What are subsequent signs & symptoms?

Answer 26

-Omphalitis
(swelling & redness around stalk of umbilical cord)

-Recurrent, chronic bacterial infections
(responding to antibiotics but recurrent)

• No pus formation/ No abscess
  -leukocytosis
  (↑granulocytes in circulation but migration into sites of infection not possible)

-Delayed (> 3 weeks) umbilical cord detachment

Question 27

What is treatment for LAD leukocyte adhesion deficiency?

Answer 27

Hematopoietic stem cell transplantation (bone marrow transplant)

Question 28

How do you test for LAD leukocyte adhesion deficiency?

Answer 28

Monoclonal antibodies
(detecting absence or severe deficiency of adhesive glycoproteins on the surface of WBCs using monoclonal antibodies (eg, anti-CD11, anti-CD18))

Flow cytometry

Question 29

No pus formation & lack of abscesses in an infection in neonates is a sign of which disorder?

Deficiency of which receptor molecule?

Answer 29

LAD leukocyte adhesion deficiency

CD18