1 During embryonic development B1 cells produce a antibody a

1. During embryonic development B1 cells produce....

a. antibody against self protein (autoantibody)

b. antibody against polysaccharides

c. antibody to microbial protein

d. antibody to microbial DNA

e. antibody of the IgE class

2. All of the following events can trigger mast cells to degranulate, except....

a. C3a molecules bind to C3a receptors on mast cell

b. C5a molecules bind to C5a receptors on mast cell

c. anaphylatoxins bind to their receptors on mast cell

d. circulating IgE antibodies bind to parasitic worms

e. allergens bind to IgE molecules that are bound to Fc epsilon RI receptors on mast cells

3. Which of the following pairs is comprised to two molecules that have oposonic activity and facilliate phagocytosis?

a. C3a; C5a

b. C3b; C5b

c. C3a; antibody

d. C3b; antibody

e. C4b2a; C3bBb

4. A hydrid cell that is formed by the fusion of a .... with a .... is called a ....

a. naive mature B cell; myeloma cell; plasma cell

b. plasma cell; myeloma cell; hydridoma

c. B1 cell ; B2 cell; hydridoma

d. plasma cell; hepatocyte; hydridoma

e. hydridoma; plasma cell; myeloma

5. Antibody diversity is generated by the recombination of antibody gene segments in the heavy chain gene, as well as in the kappa light chain gene and lambda chain gene. Which of the following is the first recombination?

a. Kappa light chain gene segments V and JC

b. Heavy chain V gene segment to D gene segment

c. Heavy chain V gene segment with C gene segment

d. Heavy chain D gene segment with J gene segment

e. Lambda V gene segment with J gene segment

Solution

1. B1 cell consists of two counterparts :  CD5 and CD5+ where  CD5 produce antibodies against polysaccharide antigen. So the answer is option (B).

2. Only option (D) doesnot trigger mast cell to degranulate.

3.C4b2a; C3bBb are components of C3 convertase that take part in opsonisation and facilitate phagocytosis.Thus the answer is option (D).

4.Hybrid cell that is formed by fusion of plasma and myeloma cell is called Hybridoma.Thus the answer is option (B)

5.In a developing B cell, the first recombination occurs between one D and one J gene segment of the heavy chain . Thus the correct answer is option (D)