Question

5. Which of the following is a correct description of white blood cells?

A. Eosinophils and Basophils are phagocytic

B. Monocytes and lymphocytes are agranulocytes

C. All granulocytes contain histamine

D. Monocytes differentiate into antigen presenting cells

E. Both A and B F. Both B and D

6. Which of the following is true regarding T-cells?

A. TCRs are secreted by T cells to target free floating antigens

B. CD8 T cells can be activated by any infected cell

C. T-cell peripheral tolerance is developed in the thymus

D. Cytotoxic CD4 T-cells enhance killing function of macrophages

8. Which of the following statements is true?

A. In the secondary response to an antigen, higher levels of IgM will be detected in an individual’s serum.

B. In the secondary response to an antigen, lower levels of IgM will be detected in an individual’s serum.

C. The lag period following secondary exposure to an antigen is longer than the lag period following primary exposure.

D. The lag period following secondary exposure to an antigen is shorter than the lag period following primary exposure.

9. Which of the following is incorrect regarding antibody classes?

A. The Fc region of IgE interacts with eosinophils and is protective against parasites

B. IgM acts as a B-cell receptor when it is membrane bound and forms a pentamer when secreted

C. IgA provides natural passive immunity

D. All antibodies have the same antigen binding specificity when plasma cell class switching occurs

E. All of the above are correct F. none of the above are incorrect

Answer 1

5. F (both B & D )

Esonophilis are phagocytic but basophils are mainly involved in inflammatory reactions eapecially has histamine in its granules which is an anticoagulant.

Monocytes and lymphocytes are agranulocytes. The cell contain large granules hence large nucleus present. Monocytes differentiate into dendritic cells and macrophages which have role in cell mediated immunity. They present Antigen to T cells.

6.D

CD4T cells stimulate other immune cell including macrophages to function thereby enhancing immunity.

T cell receptor doesnt recognise free Ag unless it is presented to it by MHC molecules. While B cells receptor recognise it directly.

CD8T cells are activated by CD4T cells. While CD 4T cells are activatec directly by infection

Peripheral tolernce of T cell occur in spleen and lymphoid organs.

8. B and D are right

9.E, all correct