Question

1) Class II MHC molecules are found on which of the following?

liver cells and macrophages in the spleen

granulocytes and microphages

red blood cells

lymphocytes and antigen-presenting cells

all body cells with a nucleus

2) All of the following are true of the primary response of humoral immunity except that

circulating antibodies undergo a gradual, sustained rise.

it depends on memory B cells.

it requires B cell differentiation into plasma cells.

it depends on antigen triggering the appropriate B cell.

it peaks 1 to 2 weeks after the initial exposure.

Answer 1

Answer 1: Lymphocyte and antigen presenting cells.

Explanation:

1. It contains 2 alpha and 2 beta domains.
2. It presents exogenous antigens.
3. It is present on B cells, dendritic cells, macrophages.
4. It presents antigens to helper T cells.

Incorrect answer - all nucleated cells have MHC I.

RBC have no MHC molecule.

Answer 2. It depends upon memory B cells.

Explanation:

• The humoral response can be divided into primary and secondary.
• The primary response occurs after first exposure to antigen.
• This antigen causes B- cells to differentiate into plasma cells.
• These plasma cells produce immunoglobulin.
• These immunoglobulin then bind to antigens and neutralize it.
• This process takes time.
• Some of the antigen specific plasma cells differentiate into memory B cells.
• These memory B cells only get stimulated on second exposure to antigen.