The examples in questions 1 and 2 are:
a. Direct tests
b. Indirect tests

Put the following in the correct sequence to elicit an antibody response:

(1) TH cell produces cytokines

(2) B cell contacts antigen

(3) antigen fragment goes to surface of the B cell

(4) TH recognizes antigen fragment and MHC

(5) B cell proliferates.

a. 1, 2, 3, 4, 5

b. 5, 4, 3, 2, 1

c. 3, 4, 5, 1, 2

d. 2, 3, 4, 1, 5

e. 4, 5, 3, 1, 2

Explain the effects of excess antigen and antibody on the precipitation reaction. How is the precipitin ring test different from an immunodiffusion test?

Match the following serological tests in column A to the descriptions in column B.

Match each of the following tests in column A to its positive reaction in column B.

Use the following choices to answer questions 4 and 5:

a. Anti-Brucella

b. Brucella

c. Substrate for the enzyme

Which is the third step in a direct ELISA test?

A purified protein from Mycobacterium tuberculosis is injected into a person’s skin. A hardened, red area develops around the injection site within 3 days.

Use the following choices to answer questions 4 and 5:

a. Anti-Brucella

b. Brucella

c. Substrate for the enzyme

Which item is from the patient in an indirect ELISA test?

In an immunodiffusion test, a strip of filter paper containing diphtheria antitoxin is placed on a solid culture medium. Then bacteria are streaked perpendicular to the filter paper. If the bacteria are toxigenic,

a. The filter paper will turn red

b. A line of antigen–antibody precipitate will form

c. The cells will lyse

d. The cells will fluoresce

e. None of the above