When antigen and antibodies combine, maximal precipitation occurs when:
a. Antigen is in excess
b. Antibody is in excess
c. Antigen and antibody are at equivalent concentrations
d. Antigen is added to the antibody

Indicate the true statements, and then reword the false statements so they are true.

a. Immunodeficiencies are associated with a decreased cancer risk

b. Type I reactions are mediated by IgG antibodies

c. Autoimmune disorders are not caused by type I hypersensitivities

d. Systemic lupus is mainly mediated by a type III hypersensitivity

e. A person with type 0- blood is called a universal donor

f. Immunotherapies are useful to reduce type II reactions

How does an antibody neutralize a virus?

a. By preventing the virus from binding to a receptor protein on a host cell

b. By preventing the virus from injecting its nucleic acid into its host cell

c. By degrading the capsid

d. By inserting holes into the viral envelope

e. By preventing the virus from replicating while inside the host

A direct ELISA test is utilized as a pregnancy test because it tests for:

a. Antibodies to the fetus in urine

b. Antibodies to a pregnancy hormone in urine

c. An antigen that recognizes a pregnancy hormone in urine

d. T cells that recognize a pregnancy hormone in urine

e. The presence of a pregnancy hormone in urine

Describe one difference between a direct ELISA and an indirect ELISA.

An anti-antibody is used when:

a. An antigen is not precipitating

b. An antibody is not agglutinating

c. An antibody does not activate complement

d. The antigen is an antibody

The many different proteins in serum can be analyzed by a(n):

a. Anti-antibody test

b. Complement fixation test

c. Precipitation test

d. Immunodiffusion test

A direct fluorescent immunoassay requires which of the following?

a. Heat-inactivated serum

b. Fluorescent serum

c. Immune complexes

d. Antibodies against the antigen

An ELISA uses which of the following reagents?

a. Enzyme-labeled anti-antibody

b. Radioactive anti-antibody

c. Source of complement

d. Enzyme-labeled antigen