In the immunoglobulin molecule, light chains are attached to heavy chains by:

Which of the following sets includes immunoglobulins that are all capable of fixing complement:

A test method that determines whether an antigen or antibody is present, but will not determine the amount present is:

An Ouchterlony double immunodiffusion is performed, crossed lines of precipitation are observed. Which of the following is true?

Which outcome results from improper washing of a tube or well after adding the enzyme-antibody conjugate in an ELISA system?  Assume all steps taken prior to this step were performed properly. 

Mannose-binding protein in the lectin pathway is most similar to which classical pathway component?

Match the appropriate T lymphocyte population with the correct description. 

CD4+ T cells are called helper cells because they help activate other cells; the most important recipients of the CD4+ helper effector function are:

If a slide agglutination test is rotated for less than 1 minute as the directions specify, what source of error can occur?

In an immunoassay, serum is added  to a microtiter well coated with specific antibody. After incubation and washing, enzyme-labeled specific antibody is added. This procedure is: