You Are About to Graduate as a RN

Multiple Choice

You are about to graduate as a RN. Your final term project is to prepare a presentation on HIV/AIDS. HIV (human immunodeficiency virus) is a retrovirus—it is an enveloped single-stranded virus that has duplicate copies of a single-stranded RNA genome. All retroviruses encode reverse transcriptase, an enzyme that uses an RNA genome as a template to make a complementary DNA strand. HIV can infect a variety of human cell types, but the most important are the helper T cells (also called CD4 cells) —the virus infects these cells and causes their death; their numbers slowly decline until the immune system can no longer resist infections or tumor development. You give your presentation to the class and are asked by your professor at the end of the session to answer some questions that your peers have on diagnosing HIV.
-The Western blot is used to confirm the results of an ELISA test. Which of the following is the correct sequence of steps involved in this procedure?
1)  To determine if a patient's serum has antibodies specific for any of the proteins in the sample (in this case HIV proteins) , some of that serum is added to the blot, after which unbound antibodies are washed off.
2)  The antigen proteins separate according to size. The separated proteins in the gel are then transferred ("blotted") to a nylon membrane to immobilize them in the same positions they were in the gel.
3)  A type of gel electrophoresis (SDS-PAGE)  is used to separate the proteins of an antigen, which involves loading the sample onto a polyacrylamide gel matrix, and running an electrical current through it.
4)  Labeled anti-human IgG antibodies are added, which bind to any serum antibodies that have attached to the proteins. Unbound labeled antibodies are then washed off and attached label is detected. 

A) 1, 2, 3, 4
B) 3, 2, 4, 1
C) 3, 4, 2, 1
D) 3, 2, 1, 4
E) 2, 4, 3, 1