Question

2 Suppose yo performed this test and gor agglatinttion in both samples. Elminatieg contamination of the antigen and antiserun samples as a possib attribwtable so poor sensitiity or to de an explan.ation of this hypothetical resulr. Is this ficity of the test system 5 Suppose yow performed this test and neither sample produced agglstination even though you know the antigens and antibodies should react. Would this be attributable to poor sensitivity or specificity of the test systemt 4 Higher vertebrates produce antibodies; Salmonella is a prokaryote. Given these facts, how can Salmonella antiserum be produced? 764 MICROBIOLOGY: Laboratory Theory &Application

Answer 1

2. Suppose you performed this test and got agglutination in both samples. Eliminating contamination of the antigen and antiserum samples as possibility, provide an explanation of this hypothetical result. Is this attributable to poor sensitivity or specificity of the test system?

Answer - One possibility is that the anti-H antibody cross-reacts with the O antigen. This would be due to poor specificity.

3. Suppose you performed this test and neither sample produced agglutination even though you know the antigens and antibodies should react. Would this be attributable to poor sensitivity or specificity of the test system?

Answer - Assuming the vials really contained what their labels said, this false negative would be due to poor sensitivity. Apparently, there is not enough H antigen in the sample to form a visible agglutinate with the ant-H antiserum.

4. Higher vertebrates produce antibodies; Salmonella is a prokaryote. Given these facts, how can Salmonella antiserum be produced?

Answer - Salmonella is the source of antigens for this exercise, not the source of antibodies. To get antibodies to Salmonella, we need to expose a vertebrate to its antigens, allow the vertebrate to mount an immune response, then isolate and purify the anti-Salmonella antibodies form the verebrate's serum. Salmonell does NOT produce Salmonella antibodies.