Question

In an experiment you develop immune response in mice against salmonella flagellar antigen. However, you observe the infection still persisted. Which if a likely possibility if immune system is functioning properly?

(a) Salmonella shed its flagella

(b) The antigen lost its specificity gradually

(c) The flagella antigen changed

(d) Infection was not due to salmonella

I got this question by my school teacher while I was bunking the class.

Question is from Chromosomal Abnormalities : Translocation topic in section Chromosomal Basis of Inheritance of Cytogenetics

Answer 1

Correct answer is (c) The flagella antigen changed

Easy explanation: In salmonella, the flagellar antigen is target for immune response. His antigen’s phase can vary with presence of insertion sequence within the gene. In this case change of antigen could lead to a loss of specificity by the immune system.