Question

: Reovirus is an enteric virus that infects mice by adhering to intestinal M cells and then using M cell transport to enter Peyer's patches. Mice that were orally

inoculated with reovirus cleared the primary infection, and upon secondary challenge 21 days later, had no detectable virus in their Peyer's patches. In contrast, naive controls
that did not receive the primary inoculation had >103 PFU of virus/mg of tissue following oral challenge with virus. The protective response induced by the primary oral inoculation would also be eliminated in:

A. FcRn-deficient mice
B. IgA-deficient mice
C. IgM-deficient mice
D. FcRI-deficient mice
E. IgG-deficient mice

Answer 1

In the scenario involving reovirus infection in mice, protective immunity gained from a primary inoculation would likely be eliminated in IgA-deficient mice.

Step-by-step explanation:

The protective response induced by a primary oral inoculation with reovirus, an enteric virus that can infect mice, would be compromised in mice deficient in IgA. IgA immunity is crucial for mucosal defense, particularly in the Peyer's patches of the small intestine where antigens are sampled through M cells and an immune response is subsequently initiated. In the context provided, naive controls—a term referring to control animals that did not undergo primary inoculation—show a significant amount of virus present upon secondary challenge, contrasting with previously inoculated mice that cleared the infection. The implication here is that IgA plays a significant role in the mucosal immune memory and defense against reoviral infections. Therefore, IgA-deficient mice (option B) would be expected to lack this protective response.