Mice Refractory to Lipopolysaccharide Manifest High Immunoglobulin A Responses to Orally Administered Antigen (1)
The interaction of antigen with gut-associated lymphoid tissues is a major pathway by which immunoglobulin A (IgA) immune responses are induced in animals. Salivary anti-HRC agglutinins were detected after 1 week of feeding and reached peak levels for approximately 3 weeks.
Antibodies specific for HRC were also in sera after 3 weeks of immunization and were significantly higher in C3H/HeJ than in C3H/HeN mice. In orally immunized C3H/HeJ mice, a significant elevation in serum IgA was noted that was approximately threefold higher than that of either C3H/HeN mice or nonimmunized controls.
At 3 weeks, IgM and IgA PFC to HRC in orally immunized C3H/HeJ mice were significantly higher than those in C3H/HeN mice.
In C3H/HeJ mice, significantly greater IgM and IgA anti-SRC PFC responses were detected that were three-fold higher than those of C3H/HeN mice.
Oral administration of antigen may also induce a state of unresponsiveness to subsequent systemic challenge by the same antigen. In C3H/HeJ mice, greater T-cell helper activity in Peyer’s patches might be expected in response to antigenic challenge. That C3H/HeJ mice lack a naturally occurring population of suppressor cells that regulate host responses to LPS.