The presence of phosphorylcholine (PC) in Trichinella was confirmed by ELISA and Western blot experiments with the PC-specific myeloma TEPC-15. Anti-PC antibody production was detected in ELISA by cross-reaction with the PC-positive somatic polysaccharide of Aspergillus and the synthetic conjugate phosphorylcholine-bovine serum albumin conjugate and by inhibition with phosphorylcholine chloride (PCCI). The kinetics of the serum and mucosal anti-PC immunoglobulin response were determined following infection of CFW mice. Anti-PC IgA was a minor fraction of the serum response. Inprimary infections IgG binding to Trichinella antigen was partially inhibited by PCCI incubation, but by Day 6 following challenge infections, incubation with PCCI did not reduce IgG binding. PCCI incubation also reduced serum IgM binding to Trichinella antigen following primary infections, and in contrast to IgG, a reduction occurred following challenge infection as well. Following primary and challenge infections PCCI incubation also reduced bile IgA binding to Trichinella antigen. The kinetics and subclass distribution of the anti-Trichinella PC response were equivalent to the group I response reported for synthetic PC-protein conjugates. Anti-PC IgA production indicates that class switching occurred without maturation of the response. Immunization by feeding Trichinella antigen plus cholera toxin, in contrast to infection with larvae, did not affect anti-PC antibody production following infection. Since the response was not anamnestic and the serum IgG response was not downregulated, larval infection and antigen feeding differ in the anti-PC responses they induce. The anti-PC response does not appear to be protective in Trichinella infections in mice. © 1993 Academic press, Inc.
