Immune response to Trichinella spiralis larvae after treatment with the anti-allergic compound ketotifen.

Ketotifen was used as an anti-allergic agent to study the relationship between eosinophil-related responses and IgG1 and IgG2a antibody responses in BALB/c mice infected with Trichinella spiralis. The results showed that leukocyte and eosinophil numbers and interleukin-5 (IL-5) concentrations in the peritoneal fluid increased after exposure to nematodes and the increases were slightly greater in animals treated with ketotifen. A decreased concentration of eosinophil peroxidase and an elevation in IgG1 accompanied the muscle phase of infection. In mice treated with ketotifen, antibody-mediated recognition of muscle larvae was delayed. The retardation of IgG1 and IgG2a responses may have been responsible for the ineffective immune response against larvae migrating into the muscle. The activation of eosinophils was accompanied by changes in IL-5 concentration, but these changes were not associated with differences in protection against infection.