Acceleration of IgE responses by treatment with recombinant interleukin-3 prior to infection with Trichinella spiralis in mice.

Treatment of mice with recombinant interleukin-3 (rIL-3) accelerated an IL-4-dependent IgE production following infection with Trichinella spiralis. When mice were treated with a total of 1.5 x 10(4) units rIL-3 for 5 days before infection with 400 muscle larvae, the serum IgE level increased prominently on day 5. Acceleration of IgE responses was dependent on the dose of rIL-3 injected. Treatment of mice with a total of 10(3) units rIL-3 could accelerate IgE responses. IgE responses were detected by a sandwich enzyme-linked immunosorbent assay at least from day 3 in mice treated with rIL-3. Acceleration of IgE responses was inhibited by anti-IL-4 monoclonal antibody. In contrast to this, IgG1 and IgG2a responses were not suppressed by the anti-IL-4 treatment. IL-3 treatment could up-regulate IgE and IgG1 responses but not the IgG2a response. IL-3 treatment could also accelerate IgE responses in W/Wv mice infected with the parasites. These results suggest that IL-3 is involved in regulation of IgE responses in mice and that mast cells do not play an essential role in acceleration of IgE responses induced by rIL-3 treatment in this system.