IL-4 is obligatory for primary IgE responses, whereas primary IgG, and secondary IgE responses are partially IL-4 independent. To investigate the effect of IL-4 on the antigen-specific memory formation for these isotypes, BALB/c mice were treated after primary TNP-KLH immunization with recombinant IL-4 for a period of 4 months. This prolonged presence of a high IL-4 level resulted in increased serum levels of total IgG1 and IgE, whereas total IgG2a did not change. The expression of CD23, but not J-Ad, increased on the splenic B cells. IL-4 treatment did not affect the IL-4 production by Con A stimulated spleen cells, whereas it did decrease the IFN-γ production. In the same mice the TNP-specific IgG1 and IgE serum levels, however, were decreased. Similar results were found when the antigen was continuously present during the IL-4 treatment. Furthermore, it was shown that IL-4 decreased the formation of IgG1, and IgE memory cells. These results point to different effects of IL-4 in regulating antigen-specific and bystander responses.,
Scandinavian Journal of Immunology

van Ommen, R, Vredendaal, A.E.C.M, & Savelkoul, H.F.J. (1994). Prolonged in vivo IL-4 treatment inhibits antigen-specific IgG1 and IgE formation. Scandinavian Journal of Immunology, 40(1), 1–9. doi:10.1111/j.1365-3083.1994.tb03425.x