INTERLEUKIN (IL)-4, THE CYTOKINE THAT ISNT THERE - REACTIVITY OF IL-4ANTIBODIES WITH CELLS IN IL-4 - - MICE/

We analyzed cytokine expression in recipient spleens and cardiac allog rafts placed in mice that were unable to synthesize interleukin (IL)-4 due to disruption of the IL-4 gene (IL-4 -/-) and in wild-type (IL-4 +/+) mice. Polyclonal BL-4P and monoclonal 11B11, 1D11, and 24G2 anti- IL-4 antibodies were used to detect cell-surface and cytoplasmic antig ens in sections of frozen tissue. All of the antibodies were found to react with non-IL-4 determinants associated with graft-infiltrating ce lls, and BL-4P, 1D11, and 24G2 bound to cells and connective tissue in the spleens of IL-4 -/- mice. The IL-4-producing cell line, X63Ag8-65 3 (X63), was used as a positive control for IL-4 staining and to test the ability of recombinant IL-4 to block the binding of antibodies to IL-4.