Murine T cell responses to melittin and its analogs.

The 26-residue peptide melittin from bee venom elicits high IgG1 and IgE responses in selected strains of mice. The antibody responses were shown previously to be specific mainly for the region of residue 20-26. The T cell epitope of melittin in H-2d-restricted mice is now found to be primarily in residue 11-19, corresponding to an alpha-helical amphiphilic segment of the molecule. Melittin-specific T cell lines have varying responses to different structural analogs of the melittin T cell epitope, and the results indicate that the antigenicity of T cell epitope peptides depend more on their primary structure than on their secondary structure. Melittin-specific T cell clones are found to be CD4+ and secrete IL-4, and are restricted to presentation on I-Ad or I-Ed. The I-Ad- or I-Ed-restricted clones differ in their responses to different analogs of melittin.