Induction of allergen-specific T cells by conjugates of N-formyl-methionyl-leucyl-phenylalanine and rye grass pollen extract.

A conjugate of the biologically active peptide N-formyl-methionyl-leucyl-phenylalanine and rye grass pollen extract (F-MLP/rye), previously shown to react with rye grass pollen extract-specific T cells, induced the formation of allergen-specific T cells in mice. Lymph node cells prepared from mice immunized with either native extract or F-MLP/rye gave an enhanced response to unmodified rye grass pollen allergens in vitro. Syngeneic spleen macrophages were able to present the unmodified allergens to T cells obtained from both groups of mice causing their proliferation in vitro. Conjugation of the peptide into the extract brought about an extensive reduction in its reactivity with grass pollen-specific human IgE, and a loss of its ability to induce specific IgG antibody in guinea-pigs. A state of delayed hypersensitivity specific for rye grass pollen extract was produced in guinea-pigs by immunization with either the F-MLP/rye or unmodified extract. It is concluded that conjugates such as F-MLP/rye or other T' allergoids could be used as probes to investigate whether changes in T cell activity are important in immunotherapy.