TRICHOPHYTON ANTIGENS ASSOCIATED WITH IGE ANTIBODIES AND DELAYED-TYPEHYPERSENSITIVITY - SEQUENCE HOMOLOGY TO 2 FAMILIES OF SERINE PROTEINASES

The dermatophyte fungus Trichophyton exhibits unique immunologic prope rties by its ability to cause both immediate and delayed type hypersen sitivity. An 83-kDa Trichophyton tonsurans allergen (Tri t 4) was prev iously shown to elicit distinct T lymphocyte cytokine profiles in vitr o, The homologous protein, Tri r 4, was cloned from a Trichophyton rub rum cDNA library, and the recombinant protein was expressed in Pichia pastoris, This 726-amino acid protein contained an arrangement of cata lytic triad residues characteristic of the prolyl oligopeptidase famil y of serine proteinases (Ser-Asp-His). In addition, a novel Trichophyt on allergen, encoding 412 amino acids, was identified by its human IgE antibody-binding activity. Sequence similarity searches showed that t his allergen, designated Tri r 2, contained all of the conserved resid ues characteristic of the class D subtilase subfamily (41-58% overall sequence identity). Forty-two percent of subjects with immediate hyper sensitivity skin test reactions to a Trichophyton extract exhibited Ig E antibody binding to a recombinant glutathione S-transferase fusion p rotein containing the carboxyl-terminal 289 amino acids of Tri r 2, Fu rthermore, this antigen was capable of inducing delayed type hypersens itivity skin test reactions. Our results define two distinct antigens derived from the dermatophyte Trichophyton that serve as targets for d iverse immune responses in humans.