Human dermatophyte‐responsive T‐cell lines recognize cross‐reactive antigens associated with mannose‐rich glycoproteins

Abstract Resistance to dermatophyte infections has been shown to be mediated in part by T lymphocytes. The dermatophyle antigens recognized by human T lymphocytes and their degree of cross‐reactivity were analyzed. Dermatophyte‐responsive T‐cell lines were generated by in vitro sensitization to crude fungal extracts obtained from Trichophyton rubrum, Trichophyton tonsurans. Microsporum canis and Epidermophyton floccosum. Proliferation was measured by incorporation of ³H‐thymidine. The human T‐cell lines responded to fungal extracts derived from these various dermatophyte species, demonstrating the recognition of cross‐reactive antigens by human T cells. However, the T cells were dermato‐phyte‐specific as they did not respond to herpes antigen, nor did herpes‐specific T cells derived from the same donors respond to dermatophyte antigens. The mannose‐rich glycoprotein fraction (mannan) isolated from T. rubrum was able to induce proliferation of T‐cell lines generated by stimulation with various fungal extracts. Furthermore, a T‐cell line generated by stimulation with mannan derived from T. rubrum proliferated in response to extracts from various fungal species, indicating that a major cross‐reactive dermatophyte T‐cell antigen was present in the mannose‐rich glycoprotein fraction.