Induction of a proliferative response of T cells by a high-molecular antigen in Dermatophagoides farinae feces.

Background: We have previously demonstrated that high-molecular mite antigen (HM1) from Dermatophagoides farinae feces is an allergen which binds to mite-allergic patients IgE. HM1 also induced a proliferative response in lymph node cells from mite-immunized mice as well as nonimmunized mice. In the present study, we demonstrated that HM1 induced T cell proliferation and investigated the HM1-stimulated T cell proliferative pathways using nonallergic human peripheral blood mononuclear cells (PMBC).
Methods: Blood samples were obtained from 10 healthy donors. Using primary culture, T cell response stimulated with HM1 was performed on purified T cells, CD19+ cell-depleted PBMC and CD11b+ cell-depleted PBMC. In addition, interleukin (IL)-5 and interferon (IFN)-gamma produced by mite-allergic and healthy donors stimulated with HM1 were estimated by enzyme immunoassay.
Results: T cell proliferation was detected only in CD19+ cell-depleted PBMC. When T cells were cocultured with CD11b+ cells they recovered their proliferative response to HM1. In addition, the pathway of HM1-stimulated T cell proliferation did not involve HLA class II restriction. Both activated CD11b+ cells and their conditioned media were needed to induce HM1-stimulated T cell proliferation. Furthermore, HM1 induced IFN-gamma production in both healthy and allergic donors.
Conclusion: The high-molecular mite antigen, HM1, induced a proliferative response of T cells in healthy as well as allergic donors, without HLA class II restriction. Our results suggest that further investigation of HM1 could constitute a valuable avenue of research into complex allergic diseases.
(Copyright 2002 S. Karger AG, Basel)