Generation of highly purified and functionally active human TH1 cells against Aspergillus fumigatus

Abstract

Invasive aspergillosis remains a serious complication in patients undergoing allogeneic stem cell transplantation (SCT). Since it became clear that lymphocytes provide a critical secondary defense against fungi, adoptive transfer of functionally active anti-Aspergillus T cells might be an option to restore adaptive immune effector mechanisms. Using the interferon (IFN)-gamma secretion assay, we isolated human activated T cells upon stimulation with a cellular extract of Aspergillus fumigatus. Culturing this cell population for 14 days, we obtained an average of 1.1 x 10(7) cells from a single 100-mL blood draw in 7 of 7 healthy individuals. Within another 14 days, these cells were expanded to an average number of 2.0 x 10(8) T-helper 1 (T(H)1) cells secreting IFN-gamma on stimulation with Aspergillus antigens. Testing various fungal antigen extracts, similar proportions of IFN-gamma-producing CD3+/CD4+ cells were obtained upon activation with antigen extracts of A. fumigatus, A. flavus, A. niger, and Penicillium chrysogenum, whereas no significant IFN-gamma production was observed upon activation with antigen extracts of Alternaria alternata and Candida albicans. In addition, generated T cells were able to induce damage to A. fumigatus hyphae, and significantly increased hyphal damage induced by human neutrophils. CD4+ T-cell-mediated alloreactivity of generated anti-Aspergillus T cells was clearly reduced compared with that of the original cell population. In conclusion, we present a simple and feasible strategy for rapid generation of a high number of functional active T cells against Aspergillus from a single blood draw. Our data suggest that functionally active T cells against Aspergillus could be a promising treatment option for patients undergoing allogeneic SCT.