Characterization of the cellular immune responses to Rhizopus oryzae with potential impact on immunotherapeutic strategies in hematopoietic stem cell transplantation.

Infections due to mucormycetes have a poor outcome, in particular in allogeneic hematopoietic stem cell transplantation (HSCT). In order to evaluate the cellular host response against mucormycetes, we enriched and cultivated anti-Rhizopus oryzae T cells from healthy individuals. These cells were characterized as memory/effector T(H)1 cells, they proliferated upon restimulation, they exhibited cross-reactivity to some but not all Mucorales species tested, and they increased the activity of phagocytes. Compared with the original cell fraction, the generated cells exhibited significant lower alloreactivity. Our data may form the basis for further investigations, which may ultimately lead to adoptive immunotherapeutic strategies for allogeneic HSCT recipients suffering from mucormycosis.