Immunosuppressive compounds exhibit particular effects on functional properties of human anti-Aspergillus Th1 cells.

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at high risk for invasive aspergillosis. Whereas adoptive immunotherapy transferring donor-derived anti-Aspergillus TH1 cells has been shown to be beneficial for HSCT recipients suffering from invasive aspergillosis, little is known about the impact of commonly used immunosuppressants on the functional properties of anti-Aspergillus TH1 cells. Anti-Aspergillus TH1 cells were coincubated with different concentrations of methylprednisolone, cyclosporine (CsA), mycophenolic acid (MPA), the active component of mycophenolate mofetil, and rapamycin. Immunosuppressants were tested in concentrations reflecting common target levels in serum and in significantly lower and higher concentrations. Apoptosis of anti-Aspergillus TH1 cells, as well as proliferation and production of gamma interferon (IFN-γ) and CD154 upon restimulation, was evaluated in the presence and absence of immunosuppressive compounds. All dosages of CsA, MPA, and methylprednisolone significantly decreased the number of viable anti-Aspergillus TH1 cells in the cell culture, which was due partly to an impaired proliferative capacity of the cells and partly to an increased rate of apoptosis. In addition, CsA significantly decreased the number of IFN-γ-producing cells and had the highest impact of all immunosuppressants on IFN-γ levels in the supernatant. CsA also significantly decreased the expression of CD154 by anti-Aspergillus TH1 cells. Variant dosages of immunosuppressants exhibit particular effects on essential functional properties of anti-Aspergillus TH1 cells. Our findings may have an important impact on the design of clinical trials evaluating the therapeutic benefit of anti-Aspergillus TH1 cells in allogeneic HSCT recipients suffering from invasive aspergillosis.

Clinical-scale generation of multi-specific anti-fungal T cells targeting Candida, Aspergillus and mucormycetes.

BACKGROUND AIMS: Invasive fungal infections, in particular, infections caused by Candida, Aspergillus and mucormycetes, are a major cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplantation. Adoptive transfer of donor-derived anti-fungal T cells shows promise to restore immunity and to offer a cure. Because T cells recognize only specific epitopes, the low rate of patients in which the causal fungal pathogen can be identified and the considerable number of patients with co-infection with several genera or species of fungi significantly limit the application of adoptive immunotherapy. METHODS: Using the interferon-γ secretion assay, we isolated multi-specific human anti-fungal T cells after simultaneous stimulation with cellular extracts of Aspergillus fumigatus, Candida albicans and Rhizopus oryzae. Cells were phenotypically and functionally characterized by flow cytometry. RESULTS: Of a total of 1.1 × 10(9) peripheral blood mononuclear cells, a median number of 5.2 × 10(7) CD3+ CD4+ T cells was generated within 12 days. This cell population consisted of activated memory TH1 cells and reproducibly responded to a multitude of Aspergillus spp., Candida spp. and mucormycetes with interferon-γ production. On re-stimulation, the generated T cells proliferated and enhanced anti-fungal activity of phagocytes and showed reduced alloreactivity compared with the original cell fraction. CONCLUSIONS: Our rapid and simple method of simultaneously generating functionally active multi-specific T cells that recognize a wide variety of medically relevant fungi may form the basis for future clinical trials investigating adoptive immunotherapy in allogeneic hematopoietic stem cell transplantation recipients with invasive fungal infection.

Challenges and prospects of adoptive immunotherapy in prevention and treatment of opportunistic mycoses in hematologic transplant recipients.

Invasive fungal infections remain a serious and life-threatening complication in patients undergoing hematopoietic stem cell transplantation. Since it became clear that lymphocytes, in particular lymphocytes from the T helper 1 (T(H)1) subset, play a critical secondary defense against fungal pathogens, the adoptive transfer of functionally active antifungal T(H)1 cells might be an attractive option to restore adaptive antifungal immune effector mechanisms. Major advances have been made in the generation and characterization of antifungal T cells, which are active against medical important fungi such as Aspergillus spp and Candida spp. However, given the paucity of large homogenous patient populations, major challenges remain in evaluating the clinical usefulness of adoptive antifungal immunotherapy, which should be performed in international collaborative trials.