Interleukin‐4 and Interferon‐Gamma Production by Leishmania Stimulated Peripheral Blood Mononuclear Cells from Nonexposed Individuals

Publisher Website
Google Scholar
Abstract
Interferon‐gamma (IFN‐γ) and interleukin‐4 (IL‐4) production by Leishmania reactive peripheral blood mononuclear cells (PBMC) from non‐exposed individuals was investigated. IFN‐γ was measured in culture supernatants after antigen stimulation. For the measurement of IL‐4, antigen stimulated cells were pulsed with PMA and ionomycin before IL‐4 release was measured. L. donovani and L. major antigens induced IL‐4 production (105–1748pg/ml) in 13 and seven cultures, and IFN‐γ production (1.7‐ > 66IU/ml) in 14 and 11 of 20 cultures, respectively. IL‐4 production rose steeply after 6 days of antigen stimulation suggesting a response due to antigen recognition. Both IL‐4 and IFN‐γ production was abrogated by depletion of CD2+ or CD4+ but not CD8+ cells. CD2+ or CD4+ but not CD8+ enriched cultures produced cytokines as unseparated PBMC. Thus, in non‐exposed individuals circulating Leishmania reactive CD4+ T cells could be demonstrated. The cells from different individuals showed different patterns of IFN‐γ and/or IL‐4 production upon antigenic stimulation. In experimental leishmaniasis the early balance between IFN‐γ and IL‐4 is important for the clinical outcome. Our findings call for studies of the importance of cytokine production by cross‐reactive T cells for the outcome of L. donovani infections in humans and show that the method for IL‐4 detection is useful for this purpose.