Impairment of T cell stimulation by pre-patent schistosome infection is independent of arginase, NOS, IL-10, PD-L1 and TGF-β.

<p>A, Splenocytes isolated from 4 week <i>S. mansoni</i>-infected or non-infected RAG-1^−/− mice co-cultured with CFSE-stained CD4⁺ T cells isolated from non-infected OT-II/RAG-1^−/− mice for 72 hrs with OVA peptide stimulation in the presence of Nor-NOHA, L-NMMA, anti-IL-10R or anti-PD-L1. Cells recovered from culture were stained for surface markers then analyzed for CD4⁺ T cell proliferation by flow cytometry. Proliferation Index was calculated. Horizontal bars represent mean of 5 independent mice. B, In a replicate, independent experiment, cells were isolated as in (A) and cultured in the presence of OVA peptide stimulation with anti-TGF-β1, β2, β3 antibody (B) or recombinant IL-2 (C) and. CD4⁺ T cell proliferation was analyzed by flow cytometry. Horizontal bars represent mean of 5 independent mice. Data are representative of at least 3 independent experiments. Nor-NOHA, N^ω-hydroxy-nor-Arginine; L-NMMA, L-N^G-monomethyl Arginine citrate; αIL-10R, anti-IL-10 receptor monoclonal antibody; αPD-L1, anti-PD-L1 monoclonal antibody; αTGF-β, anti-TGF-β1, β2, β3 monoclonal antibody.