CD8⁺ T cells upregulate Nrp-1 expression during LCMV infection and T cell-specific Nrp-1 ablation ameliorates immunopathology.

Abstract

C57BL/6 mice (A-D) or Nrp-1fl/fl x CD4cretg (KO, white bars) and Nrp-1fl/fl x CD4crewt littermates (WT, black bars) (E) were infected with 200 PFU LCMV-WE i.v. and T cell phenotypes were analyzed in the spleen 8 days post infection. (A) Nrp-1 expression on CD8+ T cells was measured by flow cytometry in the spleen and liver of naïve (white bar, grey dots) and LCMV-infected C57BL/6 mice (black bars, white dots). (B) The correlation of the frequency of Nrp-1+CD8+ T cells in the spleen with serum LDH and AST concentrations was determined in C57BL/6 mice infected with 200 PFU LCMV-WE, 200 PFU LCMV-docile and 2x106 PFU LCMV-docile on day 8 post infection. (C and D) Expression of CD69, Lag-3, PD-1, GzmB and TNF-α was determined on Nrp-1+ (black bars) and Nrp-1- CD8+ T cells (white bars) (C) or Tet+CD8+T cells (D). (E and F) Nrp-1, GzmB, TNF-α or IFN-γ expression was determined on antigen-specific Tet+CD8+ T cells in the spleen (E) and in the liver (F) of infected Nrp-1WT or Nrp-1KO mice by flow cytometry. LDH concentrations were measured in the serum at day 8 post LCMV infection. Data from two independent experiments with n = 5–8 mice per group are shown as mean values with SD. Statistical significance was calculated with (A) ordinary one-way ANOVA and Tukey’s multiple comparisons test. (B) Correlation is based on two independent experiments with n = 18 mice and statistics were analyzed using Pearson correlation coefficients. P and r values are displayed in the graphs. (C-F) Significance was tested using unpaired Student’s t test. *, p<0.05; **, p<0.01; ***, p<0.001; ****, p<0.0001.</p