CD8⁺ T cells are activated by CHIKV-infected cells when peptide processing and ER transport are bypassed.

Abstract

(A-B) EVA cells were inoculated with 106 PFU CHIKV-VENKL or CHIKV-SIINFEKLβ2m. At 24 hpi, EVA cells were cocultured with a 1:1 mixture of 106 bystander and 106 OT-I SIINFEKL-specific CD8+ T cells for 6 h. Bystander CD8+ T cells were distinguished from OT-I CD8+ T cells by gating on CD8+, KbOVA257-264 tetramer positive or negative cells, and both populations were assessed for the expression of CD69, CD25, IRF4 and CD8 by flow cytometry. (A) Representative flow cytometry plots. (B) Quantification of CD25, CD69, IRF4 (intracellular), and CD8 cell surface expression (upper graphs) and frequency (lower graphs) for OT-I cells above bystander CD8+ T cells. Data are representative of two independent experiments (n = 6). P-values were determined by unpaired student’s t-test. *, PPPP<0.0001.</p