Human filarial infection reshapes CD8+ T-cell transcription and function at homeostasis and following viral activation

Given the chronic nature of these infections, individuals living in endemic regions are frequently exposed to other pathogens including viruses. Because CD8 cells are essential for anti-viral immunity, understanding how filarial infections shape the cytotoxic compartment is essential to elucidate their impact on bystander immunity.

We evaluated the phenotype and function of CD8+ T cells from Loa loainfected (Fil+) and -uninfected (Fil-) individuals at baseline and following cytomegalovirus (CMV) re-stimulation. Filarial infection was associated with increased activation and proliferation of CD8+ T cells, characterized by elevated expression of Ki-67, CD107a, and production of type 1 and 17 cytokines. Upon CMV re-stimulation, Fil+ individuals showed markedly reduced expansion of antigen-experienced (CD137+) and polyfunctional (CD137+IFN-g+TNF-α+ and CD137+IFN-g+TNF-α+IL-2+) CD8+ T cells, along with decreased cytotoxic activity.