Endogenous n-3 Polyunsaturated Fatty Acids Are Beneficial to Dampen CD8+ T Cell-Mediated Inflammatory Response upon the Viral Infection in Mice

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) have been known to exert anti-inflammatory effects on various disease states. However, its effect on CD8(+) T cell-mediated immunopathology upon viral infection has not been well elucidated yet. In this study, we investigated the possible implication of n-3 PUFAs in CD8(+) T cell responses against an acute viral infection. Infection of FAT-1 transgenic mice that are capable of synthesizing n-3 PUFAs from n-6 PUFAs with lymphocytic choriomeningitis virus (LCMV) resulted in significant reduction of anti-viral CD8(+) T cell responses. Interestingly, expansion of adoptively transferred wild-type (WT) LCMV-specific T cell receptor (TCR) transgenic CD8(+) (P14) T cells into FAT-1 mice was significantly decreased. Also, activation of anti-viral CD4(+) helper T cells was reduced in FAT-1 mice. Importantly, P14 cells carrying the fat-1 gene that were adoptively transferred into WT mice exhibited a substantially decreased ability to proliferate and produce cytokines against LCMV infection. Together, n-3 PUFAs attenuated anti-viral CD8(+) T cell responses against an acute viral infection and thus could be used to alleviate immunopathology mediated by the viral infection.