Dietary (n-3) polyunsaturated fatty acids do not affect the in vivo development and function of Listeria-specific CD4+ and CD8+ effector and memory/effector T cells in mice.

We previously reported that in a mouse model, a diet high in (n-3) PUFA diminishes host survival following an infection from Listeria monocytogenes, a gram-positive bacterial pathogen. In this study we investigated the impact of (n-3) PUFA on the adaptive immune response to L. monocytogenes. BALB/c mice were fed experimental diets either devoid of or rich in (n-3) PUFA from fish oil for 4 wk and then infected with 10(6) actA-deficient L. monocytogenes. At 7 and 35 d postchallenge, effector and memory/effector T cells in the spleen were enumerated by flow cytometry. Surprisingly, the number of Listeria-specific CD4(+) and CD8(+) effector and memory/effector T cells in the spleen was not affected by (n-3) PUFA. Also, the effector cells derived from mice fed either diet were equally capable of conferring protective immunity upon adoptive transfer to naive recipients. Despite our previous data, which demonstrated that (n-3) PUFA profoundly impaired host resistance to L. monocytogenes, pathogen-specific T cell responses were not substantially affected by dietary (n-3) PUFA.