Dietary polyunsaturated fatty acids modulate in vivo, antigen-driven CD4+ T-cell proliferation in mice

Our objective was to determine whether dietary lipids affect in vivo, antigen-driven, proliferation of native CD4(+) T lymphocytes. To accomplish this, we adoptively transfer-red lymphocytes from T-cell receptor (TCR) transgenic DO11.10 (i.e., donor) mice into syngeneic, nontransgenic BALB/c (i.e., recipient) mice. Before adoptive transfer, recipient mice were fed for 4 wk AIN93G-type diets that differed only in fat source: lard, low in PUFA, fish oil, rich in (n-3) PUFA, and soybean oil, rich in (n-6) PUFA. One week after transfer, recipient mice were immunized with antigen (i.e., ovalbumin), and expansion of CD4+ T-DO11.10 cells in the spleen and draining lymph nodes (LN) was measured by flow cytometry. Five days postimmunization (p.i.), at the peak of expansion, CD4+ T-DO11.10 cells in the draining LN and spleen were 5- to 10-fold higher than in unimmunized mice, then quickly declined during the contraction phase (i.e., 7 and 10 d p.i.). Recipients fed the (n-6) PUFA rich diet had similar to25% greater in vivo expansion of CD4(+) TDO11-10 cells than lard- and fish oil-fed recipient mice at 5 d p.i. (P < 0.05). However, at 7 and 10 d p.i., CD4(+) TDO11-10 cells in the draining lymph nodes did not differ between groups, nor in the spleen at 5, 7, and 10 d p.i. In summary, we are the first to demonstrate that dietary PUFAs affect antigen-driven expansion of naive CD4(+) T cells in vivo. Surprisingly, (n-3) PUFA consumption did not reduce CD4(+) T-cell expansion.