Effects of high fat diets on the immune responses of Peyer's patch-immunized rats

Abstract

Effects of dietary high fats on the imune responses of thoracic duct lymphocytes were investigated by comparing with phagocytic activity of alveolar macrophages (Mø) in rats immunized by intra-Peyer's patch injection of keyhole lympet hemocyanin (KLH). The oils used in this experiment were rich in either saturated fatty acid (SFA, lard oil) or polyunsaturated fatty acid (PUFA, perilla seed oil). When stimulated with mitogens (PHA, Con A and LPS), blastogenesis of thoracic duct lymphocytes was significantly greater in KLH-immunized group than saline- treated one. Degree of the enhanced response to these mitogens was much more in rats fed high PUFA diet than high SFA diet. Number of IgA-antibody presenting cells in thoracic duct lymph was increased following immunization of the Peyer's patches with KLH in rats fed PUFA diet than SFA diet. Phagocytic activity of alveolar Mø was enhanced in KLH-treated rats compared to saline-treated rats, and then after stimulation with Mø-activating factor, their activity was further increased in high PUFA diet group than in high SFA diet one. These results suggest that high-dietary PUFA in Peyer's patchimmunized rats is capable of more increasing the immune responses of thoracic duct lymphocytes and sequentially of enhancing phagocytic activity of alveolar Mø compared to high SFA.