Plant- and Animal-Derived Dietary Sources of Phosphatidylcholine Have Differential Effects on Immune Function in The Context of A High-Fat Diet in Male Wistar Rats

Phosphatidylcholine (PC) derived from eggs has been shown to beneficially modulate T cell response and intestinal permeability under the context of a high-fat diet. The objective of this study was to determine whether there is a differential effect of plant and animal-derived sources of PC on immune function. Four-week-old male Wistar rats were randomized to consume one of 4 diets (n=10/group) for 12 weeks, all containing 1.5g of total choline/kg of diet but differing in choline forms: 1- Control Low-Fat (CLF, 20% fat, 100% free choline (FC)); 2- Control High-Fat (CHF, 50% fat, 100% FC); 3- High-Fat Egg-derived PC (EPC, 50% fat, 100% Egg-PC); 4- High-Fat Soy-derived PC (SPC, 50% fat, 100% Soy-PC). Immune cell functions and phenotypes were measured in splenocytes by ex vivo cytokine production after mitogen stimulation and flow cytometry, respectively. The SPC diet increased splenocyte IL-2 production after PMA+I stimulation compared to the CHF diet. However, the SPC group had a lower proportion of splenocytes expressing the IL-2 receptor (CD25+, p < 0.05). After PMA+I stimulation, feeding EPC normalized splenocyte production of IL-10 relative to the CLF diet while SPC did not (p < 0.05). In mesenteric lymph node lymphocytes, the SPC diet group produced more IL-2 and TNF-α after PMA+I stimulation than the CHF diet, while the EPC diet group did not. Our results suggest that both egg- and soy-derived PC may attenuate high-fat diet-induced T cell dysfunction. However, egg-PC enhances to a greater extent IL-10, a cytokine involved in promoting the resolution phase of inflammation, while soy-PC appears to elicit a greater effect on gut-associated immune responses.