Bouamama, S.

Background: Both dietary factors and biological sex are recognized as key modulators of immune responses. Nutritional components, particularly lipids, can influence immune cell metabolism, signaling pathways, and the balance between pro- and anti-inflammatory processes. Objective: The present study aimed to examine whether commonly consumed dietary oils exert sex-specific effects on immune cell function and cellular oxidative balance. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from 16 healthy adults (10 men and 6 women; mean age 48 years, BMI 23 kg/m2) using Histopaque density gradient centrifugation. Cells were cultured in RPMI-1640 medium and stimulated with concanavalin A (Con A) in the presence of olive, Nigella sativa, or walnut oils (23 micro g/mL) for 48 h. Cell proliferation was assessed using the MTT assay. Intracellular malondialdehyde (MDA), protein carbonyls (PCAR), and reduced glutathione (GSH) were determined by spectrophotometric methods. All statistical analyses were performed by Minitab 16 statistical software and Microsoft Excel 2007. Differences between groups were performed by Wilcoxon ranked test Results: Baseline proliferation, MDA, and PCAR levels were comparable between sexes, whereas GSH levels were higher in male PBMCs. Oil supplementation significantly reduced proliferation in male cells compared to female cells (p = 0.008). In female PBMCs, olive oil significantly increased MDA levels, while all tested oils increased protein carbonyl levels. Walnut and olive oils selectively enhanced GSH levels in female cells. Conclusion: Dietary oils modulate immune cell proliferation and oxidative balance in a sex-dependent manner. Female PBMCs appear more susceptible to lipid-induced oxidative stress, highlighting the importance of considering sex in nutritional immunology. Keywords: PBMCs, oxidative stress, dietary oils, sex differences, fatty acids, immunity.