Abstract

Fatty acids are essential components of the membranes of immune cells and are required for the growth and maintenance of these cells. Animal and human studies showed that increasing the amount of n-3 polyunsaturated fatty acids in the diet can modulate different lymphocyte functions. The objective of the present study was to determine the in vivo and ex vivo effects of eicosapentaenoic acid-28 (EPA-28) treatment on the status and function of different immune cells of mice. Female C3H/he mice were subcutaneously injected with 50 μl of EPA-28 (14 mg/injection) twice a week for 2 weeks. The results showed that EPA-28 treatment elicited a significant increase in the total number of spleen cells including an increase in the % of both macrophages (MΦ) and natural killer (NK) cells and a decrease in the percentages of both CD8 T cells and B cells. After stimulation with thioglycolate, EPA-28 treatment elicited a significant increase in the total number of peritoneal exudates cells (PECs) including an increase in the percentages of both granulocytes (Gr+) and immature MΦ and a decrease in the percentage of mature MΦ. Stimulation with thioglycolate also increased the total number of spleen cells of EPA-28 treated mice with a significant increase in the % of both Gr+ and immature MΦ and a significant decrease in the % of both mature MΦ and NK cells. Ex vivo studies showed that spleen cell proliferation from EPA-28 treated mice decreased significantly after incubation with either concanavalin A (Con A) or lipopolysccharide (LPS) mitogens. By analyzing the suppressor cell activity as well as mixed lymphocyte reaction of both PECs and spleen cells from EPA-28 treated mice, the results showed a significant inhibitory effects on blastogenic responses. These effects are important when considering the treatment of patients with chronic inflammatory diseases as well as immunosuppressed patients and those with autoimmune conditions. Therefore, the importance of n-3 PUFAs for both the immune and inflammatory systems cannot overlook and should employed in our clinical practice with this understanding.

Key words: Eicosapentaenoic acid-28 – MΦ – T cell – B cell – NK cell – Con A – LPS – Suppressor activity