Conjugated linoleic acid enhances intestinal mucosal innate immunity against parasite Giardia lamblia in a murine model

Abstract

Introduction: Giardia lamblia, a protozoan intestinal parasite is able to evade or suppress defense mechanisms, such as innate response. Antigen presenting cells (APC) like dendritic cells may orchestrate an immune response and support a more effective adaptive defense. Conjugated linoleic acid (CLA), a dietary lipid, has shown biological activity on APC. The aim was to evaluate the effect of CLA in intestinal innate response measuring the frequency of mucosal APC populations in Giardia lamblia murine infection.Method: The giardiasis infection model was established in C3H/HeN mice (n=32), and parasite load was followed at 0, 2, 6 and 8 days post infection (dpi). APC obtained from small intestine by enzymatic digestion were assessed by flow cytometry. Oral supplementation with CLA (50:50 of cis-9, trans-11-CLA and trans-10, cis-12-CLA isomers) and placebo control begun three days before infection and continued during first week post infection.Results: Infection kinetics showed a peak of trophozoites at 6 dpi in acute phase. Parasite load was lower in CLA group in comparison with control infected group (p<0.05). Conjugated linoleic acid stimulates innate immune response, percentage of intestinal CD11chiMHC-IIhi increases after 2 dpi, meanwhile CD11chiMHC-IIhiCD103+ APC was higher after three days of CLA supplementation than control (p<0.05). Also, the CD11c+ F4/80+ population shown a percentage increases after 6 and 8 dpi by the effect of treatment and time of infection (p<0.05).Conclusion: In conclusion CLA increased percentages of small intestine APC phenotypes CD11chiMHCIIhi, CD11chiMHCIIhiCD103+ and CD11c+ F4/80+, and reduced G. lamblia parasitic load. Further studies are needed to elucidate potential mechanisms involved in CLA immunomodulatory effect and its contribution in adaptive immune response.