Immunomodulatory properties of conjugated linoleic acid

Abstract

In vitro studies of the use of immune cells and animal models demonstrate that conjugated linoleic acid (CLA), a lipid, modulates immune function. In addition, recent publications demonstrate that 2 active CLA isomers (ie, cis-9,trans-11 CLA and trans-10,cis-12 CLA) modulate immune function in humans. Aspects of both the innate and adaptive immune responses are affected by dietary CLA supplementation. CLA consists of a mixture of isomers, which reduced immune-induced wasting and enhanced ex vivo lymphocyte proliferation in broilers and decreased tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) production in rat models. In mice, ex vivo lymphocyte proliferation and IL-2 production were increased. Furthermore, evidence suggests that the cis-9,trans-11 and trans-10,cis-12 CLA isomers exert distinct effects on immune function. Specifically, these 2 isomers have differential effects on specific T cell populations and immunoglobulin subclasses in animal and human studies. Herein, a systematic review of the literature and relevant new data are presented with an aim to compare data and to present an overview covering the innate and adaptive components of the immune response that are regulated by CLA. In addition, potential mechanisms of action are discussed and the need for future studies on the immunomodulatory properties of CLA are outlined in detail. The understanding of the mechanism(s) by which CLA increases immune function will aid in the development of nutritionally based therapeutic applications to augment host resistance against infectious diseases and to treat immune imbalances, which result in inflammatory disorders, allergic reactions, or both.

The fatty acid composition of longissimus <i>lumborum</i> muscle of suckling and earlyweaned dual-purpose wool/meat lambs

“…This isomer is the most biologically active conjugated linoleic acids isomer and has positive effect on preventing cancer, cardiovascular disease, diabetes and immune system (Pariza et al 2001, Lock et al 2004, O'Shea et al 2004, Terpstra 2004). …”

Biological effects of conjugated linoleic acids supplementation

“…The latter has been implied in inflammatory bowel disease (O'Shea et al 2004, Bassaganya-Riera and Hontecillas 2010). Linoleic acid and cis-9, trans-11 CLA isomer had no detectable effects on lipopolysaccharide (LPS)-induced TNF alpha production in cultured bovine blood.…”

“…It has been reported that CLA up-regulates the humoral function by increased IgG, IgM and IgA production of spleen lymphocytes in a dose -dependent manner and reduces macrophage function by decreasing synthesis of inflammatory mediators and/or inflammatory enzymes (O'Shea et al 2004). CLA also reduces IgE (as well as PGE2 and IL-12) which plays a crucial role in type-I allergic reactions (Sugano et al 1998).…”

“…CLA decreases the innate immune response by diminishing the activity of monocytes, macrophages and natural killers cells and lowering prostaglandins and leucotriens production (O'Shea et al 2004). CLA dietary supplementation also improves antigen-specific adaptive immune response to viral and bacterial antigens.…”

Effects of dietary conjugated linoleic acids on cellular immune response of piglets after cyclosporin A injection

“…CLA has many important properties that regulate physiological and metabolic responses, for example, immune modulation, anti-cancer effects, prevention of cardiovascular disease and diabetes, and weight control (Ip et al, 1991;Houseknecht et al, 1998;Islam et al, 2010;Eftekhari et al, 2013;Kim et al, 2013). In animal production, studies on the effects of CLA on immune function have thus far been conducted in the normal physiological status or inflammatory challenge status (O'Shea et al, 2004;Lai et al, 2005;Zhang et al, 2005;Renner et al, 2012).…”