Administration of Lacticaseibacillus paracasei subsp. paracasei CRL75 modulates humoral and cytokine production during food allergy

Abstract

In general, food allergies are not exclusive to one type of food, but rather many of them have cross-reactions with other foods and/or pollen. Some examples of allergenic foods are shellfish, fish, eggs, soy, peanuts, strawberries, and cow's milk, among others. On the other hand, lactic acid bacteria (LAB) have been demonstrated to be useful in improving immune responses in many different diseases. Their beneficial effect on consumer health is widely reported, as their ability to release and/or produce specific compounds (nutraceuticals) with positive outcomes for the human or animal host. Many exopolysaccharides (EPS) produced by beneficial LAB are powerful immunomodulatory molecules. Previously, it was demonstrated that Lacticaseibacillus (L.) paracasei subsp. paracasei CRL75 has a potent immunostimulatory effect and produces functional EPS. The aim was to evaluate the ability of L. paracasei CRL75 to modulate the immune response during food allergy induction by regulating the humoral immune response and related cytokines. The immunomodulatory capacity of L. paracasei CRL75 was evaluated in vivo in an OVA-induced intestinal allergy mouse model. Six-week-old BALB/c mice were divided into 3 groups: a) Control (C): non-sensitized animals received a conventional balanced diet and water ad libitum; b) OVA: animals sensitized to OVA by bi-weekly intraperitoneal injection; c) L. paracasei CRL75 (CRL75): OVA-sensitized animals supplemented with L. paracasei CRL75 in drinking water simultaneously to OVA challenge. Two weeks after second injection, the intestinal allergy was induced by feeding an egg white diet for 7 days. Samples were obtained to evaluate: a) cytokines: IL-4, IL-10, IFN-γ, TNF-α, and IL-6; b) OVA-specific antibodies (OD450nm): IgE, IgG, IgG1, and IgG2a; c) bacterial translocation to the liver and spleen. Results demonstrated that administration of L. paracasei CRL75 induced the production of IL-10 (pg/ml, C: 89.18±8.11; OVA: 176.3±18.7; CRL75: 371.99±25.49, p<0.0001) and IFN-γ, with a significant decrease in IL-4 levels (pg/ml, C: 71.43±18.1, OVA: 941±94.77; CRL75: 545.49±66.92, p<0.0001). Regarding humoral response, L. paracasei CRL75 induced a significant decrease of OVA-specific IgE levels in serum (OD450nm, C: 0.064±0.017; OVA: 0.717±0.085; CRL75: 0.449±0.085, p<0.001), but increased OVA-specific IgG1 and IgG2a compared to the OVA group. No bacterial translocation was detected in any experimental group. In conclusion, L. parcasei CRL75 is able to regulate the allergic immune response when administered simultaneously with allergy induction. L. paracasei CRL75 developed a Th-1 response, decreasing Th-2 response, with reduced levels of OVA-specific IgE and IL-4. L. paracasei CRL75 constitutes a promising option for designing functional foods with beneficial effects on food allergies.