The immunomodulatory activity of chitosan on bovine mammary epithelial cells

PORPORATTO CARINA; ICELY PAULA A; FELIPE, VERÓNICA; MORGANTE CAROLINA; CORREA, SILVIA G

Buenos Aires

Congreso; 1º Congreso Franco-Argentino de Inmunología. LVIII Reunión Anual de la Sociedad Argentina de Inmunología; 2010

Sociedad Argentina de Inmunología

Staphylococcus aureus is an important cause of udder infections in dairy herds, affecting both the quality and quantity of milk production. Bovine mammary epithelial cells (bMEC) contribute to the innate immune response to intramammary infections. An effective strategy to prevent S. aureus infection could be to block bacterial adhesion to bMEC and promote the innate immune response by the epithelium. Chitosan (Ch) is an acetylglucosamine polysaccharide obtained from deacetylated chitin and one of the most abundant polymers in nature. It presents antibacterial effects and ability to modulate the immune response. Herein we studied the modulatory activity of the polysaccharide in bMEC. We evaluated the ability to modify the adherence and internalization of V329 S. aureus strain in bMEC, using the MACT cell line. MACT cells were incubated in the presence of increasing concentrations of Ch (0.01 to 100 ug/ml) for 24 h. The adherence of V329 to the MACT decreased by 80% in presence of 10 ug/ml Ch (CFU count, p<0.05). The V329-FITC internalization showed a reduced percentage after Ch pre-treatment in a dose dependent manner (34 to 61% of inhibition, flow cytometry (FC), p<0.05). Alternatively, we evaluated the effect of Ch in the epithelial innate immune response. We studied the response of V329 infected MACT cells after treatment with 10 ug/ml Ch. We observed an increase in the epithelial MHC-II expression (2.5% vs. 13.6%) and IL-1b production (4.0% vs 15.1%) after stimulation with Ch (FC). In addition, we observed an increase in mRNA expression of IL8, TNFa and CCL2 evaluated by RT-PCR (p<0.05). Also, the mRNA of TLR2 and TLR4 receptors was up-regulated. Ch inhibits S. aureus internalization and adherence, and stimulates an inflammatory response by bMEC. These data suggest that Ch might be useful in the control of bovine mastitis and epithelial bacterial infection.