Probiotic Properties and Immunomodulatory Activity of Lactobacillus Strains Isolated from Dairy Products

Abstract

<i>Lactobacilli</i> species are an effective biotherapeutic alternative against bacterial infections and intestinal inflammatory disorders. However, it is important to evaluate their beneficial properties, before considering them as probiotics for medical use. In this study we evaluated some probiotic properties of <i>Lactobacillus rhamnosus</i> GG, <i>Lactobacillus rhamnosus</i> KLSD, <i>Lactobacillus helveticus</i> IMAU70129, and <i>Lactobacillus casei</i> IMAU60214 previously isolated from dairy products and as control <i>Lactobacillus casei</i> Shirota. Experimental evaluations revealed that all strains expressed hydrophobicity (25-40%), auto-aggregation (55-60%), NaCl tolerance (1-4%), adhesion to Caco-2 cells (25-33%), partial inhibition on adherence of <i>Escherichia coli</i> ATCC 35218, <i>Salmonella</i> Typhimurium ATCC 14028, and <i>Staphylococcus aureus</i> ATCC 23219. Cell-free supernatants (CFS) of <i>Lactobacilli</i> also inhibit growth of these pathogens. In immunomodulatory properties a reduction of interleukin-8 (IL-8) and nitric oxide (NO) release was observed in assays with Caco-2 cells stimulated with interleukin-1β (1 ng/mL), or lipopolysaccharide (0.1 µg/mL). On the other hand, the damage induced to Caco-2 cells with sodium dodecyl sulfate (SDS) was attenuated when the cultured cells were pretreated with <i>L. rhamnosus</i> KLDS, <i>L. helveticus</i> IMAU70129 and <i>L. casei</i> IMAU60214. These <i>Lactobacilli</i> possess probiotic properties determined by both an antagonistic activity on pathogenic bacteria and reduction in the inflammatory response of cells treated with SDS, a pro-inflammatory stimulant.