The treatment of mice with Lactobacillus casei induces protection against Babesia microti infection

Abstract

In this study, we report that administration of Lactobacillus casei confers protection to mice against the intracellular protozoan Babesia microti. Mice treated with L. casei orally or intraperitoneally were inoculated 7 days later with an infectious dose of B. microti. Mice treated with lactobacilli showed significant reduction in the percentage of parasitized erythrocytes (PPE) compared to untreated mice. When mice were inoculated intraperitoneally with L. casei 3 or 0 days before challenge with B. microti, the PPE was significantly lower compared to untreated mice and there were no differences between treated mice and mice immune to B. microti infection. When mice treated with live or dead L. casei were compared to mice inoculated with Freund Complete Adjuvant before a B. microti infection, a significant reduction of PPE was observed. These results show the protective effect of L. casei administered to mice against a B. microti infection and suggest that it might act by stimulating the innate immune system.

Co-immunization of cattle with a vaccine against babesiosis and Lactobacillus casei increases specific IgG1 levels to Babesia bovis and B. bigemina

“…It is important to note that bovines immunized with VAC-LC do not show the clinical signs observed in cattle inoculated with VAC after vaccination [19,20]; however, the underlying mechanism responsible for this protection is not known. The only evidence we have is the recorded level of total IgG anti-Babesia [21], which is higher in animals treated with VAC and L. casei than in bovines immunized with VAC [18,19]. To date, there are no published studies on the levels of IgG1 and IgG2 against Babesia in bovines immunized with VAC or VAC and L. casei.…”

“…On the other hand, the use of the immunostimulant lactic-acid bacteria Lactobacillus casei as an alternative control measure of distinct parasitic diseases has been proposed [17]. In this context, it was demonstrated that L. casei, by itself, induces protective responses against Babesia microti in mice when inoculated before or the same day of the challenge infection [18] and against B. bovis and B. bigemina in cattle when the lactic-acid bacteria is administered with VAC under laboratory controlled conditions [19] and in extreme natural field conditions [20]. It is important to note that bovines immunized with VAC-LC do not show the clinical signs observed in cattle inoculated with VAC after vaccination [19,20]; however, the underlying mechanism responsible for this protection is not known.…”

Probiotics for the Control of Parasites: An Overview

“…Oral or intraperitoneal treatments of L. casei ATCC 7469 in Babesia microti (Gray strain) infected mice significantly reduced parasitemia, potentially through a stimulation of the innate immune system [56]. The protective response was improved when the lactobacilli were administered 3 days before or on the same day of parasite infection versus 7 days before.…”

Enhancement of the Mexican Bovine Babesiosis Vaccine Efficacy by Using Lactobacillus casei

“…It has been demonstrated that the administration of L. casei to mice also stimulates a protective immune response against a variety of parasites 4 . In recent studies it was demonstrated that mice treated with L. casei and then exposed to B. microti showed a significantly lower parasitemia compared to that observed in control mice, and, after which, the mice showed a solid immunity against reinfection 5 . It is also known that in bovines a protective immune response against B. bovis involves a Th1‐type response with the production of interferon gamma (IFN‐γ), interleukin 12 (IL‐12), nitric oxide, and immunoglobulin G2 6,7 .…”