Expression analysis of cannabinoid receptors 1 and 2 in B cells during pregnancy and their role on cytokine production.

The endocannabinoid system consists in a family of lipids that binds to and activates cannabinoid receptors. There are two receptors so far described, the cannabinoid receptor 1 (CB1) and 2 (CB2). In the context of pregnancy, the endocannabinoid system was shown participates in different key aspects of reproductive events. B-lymphocytes are pleiotropic cells belonging to the adaptive arm of the immune system. Besides immunoglobulin production, B-lymphocytes were recently shown to be actively involved in antigen presentation as well as cytokine production, thus playing a central role in immunity. In this study we first aimed to characterize the expression of CB1 and CB2 receptors in B cells during pregnancy and then analyze the impact of their activation in term of cytokine production by B cells from pregnant and non-pregnant mice. We observed that the expression of CB1 and CB2 receptors in B-lymphocytes is differentially regulated during pregnancy. While CB2 expression is down regulated CB1 is augmented in B-lymphocytes of pregnant mice. Additionally, the treatment of activated B-lymphocytes with specific CB1 and CB2 agonists, showed a different response in term of cytokine production. Particularly, CB1 against boosted the production of the anti-inflammatory cytokine IL-10 by activated B-lymphocytes from pregnant mice.

Identification of protective outer membrane antigens of Brucella ovis by passive immunization of mice with monoclonal antibodies.

Outer membrane proteins (OMPs) and rough lipopolysaccharide (R-LPS), the main surface antigens of Brucella ovis, display surface-exposed epitopes. Mixtures of monoclonal antibodies (mAbs) to both antigens were previously shown to protect mice against a B. ovis challenge. To further identify the antigens involved, seven mAbs against Brucella OMPs (Omp10, Omp16, Omp19, Omp25, Omp31, Omp2b and Omp1) and three to R-LPS were tested for protection either individually or in combinations. Significant reduction in spleen infection in challenged mice, relative to controls, was used as the protection criteri. Controls included nonimmunized mice and mice given an irrelevant, anti-O-polysaccharide (OPS), mAb. For comparison, a group received a mouse serum containing antibodies to both OMPs and R-LPS; this serum was prepared by immunization with a B. ovis hot-saline extract which, as described previously, induces protective immunity in mice and rams. Significant protection was observed with both mAbs to OMPs and R-LPS. mAbs to Omp16, Omp19 and Omp31 afforded the highest protection and prevented the development of splenomegaly. The protective effect of mAb to Omp31 was not interfered with by nonprotective mAbs in different mixtures. The data presented confirm the protective role of antibodies to OMPs and R-LPS against B. ovis, and identify several OMPs, especially Omp31, which are promising candidates for a subunit vaccine against ram epididymitis.

Evaluation of an enzyme-linked immunosorbent assay using recombinant major surface protein 5 for serological diagnosis of bovine anaplasmosis in Venezuela.

An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum antibody responses against MSP5 were detected in calves experimentally infected with A. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. The MSP5 ELISA performed with serum samples taken from field cattle from different regions of Venezuela showed a seroprevalence of 47%, which seems to be in accordance with the reported epidemiological status of bovine anaplasmosis in Venezuela. Positive results obtained in the MSP5 ELISA were further confirmed by immunoblotting, with the recombinant MSP5 as the antigen. Thus, these results confirmed the importance of MSP5 as a suitable antigen for the serological diagnosis of bovine anaplasmosis.