Effect of lipoarabinomannan from Mycobacterium avium subsp avium in Freund’s incomplete adjuvant on the immune response of cattle

The aim of the present study was to determine whether lipoarabinomannan (LAM), in combination with Freund’s incomplete adjuvant (FIA), was able to improve cell-mediated and antibody-mediated immune responses against ovalbumin (OVA) in cattle. Twenty-three calves were assigned to four treatment groups, which were subcutaneously immunized with either OVA plus FIA, OVA plus FIA and LAM from Mycobacterium avium subsp avium, FIA plus LAM, or FIA alone. Lymphoproliferation, IFN-γ production and cell subpopulations on peripheral blood mononuclear cells before and 15 days after treatment were evaluated. Delayed hypersensitivity was evaluated on day 57. Specific humoral immune response was measured by ELISA. Inoculation with LAM induced higher levels of lymphoproliferation and IFN-γ production in response to ConA and OVA (P < 0.05). Specific antibody titers were similar in both OVA-immunized groups. Interestingly, our results showed that the use of LAM in vaccine preparations improved specific cell immune response evaluated by lymphoproliferation and IFN-γ production by at least 50 and 25 percent, respectively, in cattle without interfering with tuberculosis and paratuberculosis diagnosis.

Leptospira interrogans serovar Pomona: detección de diferencias antigenicas entre tres aislamientos regionales de bovinos y una cepa de referencia / Leptospira interrogans serovar Pomona: detection of antigenic differences among 3 regional isolates from cattle and a reference strain

Leptospirosis is a zoonosis caused by Leptospira interrogans. This disease is diagnosed by quantification of specific immunoglobulins in serum by the microagglutination test (MAT). The aims of this research were: a) to compare the protein profiles of 3 clinical isolates of bovine leptospirosis with the reference strain used for the MAT, and b) to identify the immunodomain antigens of the regional isolates through PAGE and immunoblotting techniques of bovine sera from infected, vaccinated and MAT-negative animals. Coomassie-blue stained gels revealed extensive protein similarities between pathogenic and reference strain. Most infected (8/10) and vaccinated animal sera (4/7) showed by immunoblotting a similar reactivity against the proteins from pathogenic leptospires, with a strong band of 25-30 kDa which was not detected in the reference strain. The lack of correlation between MAT and immunoblotting techniques for infected animals could be due either to the infection stage at which the diagnosis was made or to the immunoglobulin isotype involved in the response. Results obtained would confirm the antigenic differences between the 3 isolates and the reference strain.