Comparison of immune response induced by Brucella abortus S-19 vaccine and B. abortus S-99 outer membrane proteins

Brucellosis, an important bacterial zoonosis has direct public health and economic implications. The development of an effective sub-cellular vaccine devoid of S-LPS is considered an effective tool to manage these problems. This study was conducted to determine immunogenicity of outer membrane proteins (OMPs) of Brucella abortus S-99 and to compare this with that generated through B. abortus S-19 vaccine in rabbits. Brucella abortus S-99 culture was used for extraction of OMPs. In Sodium deodecyl polyacrylamide gel electrophoresis (SDS-PAGE) 5 polypeptide bands of MW 45, 25.2, 12.6, 10 and 8 kDa, respectively, were resolved by SDS-PAGE. Rabbits were tested for their Brucella free status through RBPT and STAT before subjecting them to trials. The animals were divided into three groups (A, B and C) as S-19 vaccine, OMP and control groups, respectively. Immune responses were recorded earlier in OMP inoculated animals than S-19 vaccinated animals. Immune responses were recorded earlier in OMP inoculated animals than S-19 vaccinated animals. Response of S-19 vaccinated group as measured by STAT was less intense. It can be suggested that an optimum number of the S-19 vaccine cells (adequate dose) are required to initiate a good immune response and booster dosing is not necessary. On the basis of RBPT, SAT and 2-MET results that indicated some maintainability of titers, it can be concluded that OMP-LPS immune response might be more IgM directed. It can also be suggested that sub-cellular antigens that include OMPs and SLPS, could in substantial measure induce immune response comparable to live cells.