Cell mediated immune response in sheep vaccinated with Brucella melitensis Rev. 1*

Abstract

The cell mediated immune (CMI) response of the sheep vaccinated with Brucella melitensis Rev. 1 was studied by measuring the lymphocyte proliferation and estimation of hydrogen peroxide (H2O2) and nitric oxide (NO) from monocyte derived macrophages from control as well as Rev. 1 vaccinated sheep. Three sheep were inoculated with B. melitensis Rev. 1 (109 CFU) while sterile PBS was given to control sheep. Peripheral blood monocytes were separated at defined interval (0 to 98 days post-vaccination) and cultured in 96 wells tissue culture plates for 48 h with different concentrations of B. melitensis 16 M soluble antigens (BmSA). The lymphoproliferation was estimated with 3-(4,5-dimethyl thiozol-2yl)-2,5 diphenyl tetrazolium bromide (MTT) colorimetric method. A significantly higher stimulation index (SI) in vaccinated as compared to control sheep from 14th to 84th day post-vaccination was observed. The H2O2 and NO productions by the monocyte-derived macrophages from the vaccinated and control sheep were also estimated. All through the study period, both H2O2 and NO production were significantly higher in vaccinated than in control sheep. The study revealed that vaccination stimulates significant CMI response in sheep as indicated by higher proliferation of the lymphocytes and increased production of H2O2 as well as NO by the macrophages.