1994 Volume 4 Issue 3 Pages 98-104
Cross reactivity of Babesia rodhaini (B. rodhaini) and Babesia microti (B. microti) antigens against Babesia-chronically infected mice sera was examined using indirect fluorescent antibody (IFA) technique and westernblotting. The effect of monoclonal antibody #7 (mAb #7), which recognized both B. microti and B. rodhaini antigens, was also studied against Babesia-infections. Passive immunization with mAb #7 was carried out to clarify the relationship between cross-reactive antigens and progression of Babesia infection. Results of IFA assay showed cross reactivity in B. microti and B. rodhaini antisera at a dilutions of 1:512 and 1:128, respectively. Each type of antiserum exhibited parasite specific fluorescence. Immunoblotting demonstrated the reactivity of B. microti and B. rodhaini antisera with the 70 and 32 kilodaltons (kDa) B. rodhaini antigens, and with the 70 kDa B. microti antigen, respectively. These results suggest a stronger cross reactivity of B. microti antiserum compared to B. rodhaini antiserum. Monoclonal antibody #7 reacted with 70 and 30 kDa antigens of B. microti, and with 70 and 32 kDa antigens of B. rodhaini. Passive immunization using mAb #7 showed a delayed development in high levels of parasitemia in both Babesia spp., compared to the control groups. These results demonstrate the apparent role of mAb #7 in suppressing the onset of parasitemia.