A splenectomized cattle was expetimentallv infected with Babesia bigemina (Bb) isolated in Taiwan. The infected cattle was bled for Bb collection when the concentration of B in blood was counted to be l03 to 10’4 ml at 4- das post infection (P1). The red cells from the half vohmie of blood obtained from infected cattle were lysed. The Bbs were concentrated and were frozen and thawed for their inactivation. Eventraily. the anactiveated nimunoen (c°) was prepared by adding DEAE-.dextran into that Bb preparation. An activated immunogen (Al) was prepared from the rest part of blood by concentrating and mixing it with phosphate buffer saline containing glucose and calf serum
An attempt to evaluate their safety and iimnunogenecitv of both immunogens described above was made on 2groups of cattle. The C° was used to immunize both groups of cattle in farms with and without Bb contamination, so was th AL The results showed that some cattle without Bb contamination produced a complement fixation antibody (CF Ab) titer of around xl at 2 weeks P1 with c°. The CF Ab titer was increasing up to x4 to xS at 4 weeks Pt and dropping down to nil at 12 weeks P1. However-, the CF Ab in the cattle with Bb contamination was found to be not evident following the inoculation of cattle with c°
When the cattle was immunized with A!. different results were obtained.
The Cf Ab response in cattle without Bb contaminatin was detectatable at 2 weeks P1 and the highest titer was detected at S weeks P1. A CF A1 titer of X4 was still detectable at 20 weeks P1. On the other hand. the production of CF At, in cattle with Bb contamination could be detected until 8th week P1 The CF Ab titer in cattle with Bb centarnination were not fluctuate in the comparison to that in cattle without Bb centamination were not fluctuate in the comparison to that in cattle without Bb contamination.
Most of cattle inoculated with Al did not show any abrionnal response with the exception of a few cattle that revealed fever. Generally. parasiteinia was found at 2 weeks P1. It’s peak was detected at 4 weeks P1 and parasite (Bb)was found disapparentlv. On the basis of these results. It would be suggested that the immunogens prepared in this study are safe and their immunogenecity is highly evident Furthermore. the Al can strongly induce Ab response in cattle.