Safety evaluation of Q fever vaccine of Coxiella burnetii treated with chloroform-methanol.

To evaluate the safety of Q fever vaccine developed with a Chinese isolate of Coxiella burnetii treated with chloroform-methanol(CMRV).three batches of CMRV and the whole cells vaccine of Coxiella burnetii inactivated with formalin(WCV)were used to sensitize guinea pigs,respectively and the sensitized animals were intradermally inoculated with the homologous vaccine for the skin tests 4 weeks post sensitization.No significant difference in the sizes of inflamed skin was found between CMRV-and WCV-sensitized guinea pigs 1~6 days post inoculation.However,the sizes of inflamed skin of WCV-sensitized guinea pigs were markedly larger than that of CMRV-sensitized guinea pigs 7 days post inoculation.On 14 days inoculation,the skin samples of inoculating sits were collected for pathological examination.For CMRV-sensitized guinea pigs,the skin tissues were almost normal for most of the animals and only focal degeneration was found in a few of these animals under microscopy.Nevertheless,the serious pathological alteration,including focal degeneration and necrosis and a large amount of inflammatory cell infiltration,was found in the skin tissues of WCV-sensitized guinea pigs.The pathological alterations of CMRV-sensitized animals inoculated with any of the three batches of CMRV were significantly weaker than that of WCV-sensitized animals inoculated with WCV.The results demonstrate that the adverse reaction of CMRV developed with the Chinese isolate of C.burnetii is markedly lighter than that of WCV and it is much better than WCV in safety.