Transfer of Immunity against Strongyloides ratti (Nematoda) Using Immune Spleen Cells

cause all lanes contained antigens of epimastigotes that could be contaminated with antigens of the medium used to grow these organisms a further control was performed in which lanes with epimastigote medium were reacted with each of the antisera employed. No bands were noted in this control. These results are of interest particularly when the 90and 72-kd antigens are considered. The observation that the 90-kd antigen has been shown to be protective (Snary, 1983, loc. cit.), and our results, which reveal that antibodies to this antigen were present in the sera of rabbits injected with live epimastigotes and absent in sera of rabbits immunized with formalin-killed organisms of this stage, suggest that the antigen was apparently inactivated or destroyed by formalinization or was in such low concentration that it did not induce a sufficient antibody response. This might explain why immunization with formalin-killed organisms is far less effective in inducing resistance than immunization with live organisms (Brener, 1980, loc. cit.). Antibodies to the 72-kd antigen were not produced following immunization with killed amastigotes, but antibodies to the 90-kd antigen were. This confirms previous reports that this stage lacks the 72-kd but expresses the 90-kd antigen (Snary ause all anes contai ed antige s of epimastiotes that could be contamin ted wi h antigens the medium used to grow these organisms a rther control was performed in which lanes ith epimastigote m dium were react d with each the antisera employed. No bands were noted et al., 1981, loc. cit.). However, the 90-kd antigen in the amastigote was not affected by treatment with formalin. This suggests that in the amastigote, this antigen is either resistant to or protected against the inactivating capacity of formalin, whereas in the epimastigote, it may be located in a region of the cell membrane, or it is in a form that makes it more susceptible to inactivation by formalin. Infection with blood-form trypomastigotes resulted in formation of antibodies that recognized both the 90and 72-kd antigens of epimastigotes (Lanes 4). This indicates that, contrary to previous reports (Snary et al., 1981, loc. cit.; Nogueira et al., 1981, loc. cit.), either the blood-form trypomastigotes also express the 72-kd antigen, or a stage expressing this epimastigote antigen is present in the vertebrate host. The fact that only immunization with amastigotes resulted in antibodies that clearly and strongly recognized a number of antigens of epimastigotes located between the 21.5and 14.4kd markers is interesting. It may be that these antigens are in a highly immunogenic form in the amastigote; whereas in the epimastigote, they are poorly immunogenic. Supported by the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases and NIH Grant Al 18794. i