Studies in immunity to tetanus bacilli

So much emphasis has been placed on the part played by antitoxin in immunity that when we found this antibody in the sera of guinea pigs carrying tetanus bacilli in their intestinal tract, we assumed that those animals would be immune to all types of this organism. We felt all the more secure in this assumption since Tulloch 1 has shown that the toxin produced by one type of tetanus is the same as that produced by any of the other types in that they are all neutralized by one antitoxin. When put to a test we found that this assumption is not entirely correct, as is shown by the results outlined below.

We were not satisfied with the methods used by others for the production of tetanus as the incubation period was too short and the animals usually died within two or three days after inoculation. After considerable search we have adopted aleuronot as an irritating agent, when injected with a small number of spores, as symptoms appear on the fifth day, and death follows on the seventh or eighth day after inoculation.

All control animals as well as those used for testing the protective power of sera were bled, and their serum was shown to be free from antitoxin. In addition cultures of their feces were negative for tetanus-like bacilli.

As has already been pointed out 2 guinea pigs that carry one type of tetanus bacilli for about five months show appreciable amounts of antitoxin in their sera. When tested it is found that these animals are immune only to the type of bacilli which they are carrying. When injected with any other types they die in the same length of time as the controls.