Several theophylline derivatives were examined for effect against the toxicity of Clostridium botulinum type A. Mice were injected intraperitoneally with a mixture of 1.0ml (3.1×105 LD50/mgN) of toxin and 2.5mg of theophylline. The amounts (from 2.5 to 3.5mg/ml) of theophylline and theobromine offered 100 percent protection to mice against the toxicity of 3.1×105LD50/mgN, but those of caffeine, aminophylline, diprophylline, or proxyphylline did not.
Previously, it was repoted that a definite cross-reaction was observed in the serological reaction between M. tuberculosis (AOYAMA) and C. diphtheriae (P.W. 8). In order to obtain further evidence for the existence of cross-reacting antigen between M. tuberculosis (AOYAMA B) and C. equi (Ko-85), experiments were carrid out by means of passive hemagglutination, conditioned hemolysis, Ouchterlony technique, and skin test with fractions TA2 and CP, which were Presumed to be protein in nature, as antigens. Fraction TA2 was prepared from old tuberculin, and fraction CP from C. equi (Ko-85) by a similar technique. The absorption test was performed with anti-M. tuberculosis and anti-C. equi rabbit sera with results similar to those reported previously. The Ouchterlony double diffution technique was carried out with anti-M. tuberculosis and anti-C. equi rabbit sera and with fractions TA2 and CP as antigens. It gave rise to a clear reaction of identity in each case. Guinea pigs immunized with cells of M. tuberculosis or C. equi showed a clear cross-reaction in the Arthus reaction induced by bacterial antigen. These results may indicate the presence of antigens causing a cross-reaction between fractions TA2 and CP.