We have undertaken a clinical and immunologic study involving the antitoxin immunity actively induced and passively conferred in well and in ill children, based on the fact recently demonstrated by Merritt Roberts 1 that endotoxin and exotoxin of Hemophilus pertussis are identical and on the fact previously demonstrated that this toxin is antigenic. Bordet and Gengou2 extracted a toxic substance from H. pertussis by grind-ing the organisms. They did not demonstrate its antigenicity and termed it endotoxin. Other investigators, notably Tessier and his co-workers,3 Lawson 4 and Roberts,1 demonstrated that such extracts were antigenic. Subsequently washings from whole organisms and broth mediums in which the organisms had grown were found by Evans 5 and Mishulow 6 to be toxic and to produce antitoxins. Mishulow and later Koplik 7 demonstrated, by the Shwartzman phenomenon, a toxin in some cultures of H. pertussis. Sprunt8 produced identical pneumonic lesions by intratracheal injections of bacilli (living and dead) and of toxin in normal mice, rabbits and monkeys which were prevented by anti¬ toxin. Merritt Roberts recently offered evidence to show that the toxic filtrate or endotoxin and exotoxin were identical and that the two produced a neutralizing antitoxin. The exotoxin obtained in broth cultures and the endotoxin from bacterial extracts have been shown to be identical in four respects : heat stability. lethal power in mice, necrotizing effect on the skin of rabbits and the specific reactivity with pertussis anti¬ toxin. Both are capable of antibody production.These studies were conducted mainly in the wards of the Willard Parker Hospital with the assistance of the resident physicians, on siblings of patients admitted there, and at the Central Harlem Health Center.
ACTIVE IMMUNIZATION WITH TOXOID PROPHYLAXISOne hundred and thirty-five unselected children living at home were given prophylactic injections. One hun-ANTITOXIN TITRE AGE.. Chart 1.-Antigen titer of children given injections of 300 units of pertussis toxin per cubic centimeter of antigen. The total dose is 6 to 8 cc. in four weekly injections. Titer increased, 22 children (68.75 per cent); titer unchanged, 6 children (18.75 per cent; 3 had temporary increase); titer decreased, 4 children (12.5 per cent). Among children under 1 year titer increased in 8, was unchanged in 1 and decreased in 1. In charts 1-4 and in chart 7 the black dot indicates initial and final titer in each case; dashes, initial titer unobtained; white dot, average change; caret pointing to left, less than 0.3; arrow pointing up, vaccine administration or antigen administration, as the case may be. Y, years; M, months.
