Immunization of Humans with Alum Precipitated Tetanus Toxoid

Abstract

The toxoid employed in the studies was prepared from a toxin containing 10,000 m.l.d. per cc. The toxoid was precipitated with 2% of potash alum, washed twice with and re-suspended in normal saline solution and preserved with merthiolate in 1:10,000 dilution. The antigenic value of the alum precipitated toxoid was tested on guinea pigs by injecting 1 cc. subcut. 8 weeks after the injection of 1 cc. of the toxoid the pooled serum of the animals contained at least 0.5 units of antitoxin per cc. A group of 33 adults and a boy 10 yrs. old were given a dose of 1.0 cc. of the alum precipitated tetanus toxoid; 25 days later, when the serums of 5 individuals were tested, the serum of 1 person showed no antitoxin, that of the other 4 contained from 1/1000 to 3/1000 of a unit of antitoxin. The development of antitoxin is slow, several mos. being required before appreciable amts. can be detected. The points of special importance in the use of alum precipitated tetanus toxoid are: The induction of an active immunity in 3-6 mos.; the absence of either local or general reactions; and the absence of danger of sensitizing the individual to horse serum proteins such as may occur from repeated prophylactic doses of tetanus antitoxin when used for prophylaxis following injuries.