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From the Antitoxin and Vaccine Laboratory of the Massachusetts Department of Public Health
Abstract
A flocculative test for the titration of hemolytic-streptococcal toxins and antitoxins has been developed which is comparable to the Ramon method for titrating diphtherial toxins and antitoxins. The technic employed in flocculation is essentially that of the Ramon test.
Concentrated toxins, prepared by the method described, are preferable to crude toxins because they flocculate with greater rapidity.
One unit of antitoxin will combine in the flocculative reaction with 60,000 STD of toxin instead of with the 50 STD to be expected on the basis of the definition of an in vivo unit of antitoxin. This relationship has been true of all toxins tested except those modified by formalin.
Streptococcal toxins and antitoxins display individual variations in their flocculating time and are influenced by the same factors as diphtherial toxins and antitoxins.
The flocculating antibody is produced in horses in amounts which parallel the antibody produced against the erythrogenic toxin. It is at least possible that the two antibodies are identical. The average of the in vivo/in vitro ratios was found to be 0.963. The correlation-coefficient of the values obtained by the flocculative test and by the intracutaneous test in rabbits was 0.947 ± 0.023.
The Dochez NY 5 strain of hemolytic streptococcus was used as the basis for this study although flocculation was produced with other strains of hemolytic streptococci and their homologous antitoxins. The question of multiplicity of streptococcus-toxins is not dealt with in this report.
Footnotes
1 Papers I–IV of this series appeared in the Jour. Immunol., 1936, 28: 31–54.
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