﻿VIII. THE FORMATION OP AGGLUTININS IN PLAGUE 

 IMMUNE SERUM. 



After having concluded from the experiments recited above that true 

 plague vaccination (inoculation with living, attenuated cultures) produced 

 the highest immunity, inoculations were made in human beings with 

 the strain "Pest Avirulent." In order to ascertain if any evidences of 

 immunity could be demonstrated in the inoculated, their blood was 

 tested for the presence of agglutinins, anti-infectious substances and 

 opsonins. This led me to investigate in detail whether, and if so, to 

 what extent, these same anti-bodies existed in the blood sera of animals 

 which had been immunized against plague infection. 



AGGLUTINATION OP THE PEST BACILLUS. 



Wyssokowitz and Zabolotny 53 and the German Plague Commission called 

 attention to the fact that the blood serum of persons who had suffered an attack 

 of plague sometimes showed a weak agglutinating action against the pest bacillus. 

 The German Plague Commission further emphasized that under these circum- 

 stances the reaction was not always present and that its occurrence bore no 

 relation to the severity of the disease, since in the most severe case which they 

 examined it was absent, while in a mild case of plague, the strongest positive 

 reaction was obtained. They studied the sera of two persons who about three 

 weeks before had been vaccinated against pest by Haffkine, but found no trace 

 of an agglutinating reaction. They also examined four different pest immune 

 sera produced in horses and in three found practically no agglutinative action or 

 only traces of it; but one of the sera showed a suggestion of a reaction above 

 the dilution of 1 to 20. A goat which received four injections of killed cultures 

 of the pest bacillus, six cultures being finally injected, was killed about one week 

 after the final inoculation. Its blood serum then showed a strong agglutinative 

 action in a dilution of 1 to 30. The commission conclude that in plague infection 

 the agglutination is not at all parallel with the protective and immunizing power 

 of the serum. Pest sera which showed a strong agglutinating reaction, in the 

 animal body proved to be entirely inactive against pest infection and vice versa. 



Zabolotny M also found that the agglutinative action of the blood serum of 

 those who had suffered with pest was very inconstant. In some eases which had 

 been inoculated with Haffkine's prophylactic, lie found a weak agglutinative power 

 which, however, was not so marked as in cases which had recovered from a natural 

 attack of the disease. 



Vagedes 55 investigated the agglutinative action of the sera of thirteen persons 

 who had suffered with pest in Oporto. In only two cases was a very weak, 



53 Ann. d. I'mst. Pasteur (1897), 11, 662. 

 "Arch. d. Set. Biologiqucs (1901), 8, 85. 



m Elin. Jahrbch. (1900), 7, 537, and Arh. a. d. Jr. Gsndhtsamte Berl. (1900), 

 17, 181. 



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