Studies in the Agglutination Prozone.

Abstract

In the course of studies of the mechanism of agglutination, we have sought to explain the pro-agglutinoid zone. Agglutinative sera showing a natural prozone have been so rare in our experience that we have resorted to the study of the prozone in serum produced artificially by heating.

The following is a summary of results observed with such “heat” prozones. Horse and rabbit sera were used. The temperature used for securing this type of prozone is usually stated to be 70° to 75° C. Our observations have shown that with certain sera, temperatures ranging from 56°, or possibly lower, to 76° C. are effective (at pH's 5.0 to 7.0), longer heating being required at the lower temperatures, e. g., 3 minutes at 68° produces a prozone, while 2 to 4 hours is necessary at 60°. Heating to 76-78° destroys all agglutinin. In the case of some of the typhoid sera, the production of a prozone was accompanied by a faint opalescence. Centrifugalization failed to clear the serum but passage through Berkfeld V candles was successful. Accompanying this removal of turbidity, the prozone disappears and coincidentally the titre of the the serum falls (Table 1).

In the case of a dysentery prozone serum not showing this turbidity a similar eradication of prozone and coincident reduction of titre was obtained by adding kaolin.

When prozone serum (typhoid) was added in proportions of 1 :1, 2:l and 4:l to an untreated B. Melitensis serum no inhibition of agglutination of the melitensis organism occurred, i. e., typhoid prosone serum does not produce a prozone in melitensis serum. Also, in the case of closely related bacteria (dysentery strains), the addition of Shiga prozone seruni to Flexner, Mt. Desert, “Y” and Sonne B sera in similar fashion failed to produce prozones.