VIRAL AGGREGATION - BUFFER EFFECTS IN THE AGGREGATION OF POLIOVIRUS AND REOVIRUS AT LOW AND HIGH PH

Effects of the buffer employed in maintaining a given pH value were tested on aggregation of 2 viruses, poliovirus and reovirus. Poliovirus aggregated at pH 6 and below, but not at pH 7 or above, except in borate buffer. Reovirus aggregated at pH 4 and below, but aggregated only in acetate or tris(hydroxymethyl)aminomethane-citrate buffers at pH 5. Other buffers tested for aggregation of reovirus at pH 5 (succinate, citrate and phosphate-citrate) induced little aggregation. No significant aggregation was found for reovirus at pH 6 and above. The most effective aggregation for both viruses was induced by buffers having a substantial monovalently charged anionic component, such as acetate at pH 5 and 6 or citrate at pH 3. Cationic buffers at low pH, such as glycine, were generally weaker in aggregating ability than anionic buffers at the same pH. These results, when correlated with the isoelectric point of the viruses (poliovirus at pH 8.2; reovirus at pH 3.9) indicated that both viruses aggregated strongly when their overall charge was positive, but only under certain circumstances when it was negative. Although reovirus aggregated massively at its isoelectric point, poliovirus remained dispersed at its isoelectric point. Those pH and buffer conditions inducing aggregation of 1 virus do not necessarily induce it in another.