Polyadenylic acid-polyuridylic acid (poly A : U) and experimental murine brucellosis. I. Effect of single and double-stranded polynucleotides on Brucella abortus in vivo and in vitro.

The double stranded polynucleotide, poly A : U, when administered intraperitoneally at the same time as intravenous infection with Brucella abortus, suppressed the growth of that organism in the spleen and liver of mice. Single stranded poly A or poly U were not effective. On the other hand both the single and double stranded forms enhanced the growth of Br. abortus in broth culture. Poly A : U did not enhance the blood clearance of intravenously administered Br. abortus. Indeed its suppressive effect was not apparent until 2 days after administration. When mice given Br. abortus and poly A : U were given a second infection 2 days later, with either Br. abortus or Listeria monocytogens, the second infection was exacerbated, indicating a biphasic effect of poly A : U and antigen.