Influence of Size of Individual Homopolynucleotides on the Physical and Biological Properties of Complexed rIn:rCn (Poly I:C)

Abstract

Reduction in the size of rC_n by sonic radiation caused a decrease in viscosity when complexed with rI_n of high molecular weight but did not bring about a decrease in protective activity of the rI_n:rC_n against PVM or VSV viruses. Greater reduction in size of rC_n by treatment with RNase resulted in progressive loss of capacity to complex with rI_n and to protect against viral infections. The capacity of rI_n:rC_n to induce resistance to VSV virus in vitro and to PVM virus in vivo was more dependent upon maintaining a high molecular weight of rI_n than of rC_n. Activity was markedly diminished when the average molecular weight of rI_n was below 1.9 × 10⁵ and of rC_n below 2.3 × 10⁴.