Inducers of interferon and host resistance, V. In vitro studies.

Abstract

Previous reports1-6 from this laboratory recorded that double-stranded ribonucleic acid molecules from numerous sources are efficient inducers of interferon and of resistance to viral infection in vivo and in vitro.The present report describes the induction of resistance against several viruses in a variety of cell cultures by the complex of polyriboinosinic and polyribocytidylic acids (rI: rC) and presents evidence to associate such resistance with interferon induction.The inactivity of the individual homopolymers, rI and rC, is reaffirmed, and interferon induction by rI: rC in vitro is shown to be inhibited by exposure of cells to actino- mycin D.Materials and Methods.-(I)Polyrzboinosinic acid (rI) and polyribocytidylic acid (rC) were purchased from Miles Laboratories, Elkhart, Indiana.The rI:rC complex was prepared by mixing rI and rC in equimolar concentration in phosphate-buffered saline (0.006 M sodium phosphate 0.15 M NaCl pH 7.0).( 2) Cell cultures: The various pri- mary, cell strain, and line cell cultures listed in Table 1 were prepared and maintained by ordinary procedures.The RK13 culture is a stable line of rabbit kidney cells, and the WI-38 and HFL cultures are diploid cell strains of human embryonic lung.The RK13