Effects of synthetic single- and multistranded polynucleotides on human monocyte IgG receptor activity in vitro.

Human peripheral monocytes demonstrated a higher IgG receptor activity in vitro after incubation with multistranded polynucleotides (poly(I:C) and poly(I:C:U)) after 6-hr cultivation periods. These changes were most pronounced using SRBC coated with low anti-Forssman antibody concentrations (EA, 1:1600 and 1:6400). Polyinosinic and polycytidylic acids failed to show changes in receptor activity. These findings suggest monocyte activation in vitro by multistranded polynucleotides and may in part explain their antitumor activity.