Human Serum Digests Poly(rI) • Poly(rC) Differently from Other Mammalian Sera

Abstract

Using a new spectrophotometric assay, we found that human serum digests predominately (rC)_n of (rI)_n·(rC)_n, in agreement with results of Nordlund et al. (Proc. Soc. Exp. Biol. Med., 1970, 133, 439-444) and DeClercq (Eur. J. Biochem., 1979, 93, 165-172) while rhesus monkey, cat, and rabbit sera digest primarily (rI)_n. The results of Nordlund et al. also show (in agreement with our results) that human serum digests more of the (rC)_n strand of (rI)_n·(rC)_n than rabbit serum. However, their results differ from ours, since they found that rabbit serum digests nearly equal, but small amounts of (rI)_n and (rC)_n. Results are discussed in relation to interferon (IFN) induction and toxicity following administration of (rI)_n·(rC)_n.