[Interrelationship between the chain length of poly-L-lysine and the degree of protection of polyribonucleotide interferon inducers from human blood nucleases].

The action of the human total blood serum on polynucleotide interferon inducers, larifan and ridostin (natural double-stranded RNAs) and poly(I).poly(C) (a double-stranded complex of synthetic polyribonucleotides) used both in the free state and in the state shielded with poly-L-lysine was studied. The rate of the accumulation of the acid soluble products was compared with the residual interferon-inducing activity in mice. All the unshielded inducers were shown to completely loose their activity after a 4-hour contact with the serum. The protective activity of poly-L-lysine increased in parallel with the increase of its molecular weight and was maximal for the preparation with the molecular weight of 12300 +/- 1000 Da. Differences in the structure of the inducers and the mechanism of their biosynthesis and degradation must be taken into account.