An Integrated and Comparative Study of the Antiviral Effects and Other Biological Properties of the Polyinosinic Acid-Polycytidylic Acid and Its Mismatched Analogues

Extensive investigations were made of the biological properties of the polynucleotide duplex, rI n ·rC n , along with two modified duplexes having mismatched base pairs, rI n ·r(C 12 ,U) n [as well as rI n ·r(C 13 ,U) n ] and rI n ·r(C 29 ,G) n 5 [as well as rI n ·r(C 20 ,G) n ]. These duplexes were studied using a variety of biological systems to determine their efficacy in producing antiviral activity (e.g., interferon) relative to their accompanying secondary biological properties (e.g. , acute toxicity, pyrogenicity, and mitogenic activity). These duplexes were studied on a comparative basis in the mouse for their ability to elicit protection against a lethal viral challenge, their acute toxicity, and their relative mitogenic effects on splenic cells. In the intact rabbit, circulating interferon and pyrogenicity were studied, and complementary studies were done with rabbit kidney cells in culture. In human neonatal fibroblasts in culture, these duplexes were studied for their antiviral protection and relative levels of interferon production. Our results indicate that the mismatched polynucleotide duplexes are comparable in their antiviral properties to rI n ·rC n but possess much less pronounced secondary effects than the rI n ·rC n molecule. The utility of these duplexes in elucidating mechanisms of biological responses to double-stranded RNA is discussed along with the presentation of a theoretical framework for design and development of polynucleotide duplexes having a therapeutic efficacy greater than rI n ·rC n .