Antigenic structure of double-stranded RNA analogs having varying activity in interferon induction

Publisher Website
Google Scholar
Abstract
Antibodies [Ab] were induced by immunization of rabbits with methylated bovine serum albumin complexes of the following polynucleotides: poly(I).cntdot.poly(BC)[poly(5-bromocytidylic acid], an effective interferon inducer; poly(c7A)[poly(7-deazaadenylic acid].cntdot.poly(rT), a noninducer that can block induction by active poly(A).cntdot.poly(rT); and poly(A).cntdot.poly(Um)[poly(2''-O-methyluridylic acid)], which has neither inducing nor blocking activity. Similar complexes of f2 phage RNA or tRNA did not induce anti-nucleic acid Ab. Each anti-polynucleotide serum contained some Ab specific for double-stranded structure. Ab were immunospecifically purified from precipitates made with each serum and homologous or cross-reacting double-stranded polynucleotides. The purified Ab distinguished among varying helices bearing base of ribose modifications. Anti-poly(I).cntdot.poly(BC) specificity paralleled that of the interferon induction system. Anti-poly(A).cntdot.poly(Um) specificity favored the 2''-modified polymers. Anti-poly(c7A).cntdot.poly(rT) Ab were the least discriminating. Cross-reaction results indicated that some Ab reacted with determinants that included both sugar-phosphate backbones. In far Ab excess, antigen:Ab ratios in precipitating complexes reached a minimum of 7-12 base pairs per bivalent Ig[immunoglobulin]G molecule. Single antigenic determinants may span about 4 base pairs, with primary contact sites including the phosphate groups and the furanose.

This publication has 10 references indexed in Scilit: