Doubls-helical polynucleotides: immunochemical recognition of differing conformations.

Rabbit antibodies to double-helical RNA react by complement fixation with synthetic or natural double-strand RNA but not with native DNA. In turn, human (from systemic lupus erythematosus patients) antibodies to native DNA do not react with double-strand RNA. Both types of antibodies show cross-reactions (from 1 percent to 50 percent) with RNA-DNA hybrids, but antibodies to the hybrids do not react at all with double-strand RNA or with native DNA. Antibodies to polydeoxyguanylate.polydeoxycytidylate also failed to react with native DNA.