Antibodies to poly d(A-T) and their reactions with oligonucleotides and nucleic acids

Antibodies to poly d(A-T)‡ were elicited in two rabbits by immunization with complexes of heat-denatured poly d(A-T) and MBSA. Denaturation of poly d(A-T) was carried out in a salt solution and in distilled water. The antibodies were characterized by precipitation, hemagglutination and radioimmunoassay procedures. The antibody bound poly d(A-T) and cross reactions were observed with dAdo, dThd, poly(b) and ApU but not with UpA.V.faba satellite and calf thymus DNAs were bound at least as well as poly d(A-T); DNA fromB. subtilis andPseudomonas were poorly bound. After absorption of the serum with Ado-RSA, Thd-RSA and BSA, the antisera were directed primarily to heat-denatured poly d(A-T). Cross-reactions were observed with mouse myeloma DNA, poly(dT), poly(dA)-poly(dT) but not with poly(dA). The results indicated that anti-poly d(A-T) recognizes sequence and secondary structures. The immunochemical data are in accord with findings made by other workers on DNA and synthetic polynucleotides by physical studies, such as X-ray diffraction and scattering. Moreover, the immunochemical data support earlier contentions that local conformations in nucleic acids are responsive to primary sequences as is the case with proteins.

Also described are procedures for the synthesis of poly d(A-T)-[³H]A and poly ([³H]A-T). For the preparation of the latter, TTP was synthesized from TMP which was prepared enzymically from Thd.