Formation of an Antibody with Serologic Specificity for N6-(Δ2-Isopentenyl) Adenosine

Abstract

Abstract Recent reports have dealt with the demonstration of specific antibodies found in response to immunization of rabbits with conjugates of methylated nucleoside haptens (1, 2). Not surprising were the findings that the methyl group and its position on the purine or pyrimidine ring dominated the degree of complementarity between hapten and antibody. Nevertheless, some recognition by these antibodies of heterologous methylated bases and even normal bases was observed. We have recently produced in rabbits antibodies directed toward N6-(Δ2-isopentenyl) adenosine (iA). As expected, the N6-(Δ2-isopentenyl) group on the nucleoside was immunodominant. These antibodies do react with N6-methyladenosine; yet 1 × 104 more N6-methyladenosine molecules were required for equivalent activity. Even at a 1 × 105 higher concentration, normal bases did not cross-react. The iA in the tRNATyryeast was available for reaction with the antibody of iA. Isolation and characterization of the iA used for synthesis of the immunizing antigens have been described previously (3).