EPITOPE COMPLEMENTARITY AND IDIOTYPIC INTERACTIONS - A STUDY OF IDIOTYPIC-LIKE INTERACTIONS BETWEEN ANTI-CYTIDINE AND ANTI-GUANOSINE A/J-MOUSE MONOCLONAL-ANTIBODIES .1. CHARACTERIZATION OF THESE INTERACTIONS

Idiotypic-like interactions between mAbs directed against cytidine (Cyd) or guanosine (Guo) nucleosides were characterized. These mAbs, Cyd-1 (IgG2b, kappa), Guo-1 (IgG1, kappa) and Guo-2 (IgG1, kappa) were derived from splenocytes of A/J mice immunized with Cyd-KLH or Guo-KLH and recognized the nucleoside base moieties involved in hydrogen bonding. The interactions between Guo-1 or Guo-2 and Cyd-1 involved cross-reactive or distinct-but-neighboring paratope-associated idiotopes. These interactions were characterized by K(D) values of 4.6 x 10(-6) and 1.8 x 10(-6) M, respectively. The three anti-nucleoside mAbs exhibited Ab2beta properties and manifested epibody (Ab2epsilon) activity towards ssDNA. We compared these idiotypic-like reactivities with the anti-idiotypic activity of an intentionally induced IgG1, kappa anti-idiotype mAb prepared with splenocytes from A/J mice immunized with Cyd-1. This Ab2 antibody which bound to Cyd-1 with a K(D) of 1.1 x 10(-9) M, manifested an Ab2gamma activity, i.e. it recognized a paratope-associated idiotope on Cyd-1 without exhibiting Ab2beta properties. In addition, the anti-(Cyd-1) completely inhibited (Cyd-1)-(Guo-1) and (Cyd-1)-(Guo-2) interactions.