Structural bases for public idiotypic specificities of monoclonal antibodies directed against poly(Glu60Ala30Tyr10) and poly(Glu60Ala40) random copolymers.

Abstract

NH2-terminal amino acid sequences of heavy and light chains of seven poly(Glu'Ala30Tyr'0) (GAT) specific hybridoma products derived from DBA/2 and (DBA/2 X BALB/c)Fl hybrid mice and those of BALB/B polyclonal antibodies have been determined over the first 40 residues. Comparison of these sequences with those of nine other GAT or poly(GluWMaW) (GA) specific hybridoma products previously reported allowed the following conclusions. (i) Sequences of hybridoma H and L chains are present in the pool of polyclonal antibodies. (ii) The public CGAT (or pGAT) idiotypic specificities are strictly confined to antibodies exhibiting limited heterogeneity with regard to both the variable heavy (VH) and the variable K (Va) sequences that may be accounted for by one and two germ-line genes, respectively. (iii) The public idiotypic specificities GA-1, expressed by some anti-GAT and most anti-GA antibodies, make use of the same (or similar) VH germ-line genes as the CGAT or pGAT antibodies butpossess a distinctive VK sequence. (iv) Antibodies expressing neither of the alternative public specificities mentioned above appear to be more heterogeneous and express VH and V,, sequences that were found to differ from the basic structures defining the CGAT (pGAT) or GA-1 correlates. It is concluded that CGAT (or pGAT) and GA-1 public idiotypic specificities are germ-line markers of both VH and Vi regions, an observation in agreement with previously reported serological data.In various inbred strains of mice, the random terpolymer (Glu-60 Ala30Tyr'0)n (GAT) elicits specific antibodies, most of which express crossreactive, or public, idiotypic specificities. These were initially defined by using heterologous anti-idiotypic antisera prepared against polyclonal anti-GAT antibodies from DL.LP (1, 2) or BALB/c (3, 4) mice. The -guinea pig antiserum against D1.LP anti-GAT antibodies identified idiotypic markers that were called CGAT (1, 2), whereas idiotypic specificities of BALB/ c anti-GAT antibodies detected by a rabbit antiserum were termed pGAT (3,4). For simplification, it may be considered that both reagents identify similar or identical public idiotypes, hereafter referred to as pGAT or CGAT idiotypes.

Immunoglobulin diversity: analysis of the germ-line VHgene repertoire of the murine anti-GAT response

“…The sequence determined according to the strategy given in Fig.1 is in complete agreement with the NH2-terminal amino acid sequence (residues 1-43) reported for the corresponding heavy chain (16), and is presented in Fig. 2.…”

“…We have found that BALB/c and DBA/2 anti-GAT monoclonal antibodies use a restricted repertoire of VH and VL chains likely controlled by a structurally closely related subset of a very few germ-line genes (16,17).…”

“…These specificities require both the H and L chains of the idiotype in order to be expressed (15). Analyses of the NH 2-terminal amino acid sequences (residues 1-43) of 16 H-L pairs isolated from monoclonal anti-GAT antibodies (16) suggest that the VH and the VL regions of the pGAT idiotype are each encoded by a very small number of germ-line genes. More recently, we reported (17) on the complete sequence of four BALB/c VH regions, using mRNA nucleotide sequencing, as determined by a modification (18) of the chain terminator method (19).…”

Monoclonal BALB/c anti‐progesterone antibodies use family IX variable region heavy chain genes

“…This subgroup is widespread and has been expressed in mAb against oxazolone [23], polyGAT [24], phosphorylcholine [25] [14]. CDRl and CDR2 are indicated.…”

Gene repertoire of the anti-poly(Glu60Ala30Tyr10) (GAT) immune response: comparison of VH, V kappa, and D regions used by anti-GAT antibodies and monoclonal antibodies produced after anti-idiotypic immunization.

“…Their partial amino acid sequences and complete nucleotide sequences have been reported. A limited number of sequences for the heavy chain variable region (VH) (12,16) and K light chain variable region (VK) (17)(18)(19) are used. At the idiotypic level the anti-GAT response is characterized by the expression of the public idiotypic specificity p.GAT defined by a xenogeneic antiserum (20,21) and expressed in all HP-GAT (15).…”