T15 D region germ line amino acid sequences distinguished by monoclonal anti-idiotope antibody.
Monoclonal antibody NL16, prepared with phosphorylcholine (PC)-binding myeloma protein C.BBPC3 (C3), identified an idiotope (C3-16 Id) that was present on T15 IdX+ myeloma proteins (MP) C3, T15, and H8, but not the T15 IdX- MP M167 and M603. The binding of C3 to NL16 is PC inhibitable, indicating that C3-16 Id is site associated. Inhibition studies with PC-specific hybridoma proteins (HP) demonstrated that the T15-type L chain VK22 and elements of the H chain were required for C3-16 Id expression. Studies of amino acid sequences of these PC-binding HP and MP showed that VK22+, T15 IdX+ HP, and MP that use the T15 D region (YYGSS) sequences were always C3-16 Id+. However, the reverse was not true, because all but one VK22+, T15 IdX+ HP with D region sequence changes were C3-16 Id-. This suggested that NL16 defined a specificity mainly determined by the D region of the H chain. A direct test of this hypothesis with heterologous heavy/light chain recombinant molecules obtained from C3-16 Id+ and C3-16 Id- HP of known sequence, showed that the D region was critical to idiotope expression. Additionally, an examination of the amino acid sequences of VK22+, T15 IdX- HP, HPCG14, and HPCM6 suggest that profound changes in the D region may also alter the expression of T15 IdX (an Id defined by a multispecific antiserum from A/He mice). The C3-16 Id+ was found in anti-PC serum of most Ig haplotype-inbred strains except for CBA/J, C3H, and PL, which are all of the Igh-Cj haplotype. Amino acid sequences of PC-binding CBA and PL HP showed marked changes in the D region from the T15 type, and this may account for the C3-16 Id- character of Igh-Cj strains.
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes / Q000235:genetics*; D007075:Immunoglobulin M; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D009194:Myeloma Proteins / Q000235:genetics*; D013045:Species Specificity
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M; D009194:Myeloma Proteins