Restricted Rabbit Antibodies: Amino Acid Sequences of Rabbit H Chains of Allotype a1, a2, and a3 in the Region 80 to 94

The partial amino acid sequence of rabbit heavy (H) chains of allotype a1, a2, and a3 was determined. The H chains were derived from restricted antipolysaccharide antibodies which were shown to be precipitated quantitatively by antiallotype sera raised against pooled immunoglobulins. The N-terminal half of the H chains (C1 fragment) was isolated from a CNBr digest and subjected to automated Edman degradation. Extended homology with known sequences from rabbit pooled H chains indicated that C1 fragments were cleaved between residues 34 and 35 and/or 79 and 80. One additional cleavage site was observed at position 110 in two H chains. Section 80 to 94 of a1, a2, and a3 restricted H chains showed little sequence variation. No simple correlation between the identity of a single amino acid residue and the allotype of the H chain could be determined.