Abstract. The variable regions of cold agglutinins with anti‐I and anti‐Pr specificities were investigated by N‐terminal amino acid sequencing and by analyses of pyrrolidone‐carboxylic acid‐blocked peptides after digestion of polypeptide chains with Nargase. Results showed that the heavy chains of four IgM anti‐I cold agglutinins are exclusively VHI subgroups and their light chains are exclusively VKII subgroup. In contrast, the light chains of two cold agglutinins with anti‐Pr specificity are not VKII, while their heavy chains are not restricted to a single subgroup. The amino acid sequences at the first hypervariable region of light chains (positions 25–35) are similar in two of the four anti‐I cold agglutinins. These sequences are different from that of the light chain of another cold agglutinin with anti‐Pr specificity. These results support the concept that only antibodies with the same specificity can share similar primary structure at their antigen combining sites.
|Number of pages||9|
|Publication status||Published - May 1973|
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