[Functioning and silent regrouped immunoglobulin genes in the hybridoma genome]

Rearranged genes for heavy and light immunoglobulin chains have been studied in the genomes of hybridoma PTF-02 and parent myeloma P3-X63.Ag8.653. The hybridoma was shown to contain three rearranged allelic variants of the heavy chain gene's locus. Gene H2, responsible for the synthesis of the heavy chain of the antibody to transferrin, was transmitted to the hybridoma cell from a lymphocyte. The structure of the 5'-terminal codons of this gene corresponds to N-terminal amino acid residues of a heavy chain expressed by PTF-02 hybridoma. Two other genes (H1 and H3) were found both in the hybridoma and parent myeloma. Both H1 and H3 genes have serious defects in their structure and do not function. Rearranged k-genes were also identified both in the hybridoma and parent myeloma. A functional (K2) gene appeared in the hybridoma genome from an antigen-stimulated lymphocyte. The fetal mouse Vk gene, which has high homology (96.5%) with the K2 gene, was cloned and sequenced. Both K2 and the Vk fetal gene belong to one subfamily of k-genes. The rearranged gene K1 is nonfunctional because it has lost the Jk locus. This gene was transmitted from myeloma used for fusion. In such a way, the origin of all rearranged heavy and light chain genes in hybridoma PTF-02 was established.