Relationship of human cord blood mononuclear cell lines, established by the HTLV-I integration, to expression of T-cell phenotypes and the T-cell receptor gene rearrangement.

The HTLV-I integrated cell lines originated from human cord blood mononuclear cells were examined for the T-cell receptor beta chain gene rearrangement in conjunction with immunological phenotype analysis. Five of seven cell lines contained the rearranged T-cell receptor beta chain gene. Interestingly, most of the rearranged lines failed to express the T cell differentiation antigens, OKT 4 and 8, though their positive expression of Leu 1 antigen indicated the commitment to the T-cell lineage. On the other hand, two cell lines retained the germ-line configuration of the beta chain gene, while phenotypical examination revealed that the two cell lines have distinct T-cell antigens. Non-rearranged cell lines have proved to be nearly monoclonal from HTLV-I integration pattern and/or surface marker clonality. Thus, the relationship between the immunological phenotypes and the T-cell receptor gene rearrangement observed in the T-cell lineage is not strict and often dissociates. A possible involvement of HTLV-I infection on the dissociation between phenotype and genotype is discussed from the viewpoint of phenotypical modulation.