title: HTLV-I infection of T and B cells of a patient with adult T-cell leukemia-lymphoma (ATLL) and transmission of HTLV-I from B cells to normal T cells.
abstract: We analysed the DNA of different tissues of a patient (HS) with adult T-cell leukemia/lymphoma virus (HTLV-I). We detected viral sequences in fresh specimens from spleen, thymus, liver, skin and peripheral blood neoplastic lymphocytes. The pattern of HTLV-I integration is identical in the leukemic cells and in all other tissues analysed, but the signal intensity is strongest in the leukemic cells, indicating the source of HTLV-I proviral sequences was the leukemic T-cells which had infiltrated these tissues. In fact, the cultured skin fibroblasts of the patient did not contain HTLV-I sequence. However, cultured lymphocytes of this patient was consistently an immortalized B-cell line containing HTLV-I sequences in a manner indicative of a polyclonal infection. This cell line was also infected with the Epstein-Barr virus (EBV). In order to determine whether HTLV-I alone was sufficient for B-cell immortalization, we obtained single cell clones by limiting dilution. The DNA of all the cell clones that we analysed contained both the HTLV-I and EBV genomes, suggesting that immortalization of the B-cell was more likely due to the EBV rather than HTLV-I. Infectious HTLV-I viruses produced by the B-cell line still had the propensity to infect and transform T-lymphocytes in normal human umbilical cord blood. Unlike the parental B cells, the transformed T lymphocytes were clonally selected. Our results indicate that although the predominant infected cell population of the patient was his leukemic T lymphocytes, some of his EBV-positive B-lymphocytes were also polyclonally infected. The latter had a growth advantage in culture over the T lymphocytes but the virus produced by these immortalized B cells has not been adapted and has maintained its tropism for T cells.
mesh_terms: D001402:B-Lymphocytes / Q000382:microbiology*; D001483:Base Sequence; D002478:Cells, Cultured; D004279:DNA, Viral / Q000032:analysis; D017977:Deltaretrovirus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007938:Leukemia / Q000382:microbiology*; D012192:Retroviridae Infections / Q000382:microbiology*; D013601:T-Lymphocytes / Q000382:microbiology*
chemical_list: D004279:DNA, Viral