Isolation and characterization of an early T-helper/inducer cell line with a unique pattern of surface phenotype, constitutive cytokine secretion and myc oncogene expression.

The cell line AG-F was isolated from the marrow of a neuroblastoma patient undergoing myeloablative treatment and autologous bone marrow rescue. A year later, the patient developed a Hodgkin's type lymphoma. AG-F cell line demonstrated an unusual phenotype, lacking surface CD2 and CD3, but expressing high levels of CD4, CD5, CD7, CD29, and CD45RO. Markers associated with Hodgkin's lymphoma cells, CD15 and CD30, were also positive. AG-F cells grow in suspension in clusters of 50-200 cells, with a doubling time of 9 h. They can also grow in serum-free medium and form tumors in nude mice. AG-F cells have amplified N-myc and c-myc and high levels of the corresponding mRNA transcripts. Cytogenetic analysis revealed a DNA index by flow cytometry of near tetraploid cells and a karyotype of 85-87 chromosomes, with consistent abnormalities in chromosomes 1, 5, and 9. Gene rearrangement studies revealed rearrangement of the beta gene of the T-cell receptor. AG-F cells secrete high levels of IL-6, IL-8, IL-10, and GM-CSF. Cell adherence and formation of long processes could be induced by fibronectin and were enhanced by exposure to PMA. Cells exposed to phorbol myristate acetate (PMA) had increased expression of CD11a, CD11b, CD18, CD45RO, and HLA-DR, whereas expression of CD15 and CD30 was markedly decreased. Similarly, the level of c-myc and N-myc oncoproteins and the levels of the cytoskeletal proteins, actin, tubulin, and vimentin markedly decreased early after PMA-induced differentiation.