Differentiation of chronic lymphocytic leukemia cells after in vitro treatment with epstein‐barr virus or phorbol ester. I. Immunologic and morphologic studies

Abstract

Leukemic cells from ten patients with "nonsecretory," B-type chronic lymphocytic leukemia (CLL) were cultured alone or in the presence of Epstein-Barr virus (EBV) or a phorbol ester (12-0-tetradecanoylphorbol-13-acetate; TPA) for 7 days. At periodic intervals the cell morphology, cytoplasmic immunoglobulin content (direct immunofluorescence) and capacity for immunoglobulin secretion (hemolytic plaque assay) were assessed. A variable but significant number of the TPA-treated CLL cells from all patients expressed cytoplasmic immunoglobulin of a single light-chain type at some stage, usually within the first 3 days. EBV induced similar changes in seven of eight cases tested. Untreated cell cultures were negative or contained a few cytoplasmic immunoglobulin-positive cells. Cells from five of nine cases secreted immunoglobulin of a single light-chain type. In every instance this was identical to the surface and cytoplasmic immunoglobulin. Cytologic changes were observed in the leukemic cells after treatment with one or both agents in nine of ten cases. The major feature was an increase in cell size associated with immunoblastic or plasma-cytoid features. Mitotic figures and binucleate cells were also present. These studies indicate that EBV and TPA are effective at inducing immunoglobulin synthesis and secretion in "nonsecretory" B cell neoplasms and are useful tools for studying the maturation potential inherent in these tumors. The study also suggests that the secreted immunoglobulin is a monoclonal product.

Morphological and isoenzymatic differentiation of B-chronic lymphocytic leukaemia cells induced by phorbolester

“…These suggestions are strengthened by the fact that normal and malignant B cells can only be 'immortalized' and grown as continuous B lymphoblastoid or B leukaemia/lymphoma cell lines after infection with Epstein-Barr virus (EBV). On the other hand, it was found that EBV induced phenotypic changes in B-CLL cells similar to those seen after TPA-treatment (Deegan & Maeda, 1984).…”

“…The phorbolester 12-0-tetradecanoylphorbol 13-acetate (TPA) could induce the differentiation of B-CLL cells in vitro (Toetterman et al, 1980). Several investigators have found morphological, functional, cytochemical and immunological changes in B-CLL cells caused by treatment with TPA (Gordon et al, 1984;Dufer & Bernard, 1984;Toetterman et al, 1981a,b;Deegan & Maeda, 1984).…”

Activation of malignant B‐lymphocytes: pathophysiologic and clinical importance

“…The close interrelationship is further demonstrated by the possibility of transforming CLL cells in vitro into cells that display all the characteristics of IC and PLL (34)(35)(36)(37)(38). Some activated CLL cells changes phenotype into immunoblasts.…”

Complement activation by malignant B cells from patients with chronic lymphocytic leukaemia (CLL)

“…Epstein-Barr virus (EBV) is only capable of stimulating B CLL cells to proliferate and secrete monoclonal immunoglobulin in short-term culture [8], and difficulty has been encountered in establishing immortalized cell lines from B Correspondence: Dr Hanne V. Marquart, Institute of Medical Biology. Department of Medical Microbiology, Odense University.…”

“…B CLL CD5 ' cells are capable of producing autoantibody in vitro [6] but show lack of humoral response to foreign antigens [7]. Epstein-Barr virus (EBV) is only capable of stimulating B CLL cells to proliferate and secrete monoclonal immunoglobulin in short-term culture [8], and difficulty has been encountered in establishing immortalized cell lines from B Correspondence: Dr Hanne V. Marquart CLL cells [9]. This difficulty may be explained by the fact that CLL cells express only low numbers of CR2 which functions as the receptor for EBV (reviewed in [10]).…”