The purpose of this study was to develop a flow cytometric method for the detection of adenosine deaminase (ADA) in a single cell suspension of mononuclear cells. Anti-human ADA antibody was purified by affinity chromatography on a column of Sepharose 4B to which calf ADA was covalently linked. This antibody was used for indirect immunofluorescent staining of cells fixed in 4% paraformaldehyde. The specificity of staining was proved by substitution of anti-human ADA with normal rabbit IgG and by absorption experiments. The fluorescence profile of the cells was then analyzed by flow cytometry. Two groups of cells were studied: (a) thymocytes, tonsil cells and peripheral blood mononuclear cells (PBMC), (b) ADA-positive and ADA-deficient cell lines. In each of these populations of cells a peak of specific immunofluorescence staining for the enzyme could be easily distinguished from weak background staining of control preparations. Within each group, the cell population with higher ADA activity also displayed a greater intensity of cell fluorescence. Flow cytometry provides a means for quantitation of ADA in individual mononuclear cells.

Annals of the New York Academy of SciencesVolume 451, Issue 1 p. 169-179 Association of Adenosine Deaminase with Differentiation of Normal and Leukemic T and B Lymphocytesa B. E. CHECHIK, B. E. CHECHIK Harold Tanenbaum Department of Research Department of Medicine Mount Sinai Hospital Toronto M5G 1X5, Ontario, CanadaSearch for more papers by this authorW. P. SCHRADER, W. P. SCHRADER Division of Laboratories and Research Kidney Disease Institute Albany, New York 12201Search for more papers by this authorB. FERNANDES, B. FERNANDES Department of Pathology Mount Sinai Hospital Toronto, OntarioSearch for more papers by this authorS. SENGUPTA, S. SENGUPTA Harold Tanenbaum Department of Research Department of Medicine Mount Sinai Hospital Toronto M5G 1X5, Ontario, CanadaSearch for more papers by this authorE. W. GELFAND, E. W. GELFAND Division of Immunology and Rheumatology Research Institute The Hospital for Sick Children Toronto M5G 1X8, Ontario, CanadaSearch for more papers by this author B. E. CHECHIK, B. E. CHECHIK Harold Tanenbaum Department of Research Department of Medicine Mount Sinai Hospital Toronto M5G 1X5, Ontario, CanadaSearch for more papers by this authorW. P. SCHRADER, W. P. SCHRADER Division of Laboratories and Research Kidney Disease Institute Albany, New York 12201Search for more papers by this authorB. FERNANDES, B. FERNANDES Department of Pathology Mount Sinai Hospital Toronto, OntarioSearch for more papers by this authorS. SENGUPTA, S. SENGUPTA Harold Tanenbaum Department of Research Department of Medicine Mount Sinai Hospital Toronto M5G 1X5, Ontario, CanadaSearch for more papers by this authorE. W. GELFAND, E. W. GELFAND Division of Immunology and Rheumatology Research Institute The Hospital for Sick Children Toronto M5G 1X8, Ontario, CanadaSearch for more papers by this author First published: October 1985 https://doi.org/10.1111/j.1749-6632.1985.tb27108.xCitations: 5 † This work was supported in part by grants from the National Cancer Institute, Canada, the Leukemia Research Fund, Toronto, and the National Institute of Allergy and Infectious Disease, U.S.A. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume451, Issue1Adenosine Deaminase in Disorders of Purine Metabolism and in Immune DeficiencyOctober 1985Pages 169-179 RelatedInformation

The possible association of ecto-5'-nucleotidase (5'-NT) with differentiation of B-cells was explored with the use of normal and neoplastic lymphoblastoid cell lines representing sequential stages of B-cell maturation. There was no relationship between patterns of enzyme expression in the cell lines and immunoglobulin (Ig) secretion, chromosome constitution, proliferative rate, cell volume, or the presence of B1 and B2 antigens. Pre-B-cell lines, which were negative for surface Ig or Ig secretion but positive for cytoplasmic mu-chains, showed the presence of 5'-NT, whereas 9 of 11 lymphoma cell lines, Burkitt's or non-Burkitt's type, both secreting and nonsecreting, did not exhibit enzyme activity. Four myeloma cell lines and 13 of 15 normal B-cell lines were positive for 5'-NT. These results suggested that 5'-NT was present in pre-B-cells and in some very early B-cells. 5'-NT usually disappeared from early and some intermediate B-cells and reappeared in mature B-cells and plasmacytoid cells.

Immature B-cells, including B-cell lymphoma lines, are often deficient in ecto-5'-nucleotidase (5'-NT) activity. 12-O-Tetradecanoylphorbol 13-acetate (TPA) was shown to be capable of inducing maturation toward plasmacytoid-like cells in immunoglobulin (Ig)-secreting B-cell lines. An attempt was made to induce the enzyme in 5'-NT-negative B-cell lymphoma lines with TPA to clarify the relationship between 5'-NT and B-cell differentiation. After 3 days in the presence or absence of TPA, these cell lines were examined morphologically, and their 5'-NT activity, Ig secretion, surface Ig, and Ia, B1, and B2 antigens were estimated. Neither Ig secretion nor 5'-NT activity was induced by TPA in any of 4 nonsecreting cell lines studied. Ig secretion was significantly increased in 4 of 5 lg-secreting cell lines. Two of these inducible cell lines, JD 38 and ST 486, became positive for 5'-NT activity and acquired morphologic characteristics of plasma cells after culture with TPA. The lymphoma cell line JD 38 was transplanted into nude mice and gave rise to a solid tumor. Although the tumor cells remained negative for 5'-NT, they could be induced by TPA to express both the enzyme activity and plasmacytoid-like appearance. These data suggested that in the Ig-secreting B-cell lymphoma lines, there was an association between the inducibility of 5'-NT and the capacity of these cell lines to undergo plasma-cytoid-like transformation in response to TPA.

Immunomorphologic methods were utilized to localize adenosine deaminase (ADA) in extrathymic benign lymphoid tissues and B-cell lymphomas. In reactive lymph nodes, tonsils and appendix, germinal centers displayed strong ADA-positive nuclear staining in small cleaved lymphocytes and weak nuclear and/or cytoplasmic staining in large lymphoid cells. A significant proportion of ADA-positive lymphocytes in the germinal centers were B-cells. The mantle zone of secondary follicles did not stain for ADA. The plasma cells in the medullary cords demonstrated mainly cytoplasmic staining. In the spleen, ADA-positive lymphocytes were located in the periarteriolar sheath and paratrabecular white pulp. In lymphoma B-cells, patterns of ADA staining were similar to those observed in normal B-lymphocytes of similar morphology. This study demonstrated that human normal and lymphoma B-lymphoid cells are heterogeneous with respect to ADA expression. This heterogeneity appears to be associated with differentiation and/or proliferation of B-lymphocytes.

During the last decade, adenosine deaminase (ADA) has attracted a great deal of attention because of its involvement in the development of the immune system. In humans, deficiency of ADA is usually associated with a hereditary form of severe combined immunodeficiency (Giblett et al., 1972). The largest amounts of enzyme have been found in lymphoid tissues, particularly in the thymus gland (Adams et al., 1976) and leukemic lymphoblasts of thymic phenotype (Smith et al., 1978). Within the thymus, ADA is predominantly located in cortical thymocytes (Chechik et al., 1981), which express higher enzyme activity than do medullary and extrathymic lymphocytes (Barton et al., 1979). These findings led to the suggestion that ADA is associated with the intrathymic differentiation of T cells.

The possible association of ecto-5'-nucleotidase (5'-NT) with differentiation of B-cells was explored with the use of normal and neoplastic lymphoblastoid cell lines representing sequential stages of B-cell maturation. There was no relationship between patterns of enzyme expression in the cell lines and immunoglobulin (Ig) secretion, chromosome constitution, proliferative rate, cell volume, or the presence of B1 and B2 antigens. Pre-B-cell lines, which were negative for surface Ig or Ig secretion but positive for cytoplasmic mu-chains, showed the presence of 5'-NT, whereas 9 of 11 lymphoma cell lines, Burkitt's or non-Burkitt's type, both secreting and nonsecreting, did not exhibit enzyme activity. Four myeloma cell lines and 13 of 15 normal B-cell lines were positive for 5'-NT. These results suggested that 5'-NT was present in pre-B-cells and in some very early B-cells. 5'-NT usually disappeared from early and some intermediate B-cells and reappeared in mature B-cells and plasmacytoid cells.

2'-Deoxycoformycin (DCF) is a potent inhibitor of adenosine deaminase (ADA) and a potential antineoplastic and immunosuppressive agent. In this study the kinetics of ADA expression was assessed by immunomorphologic and enzymatic methods in tissues of ACI rats given injections of DCF. The rats received a daily ip injection of 10 mg DCF/kg for 3 consecutive days. This treatment destroyed cortical thymocytes, whereas lymphocytes of the thymic medulla were mainly preserved. In control phosphate-buffered saline-injected rats, cortical thymocytes were not affected morphologically and displayed strong ADA staining. It was found unexpectedly that injections of DCF produced activation and, possibly, differentiation of B-cells in the mesenteric lymph nodes and spleen. These activated B-lymphocytes and plasma cells stained strongly for ADA. Transient changes in patterns of ADA expression were also observed in endothelial cells of blood vessels and liver Kupffer's cells, but these changes were not accompanied by degeneration of the cells. The treatment with DCF did not result in any permanent abnormalities in the rat tissues.

A commercial preparation of calf adenosine deaminase (calf ADA) was further purified by affinity chromatograohy and used for immunization of rabbits. The resulting anti-calf-ADA sera reacted by immunodiffusion with both calf and human ADA, and precipitated about 90% of radiolabeled enzyme isolated from human thymus tissue. Moreover, ADA activity was detected in the pellets formed by immunoprecipitation of unlabeled human enzyme by anti-calf-ADA sera. These antisera were successfully used for the immunomorphologic localization of ADA in human thymus tissue and in lymphoid cell preparations. The anti-calf-ADA sera could also be used for the immunofluorescent detection of enzyme in rat and mouse thymocytes. The utilization of anti-calf-ADA serum for immunochemical and immunomorphologic detection of enzyme provides a valuable and sensitive reagent for the identification of ADA-positive cells in humans and several other species.

Adenosine deaminase (ADA) has been detected immunohistochemically in human thymus. The enzyme was localized predominantly in cortical thymocytes. Occasional lymphocytes in the medulla were also positive for ADA. Blood vessels, connective tissue, and Hassall's corpuscles were not stained for the enzyme. Using single-cell immunofluorescence and immunoperoxidase assays, we found that thymocytes and lymphoid cells of peripheral blood (PBL) and tonsils were heterogeneous with respect to ADA expression. About 70% of thymocytes were strongly stained for the enzyme whereas weak staining was seen in 20% of cells. About 10% of thymocytes were ADA negative. Twenty percent of PBL and tonsil cells were strongly positive for ADA, 10% of cells were negative for the enzyme, and weak staining was seen in the remainder. Bone marrow mononuclear cells were not stained for ADA. One hundred percent of lymphoblasts of 3 T cells leukemia lines were strongly stained for the enzyme whereas weak staining was seen in a pre-B cell leukemia line, 4 B cell lymphoma/normal lines, 2 non-T, non-B cell leukemia lines and 2 myeloid cell leukemia lines. There was a good correlation between intensity of cellular staining and quantity and activity of ADA detected in cell extracts by radioimmunoassay and enzymatically. The development of immunomorphologic methods for the detection of ADA provides a tool to study the role of the enzyme in function(s) and differentiation of normal and leukemic cells.

The purpose of this paper was to study the heterogeneity of human thymocytes and leukemic cells of the T-cell line MOLT-3 by velocity sedimentation. Analysis of the subpopulations of thymocytes demonstrated that they represent a heterogeneous population of cells with respect to their size, proliferative activity, and presence and quantities of terminal deoxynucleotidyl transferase and human thymus leukemia-associated antigen, a thymic isozyme of adenosine deaminase (HThy-L/ADA). Only a minor subpopulation of thymocytes (large cells) was in active cycle. The highest level of HThy-L/ADA was associated with the main subpopulation of thymocytes sedimenting at 3 to 4 mm/hr while low amounts of the HThy-L/ADA antigen (enzyme) were found in the minor fractions of the small and large cells. The distribution of terminal deoxynucleotidyl transferase-positive cells indicated that most, but not all, thymocytes contain the enzyme. Analysis of the T-cell line MOLT-3 showed that these cells could be separated into subpopulations with different biochemical and biological properties. More than one subpopulation of cells was capable of DNA synthesis. In contrast to the thymocytes, all fractions of MOLT-3 cells contained high amounts of HThy-L/ADA. The proportion of terminal deoxynucleotidyl transferase-positive cells as a function of sedimentation velocity was also quite constant although there was a slight but reproducible drop in the percentage of these cells in the slowly sedimenting fractions. The percentage of cells with receptors for sheep erythrocytes also remained high in fractions separated on the basis of size, although a consistently higher percentage was found in smaller cells. These studies indicated that thymus cells as well as the malignant T-cell line MOLT-3 can be separated on the basis of sedimentation velocity into subpopulations with different biological and biochemical properties. The data also indicated that the heterogeneity of MOLT-3 line cannot be explained solely on the basis of volume changes due to cell cycle, suggesting that they may represent heterogeneous populations of cells.

In the determination of whether human thymus-leukemia-associated antigen (HThy-L) is a low-molecular-weight form of adenosine deaminase (ADA), both HThy-L and ADA were found to have the same molecular weight of 45,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antigen and enzyme displayed a phenomenon of complete identity in immunodiffusion and a high degree of cross-reaction in a competitive radioimmunoassay for HThy-L or ADA. When tested for adenosine-deaminating activity, HThy-L was nearly as active as purified low-molecular-weight ADA from erythrocytes. However, HThy-L and ADA differed in their capacity to combine with the complexing protein isolated from human kidney. Apparently, HThy-L represents a thymic isoenzyme of ADA and is the first antigen to be associated with differentiation of hematopoietic cells for which a functional activity is established.

A water soluble human thymus/leukaemia-associated antigen (HThy-L) was recently identified as a low-molecular-weight form of adenosine deaminase (ADA). In the present study levels of the enzyme in normal and leukaemic cells and plasma have been assessed by an enzymatic method and/or radioimmunoassay (RIA) for HThy-L. In addition, the relationship between the levels of enzyme and the phenotype of leukaemic cells was evaluated. The findings can be summarised as follows: 1. There is a good correlation between levels of ADA detected by the RIA and the enzymatic method in normal and leukaemic cells but a poor correlation between levels in cells versus plasma in leukaemic patients. 2. All patients with T-cell acute lymphoblastic leukaemia (ALL) tested had high quantities of ADA in plasma and blast cells compared with normal blood or marrow cells. 3. Approximately 50% of patients with common ALL had increased quantities of ADA in leukaemic cells. 4. Patients with chronic myeloid leukaemia both in the stable phase of disease and in blast crisis generally had low quantities of ADA in leukaemic cells although some cases of blast crises (both ‘lymphoid’ and ‘myeloid’) had raised plasma levels. These data further support the view that ADA activity is highest in the early stages of T-lymphocyte maturation and in corresponding leukaemias.

Using a radioimmunoassay, increased levels of a human thymus/leukemia- associated antigen (HThy-L) have been detected in leukemic cells and plasma from most patients with E-rosette-positive acute lymphoblastic leukemia (ALL) and a number of patients with E-rosette-negative ALL, acute myeloblastic leukemia (AML), acute monomyelocytic leukemia (AMML), and acute undifferentiated leukemia (AVL). Low levels of HThy-L have been demonstrated in white cells from patients with chronic myelocytic leukemia (stable phase) and in mononuclear cells from patients with chronic lymphatic leukemia. The relationship between HThy- L and differentiation of hematopoietic cells is discussed.

A competitive radioimmunoassay for a saline-soluble human thymus-leukemia-associated antigen (HThy-L) was applied for quantitation of this antigen in leukemia and normal hematopoietic cell lines. Highly increased quantities of HThy-L were detected in all T-cell leukemia lines tested, regardless of the presence or absence of receptors for sheep erythrocytes. This elevated level of HThy-L in combination with high terminal deoxynucleotidyl transferase and adenosine deaminase activities and the presence of a T-lymphocyte-specific surface antigen appear to represent stable phenotypic characteristics of T-cell lines. Most normal B-cell lines had low quantities of HTy-L. The level of HThy-L was slightly elevated in a considerable number of lymphoma B-cell lines and in all non-T, non-B leukemia cell lines tested. No relationship existed between quantities of HThy-L and an expression of different surface immunoglobulin isotypes in B-cell lines. Low quantities of HThy-L were detected in leukemia myeloid and myeloma cell lines as well as in B-cell leukemia lines originating from patients with B-cells acute lymphoblastic leukemia. Apparently, the increased quantities of HThy-L in T-cell leukemia lines may be related to certain stages of T-cell differentiation at which leukemia cell transformation occurs.

A competitive radioimmunoprecipitation method was developed for the quantitation of human thymus-leukemia-associated antigen (HThy-L) isolated from human thymus tissue. Antisera to the antigen were raised by immunization of rabbits with purified fractions of HThy-L. The antigen was labeled with 125l by means of a modification of the lactoperoxidase technique and subjected to Sephadex G-100 gel filtration. Analysis of fractions eluted from this column by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two labeled components with apparent molecular weights of 45,000 and 25,000 daltons, respectively. Immunoprecipitation with anti-HThy-L antiserum demonstrated directly that the 45,000-dalton component carried HThy-L antigenicity. This fraction served as the source of labeled antigen in a competitive radioimmunoassay that permitted the detection of approximately 1 ng HThy-L. With the use of this assay, we confirmed quantitatively that the highest amounts of HThy-L were found in extracts of thymocytes, normal thymus tissues, and lymphoblasts for T-cell lines.

Human thymus-leukemia-associated antigen (HThy-L), a saline-soluble antigen, was previously detected by immunodiffusion (but not on the cell surface) in significant quantity in extracts of normal thymocytes, cells from cultured T-cell lines, and erythrocyte-rosette-positive leukemia blasts. Two species of HThy-L were identified and isolated from normal human thymus tissue after extraction in tris buffer, ammonium sulfate fractionation, acid precipitation of inactive fractions, DEAE-cellulose (DE-52) chromatography, Sephadex G-100 gel filtration, and carboxymethyl-cellulose (CM-52) chromatography; On Sephadex G-100, both HThy-L species had a similar molecular weight (40,000--50,000), but they eluted in different positions on DE-52 and CM-52. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that each of the 2 HThy-L species contained 2 components with molecular weights of approximately 43,000 and 23,000. Further purification of HThy-L on Sephadex G-50 showed that the 43,000-dalton component possessed HThy-L activity.