Characterization of extracellular particles released from continuous cell cultures derived from human leukemia.

Extracellular particles, with a density of 1.18-1.22 g/cm3 in sucrose, were detected in the culture medium of a continuous cell line (JIII) derived from a patient with monocytic leukemia. These particles contained RNA, DNA, and a DNA polymerase. They synthesized DNA with endogenous templates and primers and also used exogenous DNA but not poly(rC) oligo(dG) as a template. Pretreatment with Nonidet P-40 stimulated DNA polymerase activity while treatment with ribonuclease partially inhibited the enzyme activity. Fluorescent antibodies made to the particles stained both JIII and Z-597 cells derived from human leukemias but not other types of human or nonhuman cultured cells tested. The particles do not appear to be oncornaviruses but may be a particulate antigen associated with malignant cells of hemopoietic and lymphoid origin.     

Antibody-producing human-human hybridomas. III. Derivation and characterization of two antibodies with specificity for human myeloid cells

Peripheral blood mononuclear cells from a patient with acute myeloid leukemia (AML) and spleen cells from a patient with chronic myeloid leukemia (CML) were fused with HAT-sensitive human B lymphoma cells (RH-L4) in attempts to generate human monoclonal antibodies (Mab) against antigens with high specificity for myeloid leukemia cells. Forty-seven of 246 hybridomas secreted Ig that bound to AML cell surface constituents, as determined by FACS analysis of viable cells that were FITC-stained with the human Mab as the first-step reagent and FITC-conjugated rabbit anti-human Ig as second-step. Two of the 47 human Mab (one from each patient and designated AML-19 and CML-20, respectively) bound to both autologous and allogeneic myeloid leukemia cells. No significant binding was observed to cell surface constituents on human bone marrow cells, granulocytes, lymphocytes, erythrocytes, thymocytes, monocytes, lymphoblastic leukemia cells, fibroblasts, malignant B and T lymphocytic cell lines, and murine bone marrow cells. Both human Mab were IgG and were cytotoxic to myeloid leukemia cells in the presence of complement. About 70% of peripheral blood cell samples from 46 AML patients contained AML-19- and CML-20-positive cells, but the reactivity pattern had no correlation to the morphologic FAB classification of the samples. The promyelocytic HL60 cell line and the K562 cell line reacted with the two antibodies. Dot blot analysis of binding of AML-19 and CML-20 to cellular extracts immobilized on nitrocellulose paper showed that both human Mab in this assay also reacted with normal bone marrow cells. This was supported by microscopic immunofluorescence because both human Mab stained intracytoplasmatic structures in normal bone marrow cells, but both intracytoplasmatic and cell surface components stained in myeloid leukemia cells. Moreover, immunoblotting demonstrated that both human Mab in leukemia cells reacted with two cellular proteins with Mr approximately 14,500 and 18,000, and in normal bone marrow cells with a molecule with Mr approximately 20,000. Immunoprecipitation of cell membrane molecules with both the AML-19 and CML-20 antibody precipitated from leukemic cells only the molecule with Mr approximately 18,000 and no components from normal bone marrow cells. It is concluded that myeloid leukemogenesis may result in generation of cell surface expression of either new or abnormally processed molecules that are immunogenic in the autochthonous host. These molecules may also be useful as markers in diagnosis of myeloid leukemia.     

Two new monoclonal antibodies (LN-1, LN-2) reactive in B5 formalin-fixed, paraffin-embedded tissues with follicular center and mantle zone human B lymphocytes and derived tumors

Two monoclonal antibodies (LN-1, LN-2) reactive with B lymphocytes in B5 formalin-fixed, paraffin-embedded tissue sections have been produced by utilizing cell extracts from pokeweed mitogen-stimulated peripheral blood lymphocytes and diffuse histiocytic lymphoma SU-DHL-4 cells, respectively. Both monoclonal antibodies were initially identified by indirect immunofluorescence screening techniques on paraformaldehyde-acetone-fixed cell preparations. Specificity screens with 36 well-characterized human lymphoma and leukemia cell lines showed that both LN-1 and LN-2 stained cell lines of B cell lineage but were unreactive with those of T cell or, with one exception, myeloid derivation. Null cell acute lymphoblastic leukemia cell lines were found to be LN-2+ but LN-1-. The B cell specificity of these reagents was confirmed on 15 lymphoma and 17 leukemia biopsy specimens by using indirect immunofluorescence techniques. Immunoperoxidase staining of sections from B5-fixed, paraffin-embedded human lymphoid tissues showed that LN-1 bound to the cell membrane and cytoplasm of germinal center cells whereas LN-2 stained the nuclear membrane and cytoplasm of germinal center and mantle zone B lymphocytes as well as interfollicular histiocytes and thymic medullary dendritic cells. Both monoclonal antibodies failed to stain cortical thymocytes, lymph node T cells, and peripheral blood T and myeloid cells. Immunoperoxidase staining of 20 nonlymphoid human organs and tissues revealed that LN-1 reacted positively with red blood cell precursors of the bone marrow, ciliated epithelial cells of the bronchus, distal tubular cells of the kidney, and ductal cells from several organs including the breast and prostate. In contrast, LN-2 was unreactive with all human nonlymphoid organs and tissues including the bone marrow. Indirect immunofluorescence staining of a panel of 26 solid tumor cells lines showed that LN-1 was reactive with the majority of epithelium-derived cell lines, glioblastomas, and astrocytomas but was unreactive with neuroblastomas, small cell carcinoma of the lung, and sarcomas. LN-2 was unreactive with 25 of 26 of the solid tumor cell lines by these techniques. Immunobiochemical studies have shown that LN-1 recognizes a cell surface sialoantigen whereas LN-2 is directed against a 35,000 dalton nuclear membrane protein. Because of their high specificity for B cell tumors and their ability to stain B5-fixed, paraffin-embedded tissues, LN-1 and LN-2 are useful reagents for the diagnosis and classification of the human lymphomas and leukemias.     

Nucleolar immunofluorescence in human hematological malignancies.

Rabbit antibodies to the nuclear Tris extract of HeLa cells which have been shown by the indirect immunofluorescence technique to localize in nucleoli of a variety of human malignant tumors but not in a number of nontumor tissues also produced bright fluorescence in nucleoli of tumor cells in several hematological malignancies. The tumors studied included Hodgkins malignant lymphoma, non-Hodgkins malignant lymphoma, acute myeloid and acute myelomonocytic leukemia, chronic lymphatic and chronic myeloid leukemia. In contrast, none of the corresponding normal cell lines in the bone marrow exhibited bright nucleolar fluorescence. In addition, neither the cells of patients with acute infectious mononucleosis nor lymphoid hyperplasia exhibited bright nucleolar fluorescence. These studies suggest that antibodies to HeLa cell nucleolar antigens may be useful in immunodiagnosis of human malignancies.     

A notable phenomenon recapitulated. A fusion product of a murine lymphoma cell and a leukemia virus-neutralizing antibody-producer host plasma cell formed spontaneously and secreting the specific antibody continuously

In the mid-1960s the #620 cell passage line of a murine lymphoma-leukemia was developed at the Section of Clinical Tumor Virology and Immunology, Department of Medicine, The University of Texas M.D. Anderson Hospital in Houston, TX. The diploid lymphoma cells released a retrovirus and were antigenic in young adult Swiss (YAS) mice. Small lymphoma cell inocula were rejected with immunity acquired against large inocula of lymphoma cells. Tissue sections revealed the "starry sky" configurations. In one of the tissue cultures set up from lymphoma #620, a cell line consisting of large round poly- or tetraploid cells arose and was referred to as lymphoma cell line #818. The #818 cells grew in suspension cultures and in the form of large, lethal ascitic tumors in YAS mice. Diploid #620 lymphoma cells stained for retroviral antigens; #818 cells stained both for retroviral antigens and immunoglobulins. Fluids withdrawn from #818 cultures neutralized the leukemia virus in spleen focus assays. Immunoglobulin precipitated from #818 suspension culture fluids strongly and specifically neutralized the leukemia virus. The growth of #620 or #818 cells in YAS mice treated with rabbit anti-lymphoma cell immune sera was strongly inhibited but culture fluids of #818 cells showed weak and insignificant inhibition against leukemia-lymphoma #620 (in one experiment, unpublished). In two experiments #620 lymphoma cells were co-inoculated with immune spleen cells into the peritoneal cavities of YAS mice. The immune spleen cells derived from mice that rejected #620 cell inocula or were actively immunized with a photodynamically inactivated mouse leukemia virus vaccine. In the peritoneal cavities of mice co-inoculated with #620 cells and immune spleen cells, clones of large round cells emerged with tetra- or polyploid chromosomal modes. These cells stained for leukemia viral antigens and immunoglobulins. When passaged in YAS mice these cells induced lethal ascites tumors. It was concluded as early as in 1968-69 that an immune plasma cell can fuse with a lymphoma cell, if the lymphoma cell expresses retroviral antigens against which the plasma cell is producing a specific antibody. Some human lymphoma-leukemia cells express retroviral antigens and/or budding retroviral particles, whether due to the acquisition of new env sequences by incomplete resident endogenous retroviral genomes or due to the entry of exogenous retroviruses into lymphopoietic stem cells. In the Discussion illustrations are provided for the human cell line #778 established from a patient with "lymphosarcoma cell leukemia" in 1966. The malignant cells released unidentified retrovirus-like particles and fused with one another and with reactive lymphoid cells of the host. It should be investigated further if human lymphoma-leukemia cells could fuse with an immune plasma cell of the host and thus alter the clinical course of the disease.     

Proliferating cell nuclear antigen (PCNA) and human malignant tumor nucleolar antigens (HMTNA) in nucleoli of human hematological malignancies

Lymphoma (Lymphocytic non-Hodgkin's malignant lymphoma) and leukemic (chronic lymphocytic, acute and chronic myeloid, myelomonocytic leukemia) cells were studied by indirect immunofluorescence to evaluate the presence of proliferating cell nuclear antigen (PCNA) and human malignant tumor nuclear antigen (HMTNA) in their nucleoli. Most cells in lymph node smears of lymphocytic non-Hodgkin's malignant lymphoma (NHML) developed a bright nucleolar fluorescence with HMTNA antibodies. PCNA was detected in nucleoli of a limited number of cells which apparently represent the proliferating cell population in these lymphomas. Similarly, in the bone marrow smears of patients with chronic lymphocytic leukemia most cells possessed a nucleolar fluorescence for HMTNA and PCNA was present in nucleoli of a limited number of cells. In the bone marrow smears of patients with myeloid or myelomonocytic leukemias most blastic or monocytoid cells also developed a bright nucleolar fluorescence with HMTNA antibodies and PCNA was present only in a small percentage of these cells. Leukemic cells with PCNA in their nucleoli like thekhuntigen might represent a proliferating cell population in late G1-early S phase.     

DNA content analysis of peripheral blood B-lymphocytes in plasma cell malignancies

A double fluorescence assay has been employed for the detection of cell surface and/or cytoplasmic immunoglobulins (Ig) and the measurement of nuclear DNA content in the same cell. Following staining for Ig by means of FITC conjugated antibodies directed against heavy or light chains, cell suspensions or cytospin preparations were ethanol fixed and stained with a propidium iodide-RNAse solution. In this way, the cytometric DNA content of circulating B-lymphocytes was analyzed in three patients suffering from plasma cell malignancies with an excess of peripheral blood B-lymphocytes and evidence of aneuploid bone marrow plasma cells. Aneuploid circulating B-lymphocytes with the same DNA stem-line as bone marrow plasma cells were found in two patients with advanced disease but not in the only one we studied at presentation. Aneuploid lymphocytes had surface immunoglobulins bearing the same light chain as the M-protein. In addition, a significant percentage (23%) of cells lacking either surface or cytoplasmic immunoglobulins proved to be aneuploid in plasma cell leukemia. Nuclear DNA measurement combined with surface or cytoplasmic marker analysis appears to be a reliable method for studying neoplastic lymphoid precursor cells in plasma cell malignancies.     

Complement-dependent cytotoxic factor to megakaryocyte progenitors in sera from patients with idiopathic thrombocytopenic purpura

The influence of sera from patients with idiopathic thrombocytopenic purpura (ITP) was examined on colony formation from megakaryocyte (M) progenitors. Though incubation of marrow cells in Iscove's modified Dulbecco's medium (IMDM) containing 50% sera from several ITP patients stimulated M-colony formation in 8 of 13 cases, incubation in the sera from the patients and in baby rabbit serum as a source of complement significantly suppressed the colony formation. Experiments showed that sera of immunoglobulin G from ITP patients had significant complement-dependent cytotoxicity to M-progenitors in normal marrow cells or in the marrow cells from corresponding patients, but not to CFU-e, BFU-e or CFU-gm. Cytospin preparations of individually collected M-colonies from marrow cells treated with ITP patients' sera and complement revealed a reduction of megakaryocyte colonies containing cells of multilineages. These results indicate that autoantibodies detected in ITP patients can bind not only to platelets and megakaryocytes, but may also bind to M-progenitors.     

Helicobacter pylori (H. pylori) molecular signature in conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma

Conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma is an extranodal marginal zone B-cell lymphoma that is characterized by an exaggerated clonal expansion of B cells, which implicate a pathological proliferative response to antigen(s) including bacteria. Helicobacter pylori (H. pylori) infection is recognized as one of the causative agents of gastric MALT lymphoma; however, it has not been reported in extra gastric MALT lymphoma. We studied 5 patients (4 adults and 1 child) with salmon-colored conjunctival lesions. One patient also had a history of abnormal bone marrow biopsy a year earlier with lymphoid aggregates involving 5% of the overall bone marrow. The conjunctival lesions of the 5 patients were biopsied. Histopathological diagnoses were consistent with conjunctival MALT lymphoma. Lymphoma and normal conjunctival cells were microdissected using laser capture microscopy or manual techniques. DNA was extracted and subjected to PCR amplification using H. pylori gene-specific primers from the urease B and vac/m2 gene. Cells from chronic conjunctivitis (normal lymphocytes), conjunctival human T-cell lymphotropic virus type-1/adult T-cell leukemia/lymphoma (HTLV-1/ATL), and orbital B-cell lymphoma were also microdissected, processed and analyzed. PCR amplification and Southern blot hybridization demonstrated H. pylori DNA in the conjunctival MALT lymphoma cells of 4/5 cases. The negative case was the one with a history of abnormal bone marrow. In contrast, H. pylori gene was not detected in normal conjunctival cells from the cases of MALT lymphoma or the lymphocytes, ATL and orbital B-lymphoma cells from the controls. These data suggest that H. pylori may play a role in conjunctival MALT lymphoma.     

Phosphoinositides are not phosphorylated by the very active tyrosine protein kinase from the murine lymphoma LSTRA

We studied the ability to phosphorylate phosphoinositides by 3 different subcellular preparations, and immunopurified tyrosine protein kinase (TPK) from two murine lymphoma cell lines induced by the Moloney murine leukemia virus: LSTRA with a very active TPK and MBL2 without significant TPK activity. We could not find any difference in the phosphorylation of phosphoinositides by these preparations. The TPK purified with two antibodies which phosphorylate actively tyrosine on exogenous substrate were unable to phosphorylate phosphoinositides.     

Direct versus cultured preparation of bone marrow cells from 22 patients with acute myeloid leukemia

Summary The 24-h culture of bone marrow from patients with acute myeloblastic leukemia (AML) and acute promyelocytic leukemia (APL) gave more analyzable metaphase cells and improved chromosome morphology compared with direct preparations. Culture increased the proportion of cytogenetically abnormal cells, and in six bone marrows where the direct preparation failed, a result was obtained from the cultured preparation. The culture of bone marrow from patients with APL led to the detection of clones carrying the t(15;17) that were not found in direct preparations. Such sequestered clones were not found in AML and acute myelomonocytic leukemia (AMMoL). Cultured preparations were no better than direct preparations from AMMoL.     

Characterization of infectious oncornaviruses from MOPC-460 plasmacytomas: their relation to A-type particles.

MOPC-460 mouse plasmacytoma cells produce intracellular A-type particles and extracellular oncornavirus-like particles ("myeloma-associated virus," abbreviated MAV). The genomes of these two particles are closely related. During attempts to establish infections with MOPC-460 extracellular particles, we isolated ecotropic and xenotropic infectious forms of murine leukemia virus. We have investigated the relation of these isolates to A-type particles and to MAV by nucleic acid hybridization. Using complementary DNA probes prepared from the two isolates, we found that these infectious murine leukemia viruses differ from A-type particles and from MAV. Moreover, we found that MAV is the predominant extracellular component: the ecotropic and xenotropic forms of murine leukemia virus were present at only low levels (less than 5%) in MAV preparations. Neither the SC-1 cells infected with ectropic murine leukemia virus nor the mink cells infected with xenotropic murine leukemia virus showed any A-type particles in their cytoplasm when examined by electron microscopy. Our inability to demonstrate infection by the A-type particle-related component, MAV, suggests that these may be defective.     

Application of the Giemsa-11 technique in cytogenetic analysis of leukemic patients

Cultures of bone marrow obtained from patients with various forms of leukemia have been stained by the Giemsa-11 technique. The results suggest that this method can be utilized for the constant monitoring of numerical and structural anomalies in chromosome 9. Furthermore, by varying the pH, this technique can be applied not only to freshly prepared slides but also to stained preparations stored for many months.     

Immunofluorescence in cells derived from Burkitt's lymphoma

Henle, Gertrude (Children's Hospital of Philadelphia, Philadelphia, Pa.), and Werner Henle. Immunofluorescence in cells derived from Burkitt's lymphoma. J. Bacteriol. 91:1248-1256. 1966.-Indirect immunofluorescence tests led to the brilliant staining of a small proportion of the cells in five different cultures derived from Burkitt's (African) lymphomas. The reaction was not restricted to the 17 sera from cases of this disease but extended to many sera from American individuals, whether healthy donors or patients suffering from a variety of illnesses. The incidence of positive sera increased with age from about 30% in childhood to > 90% in adults. Fluorescein-isothiocyanate-conjugated human gamma-globulins were suitable for direct staining of the same proportion of cells. The stained cells appeared to be in varying stages of degeneration, but cultural conditions leading to an increase in the cellular death rates failed to result in a rise in fluorescent cells. Several observations suggest that the stainable cells might be those which are seen to harbor virus particles under the electron microscope. Two cell lines derived from leukemic patients in this country also contained a small fraction of stainable cells but two others, and numerous primary human leukocyte cultures, gave consistently negative results. Attempts to relate the staining to known viral antigens have failed to implicate herpes simplex, varicella, cytomegalo, and reo viruses types 1, 2, and 3. The nature of the virus carried by the lymphoma cells as well as of the staining reactions remains to be determined.     

Characteristics of plasma membrane isolated from a mouse T lymphoma line: comparison after nitrogen cavitation, shearing, detergent treatment, and microvesiculation

Plasma membrane was isolated from the mouse T lymphoma cell line WEHI-22 using four different methods of cell disruption followed by centrifugal fractionation. Disruption by nitrogen cavitation or by shearing with a cell pump produced plasma membrane vesicles of similar buoyant density (1.10 g/ml) and morphological appearance. Few C-type virus particles were present. Cell disruption with 2% Tween-40 produced membrane vesicles of similar morphology but lower density (1.09 g/ml). All of the above preparations resulted in vesicles with aggregated intramembranous particles after freeze fracture. Microvesiculation with sublytic concentration of a lysophosphatidylcholine analog (ET-12-H) (0.0032% w/v) produced small membrane vesicles which could be isolated without differential centrifugation. However, these had a slightly higher density than vesicles prepared by cavitation or shearing and were contaminated by virus particles. Unlike the other preparations, vesicles prepared with ET-12-H had dispersed intramembranous particles. The enzyme gamma-glutamyl transferase was enriched from 20- to 45-fold in the membrane preparations and proved a suitable plasma membrane marker for these cells whose 5'-nucleotidase content is very low.     

Generation of lymphokine-activated killer (LAK) cells and possible implications in autologous bone marrow transplantation--a preliminary report

Lymphokine-activated killer (LAK) cells were generated successfully without mitogen from blood mononuclear cells obtained from 14 patients with varying malignancies and 2 normal donors. Cells from both groups showed a positive cytotoxicity by a 4-hour 51-Cr-release assay against a variety of target cells including natural killer (NK) sensitive K562 myeloid leukemia, NK-resistant Raji lymphoma cell lines, and fresh/cryopreserved leukemia cells from patients refractory to standard chemotherapy but not normal blood cells. Higher cytotoxic activity was obtained with a higher effector:target ratio at 100:1 greater than 50:1 greater than 25:1 (P less than 0.01) in each setting of different targets. Experiments involving cocultures of the LAK cells with either allogeneic (9) or autologous (3) bone marrow cells disclosed no detrimental effect on the committed hemopoietic stem cells by semisolid agar colony forming unit (CFU-GM) assay. The findings suggest that LAK cells may have a potential role for the in vitro purging of the residual leukemic cells from the marrow inoculum prepared for autologous bone marrow transplantation.     

IgM antibodies to Epstein-Barr virus-associated membrane antigen in sera of infectious mononucleosis patients

By the indirect immunofluorescence technique, IgM antibodies to the cell surface of an Epstein-Barr virus (EBV) producer cell line, P3HR-1, were detected in sera from infectious mononucleosis (IM) patients but not in sera from patients with Burkitt lymphoma or nasopharyngeal carcinoma nor in sera from healthy adult donors having antibodies to EBV-specific viral capsid antigen (VCA). Titers of the IgM antibodies were higher in the earlier stages of IM, a pattern similar to that for IgM antibodies to VCA. The IgM antibodies to the cell surface were identified as being those against the EBV-specific membrane antigen (MA) by the following criteria: (1) The antibodies were reactive to MA-positive cell preparations but to MA-negative cell preparations. (2) Titers of the IgM antibodies were not significantly affected after absorption of sera with sheep red blood cells which could completely eliminate heterophil antibodies in the same sera. Detection of the IgM antibodies to MA may have a particular diagnostic value for providing evidence of a recent EBV infection.     

The particle morphology and some other properties of chloris striate mosaic virus

The causal agent of Chloris striate mosaic disease appears to be a virus with polyhedral particles 18 nm in diameter usually occurring as paired structures about 18 times 30 nm in negatively stained preparations. These particles were detected in the nuclei of infected plants forming characteristic inclusions in all cells except those of the epidermis. Such particles were not detected in thin sections of viruliferous leaf hopper vectors (Nesoclutha pallida). Purified virus preparations were shown to be highly infective when assayed by feeding vector leaf hoppers through membranes and confining them on indicator plants. In particle morphology, chloris striate mosaic virus (CSMV) differs from other viruses of Gramineae in Australia but resembles maize streak virus isolated in Africa, which however is serologically unrelated.     

A new human T-cell differentiation antigen: unexpected expression on chronic lymphocytic leukemia cells

Monoclonal antibody 10.2 reacts with a monomorphic antigen expressed on the surface of virtually all thymocytes, as well as thymus-dependent lymphocytes in the peripheral blood and bone marrow. In contrast, antibody 10.2 did not react with normal peripheral blood B cells, monocytes, or the non-T-cell fraction of bone marrow. This complement fixing IgG2a antibody also reacted with established leukemic T-cell lines, but not with cell lines of either normal or malignant B-cell origin. Similarly, when tested against acute leukemia blasts, the 10.2 antibody reacted with those from patients with T-cell acute leukemia, but not with those from patients with acute null cell or non-lymphocytic leukemia. An unexpected exception to this pattern was the reaction of 10.2 antibody with leukemic cells from patients with B-cell type chronic lymphocytic leukemia. Immune precipitates formed with 10.2 antibody and detergent lysates of radiolabeled T-cells contained three polypeptides with molecular weights of 65 000, 55 000, and 50 000 daltons. It has not been determined whether all three of these polypeptides contain the 10.2 antigenic determinant, or whether these proteins represent a multimeric antigen complex.