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J Cossman

Publications and source records attributed to J Cossman.

At least 73 records · Page 4Linked to original sources

Development of a second clonally discrete Burkitt's lymphoma in a human immunodeficiency virus-positive homosexual patient.

We have studied, at a molecular level, two small non-cleaved cell malignant lymphomas (Burkitt's type) that were separated by a disease-free interval of 3 years in a patient infected with the human immunodeficiency virus (HIV). The late occurrence of the apparent relapse suggested that the second lymphoma might be caused by a separate malignant transformation in a discrete clone of B cells. Although both tumors expressed the same immunologic surface markers (mu k) and carried the same t(8;14) translocation, Southern blot analysis of DNA from each tumor, using specific restriction endonucleases and probes to the c-myc and the immunoglobulin heavy chain loci, demonstrated that the chromosomal breakpoints relevant to the translocations differed between the tumors. This was corroborated by analysis of the immunoglobulin light-chain rearrangements in the two tumors. These observations indicate that the second tumor was not a recurrence of the first but represented the malignant transformation of a different clone of B cells. Thus late relapses of certain malignancies in individuals at high risk may be caused by the malignant transformation of discrete cell clones (i.e., induction of a new tumor).

Acquired Immunodeficiency Syndrome↗

Clonal evolution of t(14;18) follicular lymphomas demonstrated by immunoglobulin genes and the 18q21 major breakpoint region.

A 2.8-kilobase major breakpoint region on chromosome segment 18q21 is the site of most t(14;18) translocations typical of human follicular lymphomas. Breaks are focused at the 5' end of joining (JH) regions of immunoglobulin (Ig) on chromosome 14, indicating that the translocation occurs at a pre-B-cell stage during attempted heavy (H) chain joining. A new gene from 18q21 (Bcl-2) is placed in the H chain locus creating a unique, translocation-specific JH;18q21 rearrangement that presumably represents a transformation event. In addition, normal Ig gene joining occurs in a H before light (L) chain and K before lambda cascade, creating ordered clonal markers. These serial markers were examined to determine if variations in Ig gene patterns during the natural history of lymphomas represent the emergence of truly separate neoplasms or heterogeneity of a single neoplasm. We examined 45 serial biopsies from 16 B follicular lymphoma patients; six cases showed variation in Ig gene patterns over time. Seven individuals had a detectable JH;18q21 rearrangement present, and it remained unchanged over 5-10 years. Further rearrangements of H chain genes occurred on the normal chromosome 14 within evolving subclones of the original tumor. Lambda L chains also underwent additional rearrangements in two instances, while K gene patterns remained unchanged. All variations in the normal H and L chain genes were 2 degrees rearrangements occurring at a mature B-cell stage following the initial successful rearrangement of a H and L chain. In contrast the t(14;18) breakpoint was conserved in each individual, indicating that evolving neoplastic subpopulations arose from a common clonal progenitor cell.

Alleles↗

Limited diversity and selection of rearranged gamma genes in polyclonal T cells.

The role of a T gamma gene product in the immune response is not known. To investigate the participation of the T gamma gene in functional T cells, we estimated its variable (V gamma) gene diversity among mature polyclonal T cells and assayed for in vivo selection of rearranged V gamma genes during the immune response. In this study, we present evidence that functionally mature, normal human T cells have rearranged their T gamma genes but display a limited range of gene rearrangement choices. In contrast to clonal T cell neoplasms, an invariant array of seven T gamma gene rearrangements was found to be proportionately distributed within normal polyclonal T cell populations, as well as in benign polyclonal T cell proliferations incited by a wide variety of pathological conditions. Findings presented here indicate that the likelihood of rearrangement of each human V gamma gene may be fixed. Lack of selection of V gamma genes during the mature T cell immune response implies a limited role of any single V gamma gene at this stage of T cell development.

Antibody Diversity↗

Transformation of Epstein-Barr virus immortalized human B-cells by chemical carcinogens.

Epstein-Barr virus-immortalized human lymphocytes were used to analyze the transition from the benign hyperproliferative to the malignant transformed state. Treatment with N-acetoxy-2-acetylaminofluorene, a potent frameshift mutagen, induced conversion of the Epstein-Barr virus immortalized lymphocytes into high-grade "immunoblastic lymphomas" on injection into athymic mice, whereas injection of the untreated, original cells did not. The tumor cells were all of the B-cell lineage as determined by the presence of surface immunoglobulins and antigens detected by B-cell specific antibodies to B1 and B4, and the absence of the T-cell-specific markers, 3A1 and LEU-1. The N-acetoxy-2-acetylaminofluorene-induced tumor lines displayed abnormal diploid to tetraploid karyotypes. The fewest chromosomal rearrangement, excluding tetraploidy, observed in these chemically induced lymphomas involved a deletion in chromosome 6, and additions on both chromosomes 16 and 4. Neither major rearrangements nor amplifications were found for K-ras, H-ras, N-ras, c-myc, Blym, and c-myb in these tumor lines.

2-Acetylaminofluorene↗

DNA rearrangements in human follicular lymphoma can involve the 5' or the 3' region of the bcl-2 gene.

In most human follicular lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clustering regions on chromosome 18, the major one at the 3' untranslated region of the bcl-2 gene and the minor one at 3' of the gene. Analysis of a panel of follicular lymphoma DNAs using probes for the first exon of the bcl-2 gene indicates that DNA rearrangements may also occur 5' to the involved bcl-2 gene. In this case the IgH locus and the bcl-2 gene are found in the order 3' C gamma S gamma/mu JH 5'::5' bcl-2 3' (where C = constant, S = switch, and JH = joining segment of the heavy chain locus), suggesting that an inversion also occurred during the translocation process. The coding regions of the bcl-2 gene, however, are left intact in all cases of follicular lymphoma studied to date.

Base Sequence↗

Mechanism of the t(14;18) chromosomal translocation: structural analysis of both derivative 14 and 18 reciprocal partners.

To elucidate the mechanism of the t(14;18)(q32;q21) chromosomal translocation found in follicular lymphoma, we examined the structure of both derivative (der) chromosomal breakpoints as well as their germ-line predecessors. We noted that chromosome segment 18q21 was juxtaposed with immunoglobulin heavy (H) chain gene diversity (DH) regions on all five der(18) chromosomes we examined, and we confirmed the juncture with immunoglobulin H-chain gene joining (JH) regions on the der(14) chromosome. However, the t(14;18) was not fully reciprocal in that chromosome 14 DNA between the DH and JH regions was deleted. Furthermore, extra nucleotides, reminiscent of "N" segments, were present at the der(14) and possibly der(18) junctions. This indicates that despite the mature B-cell phenotype of follicular lymphoma, the t(14;18) occurs during attempted DH-JH joining, the earliest event in immunoglobulin rearrangement in a pre-B-cell. Our detailed analysis of the germ-line 18q21 region indicated that most breakpoints clustered within a 150-base-pair major breakpoint region. However, we found no evidence for evolutionarily conserved immunoglobulin-like recombinational signals at 18q21, arguing against a role for immunoglobulin recombinase in chromosome 18 breakage. Instead, a direct repeat duplication of chromosome 18 sequences was discovered at both chromosomal junctures, typical of the repair of a naturally occurring staggered double-stranded DNA break. These results prompt a translocation model with illegitimate pairing of a staggered double-stranded DNA break at 18q21 and an immunoglobulin endonuclease-mediated break at 14q32 and with N-segment addition, repair, and ligation to generate der(14) and der(18) chromosomes.

Base Sequence↗

Clonality of angioimmunoblastic lymphadenopathy and implications for its evolution to malignant lymphoma.

To investigate the relationship of the lymphoid hyperplasia of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) to supervening malignant lymphoma, we subjected DNA from lymph nodes and peripheral blood mononuclear cells from five AILD patients to Southern blot analysis to detect clonal rearrangements of immunoglobulin and T-cell receptor genes. Lymph nodes and peripheral blood from AILD patients were found to contain clones of lymphoid cells harboring either immunoglobulin or T-cell receptor gene rearrangements that, in some instances, regressed during the course of disease. A lymph node from one patient was involved by immunoblastic lymphoma and manifested an additional gene rearrangement pattern not seen in premalignant specimens from that patient. In contrast, DNA obtained from normal peripheral blood mononuclear cells and 11 examples of other forms of lymphoid hyperplasia showed no gene rearrangements. As a disorder of cellular immunoregulation in which lymphoid cells may escape normal growth controls, AILD provides a natural model to dissect stages of lymphomagenesis in man.

Cells, Cultured↗

Refinement of lymphoma cytogenetics by the chromosome 18q21 major breakpoint region.

A small (2.8-kilobase, kb) major breakpoint region localized to segment 18q21 rearranges in greater than 70% of t(14;18)(q32;q21) lymphomas. This rearrangement interrupts the Bcl-2 gene and introduces it into the Ig locus at 14q32. The rearrangement between the joining region (JH) of Ig on chromosome 14 and the 18q21 region creates a translocation-specific DNA rearrangement. We generated probes that distinguish the 14;18 juncture on the derivative (der) 14 and der (18) chromosomes, providing a molecular approach to t(14;18) identification. Approximately 60% of unselected follicular lymphomas, 20% of diffuse large cell lymphomas, and 50% of adult undifferentiated non-Burkitt lymphomas demonstrated 14;18 rearrangements within the major breakpoint region. Examination of DNA for 14;18 rearrangements resolved the identity of 14q+ chromosomes in two patient's cells that lacked an obvious reciprocal partner. Identification of the exact restriction fragments that mediate translocations complements routine cytogenetics. The detection of DNA rearrangements does not require dividing cells or the presence of an identifiable reciprocal partner and can detect clonal translocation rearrangements when the neoplastic cells are only a minority of all cells present.

Chromosome Banding↗

Rearranged antigen receptor genes in Hodgkin's disease.

Despite intensive efforts using a wide variety of approaches, the cellular lineage and clonality of the abnormal cells of Hodgkin's disease have remained an enigma. In the present study, cell separation techniques that enriched for Reed-Sternberg cells and their variants were used to generate sufficient percentages of abnormal cells to allow detection of rearrangements in these cell fractions. DNA from the involved tissues of eight Hodgkin's disease patients was subjected to Southern blot analysis to detect rearrangements of T cell antigen receptor genes and immunoglobulin genes. Immunoglobulin gene rearrangements were found in three of five cases in which Reed-Sternberg cells and their variants were enriched by cell separation techniques to cell frequencies greater than 1%. Rearrangements of immunoglobulin heavy chain genes occurred in two cases, and a lambda light chain gene rearrangement occurred in a third case. Rearrangements were not detected in lymphocyte fractions or in unseparated cells prepared from the same tissues. The putative Hodgkin's cell line, L428, also contained rearrangements of immunoglobulin heavy and kappa and lambda light chain genes and, in addition, harbored a single T cell receptor beta gene rearrangement. These findings indicate that Reed-Sternberg cell-enriched fractions contain clonal cell populations and provide a lead, at the molecular genetic level, to a possible lymphoid derivation of the Reed-Sternberg cell.

Antigens, Surface↗

Development of T3/T cell receptor gene expression in human pre-T neoplasms.

Acquisition of mature T cell function and the T cell antigen receptor repertoire occur in the thymus. In an effort to delineate the cascade of events leading to T cell maturation, we analyzed a series of clonal human precursor T cell neoplasms representing early, middle, and late stages of intrathymic differentiation. Rearrangements of the T cell receptor beta and gamma genes appear concurrently and are preceded by surface expression of the 3A1 (CD7) molecule. Subsequent transcription of the beta gene is coordinated with surface expression of T1 (CD5) and T11 (CD2), transcription of T3 delta mRNA, and the appearance of intracellular T3 (CD3) protein. As late events, T alpha gene transcripts appear and, finally, T3, the multichain complex linked to the T cell receptor, is presented on the cell surface. Findings reported here provide a model of the developmental orchestration of genes encoding antigen recognition in human T cells.

Antigens, Differentiation, T-Lymphocyte↗

Configuration and expression of the T cell receptor beta chain gene in human T-lymphotrophic virus I-infected cells.

We studied the configuration and expression of the gene encoding the beta chain of the T cell receptor (TCR beta) in cell lines and primary tumor cells infected by the human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I). Most of the cell lines and all the primary tumor cells showed rearrangement of the TCR beta gene, and in each case the rearrangement was distinct. The majority of cases examined were clonal with respect to a particular TCR beta gene rearrangement. Primary tumor cells from one case (SD) were found to have a tandem duplication of a portion of chromosome 7; this appears to have resulted in the presence of three alleles of the TCR beta gene, each of which is arranged differently. This suggests that the chromosomal abnormality, and possibly infection by HTLV-I, occurred before TCR beta gene rearrangement. Cell lines infected by HTLV-I express levels of TCR beta mRNA similar to PHA stimulated lymphocytes, suggesting that this gene is not transcriptionally activated as a result of infection by HTLV-I. Cloned T cells of known antigen specificity that are infected by HTLV-I in vitro show impairment of immune function, including loss of antigen-specific responsiveness and the acquisition of alloreactivity. Comparison of the configuration of the TCR beta gene before and after infection revealed no changes detectable by Southern blot analysis. Levels of expression of the TCR beta gene at the mRNA level and surface expression of the T3 complex were also not significantly altered, suggesting that changes in immune function cannot be attributed to quantitative changes in the TCR molecule. The configuration of the TCR beta gene in primary tumor cells infected by HTLV-I was compared with that in the derived cell lines. In all pairs examined, the configuration in the primary tumor cells was different from that in the cell lines, strongly suggesting that the cells that grow in culture are not the original neoplastic cells.

Antigens, Neoplasm↗

Decreased expression of class II major histocompatibility antigens on monocytes from patients with Hodgkin's disease.

Expression of class II major histocompatibility (MHC) antigens by peripheral blood monocytes from 12 patients with Hodgkin's disease (HD) were studied employing antiserum and complement-mediated cytotoxicity. Overall, the expression of class II MHC antigens was significantly decreased on HD monocytes (cytotoxicity index [C.I.] = 60.2 +/- 5.8% vs 77.6 +/- 2.8%, P less than .02). This decrease was most marked in patients with more severe disease. In fact, mean alloantigen expression for patients with advanced stages of disease was 58% of that observed in controls. The number of human lymphocyte antigen (HLA)-DR antigenic sites per cell was also reduced as determined by monoclonal anti-DR antibody and FACS analysis. There was 38% more HLA-DR per cell in normal controls than in moderately advanced Hodgkin's patients. Class II MHC antigen expression on HD monocytes were increased partially by an IFN-gamma containing concanavalin A-stimulated human mononuclear cell culture supernatants (Con A sup), although remaining subnormal. When monocytes were cultured with Con A sup and indomethacin, alloantigen expression was increased in HD and control monocytes, but indomethacin failed to normalize class II MHC antigen expression on HD monocytes (C.I. = 72.3 +/- 4.7% vs 90.2 +/- 1.8%, P less than .01). We conclude that PGE accounts only inpart for the decreased alloantigen expression by HD monocytes. Interleukin (IL) 1 production by patients' monocytes was not reduced as compared to normals and therefore does not contribute to the decreased MHC II antigen expression. Decreases in alloantigen expression may be an important determinant of the T cell-mediated immune abnormalities in Hodgkin's disease.

Adult↗

Human monoclonal antibody directed against an envelope glycoprotein of human T-cell leukemia virus type I.

We report the production and characterization of a human monoclonal antibody reactive against the major envelope glycoprotein of human T-cell leukemia virus type I (HTLV-I), a virus linked to the etiology of adult T-cell leukemia. We exposed lymph-node cells derived from a patient with adult T-cell leukemia to the Epstein-Barr virus in vitro and obtained a B-cell clone (designated 0.5 alpha) by a limiting dilution technique. The secreted product of 0.5 alpha is a monoclonal antibody (also designated 0.5 alpha; that is IgG1 and has kappa light chains) that binds to the cell membrane of T-cells infected with HTLV-I and lyses them in the presence of complement. The antibody does not react with HTLV-I-negative T cells. In electroblot assays, the monoclonal antibody detects a 46-kDa glycoprotein in disrupted HTLV-I virions and a 34-kDa product following digestion of the viral protein with endoglycosidase F. These molecules have been reported to represent the HTLV-I env gene products. The antibody does not react with HTLV-II and HTLV-III virions. Glycoproteins of 61 and 68 kDa, which are known to be encoded at least in part by the env gene of HTLV-I, are precipitated by the antibody from endogenously radiolabeled HTLV-I-infected HUT 102-B2 and MT-2 cells, respectively. These results suggest that this human monoclonal antibody reacts with an env-encoded glycoprotein of HTLV-I. By using a competition assay with a biotin-labeled 0.5 alpha antibody, we observed that 15 out of 15 patients with adult T-cell leukemia had antibodies that block binding of the 0.5 alpha antibody to HTLV-I virions. This suggests that the antigen detected by 0.5 alpha antibody is a common epitope recognized in HTLV-I-infected individuals in vivo. This antibody, as well as the general strategy for making human monoclonal antibodies reactive against pathogenic retroviruses, may have diagnostic or therapeutic application.

Antibodies, Monoclonal↗

Infection of human T lymphotropic virus-I-specific immune T cell clones by human T lymphotropic virus-I.

Human T lymphotropic virus-I (HTLV-I)-specific T cell lines were established and cloned. K5, an OKT8+ clone bearing multiple proviral integration sites, retained its HTLV-I-specific cytotoxicity and a normal dependence on interleukin 2 (IL-2), indicating that there is a finite number of transforming integration sites. R2, an OKT4+ HTLV-I-infected clone, initially mounted a proliferative response to HTLV-I; but then its IL-2-independent proliferation increased and the antigen specificity was lost. All HTLV-I-infected clones tested including K7, another OKT8+ transformed cytotoxic clone that had lost its reactivity, expressed comparable levels of T cell receptor beta-chain (TCR-beta) messenger (m)RNA. Although clones K5 and K7 had different functional properties, they had the same rearrangement of the TCR-beta gene, suggesting that they had the same clonal origin. These data indicate that HTLV-I-specific T cells retain their immune reactivity for variable periods of time following infection, but then usually lose it; in some cases, however, no alteration in function can be detected. The data also suggest that different consequences can take place in the same clone depending on the pattern of retroviral infection.

Antibodies, Monoclonal↗

3A1 (CD7) expression precedes T beta gene rearrangements in precursor T (lymphoblastic) neoplasms.

The phenotypes of early stages of T cell maturation are reflected by precursor T (lymphoblastic) neoplasms. In the present study, a series of such neoplasms was analyzed to reveal the developmental association of the expression of stage-related cell surface markers and T cell receptor gene rearrangement. Rearrangements of the T cell receptor beta-chain (T beta) gene were found in most, but not all, cases (88%) of T cell lymphoblastic neoplasms. T beta gene rearrangement preceded surface expression of the T cell receptor-linked molecular complex T3. Of all monoclonal anti-T cell antibodies tested, only antibody 3A1 was capable of reacting with neoplastic cells from all cases irrespective of the occurrence of T cell receptor gene rearrangements. In contrast, markers T1 and T11, normally expressed by mature T cells, were absent from the neoplastic cells in many cases (73% and 60% positive cases, respectively). Thus, antibody 3A1 is a valuable probe for the identification of T lymphoblastic neoplasms since its target antigen is consistently expressed and does not require prior T beta gene rearrangement. Furthermore, expression of 3A1 prior to T beta gene rearrangement suggests that it may be a cell surface protein that participates in the triggering of T cell receptor gene rearrangement and expression. It is concluded that precursor T cell neoplasms display an early T cell development hierarchy that, in sequence, consists of 3A1 expression, T beta gene rearrangements, and surface T3 expression.

Cell Differentiation↗