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A Zeevi

Publications and source records attributed to A Zeevi.

At least 199 records · Page 11Linked to original sources
PubMed1984

Heterogeneity of human T-lymphocyte clones generated from autologous mixed-lymphocyte cultures.

To assess the heterogeneity of T cells activated during the autologous mixed-lymphocyte reaction (AMLR), a cloning procedure based on the soft agar colony assay was developed. Supernatants of allogeneic MLR cultures were used as a source of interleukin 2 (IL-2) to generate two types of colonies: upper and lower colonies. Both types of colonies were expanded in long-term cultures using supernatants of phytohemagglutinin (PHA)-activated lymphocyte cultures. Cloned cells underwent secondary proliferation when stimulated by autologous monocytes, although certain clones also responded to autologous B cells. Most autoactivated clones expressed the serological determinants of HLA-DR, MB, and MT and were OKT3+, OKT4+, OKT8-. They did not induce cytolysis of autologous monocytes, B lymphoblasts, or PHA blasts nor did they express natural killer-like activity toward K562 cells. Several autoactivated clones (irradiated with 500 R) expressed helper activity, shown by an enhancing effect on AMLR proliferation. Furthermore, many irradiated clones were capable of inducing proliferation of autologous T cells in the absence of accessory cells. These observations suggest that autoactivated clones generated from soft agar colonies may interact with autologous T lymphocytes.

Adult↗
PubMed1984

Serological and cellular definition of a new HLA-DR associated determinant, MC1, and its association with rheumatoid arthritis.

A new serological HLA-DR associated determinant was defined by a cluster of six B cell alloantisera. This determinant, designated as MC1, was strongly associated with DR1 and DR4 and appeared unrelated to MB, MT, and SB. The antigen frequency of MC1 was 47% in Caucasoids and 43% in Blacks. Mixed leukocyte culture cloning yielded an alloreactive T cell clone with PLT specificity associated with MC1. We have also observed that certain alloreactive clones may also acquire expression of MC1 but not DR4 during long-term culture maintenance in the presence of DR4, MC1-positive feeder cells. Disease association studies showed a significantly increased frequency of MC1 in adult rheumatoid arthritis patients (93.5% vs 47.4% in normals; relative risk 16.1). These findings suggest that MC1 represents a novel HLA-D encoded determinant.

Alleles↗
PubMed1983

Detection of HLA-DR associated PLT determinants by alloreactive lymphocyte clones.

This study deals with alloreactive T-cell clones which recognize cellular determinants associated with HLA-DR antigens. Two clones, CB55 and DS56, exhibited a PLT specificity that was perfectly associated with DR5. On the other hand, clones CB7, DS1 and HS1 showed PLT reactivity with approximately one-half of the DR5 positive cells and none of the DR5 negative cells, whereas clone MD4 largely reacted with the other half of DR5 positive cells. Another MLR culture generated two alloreactive clones DS6 and DS9 with PLT specificity for DR2. However, these clones did not respond to DR2 cells, which were also positive for the DR2-associated HLA-B7 and B18 antigens. Monoclonal antibody (mAb) inhibition studies showed heterogenous patterns, whereby monomorphic non-DR mAbs inhibited the DR2-associated PLT clones while the DR5-associated PLT clones were inhibited by different groups of anti-DR and non-DR mAbs. These observations suggest the existence of several lymphocyte-activating determinants associated with HLA-DR antigens. This diversity may be an important consideration in studies of the role of HLA-DR in immune mechanisms and transplant compatibility.

Antibodies, Monoclonal↗
PubMed1983

Detection of non-HLA-DR determinants by alloreactive lymphocyte clones.

Using the soft-agar colony assay, we have generated three MT3-associated clones: HJ1, HJ13, and HJ39, from an MLR combination of two unrelated individuals. Another clone, HJ37, appeared to recognize a novel HLA-D determinant. PLT inhibition studies with monoclonal anti-Ia-like antibodies (Mab) were conducted on clones HJ1, HJ39, and HJ37. Five different anti-DR Mab had no significant inhibitory effect on these clones. On the other hand, two Mab SG171 and Q5/13 which appear to react with DR and MT3 (I-A like) molecules strongly inhibited the two MT3-specific PLT clones. While SG171 and Q5/13 had little effect on HJ37, it was observed that a polymorphic Mab 17.15 had a strong inhibitory effect. These results, in concordance with biochemical data on Ia molecules precipitated by these Mab, suggest that these alloreactive clones may recognize non-DR PLT determinants. They also provide further indirect support that MT3 molecules represent the human homologue of murine I-A molecules.

Antibodies, Monoclonal↗
PubMed1983

Immunogenetic analysis of the HLA complex with alloreactive T cell clones.

Recently developed technologies to clone alloreactive human lymphocytes have provided a powerful tool for the immunogenetic analysis of the HLA region. Alloreactive T cell clones can be used as specific reagents for HLA encoded cellular determinants detected in secondary proliferation assays such as the primed lymphocyte test (PLT) and, in cell-mediated lympholysis (CML). Lymphocyte clones can also be used for functional assays (e.g., for suppressor or helper activity) to determine the influence of HLA specific restriction.

Clone Cells↗
PubMed1983

Primed lymphocyte testing specificity of alloreactive lymphocyte clones for HLA-B locus determinants.

We have generated two alloreactive T-lymphocyte clones that recognize the products of the HLA-B locus. The primed lymphocyte testing (PLT) reactivity of clone HJ21 was monospecific for the HLA-B antigen Bw49, a subtype specificity of HLA-Bw21. The PLT specificity of clone RD3 was strongly associated with HLA-Bw21. Several monoclonal antibodies against class I HLA molecules inhibited the PLT responses of these clones whereas class II monoclonal antibodies had no effect. These observations provide experimental evidence that class I products of the HLA-B locus may directly be involved in lymphocyte alloactivation.

Antibodies, Monoclonal↗
PubMed1983

Bone marrow transplantation for severe aplastic anemia using a phenotypically HLA-identical, SB-compatible unrelated donor.

A three-year-old boy with severe aplastic anemia (HLA-A1,B8(Bw6), Cw7,DR3, MB2, MT2, SB4/A1,B8 (Bw6), Cw7,DR3,MB2,MT2,SB-) received a bone marrow transplant from a phenotypically HLA-identical, SB-compatible female unrelated donor. This donor was selected from eighteen HLA-A1,-B8,-blood donors after extended serotyping, mixed leukocyte culture testing and secondary proliferation assays with primed lymphocyte typing reagents specific for SB. Although patient cells proliferated well as responders in MLR, their stimulatory capability was greatly impaired. Because the patient had inherited the same serological HLA-D haplotype from each parent, it was concluded that a compatible unrelated donor must be homozygous for the same HLA-D antigens as the patient. This HLA-D homozygosity was demonstrated by the lack of MLR responses of both parents to stimulators from the donor. The SB typing results suggested SB compatibility because both the patient and the donor typed as SB4,-. Following bone marrow transplantation, there was rapid hematopoietic engraftment. The patient developed severe diarrhea caused by graft-versus-host disease of the gastrointestinal tract, which necessitated hyperalimentation. He is currently eighteen months posttransplant with full hematopoietic reconstitution and moderate chronic skin graft-versus-host disease.

Anemia, Aplastic↗
PubMed1982

Association of PLT specificity of alloreactive lymphocyte clones with HLA-DR, MB and MT determinants.

The HLA-D region encodes for several serologically defined systems, including DR, MB, and MT. The antigens of MB and MT are strongly associated with two or more DR specificities. The purpose of this study was to determine the role of MB and MT antigens in lymphocyte alloactivation. A soft agar colony assay was used to generate alloreactive lymphocyte clones primed in mixed leukocyte culture against a stimulator who typed as HLA-DR4,-;MB3,-;MT3,-. In secondary primed lymphocyte typing (PLT) assays, several clones were identified with PLT specificities strongly associated with DR4, MB3, or MT3. The data suggest that HLA-D controls different lymphocyte-activating determinants associated with the serologically defined DR, MB, or MT antigens.

Clone Cells↗
PubMed1982

Heterogeneity of cytolytic and suppressor clones of alloactivated cells generated from soft agar colonies.

Long-term cell cultures (or clones) were developed from soft agar colonies of lymphocytes alloactivated in mixed leukocyte culture reaction (MLR). Two types of colonies were identified: upper colonies that grew on the agar surface, and lower colonies found within the agar layer. Virtually all cytolytic clones originated exclusively from the upper colonies. Two groups of cytolytic clones could be distinguished, one with strong and the other with weak proliferation upon restimulation. Upper clones were capable of inhibiting primary MLR proliferation and this appeared to be related to their cytolytic effect on the stimulator. Many noncytolytic lower clones were found to suppress primary MLR cultures. Considerable heterogeneity was apparent from differences in the magnitude of suppression and the ability of the clones themselves to undergo stimulator-induced proliferation. Kinetic studies of MLR suppression were conducted to further analyze this heterogeneity. Two major kinetic patterns were observed. One showed a biphasic proliferation pattern of the MLR + clone culture. The first peak appeared to reflect an enhanced proliferation of the clone. The second phase seemed to represent diminished proliferation of the MLR responder. This type of suppression may be related to T cell growth factor depletion from MLR by the proliferating clone. The other kinetic pattern showed a consistently low proliferation of the MLR + clone culture throughout the 8-day assay period. Subsequent testing of these suppressor clones in third-party MLR cultures suggested that the specificity of suppression was unrelated to HLA-DR, MB, MT, and SB.

Cell Division↗
PubMed1980

Functional differences between cells from MLR colonies grown in soft agar cultures.

This report describes a method of growing soft agar colonies of human T lymphocytes activated in the MLR. Two types of colonies were demonstrated: lower colonies grew within the agar layer, and upper colonies grew on the surface of the agar layer. Three days of priming the lymphocytes in the MLR and the use of supernatants of day-3 MLR cultures to provide T cell colony growth factor were necessary for optimal colony formation. Lymphocytes obtained from colonies were grown in long-term (2 to 4 weeks) cultures to generate sufficient numbers of cells to be tested in different functional assays. Cells from both types of colonies exhibited PLT activity. Upper colony cells showed considerably higher CML activity than lower colony cells (mean percent cytotoxicity 37 +/- 5 vs 6 +/- 3). Cells from both types of colonies contained radiosensitive suppressor cell activity that inhibited the primary MLR. The suppressor cell effect of lower colony cells was specific for the original stimulator, but upper colony cells displayed nonspecific suppressive effects. For both types of colony cells, it appeared that suppressive effects were unrelated to the CML activity of these cells. These data suggest that the soft agar colony assay offers a promising approach to separate subpopulations of lymphocytes activated in the MLR.

Agar↗
PubMed1979

Colony growth of T lymphocytes in vitro. Control and regulation of clonal formation.

Human lymphocytes stimulated with PHA in liquid phase (step 1) and then seeded in a two-layer soft agar system (step 2) grew and developed into T cell colonies. Colony formation was enhanced when the agar culture was supplemented with culture fluid obtained from phytohemagglutin-treated lymphocytes (Ly-CF). Untreated lymphocytes plated directly in the soft agar system also developed into colonies if the culture medium contained Ly-CF. Mitogen-sensitized T lymphocytes produced a lymphocyte colony enhancing factor in the culture fluid which stimulated lymphocytes into colony formation. The best plating efficiency (1:250) was attained when blood mononuclear cells were seeded. When spleen cell culture fluid or a highly concentrated blood-adherent cell population was added to the soft agar, colony development was strongly inhibited. Monocytes-macrophages secrete a lymphocyte colony inhibiting factor in the culture medium. These lymphokines exert a competitive influence on T cells and thus control and regulate clonal proliferation.

Agar↗
PubMed1978

Partial purification and characterization of the human lymphocyte colony enhancing factor (LCEF).

The cloning potential of PHA-treated T cells is significantly enhanced when lymphocyte culture fluid (LCF) from mitogen-treated lymphocytes is added to the soft agar culture system. The mitogens seem to stimulate the release of a lymphocyte colony enhancing factor (LCEF) into the culture medium. A study of the physico-chemical properties of the LCEF revealed that it is a nondialyzable, heat-labile molecule which migrates in the haptoglobin (2--2) post-transferrin region in acrylamide electrophoresis. It is stable to RNase and DNase but labile to papain and trypsin. The LCEF was partially purified from the crude LCF using a sequence of techniques--ammonium sulphate precipitation, DEAE-cellulose and Bio-Gel P-150 chromatography and disc electrophoresis. The mol. wt of the purified LCEF, determined from gel filtration chromatography, was 90,000--110,000.

Clone Cells↗
PubMedDate not supplied

Interleukin-10 production by a B-cell line derived from human post-transplant lymphoproliferative disease.

Interleukin-10 (IL-10) is a cytokine known to regulate growth and differentiation in activated human B cells. We studied IL-10 production in a B-cell line derived from Epstein-Barr virus associated post-transplant lymphoproliferative disease (PTLD). Reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated IL-10 mRNA within the cells. Transcripts of the virally encoded homologue BCRF-1 were not detected. ELISA assays demonstrated translation of IL-10 message into the corresponding cytokine, and its subsequent secretion into the culture medium. The rate of 3H-thymidine incorporation by the PTLD cells was not affected by immunologic neutralization of the secreted cytokine, or, by addition of exogenous recombinant IL-10 to the culture medium. Thus, IL-10 does not have an autocrine growth regulatory role in this PTLD line.

B-Lymphocytes↗
PubMedDate not supplied

In vitro culture of B-lymphocytes derived from Epstein-Barr-virus-associated posttransplant lymphoproliferative disease: cytokine production and effect of interferon-alpha.

Epstein-Barr-virus-associated posttransplant lymphoproliferative disease ranges from transient lymphadenitis to aggressive lymphoma. This study characterizes an in vitro model to study the pathogenesis of this disease with a cell culture system. Five B-cell lines derived from posttransplant lymphoproliferative disease tissue were characterized with regard to immunophenotype, karyotype, molecular genetics, cytokine production, and growth regulation. All cell lines expressed CD19, CD21, CD22, CD43, and CD77, but not CD10 antigens. Immunoglobulin light chain restriction was seen in four of five cell lines, and cytogenetic abnormalities were demonstrable in three of the five. Cells proliferating in culture contained multiple Epstein-Barr virus episomes and showed lytic viral replication. All cell lines produced tumor necrosis factor-beta and interleukin-10 without evidence of autocrine growth regulatory loops involving these cytokines. No evidence of IL-1 alpha, IL-2, IL-4, IL-5 or IL-6 production was found by reverse transcriptase polymerase chain reaction. Adding 500 U IFN-alpha/ml to the culture medium resulted in 30% inhibition of [3H]thymidine incorporation.

Adult↗