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Biomedical subjects

G Gaudernack

Publications and source records attributed to G Gaudernack.

At least 91 records · Page 5Linked to original sources
PubMed1989

Reliable isolation of human immunodeficiency virus from cultures of naturally infected CD4+ T cells.

A procedure for reliable and reproducible isolation of human immunodeficiency virus (HIV) from cultures of CD4+ T cells from healthy HIV seropositive individuals is described. Using immunomagnetic cell separation techniques, CD4+ T cells were positively selected from blood or peripheral blood mononuclear cells from 34 HIV infected individuals in CDC group II. The cells were stimulated with beads coated with a monoclonal antibody specific for the T cell receptor alpha/beta dimer and cultured in medium containing recombinant IL 2. HIV was isolated from 100% of the 41 cultures from 34 individuals. As this culture system allows reproducible isolation of HIV from cultures of naturally infected CD4+ T cells in the absence of other autologous or allogeneic cells, it may provide a good test system for the study of factors affecting the replication of HIV at low multiplicities of infection.

Antibodies, Monoclonal↗
PubMed1989

Ability of pure resting CD8+ human T cells to respond to alloantigen.

The ability of highly purified resting human CD8 cells to respond to alloantigens in vitro was examined. Necessary conditions for induction of interleukin 2 receptors (IL-2R), IL-2 production, proliferative responses, and various effector functions were determined. Allogeneic non-T cells induced IL-2R expression in a high proportion of resting CD4 and CD8 cells, but only CD4 cells produced detectable amounts of IL-2. CD8 cells also became IL-2 responsive upon stimulation with purified resting allogeneic CD4 or CD8 cells, indicating that HLA class I+, II- cells alone may initiate activation of resting CD8 cells. The activated CD8 cells needed the presence of simultaneously activated CD4 cells or exogenous IL-2 to be able to synthesize DNA. Effector functions like cytotoxicity, mixed lymphocyte culture (MLC) suppression, or gamma interferon (IFN-gamma) production were also only detectable when the CD8 cells were activated in the presence of IL-2.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Expression of activation markers on CD4+ and CD8+ cells from synovial fluid, synovial tissue, and peripheral blood of patients with inflammatory arthritides.

We studied the expression of the Tac antigen, the transferrin receptor (Tfr-R), HLA class II antigens (DR, DQ, DP), CD30, and Act 1 on purified CD4+ and CD8+ cells isolated from synovial fluid (SF), synovial tissue (ST), and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and with non-RA inflammatory arthritides (not ST). Subfractionated T cells of PB from healthy individuals served as controls. SF CD4+ cells from RA and non-RA arthritides expressed the Tac antigen much more frequently than corresponding CD8+ cells (54 and 58% versus 16 and 17%). In contrast, SF CD8+ cells of both patient groups expressed the HLA class II antigens rather more frequently than the corresponding CD4+ cells (88 and 68% versus 72 and 40%). Tfr-R expression was low on CD4+ and CD8+ SF T cells from both patient groups. SF T cells did not express CD30, and their expression of Act 1 did not differ from that of normal PB T cells. The RA ST findings were similar to those of RA SF. The overall expression of activation markers on PB T cells of patients was slightly higher than on those of normal controls, and the RA group was slightly higher than the non-RA group. The results show that intra-articular T cells in arthritis are activated and that CD4+ and CD8+ subsets differ in their expression of Tac antigen and HLA class II antigens. There were also similar patterns of activation markers on both CD4+ and CD8+ SF cells from RA and non-RA arthritis patients, suggesting that several types of arthritis display a similar immunopathogenesis in the joints.

Adult↗
PubMed1989

A functional study of purified CD4+ and CD8+ cells isolated from synovial fluid of patients with rheumatoid arthritis and other arthritides.

The purpose of this investigation was to study purified synovial fluid (SF) CD4+ and CD8+ cells from patients with rheumatoid arthritis (RA) and other inflammatory joint diseases (non-RA) with respect to the proliferative response to mitogens and recombinant interleukin 2 (rIL-2). Highly purified cell subsets were isolated by an immunomagnetic technique, and spontaneous proliferation as well as proliferative reSponses to rIL-2 and a combination of phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) (to substitute for accessory cells) were measured. Some patients had SF CD4+ and/or CD8+ cells with moderately increased spontaneous proliferation, but only the CD4+ cells of the two patient groups differed significantly from the peripheral blood (PB) T-cell subsets of healthy individuals who served as controls. The response to rIL-2 was variable but generally low, although about 50% of the CD4+ and 20% of the SF CD8+ cells of both patient groups expressed the Tac antigen. The response to PHA/PMA was significantly lower for RA SF CD4+ cells than for non-RA SF CD4+ cells, which again was lower than for normal PB CD4+ cells. SF CD8+ response to PMA/PHA by both groups of patients was somewhat decreased, but not significantly lower than in the controls. Thus, the CD4+ cells seemed functionally more deviant than the CD8+ cells in both patient groups, but the abnormality was most pronounced in the RA group. The results demonstrate that the previously reported diminished response to mitogens by SF mononuclear cells is present even when SF CD4+ cells are cultured alone. This indicates that these T cells have a reduced response, probably because of prior activation.

Adult↗
PubMed1989

Specificity of gamma delta receptor-bearing cytotoxic T lymphocytes isolated from human peripheral blood.

T-cell receptor (TcR)-gamma delta-bearing lymphocytes were isolated from the peripheral blood of two healthy donors by immunomagnetic separation and subsequently cultured. The cell lines generated showed two distinct patterns of cytotoxicity. One TcR-gamma delta + cell line (HG.D) lysed K562 and U937 target cells, three TcR-gamma delta + cell lines lysed Daudi cells, and one TcR-gamma delta + cell line showed a shift from the former to the latter specificity during culture. Cold target inhibition experiments showed that the HG.D effector cells which were cytotoxic against U937 cells also lysed K562 cells. The cytotoxicity against Daudi cells was strongly inhibited by monoclonal antibodies (MoAb) against the CD3 complex, whereas the cytotoxicity of the HG.D cell line against K562 and U937 was unaffected by such antibodies. The cytotoxicity against Daudi cells was also strongly inhibited in the presence of anti-TcR-gamma delta MoAb. However, in two of the Daudi-specific cell lines, strong cytotoxicity against K562 cells was induced by anti-TcR-gamma delta MoAb. Anti-LFA-1 MoAb caused only a partial inhibition of cytotoxicity, while anti-CD2 and anti-TcR-alpha beta MoAb were found to have no effect. The results indicate that human gamma delta receptor-bearing T cells demonstrate a certain degree of target cell specificity, and that recognition of some target cells may be mediated through the TcR-gamma delta.

Adult↗
PubMed1989

Human T lymphocyte clones: influence of culture conditions and optimization of proliferative assays.

Many CD4+ human T lymphocyte clones (TLC) are found not to proliferate against appropriate stimulating cells, and many lose this capacity during culture. This may be due, not to a defect in the recognition of the antigen, but to an inability to produce sufficient amounts of interleukin 2 (IL-2) for autocrine growth, since specific HLA-restricted proliferative responses could be induced in 'non-proliferative' clones by the addition of exogenous IL-2 or phorbol myristate acetate (PMA). Of various factors tested during expansion procedures of the clones, the proliferative capacity could only be restored by changing the stimulatory cells from B lymphoblastoid cell lines (B-LCL) to peripheral blood mononuclear cells (PBM). The cytotoxicity of the TLC was found to be independent of its proliferative capacity. After restoration of the proliferative capacity, a mouse B lymphoma cell line transfected with the appropriate HLA DQA and DQB genes was still not able to induce proliferation in the absence of exogenous IL-2. We conclude that (1) 'non-proliferative' TLC may recognize their targets, but fail to proliferate due to temporary lack of IL-2 production, and (2) even 'proliferative' T cells may fail to respond to certain target cells carrying the specific antigen, such as a murine transfectant, in the absence of exogenous IL-2.

Animals↗
PubMed1989

Mitogen-induced interleukin 2 and gamma interferon production by CD4+ and CD8+ cells of patients with inflammatory arthritides. A comparison between cells from synovial fluid and peripheral blood.

The purpose of this study was to investigate interleukin 2 (IL-2) and gamma interferon (IFN-gamma) production by purified CD4+ and CD8+ cells isolated from peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and other inflammatory arthritides (non-RA). CD4+ and CD8+ cells were selected positively by immunomagnetic separation. Supernatants of unstimulated CD4+ and CD8+ cells from both compartments did not contain any detectable IL-2 or IFN-gamma, while supernatants of CD4+ and CD8+ cells stimulated with phytohaemagglutinin and irradiated Raji cells mostly contained both cytokines. In vitro stimulated SF CD4+ cells gave supernatants with significantly less IL-2 than supernatants from PB CD4+ cells, while in vitro stimulated SF CD4+-cell supernatants contained significantly more IFN-gamma. SF CD4+-cell supernatants contained significantly more IL-2 than the parallel CD8+ supernatants, while there was no significant difference with regard to IFN-gamma content. The pattern of differences between SF- and PB-derived T cells was the same for the two groups of patients, but the SF CD4+ cells from RA patients produced significantly less IL-2 than the corresponding cells from the non-RA group. The difference between SF and PB T cells with regard to lymphokine production is probably related to various degrees of in vivo pre-activation. The results do not indicate a major T-cell deficiency in relation to lymphokine production in RA.

Adult↗
PubMed1989

HLA-DQ antigens and DQ beta amino acid 57 of Japanese patients with insulin-dependent diabetes mellitus: detection of a DRw8DQw8 haplotype.

DQw8 (DQw3.2) on DR4 haplotypes is a susceptibility gene for development of insulin-dependent diabetes mellitus (IDDM) in Caucasoids, possibly because it encodes a non-Asp amino acid (aa) (i.e. Ala) at residue 57 of the DQ beta chain (non-Asp-57). Most Caucasoid IDDM patients are homozygous non-Asp-57. We have examined 14 Japanese IDDM patients, selected to be either DR4 or DRw9 (associated to IDDM among Japanese). Their DQB1 alleles and the aa encoded by their DQB1 codons 57 were identified, using 11 different sequence-specific oligonucleotide probes. Secondly, they were examined with DQw8 specific T lymphocyte clones and with anti-DQ monoclonal antibodies. The DQB1 genes on their DR4 and DRw9 haplotypes in all cases encoded Asp-57. Two patients were Asp-57 homozygous, the rest were Asp-57/non-Asp-57 heterozygous. The DR4 haplotypes all carried DQw4 (rather than DQw8), and the DRw9 haplotypes all carried DQw9. Furthermore, five of six DRw8 positive patients carried a previously undetected DRw8DQw8 haplotype, where both the DQA1 and DQB1 genes were similar to those usually found on the DR4DQw8 haplotype. Thus, the DR/DQ allele combinations and aa residue 57 of the DQ beta chain of Caucasoid and Japanese IDDM patients are largely different.

Antibodies, Monoclonal↗
PubMed1989

Characterization of a monoclonal antibody recognizing a polymorphic epitope mainly on HLA-DPw2 and DPw4 molecules.

A monoclonal antibody (MAb), 13.3.B4, was obtained from a murine hybridoma after fusing Sp2/0 myeloma cells with spleen cells from C3H mice immunized with mouse L cells transfected with the A1 and B1 genes of HLA-DPw4. In radiobinding-assays, MAb 13.3.B4 bound to HLA transfectants expressing DPw2 or DPw4 as well as DPw2 or DPw4 homozygous B-cell lines, while most cell lines expressing other DP determinants were negative. MAbs with known DP or other HLA class II-specificities were used to inhibit binding of MAb 13.3.B4 in a radioimmunoassay. Three MAbs demonstrated inhibition, but their pattern of reactivity with HLA homozygous B cell lines differed from that of MAb 13.3.B4. An evaluation of DNA sequence data showed that MAb 13.3.B4 reacts with all cell lines expressing DP beta-chains of type 2.1, 2.2, 4.1 or 4.2. No correlation between 13.3.B4-reactivity and expression of DP alpha-chain variants was found. The results indicate that MAb 13.3.B4 defines a polymorphic epitope which may be determined by the sequence gly-gly-pro-met at residues 84-87 of the DP beta-chain.

Animals↗
PubMed1989

Rapid immunomagnetic phenotyping of cells.

A new method for immunophenotyping of cells in suspension has been developed. The method is based on identification of cells that have formed rosettes with superparamagnetic particles (Dynabeads) conjugated with monoclonal antibodies directed against cell-surface antigens. The method is extremely simple. Twenty-five microliters of cells are mixed with 5 microliters of Dynabeads in U-bottom microtitre wells. Following a 1-min centrifugation step, rosette formation can be inspected in the microscope. Staining of the cells before rosetting with acridine orange/ethidium bromide allows direct quantification of viable cells carrying a given marker. The method is limited to detection of cell-surface antigens, and the results obtained are comparable to those seen with indirect immunofluorescence. The method may be used for phenotyping of leukaemia and other cancer cells, and can also be used for phenotyping of cells that can only be obtained in small numbers, such as spinal fluid cells.

Antibodies, Monoclonal↗
PubMed1989

Positive selection of Tac- (CD25) positive cells following T-cell activation. Use of immunomagnetic separation and implications for T-cell cloning.

We have investigated if positive selection for cells expressing activation antigens, which appear on the cell surface during T-lymphocyte activation, could be used for cloning purposes. For this purpose, we used paramagnetic, monodisperse Dynabeads coated with anti-Tac monoclonal antibody, which recognizes CD25 (interleukin-2 receptor light chain). After the first 6-12 h of a primary response, depletion of Tac+ cells could largely abrogate the specific response. This indicated that the specifically responding cells were found among the Tac+ population. T-cell cloning was thus performed on Tac+ blasts positively selected after 18 h of a primary response, at day 6 of a primary response or during secondary stimulation, and gave a high percentage of specific clones. This method is thus a good alternative to established techniques.

Cell Separation↗
PubMed1989

Allogenic induction of thromboplastin synthesis in monocytes and endothelial cells. Biphasic effect of cyclosporin A.

Monocytes and endothelial cells were stimulated in co-culture with allogeneic lymphocytes to produce thromboplastin (TPL). The induction was biphasic, an early response (8-24 h) was greatly augmented by cyclosporin A (CS) (0.5-5 micrograms/ml) whereas the late response (day 3-4) was inhibited. Prednisolone inhibited both responses. Both drugs inhibited lymphocyte proliferation. Interferon-gamma decreased MLC TPL activity but increased thymidine incorporation. CD4+ cells were instrumental in inducing the early TPL peak in monocytes, whereas CD8+ cells decreased the TPL effect. With endothelial cells both T cell classes were equally effective. Conditioned medium from MLC as well as from co-cultures of endothelial cells and lymphocytes induced early TPL synthesis in endothelial cells. Upon allogeneic stimulation monocytes, but not endothelial cells, produced a significant amount of F-VII, most of which was apparently undercarboxylated.

Cyclosporins↗
PubMed1988

A simple and sensitive bioassay for the detection of IL-2 activity.

A simple, one-step quantitative assay for the detection of biologically active interleukin-2 (IL-2) is described. It is based on culture of pure CD3+ T cells which have been positively selected from blood mononuclear cells by particle (M450)-bound anti-CD3 monoclonal antibody (mAb). During culture, activation of the T cells via CD3 will occur, leading to expression of IL-2 receptors but not IL-2 production. By adding IL-2 a proliferative response is evoked, giving a linear dose-response curve for IL-2 concentrations between 0.01-20 U/ml. The cells were unresponsive to IL-1, IL-4, tumor necrosis factor alpha (TNF-alpha), interferon-alpha (IFN-alpha), IFN-gamma, phytohemagglutinin and concanavalin A. The responsiveness to IL-2 was enhanced by TNF-alpha and inhibited by IFN-alpha, while the other tested lymphokines and mitogens did not influence the proliferative response. Antibodies to IL-2 and to IL-2 receptor suppressed the IL-2 response in a dose-dependent manner. The method is both simple and specific, and obviates the necessity for keeping assay cells in long term culture.

Antibodies, Monoclonal↗
PubMed1988

Successful clinical use of an anti-HLA-DR monoclonal antibody for autologous bone marrow transplantation.

It has been widely assumed that anti-HLA-DR antibodies react with pluripotent stem cells and cannot be used in bone marrow purging. We report a case of non-Hodgkin's lymphoma in which an anti-HLA-DR antibody (AB4) was used for immunomagnetic purging and the subsequent autologous bone marrow transplantation resulted in rapid marrow engraftment with no serious complications. The results indicate that the AB4 antibody, which binds to an antigen encoded by the B3 gene of the DR region, can be safely used in the clinic in the purging of bone marrow from patients with AB4-positive tumors (non-T-cell acute lymphocytic leukemia, non-Hodgkin's lymphoma, and some cases of acute myelogenous leukemia.

Adult↗
PubMed1988

Small megakaryocytes--an identification problem.

The number of bone marrow megakaryocytes (MK) was estimated in May Grunwald-Giemsa-stained (MGG) and immunoenzymatically stained smears. The latter was performed after incubation with a monoclonal antibody (ITI-PL1) directed against blood platelets and megakaryocytes (MK). The MK were grouped according to their size (diameter above or below 30 micron, respectively). Altogether 7.9% more MK were recognized in ITI-PL1 stained smears as compared to MGG-stained smears, mainly because comparatively few small MK were recognized in MGG-stained smears.

Antibodies, Monoclonal↗
PubMed1988

T lymphocyte clones recognizing an HLA-DQw3.2-associated epitope involving residue 57 on the DQ beta chain.

The DQw3.2 specificity has previously been recognized using genomic RFLP analysis and certain combinations of monoclonal antibodies. Here we report three CD4+ T lymphocyte clones (TLCs) generated from a DR3,4; DQw2,w3.1 responder stimulated with cells from a DR3,4; DQw2,w3.2 donor, and using a modified cloning procedure involving enrichment of IL-2 receptor-positive T cell during priming. The resulting TLCs were strongly inhibited by some monoclonal anti-DQ, but not anti-DR or -DP antibodies. In panel studies using HLA homozygous stimulating cells, it was found that the TLCs recognize an HLA epitope encoded by a DQ gene carried only by DR4,DQw3.2 haplotypes. By comparison with published DQ chain amino acid sequences of some stimulating cells able or not to induce a response in these clones, evidence was obtained that Ala at position 57 on the DQ beta chain is most probably involved in the epitope. The epitope is present on cells from 12 out of 12 DR4,DQw3 insulin dependent diabetes mellitus (IDDM) patients, but on cells only from 6 out of 12 healthy DR4,DQw3 controls. Thus, a DQ-encoded epitope involving residue 57 on the DQ beta chain, and which is strongly associated to IDDM, may be recognized by T cells.

Amino Acid Sequence↗