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Biomedical subjects

J Wybran

Publications and source records attributed to J Wybran.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Induction of cell surface antigens on a lymphomatous cell line by gamma interferon].

The interferons are known to induce the expression of cell surface determinants. Gamma interferon, in particular, has been shown to enhance class II antigens (DR) on the cell surface. We used this gamma interferon to induce beta 2-microglobulin (beta 2 mu) and a minor, sex related transplantation antigen called H-Y on the surface of B lymphoma cells. The antitumor effect of interferon could thus be at least twofold: an antiviral effect already known and an increase of intercellular recognition (by cell surface marker enhancement); allowing the tumor cells to be "seen" better by cells of the immune system.

Antigens, Surface↗
PubMed1985

Enkephalins and endorphins as modifiers of the immune system: present and future.

This paper summarizes the data related to the relations between enkephalins and endorphins and the immune system. It is shown that lymphocytes have surface receptors for endorphins and enkephalins. Furthermore, endorphins and enkephalins can influence several immune functions such as antibody synthesis, lymphocyte proliferation, and natural killer cytotoxicity. It is thus possible that the receptors play a functional role. In view of these observations, several hypotheses are proposed. Endorphins and enkephalins are physiological regulators of the immune response (two-hit opioid peptide lymphocyte receptor hypothesis) and they are humoral mediators between the central nervous system and the immune system. They may play a pathogenic role in a variety of diseases with primary or secondary immunological defects. Finally, enkephalins and endorphins can be considered as immunomodulators and modifiers of the biological response and as such may become a tool in the field of immunotherapy.

Animals↗
PubMed1984

[Therapeutic experiences with the immunostimulator inosine pranobex].

The reason for giving substances with immunostimulatory properties is to restore or normalize immune functions. Since various human pathogenic viruses can induce immunodepression, the administration of immunostimulants offers a possibility for therapeutic intervention in the immune system. This could be demonstrated. Various virus infections can effectively be influenced by the synthetic immunostimulating agent Inosine Pranobex.

Antibody Formation↗
PubMed1984

Deficient natural killer function in patients receiving immunosuppressive drugs: analysis at the cellular level.

Renal transplant recipients receiving low maintenance immunosuppression (azathioprine, 2 mg/kg/day, and prednisolone, 10 mg/day), tolerating their transplants well, and without viral infection disclose a profound depression of NK activity as assessed by 51Cr-release assay. By combining the analysis of the different steps of cytolysis with the agarose single-effector assays and the estimation of circulating large granular lymphocytes (LGL), the defect is shown to be due to a significant decrease of the number of NK cells capable of binding (% target-binding cells 2.0 +/- 0.3 versus 5.7 +/- 0.7 in normals, P less than 0.001) and killing (% cytotoxic target-binding cells 12.4 +/- 1.9 versus 22.0 +/- 0.5 in normals, P less than 0.001) of targets. There is also a significant reduction (P less than 0.001) of both percentages (1.0 +/- 0.2 versus 3.3 +/- 0.4 in normals) and absolute values (9.8 +/- 2.4 versus 62.3 +/- 8.0/microliters in normals) of LGL. These observations indicate that depressed NK activity is due mostly to depletion of NK cells. Functional impairment of NK cells can also be involved. Lack of direct in vitro effects of drugs (6-mercaptopurine, hydrocortisone, and methylprednisolone) at concentrations likely to be reached in vivo during treatments and relative resistance of NK activity after in vivo steroid administration suggest that immunosuppressive drugs act at the precursor cell level or on regulatory mechanisms. Despite functional integrity of two suppressor cell systems of allogeneic NK activity (suppression induced by preculture of lymphocytes with Con A and suppressor granulocytes) in immunosuppressed patients, tested on normal NK cells, NK cells of immunosuppressed patients did not disclose greater susceptibility to Con A-induced suppression. This analysis indicates that the depletion phenomenon is probably a major mechanism in NK depression of patients receiving immunosuppressive drugs.

Azathioprine↗
PubMed1984

T antigen expression by human lymphocytes in relation to E rosette affinity.

Active and late rosette-forming cells, separated on the basis of their different affinities for SRBC, were tested for their ability to react with monoclonal antibodies of the OKT series. No significant preferential distribution of T subpopulations defined by these reagents was found in the high affinity E rosette fraction, while in the low affinity T cell subset the major finding was a high number of cells lacking both OKT4 and OKT8 determinants. This seems to be related to methodology, as indicated by experiments in which sequential cycles of rosetting procedures were found to induce loss of reactivity with OKT monoclonal antibodies. The implications of these methodological observations are further discussed.

Adult↗
PubMed1984

Angioimmunoblastic lymphadenopathy with paraproteinemia. Analysis of the clinical and biological characteristics and their prognostic significance.

We report a case of a double M component appearing in the course of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD). Lymphocyte function, especially the decrease in T-suppressor cells, could play an essential role in the mechanisms of the disease. In the presence of an M component, the prognosis for AILD seems to be more pessimistic. Arguments for considering AILD as a premalignant disease are reviewed.

Female↗
PubMed1984

Ultrastructural demonstration of retrovirus antigens with immuno-gold staining in prodromal acquired immune deficiency syndrome.

The peripheral lymphocytes of a patient with prodromal acquired immune deficiency syndrome contained giant multivesicular bodies. These were specifically stained by immuno-gold labelled polyclonal antibodies against the major core protein p24 of bovine leukaemia virus and human T cell leukaemia virus I. Moreover, the patient's serum was positive for bovine leukaemia virus by the ELISA method.

Acquired Immunodeficiency Syndrome↗
PubMed1983

The active rosette mixed-lymphocyte reaction: an early marker of lymphocyte activation linked to HLA-D-DR differences.

A new approach to rapidly determine human mixed-lymphocyte culture (MLC) is presented. It is based on the identification of an early increase in the percentages of active T rosettes (TEa) in the MLC tubes. Active T rosettes represent a subset of T cells with high-avidity receptors for sheep red blood cells. All subjects tested had a full determination of their HLA-A, -B,-C, and -D-DR. The following observations were made: (1) When the MLC was done between 10 pairs of fully HLA-A,-B,-C, and -D-DR incompatible subjects, a highly significant increase (P less than 0.001) was observed after 2 hr of MLC in all pairs tested. (2) The same increase was observed in all 10 pairs of identical HLA-A,-B, and -C subjects but not sharing HLA-D-DR antigens. (3) In the cases of HLA-D-DR semi-identity, the increase in TEa percentages was less marked after 2 hr of culture (P less than 0.05) and delayed in time to reach the significance level of P less than 0.001 after 4 hr of culture. (4) In contrast, in the case of full HLA-D-DR identity, no increase in TEa percentages was observed at any time in the culture (2, 4, and 24 hr and 4 days) in nine pairs of subjects tested (two pairs of identical twins). In conclusion, these results indicate that the active T rosette MLC is a rapid approach (2 hr) to evaluate HLA-D-DR differences without influence by HLA-A,-B, or -C. As such it is an early marker for HLA-D-DR determination and may become a useful tool in the field of human histocompatibility to study the HLA-D-DR region.

HLA-DR Antigens↗
PubMed1983

Active T rosettes, human autologous T rosettes, OKT8 and OKT4 cells, con A-induced suppressive activity, and autoantibodies: clinical correlations.

Correlations between various T-cell subsets: OKT4, OKT8, TEh (human autologous T rosettes), and TEa (active T rosettes) cells and the concanavalin A-induced suppressor function assessed on Con A proliferation have been analyzed in 46 patients with various secondary immunological disorders. The different T subsets and the suppressive activity were also compared in patients with and without autoantibodies. Significant positive correlations were found between T-cell markers TEa-OKT8 and TEh-OKT4. Significant inverse correlations were also found between Con A-induced suppressive activity-OKT4/OKT8 ratios, and TEa-OKT4/OKT8 ratios suggesting that the subpopulations identified by the active T rosettes are probably involved in T immunoregulatory mechanisms. There was no association between the Con A-induced suppressive function or the T markers TEa, OKT4, and OKT8, and the presence of autoantibodies. Only subjects with autoantibodies had a lower percentage of T lymphocytes forming autologous rosettes. These observations emphasize the fact that lack of correlation may exist between markers or function and immune status in some patients.

Antibodies, Monoclonal↗
PubMed1983

Depletion of lymphocytes with membrane markers of helper phenotype: a feature of acute and chronic drug-induced immunosuppression.

T cell subsets tested with markers for Fc receptors for Ig (TM, TG and EAhu rosettes) or monoclonal antibodies (T4 and T8 lymphocytes) were investigated both in normal volunteers and in kidney transplant recipients with a well functioning graft and receiving low immunosuppressive therapy, before and 4 hr after administration of 100 mg of hydrocortisone. Hydrocortisone induced a redistribution which was characterized by a decrease in the percentages of TM (38 +/- 2.4 before; 22 +/- 2.9 after; P less than 0.0005) and T4 (48 +/- 2.6 before; 35.8 +/- 2.7 after; P less than 0.0025) lymphocytes. Transplanted patients under chronic immunosuppression already disclosed a reduction of the percentages of TM (19.4 +/- 2.6; P less than 0.005) and T4 (41.1 +/- 3.6; P less than 0.05) lymphocytes before the administration of hydrocortisone when compared to the values obtained in normals. Moreover, significant decrease of percentages of TM lymphocytes (19.4 +/- 2.6 before; 12.8 +/- 2.6 after; P less than 0.01) were obtained after hydrocortisone injection. In contrast, T8, TG and EAhu rosettes percentages were characterized by a relative resistance to immunosuppressive agents--the only exception being TG lymphocytes in transplant recipients. It is concluded that TM and T4 depletion is a common feature of acute and chronic drug-induced immunosuppression, suggesting that helper-inducer cells are important targets for immunosuppressive therapy.

Adult↗
PubMed1983

Haemodialysis, continuous ambulatory peritoneal dialysis and cellular immunity.

The cellular immunity of haemodialysis and continuous ambulatory peritoneal dialysis (CAPD) patients was studied with regards to T-lymphocyte subsets and to suppressor T-cell function. The two groups of patients showed similar alterations: low proportions of suppressor-cytotoxic T-cells and low suppressive activity. In both groups there is a deterioration of this suppressive activity with time on dialysis.

Aged↗
PubMed1981

Effect of levamisole on leukocyte adherence inhibition.

The leukocyte adherence inhibition test can serve as an in vitro model to investigate the cellular cooperation between T cells, monocytes and polymorphonuclear cells (PMN) but also the mechanism of cell adherence. Therefore, the effect of levamisole on the production of PMN activating factors by mononuclear cells and on cell adherence was studied with leukocytes from polyarthritic patients. Levamisole at concentrations ranging from 10(-9) M to 10(-4) M did not seem to affect the production of activating factors. These results differentiate levamisole from anti-inflammatory drugs which are potent inhibitors. On the other hand, levamisole increased markedly the adherence of leucocytes, mainly mononuclear cells, obtained from polyarthritic patients, or normal cells preincubated in a polyarthritic serum. This could be related to a direct effect of levamisole on the leukocyte membrane.

Anti-Inflammatory Agents↗