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Biomedical subjects

W Uracz

Publications and source records attributed to W Uracz.

At least 19 recordsLinked to original sources
PubMed1993

Detection, by in situ hybridization using sulphonated cDNA probe, the specific mRNA for HLA-DR alpha induced in monocyte cell lines by recombinant interferon gamma.

We adopted the nonradioactive method used for blot hybridization for the detection of inducible mRNA for HLA-DR alpha by the in situ hybridization. Unstimulated and interferon gamma stimulated MonoMac6 and U937 human monocytic cell lines were used as target cells. Sulphonation of plasmid pBR322 with HLA-DR alpha cDNA insert (2 x 700 bp, in Pstl restriction site) was performed according to the manufacturer's procedure (SulfoProbe Kit, Sigma). The hybridization signals were detected with mouse monoclonal, anti-sulphonated DNA antibody, followed by immunovisualization with anti-mouse IgG-alkaline phosphatase conjugates. Unstimulated MonoMac6 and U937 cells showed few granular reaction products only in small percentage of cells (1-5%), while in IFN gamma stimulated cells the fine granular immunoenzymatic reaction was observed in the cytoplasm of majority of cells (> 80%). This method seems to be easy and rapid to perform, making it applicable for routine diagnostic purposes in tissue sections and biopsies.

Blotting, Southern↗
PubMed1992

Augmentation of monocyte-mediated cytocidal activity by a low dose tumour necrosis factor measured by the kinetic colorimetric microplate assay.

This paper describes a simple kinetic colorimetric assay for the quantitation of human peripheral blood monocyte-mediated cytotoxic activity against tumour cells. Isolated effector monocytes were cultured overnight with an increasing number of target cells in 96-well microplates. Cytotoxic activity of monocytes was determined by modified nitroblue tetrazolium (MTT) dye assay using standard ELISA reader offering possible automation. The test was performed with three different effector/target cell ratios using a fixed number of monocytes. This allowed the expression of cytotoxic activity of monocytes in cytotoxic activity units. The assay was found to be a simple method to demonstrate that low doses of TNF (1 U/ml) enhanced monocyte-mediated cytotoxicity.

Colorimetry↗
PubMed1992

Effect of peritoneal macrophages from intermittent peritoneal dialysis patients on lymphocytes in culture.

To investigate the biological activity of peritoneal macrophages, cells isolated from dialysate of 30 patients with end-stage kidney disease treated by intermittent peritoneal dialysis and from ascites of 6 patients with cardiac insufficiency (relative control group) were added to autologous, phytohemagglutinin (PHA)-stimulated lymphocyte cultures. Macrophages of dialyzed patients induced a dose-dependent increase in autologous lymphocyte proliferation, whereas macrophages obtained from control subjects exerted a suppressive effect on those cultures. The enhanced lymphocyte proliferation by macrophages from dialyzed patients was corroborated by the increased metabolic activity of macrophages as evaluated by the increased nitro blue tetrazolium (NBT) reduction test and increased functional expression of Fc receptors (FcR). The subpopulation of macrophages from patients with HLA-DR antigens as determined by HB55 monoclonal antibody, inhibited lymphoproliferation in vitro. We conclude that peritoneal macrophages from dialyzed patients represent a heterogenous population of cells with different phenotypic and functional characteristics.

Adult↗
PubMed1991

Functional characteristics of peritoneal macrophages of renal failure patients on peritoneal dialysis.

Functional activity of peritoneal macrophages of 50 patients with end-stage renal failure on intermittent peritoneal dialysis (IPD) and of 30 control subjects with normal renal function was determined. Phagocytosis of latex particles by macrophages of dialyzed patients was significantly lower as compared with the controls. Further depression of the phagocytic activity was observed during bacterial peritonitis. Macrophages from the dialyzed patients also showed nonsignificantly decreased functional expression of Fc receptors (FcR) and increased spontaneous nitro blue tetrazolium (NBT) reduction.

Adolescent↗
PubMed1989

The T cell receptor in the mouse.

In the eighties the genes of the T lymphocyte antigen receptor (TcR) have been cloned. The search for the elusive and controversial TcR is over. It is clear that genes for TcR are distinct from those of Ig genes although these genes belong to the immunoglobulin supergene family. The aim of this article is to scan briefly a history of the searching for TcR, than to update our knowledge about TcR. With the search for TcR behind, a new set of question and goals lies ahead. How does TcR, which is similar to Ig, recognize foreign antigen in association with major histocompatibility complex (MHC) gene products? What is the relationship between TcR and Iat molecules, including misterious I-J product?

Animals↗
PubMed1988

The altered expression of MHC-class II determinants on monocytes of cancer patients.

The expression of MHC class II determinants Ia.7 (detected by cross reactive mouse anti-Iak antibody) and HLA-DR on monocytes (MO) of gastric and colorectal cancer patients was examined. An increased proportion of MO bearing the Ia.7 determinant was found, while the number of MO expressing DR was not elevated. In gastric cancer patients the increased expression of the Ia.7 determinant was most pronounced in advanced cancer (stage IVA and IVB). The increased expression of this determinant was related to the presence of the tumour as the number of MO expressing Ia.7 decreased 6 months following surgical resection of the tumour. Further, the increased expression of Ia.7 on MO correlated with the tumour infiltration of the serosa. The Ia.7 determinants were mainly expressed on MO which also expressed the receptor for the Fc part of immunoglobulin. Immunostaining in cellular infiltrates surrounding the tumour revealed that Ia.7+ macrophages (MO) were more numerous than in normal gastric mucosa and severe chronic gastritis and were mostly present in close proximity to tumour cells, while DR+MO were mainly localized within the stromal tissue of the tumour and their number was not increased in cancer infiltrates. These observations indicate that the Ia.7+ subpopulation of MO may be involved in the anti-tumour response of the host.

Epitopes↗
PubMed1988

Immunoregulation of lymphoproliferation in vitro by monocytes and their subpopulations. I. The induction of suppressor T cells in long term cultures and the role of MHC class II determinants and preliminary characteristics.

Peripheral blood monocyte (MO) subpopulations isolated on a basis of functional expression or a lack of Fc receptor (FcR+ and FcR- MO) were used to study the regulation of the antigen (PPD)-driven lymphoproliferation. Long-term cultures of T lymphocytes with FcR+ MO, but not FcR- MO, led to the induction of T suppressor (Ts) cells that inhibited antigen-driven lymphoproliferation in the test cultures. These Ts cells were resistant to mitomycin C, belonged to afferent-acting category of Ts cells, expressed CD8 and HLA-DR determinants, and showed no antigenic specificity nor genetic restriction in action. The expression of MHC class II molecules (HLA-DR and HLA-DP but not HLA-DQ determinants) on MO which were used for antigen presentation was critical for Ts cell induction. It was concluded that specialized MO subpopulations may regulate the lymphoproliferation by inducing Ts cells (or Ts cell circuit) that in turn inhibit antigen-driven immune response.

Cells, Cultured↗
PubMed1988

Juvenile rheumatoid arthritis. Monocyte dysfunction in selected patients.

The in vitro parameters of cell-mediated immunity were studied in 20 children with an established diagnosis of Juvenile rheumatoid arthritis (JRA) (age range 4-15 years) and 23 age- and sex-matched healthy children. (No attempt was made to correlate the observed changes with clinical course or treatment). We are not certain, at this time, of clinical relevancy or the generalizability of the findings. The normal level of T-lymphocytes (CD3+) and normal proportions of CD4+ and CD8+ lymphocytes were seen in children with JRA. The in vitro response of lymphocytes to T-cell mitogen phytohemagglutinin (PHA) also was normal. The suppressor activity of JRA monocytes was essentially the same as controls. In contrast, monocytes from patients with JRA showed the following: decreased expression of receptors for Fc part of IgG immunoglobulin (FcR), diminished nitro blue tetrazolium (NBT) reduction activity, and depressed expression of Ia.7 major histocompatibility complex (MHC) class II determinants. This indicates that certain monocyte functions in selected patients with a variety of manifestations of JRA are depressed.

Adolescent↗
PubMed1988

Iat epitopes on T cell receptor for self MHC class II determinants.

Anti-Iatk monoclonal antibodies (mAbs) were found to inhibit syngeneic mixed lymphocyte reaction (SMLR) of mice with k and a haplotypes (H-2k and H-2a) of the major histocompatibility complex (MHC) by acting on responder T cells but not stimulator cells. Only the early phase of SMLR was inhibited by anti-Iat mAbs. The inhibitory effect was due to the blocking of autoreactive T cells but not induction of suppressor lymphocytes. Cross-linking of Iat epitopes induced T cell proliferation of k haplotype strain. The inhibitory pattern of SMLR by four anti-Iat mAbs varied among different strains of mice. The inhibitory pattern seemed to depend on MHC and unidentified non-MHC background genes possessed by stimulator cells, suggesting that the shape of the MHC recognition site must have different conformation depending on both MHC and non-MHC gene products recognized. However, the inhibitory pattern of SMLR by anti-Iat mAbs of strains which differ at the I-J locus: B10.A(5R) and B10.A(3R) was dependent on the genotype of stimulator cells. The same was observed in B10.S(9R) and B10.HTT strains. The inhibitory activity of anti-Iat mAbs was entirely directed against responder T cells and was not passively carried out by the stimulators. It was concluded that Iat epitopes are I region controlled determinants that are utilized by T cells as receptors for self Ia antigens. It is suggested that anti-Iat mAbs react with an idiotype on the receptor(s) for Ia or I-J, or possibly a "receptor" for these receptors.

Animals↗
PubMed1987

Immunologic defects as possible causes of therapeutic failures in children with transposition of the great arteries.

Recurrent and severe infections and absence of thymic shadow in X-ray examination were observed in children with the transposition of the great arteries (TGA). Among 45 children (29 boys and 16 girls) with TGA whose age ranged from 3 days to 16 years and who were hospitalized during 1 year, infectious diarrhea was observed in 77.7% cases, urinary tract infections in 44.5%, respiratory tract infections in 42.2%, sepsis in 17.5%, and meningitis in 8.8%. Nine of the children died, sepsis was a cause of death in seven children, and there were postsurgical complications in two children. Immunologic abnormalities in children with TGA included a decreased level of T-lymphocytes and T29 degrees subpopulation, impaired mitogen-induced lymphoproliferation in vitro, and increased nitro blue tetrazolium (NBT) reduction activity of monocytes. Impaired parameters of cellular immunity correlated with worst clinical status. No disorders of humoral immunity were observed. These observations may be important for forming opinion about proper therapy and the cause of death in children with TGA.

Bacterial Infections↗
PubMed1986

Serial immunological testing in patients with gastric cancer.

Standard immunological parameters measuring non-specific cellular immune reactivity were determined in 175 patients with different stages of gastric cancer prior to surgery and during follow-up. Several tests measuring monocyte activity were also employed. The total number of T cells and their subpopulations Ta and T29o was unchanged except depression of T29o in stage IV. The blastogenic response of lymphocytes to PHA as assessed by stimulation of protein synthesis was only depressed in stage IV. In contrast the PHA-induced lymphokine production was increased in all patients but the differences were significant for stage III and IV. Monocyte Fc receptor expression was increased in stages II-IV, while nitro blue tetrazolium reduction and antibody dependent cellular cytotoxicity of monocytes was elevated in stage IV. The number of extractable monocytes was not increased. Longitudinal studies suggested that most of the parameters normalized during follow-up. No major long-term impact of chemoimmunotherapy (5-FU + BCG) on the immune parameters was observed except a transient increase in PPD reactivity approximately 1 year after commencement of treatment. In patients with stage III gastric cancer the increased occurrence of suppressor cells (mostly monocytes) and elevated cytostatic activity of monocytes was associated with a longer survival while the increased lymphokine production and Fc receptor expression were seen in the group of patients succumbing earlier. We concluded that most of the changes in immune parameters were seen only in advanced disease and paradoxically disappeared in the course of disease. The determination of monocyte activity seems to be a sensitive indicator of immune system dearrangements in earlier stages of cancer and a useful prognostic factor in gastric cancer.

Adult↗
PubMed1986

Regulation of human lymphocyte response in vitro by monocytes and their subsets.

This paper summarizes the observations on functional heterogeneity of human peripheral blood monocytes (MO). MO are required as accessory cells in lymphoproliferative responses in vitro, but they also inhibit such responses when added in large numbers. Most of human MO express Fc receptors (FcR), but a minority of MO do not possess these receptors as assessed by functional assays. Isolated FcR+ and FcR- MO subsets differ in their functional properties. The FcR+ MO are mostly responsible for the suppression of lymphoproliferation and cytostatic activity against tumour targets, while FcR- MO possess strong antigen-presenting capacity and also the ability to stimulate auto- and allo-MLR. The FcR- MO subset is enriched in cells expressing HLA-DQ determinants, and their ability to present antigen is blocked by anti-DQ but not by anti-DR monoclonal antibodies. In long-term cultures the FcR+ but not FcR- MO induce suppressor T cells which then inhibit antigen-driven lymphoproliferation. PWM-induced Ig synthesis in vitro is enhanced when FcR- MO are added at the beginning of culture. In contrast, FcR+ MO suppress this response possibly by arresting terminal differentiation of B lymphocytes into immunoglobulin-secreting cells and there is some evidence that OKT8 positive T (T8+) lymphocytes are involved. These observations suggest that the regulation of the lymphocyte response by MO is a complex phenomenon in which the ratio of functional different subsets may be important. This may be critical for understanding the altered function of MO in human diseases. Our previous observations suggest that MO of some cancer patients possess an increased suppressor activity, and the presence of suppressor MO is a favourable prognostic factor. A further delineation of functional MO subsets should facilitate a better understanding of the role of MO in immunoregulation.

Antibodies, Anti-Idiotypic↗
PubMed1985

Involvement of I-J epitopes in the self- and allo-recognition sites of T cells: blocking of syngeneic and allogeneic mixed lymphocyte reaction-responder cells by monoclonal anti-I-J antibodies.

Monoclonal anti-I-Jk antibodies (mAbs) were found to inhibit syngeneic and allogeneic mixed lymphocyte reactions by blocking the responder T cells but not the stimulator cells. Only the responses of H-2k and H-2a strains were inhibited. Three different anti-I-Jk mAbs (1G8, 4B11, and KN34) showed different inhibitory patterns in allogeneic mixed lymphocyte reactions of individual H-2k strains, depending on the H-2 and immunoglobulin heavy chain variable region (IgVH) genes possessed by the stimulator strains. The results indicated that I-J epitopes are involved in the self- and allo-recognition sites of T cells, which are clonally distributed and used to recognize Ia plus IgVH-linked products.

Animals↗
PubMed1984

The use of Fab-Fc recombinant antibodies for studying the mechanism of triggering the effector activities of immunoglobulins.

Immunoglobulin species, recombined from Fab and Fc fragments with anti-red cell specificity were used as cytophilic antibodies in studies of triggering the effector activity of immunoglobulins. Recombinant immunoglobulins containing a single Fab' appeared inactive in binding to cell receptors and triggering antibody dependent cellular cytotoxicity, while those with two Fab' exhibited an activity comparable to intact antibody IgG. The experiments indicate that Fab fragment may interact with Fc and inhibit its binding to cell receptors.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1984

Isolation and functional characteristics of FcR+ and FcR- human monocyte subsets.

Human peripheral blood monocytes (M phi) were separated into Fc receptor positive (FcR+) and FcR- subsets by rosetting with O,Rh+ human erythrocytes coated with IgG anti-D antibody, followed by density gradient centrifugation and adherence. The FcR+M phi suppressed PHA- and PPD-induced lympho-proliferation and also exhibited a strong cytostatic effect against tumor cell lines in vitro, but were a poor source of antigen-presenting cells. In contrast, the FcR- subset did not cause suppression but was highly active in the presentation of PPD to T cells and in stimulation of both allogeneic mixed lymphocyte reaction (allo-MLR) and autologous (auto-MLR). PWM-induced immunoglobulin secretion in vitro was greatly enhanced by the FcR- but not the FcR+ subset. Nevertheless, both FcR+ and FcR- subsets showed comparable HLA-DR antigen expression. These results indicate that human M phi, like lymphocytes, may consist of several subsets that differ significantly in their immunologic functions.

Antibodies, Monoclonal↗