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Biomedical subjects

A Grönberg

Publications and source records attributed to A Grönberg.

At least 19 recordsLinked to original sources
PubMed2002

Invasion of Salmonella into human intestinal epithelial cells is modulated by HLA-B27.

OBJECTIVE: To investigate the influence of the major histocompatibility complex (MHC) class I molecule HLA-B27 on (i) the invasion of Salmonella and Yersinia into human intestinal epithelial cells, (ii) the survival of intracellular Salmonella in these cells, and (iii) the production of certain inflammatory cytokines by the cells after Salmonella infection. METHODS: The human intestinal epithelial cell line Henle-407 was transfected with HLA-B27 DNA. These cells and HLA-B27-negative control cells were infected with Salmonella or Yersinia, and viable intracellular bacteria were determined as colony-forming units. Cytokine production was assayed with ELISA. RESULTS: Salmonella invaded HLA-B27-positive Henle cells in higher numbers than HLA-B27-negative control cells. However, HLA-B27 did not affect the invasion of Yersinia or the survival of the intracellular bacteria in these intestinal epithelial cells. Salmonella infection induced production of interleukin-8 (IL-8), IL-6 and monocyte chemotactic protein 1 (MCP-1) by Henle cells that was not affected by HLA-B27 in a specific way. CONCLUSIONS: These findings suggest that HLA-B27 enhances the invasion of Salmonella into intestinal epithelial cells. The interaction between bacteria and intestinal epithelial cells plays an important role during the early phases of ReA. HLA-B27-linked modulation of Salmonella invasion may lead to an increased load of Salmonella in intestinal tissue and thus increased susceptibility to reactive arthritis.

Cells, Cultured↗
PubMed1999

Pharmacokinetic-pharmacodynamic modeling of the immunomodulating agent susalimod and experimentally induced tumor necrosis factor-alpha levels in the mouse.

The main objective of this study was to explore the concentration-effect relationship between the immunomodulating agent susalimod and lipopolycaccharide (LPS)-induced elevated serum levels of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). Bacterial LPS (1 mg/kg) was given i.p. along with different doses of susalimod (0, 25, 50, 100, and 200 mg/kg) to female CD-1 mice. Blood samples were drawn at different time points (15-300 min), and serum was analyzed with respect to susalimod and TNF-alpha. The concentration-effect relationship was explored by modeling the data from all dose levels simultaneously using specially written program models, i.e., a three-compartment pharmacokinetic model, including biliary excretion, and an indirect mechanistically based pharmacodynamic model. The models, which were successfully fitted to the experimental data, showed that LPS induced the TNF-alpha synthesis during approximately 70 min and that during this time course, the synthesis rate was governed by the serum phamacokinetics of susalimod. Because the results supported the assumption that the maximum inhibitory effect was equal to full inhibition of the synthesis, the in vivo potency (IC(50)) of susalimod could be estimated to 293 microM. In conclusion, susalimod decreased the LPS-induced TNF-alpha mouse serum levels in a concentration-related manner. The compound is suggested to inhibit the synthesis of TNF-alpha. The integrated pharmacokinetic-pharmacodynamic model estimated the in vivo potency of susalimod in the mouse to be 293 microM.

Adjuvants, Immunologic↗
PubMed1996

Increased frequency of abnormal gamma delta T cells in blood of patients with inflammatory bowel diseases.

We have previously reported a preferential usage of V delta 1/V gamma 8 on TCR-gamma-delta-bearing intraepithelial lymphocytes of the normal human intestine as well as in the inflamed synovial tissue of patients with rheumatoid arthritis. The aim of the present study was to analyze V gene segment usage by gamma delta T cells of the intestine and peripheral blood (PB) from patients with inflammatory bowel disease. Freshly isolated lymphocytes were analyzed by flow cytometry using a panel of V gene subset-specific mAbs. The relative proportion of PB TCR-gamma delta+ cells was increased in patients with Crohn's disease as compared with controls. Interestingly, an increased proportion of PB gamma delta T cells of patients with ulcerative colitis or CrD expressed V delta and V gamma genes typically used by intraepithelial lymphocytes. Thus, increased proportions of V delta 1+ and V gamma 8+ cells were found in the PB of both patient groups. The majority of TCR-gamma delta+ intraepithelial lymphocytes (IEL) in inflamed and noninflamed intestine expressed V delta 1/V gamma 8, and a substantial proportion of V gamma(2,3,4)+ cells were found. These observations suggest a disease-associated appearance of "gut-like" gamma delta T cells in the periphery. Moreover, two patients had a large proportion of gamma delta T cells in their PB of which the majority expressed two distinct V gamma proteins. Both of these patients had a short duration of disease (1 and 10 mo, respectively) and the relative proportion of gamma delta T cells decreased in concert with stabilization of disease. Interestingly, one of the patients had a clonal expansion of a V gamma dual-expressing gamma delta T cell in the PB.

Base Sequence↗
PubMed1996

Dextran sulfate sodium (DSS) induced experimental colitis in immunodeficient mice: effects in CD4(+) -cell depleted, athymic and NK-cell depleted SCID mice.

Administration of dextran sulfate to mice, given in the drinking water results in acute or subacute colonic inflammation, depending on the administration protocol. This colonic inflammation exhibits ulceration, healing and repair, and a therapeutic response that makes it valuable for the study of mechanisms that could act in the pathogenesis of human ulcerative colitis, a disease thought to have an immunologically dependent pathogenesis. To investigate if immunological mechanisms were involved in the induction of colonic inflammation in this model, mice with different degrees of immunodeficiency were used. It was shown that dextran sulfate induced colitis could be induced in Balb/c mice depleted of CD4(+) helper T cells by treatment with monoclonal antibodies preceded by adult thymectomy. The depletion of CD4(+) was verified by flow cytometric analysis. Furthermore, the colonic inflammation could equally be induced in athymic CD-1 nu/nu mice lacking thymus-derived T cells, in T and B-cell deficient SCID mice, and also in SCID mice depleted of NK cells by treatment with anti-asialo GM1 antibodies. The NK-cell depletion was verified by measuring spleen NK-cell activity. The resulting colonic inflammation in all these types of deficient mice was qualitatively comparable, as shown by clinical and histological appearance. These results indicate that the presence of functional T, B and NK cells is not crucial for the induction of dextran sulfate colitis in mice.

Administration, Oral↗
PubMed1996

Expression of interferon-gamma (IFN-gamma), IL-10, IL-12 and transforming growth factor-beta (TGF-beta) mRNA in synovial fluid cells from patients in the early and late phases of rheumatoid arthritis (RA).

The expression of immunoregulatory cytokines was investigated in freshly isolated synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) from patients with RA, using a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. IFN-gamma, TGF-beta, IL-10 and IL-12 (p40) transcripts were detected in SFMC of patients with early disease (<1 year duration) as well as in patients with long standing arthritis (>1 year). The expression of IFN-gamma, IL-10 and IL-12 mRNA was increased in SFMC compared with RA PBMC. In addition, the expression was higher in RA SFMC than in PBMC from health control individuals. Immunoassay analysis of the secreted IL-12 heterodimer demonstrated increased levels in RA SF compared with levels found in serum from RA patients and control individuals. High levels of TGF-beta mRNA were found in SFMC, but a significantly decreased TGF-beta/beta2-microglobulin (beta2-M) ratio was found compared with PBMC from both patients and control individuals. IL-4mRNA could not be detected, either in SFMC or in PBMC. Cytokine expression in RA PBMC did not differ from control PBMC, with the exception of a decreased TGF-beta/beta2-M ratio in RA patients with early disease. Our findings of IFN-gamma mRNA and IL-12, but undetectable levels of IL-4 mRNA, suggest that the synovitis is characterized by a type 1 immune response. The presence of TGF-beta and IL-10 mRNA indicates that immunosuppressive cytokines may also operate in the inflamed joint, although their level of expression may not be sufficient for down-modulation of immune activation.

Adult↗
PubMed1996

Induction of heat shock protein 60 expression in human monocytic cell lines infected with Mycobacterium leprae.

Monocytic cell lines (HL-60 and THP-1) were infected with viable Mycobacterium leprae. Levels of human hsp60 were estimated by Western blot (immunoblot) assay and a sandwich enzyme-linked immunosorbent assay. The results showed that infection of both of the cell lines induced the synthesis of human hsp60, which may be of significance in relation to autoimmune manifestations associated with mycobacterial infections.

Cell Line↗
PubMed1995

Analysis of gamma delta V region usage in normal and diseased human intestinal biopsies and peripheral blood by polymerase chain reaction (PCR) and flow cytometry.

The intestinal population of gamma delta T cell receptor (TCR)-bearing cells was characterized with regard to V delta and V gamma subtype expression. For this purpose, we utilized V gene-specific PCR of mRNA prepared from intestinal biopsies. Predominant expression of the V delta 1 subtype was demonstrated in the small intestine of patients with coeliac disease and in the inflamed colon of patients with inflammatory bowel diseases (IBD: ulcerative colitis and Crohn's disease) as well as in colon biopsies taken from macroscopically normal areas of colon. Although intestinal gamma delta T cells preferentially expressed V delta 1, other V delta transcripts could be detected, of which V delta 2 and V delta 5 were commonly expressed. Analysis of biopsies from mesenteric lymph nodes demonstrated a V delta repertoire similar to the mucosa. In peripheral blood on the other hand, high expression of both V delta 2 and V delta 1 was found. The predominant expression of V delta 1 transcripts in the intestinal mucosa of IBD patients correlated well with protein cell surface expression as analysed by flow cytometry using V delta 1- and V delta 2-specific antibodies. Selective expansion of gamma delta T cells could not be demonstrated within the inflamed mucosa as shown by mRNA analysis and flow cytometry. Instead, IBD patients demonstrated a decreased proportion of TCR gamma delta-carrying T cells in the inflamed mucosa compared with macroscopically normal area of colon. On the other hand, a significantly increased percentage of T cells bearing the gamma delta TCR was found in peripheral blood of patients with Crohn's disease compared with healthy individuals, indicating that local mucosal inflammation may influence the circulating gamma delta T cell population.

Base Sequence↗
PubMed1995

Engagement of MHC class I proteins on natural killer cells inhibits their killing capacity.

We have studied whether engagement of MHC class I (MHC-I) molecules on natural killer (NK) cells can influence the NK killing activity. Human NK effector cells, enriched by nylon wool passage, were incubated with monoclonal antibodies (MoAb) to MHC-I followed by cross-linking with secondary rabbit anti mouse Ig or streptavidin. Cross linking of MHC-I molecules on NK cells resulted in a clear inhibition of the NK activity against the target cells K562, Molt-4 and U937. The inhibitory effect was selective for MHC-I and was not seen with MoAb to MHC-II or CD56 molecules. The inhibition was not mediated via Fc receptors since F(ab)2 fragments of the MHC-I MoAb W6/32 were as effective as the intact antibody. The best inhibition of NK activity was obtained using biotin-labelled F(ab)2 fragments of W6/32 and streptavidin as a cross-linker, where up to 70% reduction in NK cell activity was observed. Antibody dependent cellular cytotoxicity (ADCC) was also inhibited by cross-linking MHC-I molecules on the effector cells. The results show that antibody mediated cross-linking of MHC-I proteins on NK cells can inhibit their killing capacity. This indicates that MHC-I molecules on NK cells can be involved in the regulation of NK cytotoxicity, perhaps by transmitting inhibitory signals into the NK cell.

Antibodies, Monoclonal↗
PubMed1995

Attitudes of European urologists to early prostatic carcinoma. I. Diagnostic work-up on suspected prostatic cancer cases.

The diagnostic work-ups of 656 European urologists on theoretical cases of suspected early prostatic carcinoma were surveyed. The diagnostic work-ups varied considerably among the urologists. There was strong agreement that digital rectal examination (DRE) and prostate-specific antigen (PSA) should be used routinely in these cases, but there was a lack of agreement concerning the use of transrectal ultrasound examination (TRUS), prostate biopsies and bone scan. However, the use of TRUS, bone scan and biopsies was correlated positively to the PSA level and negatively to age (p < 0.0001), but was not correlated to whether the patient was asymptomatic or suffered from prostatism. Ninety-two percent of the urologists would perform biopsies if a palpable lesion were present. If the PSA was elevated, 22% would use biopsies if it was 7 ng/l, 62% if it was 15 ng/l and 83% if it was 35 ng/l. These results indicate that a majority of European urologists would attempt to diagnose prostatic cancer with biopsies only when results of DRE and PSA predict a high risk that the cancer is no longer organ-confined.

Adult↗
PubMed1995

Attitudes of European urologists to early prostatic carcinoma, II. Attitude to therapy and to screening examinations.

The attitudes of 656 European urologists toward therapy of localized prostatic cancer (PC) and screening examinations of the male population for PC were surveyed. Eighty percent of the urologists would offer curative therapy to a 60-year-old patient with localized PC, while 20% would offer watchful waiting or hormonal therapy. The choice of curative therapy was not correlated to the grade of the cancer. Radical prostatectomies were offered 2.5 times as often as external beam radiotherapy. The number of radical prostatectomies performed was considered to be increasing by 56% of the urologists surveyed, decreasing by 10% and stable by 34%. Fifty-five percent thought that screening for prostate cancer should be undertaken in their country, but only 35% believed this would decrease mortality from prostate cancer. A majority would include digital rectal examination, prostate-specific antigen and symptom evaluation in a screening program. Agreement among urologists from different European countries regarding the handling of early prostatic cancer is poor. Large regional differences were observed with a more active attitude to therapy and screening in southern and central Europe. Attitudes to screening and to therapy, however, were only weakly correlated. In conclusion, it seems paradoxal that many urologists who would offer curative therapies to patients with localized PC would not take steps to diagnose this disease via screening of the male population.

Adult↗
PubMed1994

High expression of V gamma 8 is a shared feature of human gamma delta T cells in the epithelium of the gut and in the inflamed synovial tissue.

We have analyzed the V-gene usage in gamma delta T cells of the human gut and joint by using a new mAb (B18) specific for V gamma 8 of human TCR-gamma delta+ T cells. The B18+ population constituted a minor subset of the gamma delta T cells in peripheral blood (PB) of healthy persons (6 +/- 5%) and only 1 of 35 gamma delta T cell clones analyzed was positive. In contrast, the B18+ subset was a dominant gamma delta T cell population among intraepithelial lymphocytes (IEL) derived from the human intestine (74 +/- 29, p < 0.002), and two of three IEL clones from patients with coeliac disease were B18+. Interestingly, a higher proportion of B18+ gamma delta T cells was found in the synovial fluid of patients with rheumatoid arthritis (RA) (21 +/- 18%, 0.02 < p < 0.05) compared with normal PB. Furthermore, the B18+ subset was more frequent among IL-2-expanded gamma delta T cells (42 +/- 20%) derived from synovial tissue than among IL-2-expanded cells derived from synovial fluid (p < 0.002) and PB from RA patients (p < 0.02) as well as normal PB (p < 0.002). The V-gene usage of 13 gamma delta T cell clones from the synovial fluid of arthritic patients was analyzed. All B18+ clones (n = 7) expressed mRNA for V gamma 8 together with mRNA for V delta 1 (n = 5) or mRNA for V delta 3 (n = 2). None of the B18- clones expressed V gamma 8 (n = 6). We conclude that the gamma delta T cell that expresses V gamma 8, together with mainly V delta 1, is a major gamma delta T cell subset among the IEL of the gut and a highly frequent subset in the synovial tissue of patients with RA. This subset may correspond to the mouse V gamma 7+ IEL, which has a high degree of amino acid sequence homology with the human V gamma 8 protein.

Adult↗
PubMed1993

Regulation of lymphocyte aggregation and proliferation through adhesion molecule CD54 (ICAM-1).

The effect of two mouse mAb (LB-2 and G1B2) against human CD54 (intercellular adhesion molecule-1, ICAM-1) in lymphocyte aggregation and proliferation systems was investigated. The LB-2 mAb, but not G1B2, inhibited phorbol ester-induced aggregation of B lymphoblastoid cells. In addition, LB-2, but not G1B2, induced aggregation and proliferation of peripheral blood mononuclear cells (PBMC) in cultures containing FCS. The Fab fragment of LB-2 always (10/10 donors) induced proliferation while the intact mAb was active in 3/11 donors. When cultures contained human serum (HS), LB-2 and its Fab fragment induced proliferation in 1/9 and 1/4 donors, respectively. Addition of HS to FCS cultures inhibited proliferation induced by LB-2 Fab, indicating the presence of an inhibitory factor in human serum. Addition of anti-CD18 mAb to cultures stimulated by LB-2 Fab caused partial inhibition of proliferation but did not prevent aggregate formation. A combination of anti-CD18 and anti-CD29 mAb resulted in a nearly complete inhibition of proliferation but did not inhibit aggregate formation. In these experiments it was found that the anti-CD29 mAb 4B4 in itself induced cell aggregation of PBMC and enhanced aggregation induced by the anti-CD3 mAb OKT3. Both LB-2 and G1B2 showed significant inhibition (> 60%) of proliferation when human PBMC were stimulated by the antigen PPD in the presence of HS, but not when stimulated by staphylococcal enterotoxin A (SEA) or IL-2. This study describes two mAb against separate epitopes on CD54 which are differentially involved in cell aggregation or induction of proliferation but are of similar importance in antigen-specific responses. Furthermore, the new finding that the LB-2 mAb or its Fab fragment can induce cell aggregation and proliferation defines a signaling function of CD54 which may work independent of crosslinking or costimulation.

Animals↗
PubMed1992

T cell receptor diversity and activation markers in the V delta 1 subset of rheumatoid synovial fluid and peripheral blood T lymphocytes.

In the present study we have characterized the gamma/delta T cell receptor (TcR) population in synovial fluid (SF) and peripheral blood (PB) of patients with chronic inflammatory arthritis. By double staining we have shown that (a) synovial V delta 1+ cells have a high expression of activation markers CD45R0 ("memory cells") and HLA-DR as compared to PB, indicating a preactivated population of V delta 1-carrying T cells in vivo and (b) interleukin 2-induced expansion of synovial cells yields a high proportion of gamma/delta in most samples expressing predominantly the V delta 1 TcR. Junctional sequence analysis of the TcR delta chain from interleukin 2-expanded PB cell lines demonstrated a polyclonal V delta 1 population in three out of three samples. In SF cell lines three out of four samples were polyclonally expanded. In SF from one patient, however, a limited repertoire of expressed V delta 1 genes was found. Altogether, our data demonstrate the presence of preactivated V delta 1-expressing cells in the synovial compartment. This V delta 1 population is predominantly polyclonal, except in one patient where oligoclonally expanded V delta 1 cells were detected.

Antigens, CD↗
PubMed1992

Induction of human hsp60 expression in monocytic cell lines.

Both bacterial and mammalian heat shock proteins (HSP) are recognized by some T cells, and hsp60 recognition has been implicated in rheumatoid arthritis. We have developed a model to study the induction of hsp60 in human monocytic cell lines. An anti-mycobacterial hsp65 mAb (ML30), cross-reacting with human hsp60 was used to screen 21 human tumor cell lines in Western blot analysis. All T cell and B cell lymphomas constitutively expressed hsp60 protein at moderate to high levels, while little or no hsp60 protein was detected in two monocytic leukemia lines. Moderate to high levels of hsp60 mRNA and protein could be induced in the THP-I monocytic leukemia cell line by heat shock, retinoic acid, interferon (IFN)-gamma or tumor necrosis factor (TNF)-alpha treatment, the highest levels obtained with a combination of IFN-gamma/TNF-alpha. This was also seen using two rabbit anti-hsp60 antisera directed against the N-terminal or C-terminal part of the human hsp60 protein. The determinants detected by the ML30 mAb or the two rabbit anti-hsp60 antisera were not cell surface expressed, as measured with immunofluorescence (FACS) analysis on control cultured or cytokine treated cell lines. This could be a useful model for studies related to the induction of hsp60 in human cells.

Cytokines↗
PubMed1992

Characterization of T-cell receptor alpha beta repertoire in synovial tissue from different temporal phases of rheumatoid arthritis.

With the aim of investigating the distribution of T cells expressing different T-cell receptors (TCR) in the inflamed synovial tissue of rheumatoid arthritis patients, we have used the polymerase chain reaction to amplify TCR V alpha and V beta transcripts from synovial biopsies obtained by arthroscopy from patients with arthritis of variable duration. From each of nine patients a single biopsy was taken. Southern hybridization analysis of amplified products revealed extensive heterogeneity of TCR V beta in most patients. On the other hand, restriction in V alpha gene expression was seen in several patients. A highly restricted V alpha repertoire was observed in all cases with arthritis of short duration. In addition, two of three samples of short duration yielded a more limited number of V beta transcripts than the others. No conformity was, however, seen in usage of individual V alpha and V beta transcripts among the investigated patients. The present data thus demonstrate variability in synovial TCR expression between rheumatoid arthritis patients, but they also indicate a development towards greater diversity with increasing disease duration, implicating the necessity for careful choice of cases, preferentially selecting for early stages of disease, when further analysing rheumatoid synovial T cells for TCR usage as well as for antigen specificity.

Adult↗
PubMed1991

Increased susceptibility of IFN-gamma-treated neuroblastoma cells to lysis by lymphokine-activated killer cells: participation of ICAM-1 induction on target cells.

We have investigated the effect of interferon-gamma (IFN-gamma) treatment of neuroblastoma cells on the susceptibility to lysis by lymphokine-activated killer (LAK) cells and examined the participation of cell-adhesion molecules on the target cells in LAK cell lysis. Untreated neuroblastoma cells expressed lymphocyte-function-associated antigen 3 (LFA-3) and neural-cell-adhesion molecule (NCAM), but did not express MHC-class-I, MHC-class-II, or intercellular-adhesion molecule I (ICAM-I). IFN-gamma treatment of neuroblastoma cells induced the expression of MHC-class-I and ICAM-I antigens, but did not affect the expression of MHC-class-II, LFA-3, and NCAM. This was accompanied by an increased susceptibility to lysis by LAK cells. Anti-ICAM-I antibody inhibited partially the increased sensitivity of IFN-gamma-treated neuroblastoma cells to LAK cell lysis, and blocked completely the increase in binding of LAK cells observed after IFN-gamma treatment of the target cells. These results suggest that the increased LAK sensitivity of IFN-gamma-treated neuroblastoma cells is partially attributable to the induction of ICAM-I on neuroblastoma cells and indicate that post-binding events also play a role in the increased sensitivity to LAK cell lysis observed after IFN-gamma treatment.

Cell Adhesion Molecules↗
PubMed1991

Phospholipase C treatment of certain human target cells reduces their susceptibility to NK lysis without affecting binding or sensitivity to lytic granules.

Phosphatidylinositol-specific phospholipase C (PI-PLC) is an enzyme that has the capacity to release glycosyl-phosphatidyl inositol (G-PI)-anchored proteins from the cells surface. Pretreatment of the human T-cell leukemia cell line Molt-4 with PI-PLC resulted in a decrease in the susceptibility to lysis by natural killer (NK) cells. Treatment of the erythroleukemia cell line K562 with PI-PLC had no effect on its NK susceptibility. PI-PLC-treated and untreated Molt-4 bound equally well to lymphocytes in target-binding studies with effector cell preparations enriched for NK cells. Susceptibility to cytolytic granules isolated from rat LGL tumor cells remained the same after treatment of Molt-4 or K562 with PI-PLC. Combined treatment of Molt-4 with PI-PLC and rlFN-alpha or rlFN-gamma resulted in additive reductions of the NK susceptibility, suggesting that PI-PLC and interferons act on different mechanisms to protect cells from NK lysis. When expression of a number of antigens on Molt-4 and K562 was analyzed in flow cytometry, only the expression of CD58 was reduced after PI-PLC treatment. The susceptibility of Con A blasts to MLR derived cytotoxic T-cells was not altered by treatment with phospholipase. These data suggest that PI-PLC treatment reduces the capacity of some target cells to activate NK cells upon contract. The mechanism behind this phenomenon is presently unclear.

Antigens, CD↗