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Biomedical subjects

B W Robinson

Publications and source records attributed to B W Robinson.

At least 19 recordsLinked to original sources
PubMed1998

Sera from patients with malignant mesothelioma can contain autoantibodies.

Malignant mesothelioma (MM) is resistant to all conventional forms of therapy though there is considerable evidence from clinical trials and animal models of the disease that an immune response can be elicited to the tumour. In order to define those target antigens expressed by MM cells which might provide a focus for an effective immune response we tested patients' sera for the presence of MM autoantibodies by Western blot analysis. Eight of 29 (28%) patients with MM had serum antibodies of the IgG class in high titre and each antiserum recognised different protein antigens. In those individuals where sequential samples were available, the antibody titre increased with the progression of the disease though the number of target antigens remained constant. Sera from the eight patients were studied further: six of the antigen complexes were expressed at least partially in the nucleus; two showed some specificity for the tumour in that they discriminated antigens that were highly expressed in all human MM cell lines, but were not expressed in a human SV40 transformed mesothelial line; four of the antisera recognised a homologue in mouse tissue and each of these had a different pattern of expression. Collectively, these antisera define a subset of nuclear autoantigens that are over-expressed in dividing cells.

Adult↗
PubMed1998

Epithelial cell damage is induced by neutrophil-derived, not pseudomonas-derived, proteases in cystic fibrosis sputum.

Airway histopathological changes in cystic fibrosis (CF) include damage to the epithelial tissue and accumulation of polymorphonuclear leukocytes (PMN). Airways of CF patients are usually colonized with bacteria such as mucoid Pseudomonas aeruginosa (PA). Bacteria and PMN can both release proteolytic enzymes capable of causing tissue damage. This study aims to clarify and compare the roles of these agents in epithelium damage. Epithelial cell (EC) damage and detachment induced by sputum samples from CF or non-CF patients, with and without lung infection, were assessed on amnionic EC in an in vitro model of airway epithelium. Protease activity was determined using inhibitor profiles, and compared to the proteolytic activity of isolated neutrophils and bacteria. Sputa from CF patients and infected non-CF patients induced high levels of detachment. PA also induced high levels of EC detachment but Staphylococcus aureus and Haemophilus influenzae, two other bacteria commonly isolated from CF sputa, induced no detachment. Antiprotease inhibition profiles were similar for PMN and sputa-induced EC detachment, but different for PA-induced detachment. These results suggest that PMN proteolytic enzymes, probably elastase and cathepsin G, are more likely to be the inducers of tissue damage in the airways of CF patients than PA proteolytic enzymes.

Adult↗
PubMed1998

Cytokine gene therapy or infusion as treatment for solid human cancer.

In the induction of tissue-directed immune responses, cytokines tend to be released within the affected tissues. We used two strategies to expose tumor tissues to continuous high levels of cytokines: First, a vaccinia interleukin (IL)2 recombinant was injected directly intratumorally 3-weekly at 10(7) pfus/dose in six patients with the solid tumor malignant mesothelioma (MM). No virus excretion was detectable. At each cycle vaccinia-IL-2 mRNA (SQ [semi-quantitative] reverse transcription polymerase chain reaction) was maximal 24-72 h following injection reduced at 8 days and faded by 21 days. No tumor regression occurred. Second, based on the success of granulocyte macrophage colony-stimulating factor (GM-CSF) in gene transfer experiments, we conducted a study using continuous intratumoral GM-CSF infusion in eight patients with MM using a portable pump at doses of 10 micro/cg/24 h over 8 weeks. Systemic neutrophil agglutination and local catheter-related difficulties occurred. Two patients demonstrated tumor necrosis, one of whom had a marked progressive mononuclear cell infiltration of the tumor associated with a partial response (>50% reduction in tumor area). Murine studies using our MM model in CBA and BALB/C mice have demonstrated that B7-1 and allo-class I transfections induce strong tumor-specific cytotoxic T lymphocyte responses: GM-CSF, IL-12, and IL-2 induced mixed nonspecific plus specific responses, whereas B7-2 and class II transfections were not effective. We conclude that increased intratumoral cytokine concentrations can be generated using both gene transfer and cytokine infusion approaches; however, both have their limitations and, at this stage, have not produced dramatic antitumor effects in humans.

Cytokines↗
PubMed1998

Intralesional cytokine therapy in cancer: a pilot study of GM-CSF infusion in mesothelioma.

Systemic cytokine therapy in cancer has major side effects, and we reasoned that the local infusion of cytokines into tumors could induce local immunologic responses with minimal toxicity and potentially strong systemic anticancer effects. This study investigated the toxicity and effectiveness of intralesional granulocyte/macrophage-colony-stimulating factor (GM-CSF) infusion in solid-tumor masses. We studied 14 patients (12 men, two women) with malignant mesothelioma (MM), aged 60 years (range, 46-70 years), with stage 2 disease, in whom the tumor was of sufficient size and accessibility for an intralesional catheter to be inserted. Recombinant human GM-CSF (Molgramostim; Schering Plough) was infused intralesionally for 8 weeks, by using a portable pump, at a dose of 2.5-10 micrograms/kg/day. One patient using GM-CSF developed histologically confirmed necrosis of tumor surrounding the distal catheter, one developed a marked lymphocytic infiltrate in the tumor and had a partial response measured by chest computed tomography (CT) scan, 10 progressed, and three had no response. Neutrophilia with morphologic evidence of neutrophil activation and clinical features suggestive of neutrophil plugging of blood vessels occurred at doses > 5 micrograms/kg/day. In vitro, GM-CSF doubled human neutrophil/CD11b/CD18 expression, suggesting that neutrophil clumping as seen in vivo might be due to integrin upregulation. Intralesional infusion of cytokines is feasible but can be associated with systemic toxicity and has considerable technical problems. It produces a localized immune reaction with tumor regression in a minority of patients.

Aged↗
PubMed1998

Interleukin-12 induces an effective antitumor response in malignant mesothelioma.

Malignant mesothelioma (MM) is a fatal solid tumor of the mesothelium for which there is currently no ameliorating treatment. Using our murine model of this malignancy, which closely resembles the human disease, we have shown that immunotherapy may be of value in the treatment of MM. Because recombinant interleukin-12 (rIL-12) has strong immunomodulatory effects in vivo, we studied the effects of rIL-12 on murine antitumor immune responses, using a nonimmunogenic murine MM tumor cell line (AB1) in vivo. Systemic administration of rIL-12 at the time of tumor inoculation prevented AB1 tumor growth in up to 70% of treated mice, 50% of which were still resistant to AB1 upon rechallenge, indicating that long-term immunologic antitumor effects had been established. This rIL-12-induced effect was dependent on the involvement of both CD4(+) and CD8(+) but not natural killer (NK) cells. Importantly, treatment of established tumors with intralesional injections of rIL-12 resulted in temporary tumor regression or growth inhibition. This effect was dependent on the continuous presence of rIL-12 and correlated with increased numbers of CD4(+) and CD8(+) cells infiltrating the remaining tumor mass. Effective inhibition of tumor growth also occurred when IL-12 was released within MM tumors by coadministration of MM cells that had been stably transfected with the gene for IL-12. These data indicate that IL-12 has potential in the immunotherapy of MM, through gene transfer or local cytokine administration, provided that significant intratumor levels of IL-12 can be achieved for prolonged periods.

Adjuvants, Immunologic↗
PubMed1997

Antisense oligonucleotides specific for transforming growth factor beta2 inhibit the growth of malignant mesothelioma both in vitro and in vivo.

Transforming growth factor beta (TGF-beta) is a potent growth-regulatory and immunomodulatory cytokine that exerts a diverse range of effects on many types of cells. High levels of TGF-beta are produced by several human and mouse malignant mesothelioma (MM) cell lines, and it is known to act as a growth factor for these cells. Antisense oligonucleotides (ODNs), targeted against specific TGF-beta mRNA, were used to block TGF-beta production from MM cells in vitro and in vivo. TGF-beta antisense ODNs were encapsulated in liposomes and transfected into MM cells or delivered intratumorally. TGF-beta2 mRNA levels, assessed by semiquantitative PCR, and TGF-beta2 protein secretion were reduced after TGF-beta2 antisense ODN transfection. MM cell proliferation, assessed by tritiated thymidine uptake, was specifically inhibited by both TGF-beta1- and TGF-beta2-specific antisense ODNs. In vivo administration of TGF-beta2 antisense ODNs, delivered locally, reduced tumor growth. These data show that the blockade of TGF-beta2 within this tumor reduces tumor growth and raises the possibility that TGF-beta2 antisense ODNs may be useful as a therapy for this disease.

Animals↗
PubMed1997

Transfection of the gene for B7-1 but not B7-2 can induce immunity to murine malignant mesothelioma.

Transfection of the genes encoding the co-stimulatory molecules B7-1 and B7-2 has enhanced the development of immunity to a variety of experimental tumors, although most of these were inherently immunogenic. We have determined the effect of expression of these genes on the induction of immunity to 2 non-immunogenic murine malignant mesothelioma (MM) cell lines (AC29 and AB1). We had previously shown that B7-1 transfection into AC29 delayed but did not prevent tumor development by certain of the transfectant clones. Here we demonstrate that over-expression of B7-1 can inhibit tumor development by certain AB1-B7-1 clones, that inhibition of transfectant growth is dependent on CD4+ and CD8+ T cells and that mice that reject some of these transfectant clones are capable of rejecting subsequent inocula of the parental cell line, AB1. The transfectant clones can generate tumor-specific cytotoxic T cells. By contrast, expression of B7-2 in several clones derived from either AB1 or AC29 had no significant effect on the development of tumors in vivo. Our data are consistent with data from other systems that show differences in the effect of modification by B7-1 or B7-2 on the modulation of anti-tumor immune responses. They demonstrate that such modifications can induce protective immunity against an MM cell line but confirm the intra- and inter-tumoral heterogeneity in the effect of genetic modification on the induction of immunity. Our observations are relevant to human MM because these cell lines have been derived from asbestos-induced tumors and share many properties with human cell lines of the same histological type.

Animals↗
PubMed1997

The induction of immune responses to murine malignant mesothelioma by IL-2 gene transfer.

Stable IL-2 transfectant clones have been derived from two non-immunogenic murine malignant mesothelioma (MM) cell lines to investigate the induction of protective antitumor immunity to MM. AC29-IL-2 transfectant clones grew at a slower rate in vivo than the parental cell line or a transfectant control clone but all inoculated mice developed tumours despite the continued ability of the tumour cells to express IL-2. Tumour development after inoculation of AB1-IL-2 transfectants varied, the degree of in vivo inhibition (40-100%) being directly related to the rate of IL-2 secretion of the transfectants. When mice which had rejected the AB1-IL-2 transfectants were challenged with parental AB1 cells, a proportion (16-70%) of mice from each group remained tumour free at least 45 days after challenge (naive mice developed tumours within 26 days). The inhibition of growth of the initial inoculum of AB1-IL-2 transfectants was independent of CD4+ and CD8+ cells, consistent with the demonstration of non-specific cytotoxic activity by splenocytes from mice inoculated with the IL-2 transfectants. These data suggest that IL-2 expression by MM cells is capable of generating in vivo immunity to the tumour. This immunity may be relatively weak or may be subject to down-regulation so that consistent rejection of unmodified tumour cells is not achieved. Genetic modification with combinations of genes, including IL-2 and B7-1, will be necessary for reliable generation of protective immunity to MM.

Animals↗
PubMed1997

Selective inhibition of T cell proliferation but not expression of effector function by human alveolar macrophages.

BACKGROUND: Alveolar macrophages are thought to play an important part in regulating lung immune responses. While it is clear that human alveolar macrophages suppress T cell proliferation in vitro, the mechanisms by which this is achieved are not clear, nor is it known whether alveolar macrophages also inhibit other aspects of T cell function. METHODS: Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin or house dust mite allergen, and cultured with variable numbers of autologous alveolar macrophages obtained by bronchoalveolar lavage from 20 normal subjects. RESULTS: Alveolar macrophages induced a reversible inhibition of T cell proliferation in response to both mitogen and allergen stimulation, with the latter being considerably more susceptible to inhibition. This was achieved via heterogenous mechanisms, involving both soluble factors derived from alveolar macrophages and cell-cell contact. Despite inhibiting proliferation, alveolar macrophages had little or no effect on T cell calcium flux, the characteristic changes in CD3, CD2, CD28 and interleukin-2 (IL-2) receptor expression which accompany normal T cell activation, and IL-2 and interferon gamma secretion. In contrast, alveolar macrophages inhibited the tyrosine phosphorylation of proteins which may be involved in IL-2 receptor-associated signal transduction. CONCLUSIONS: The immunoregulatory properties of alveolar macrophages are relatively selective, allowing T cell activation and cytokine secretion while inhibiting T cell proliferation within the lung.

Adult↗
PubMed1996

Altered CD3 chain and cytokine gene expression in tumor infiltrating T lymphocytes during the development of mesothelioma.

The mechanisms whereby tumors escape immunosurveillance remain poorly understood. De-activation or deviation of T lymphocyte responses may occur following exposure to tumor-associated or -derived signals. In the present study it is demonstrated that during development of syngeneic malignant mesothelioma in mice, the relative CD3 delta, CD3 gamma and CD3 zeta mRNA levels expressed by tumor infiltrating lymphocytes (TIL) decrease, while CD3 epsilon mRNA levels remain relatively constant. Expression of IFN gamma mRNA by TIL decreased during tumor development, while IL-2 mRNA levels showed slight increases. IL-3 mRNA was not detected at any time during tumor development and IL-4 transcripts were detected in the later stages of tumor development. In the spleens of tumor-bearing mice, IL-2 transcripts were detected throughout the time course from days 1 to 22(24), while IFN gamma mRNA was only detected at early times from days 0-13. Previous work demonstrated a role for tumor cell-derived TGF beta in the immunobiology of mesothelioma. Here it is shown that the suppression of CD3-subunit expression by TIL was ameliorated in tumors where TGF beta -expression was reduced by inducible TGF beta-specific antisense-RNA, thus, suggesting that lymphocytes may become de-activated upon infiltration of the tumor micro-environment.

Animals↗
PubMed1995

Interleukin-6 involvement in mesothelioma pathobiology: inhibition by interferon alpha immunotherapy.

A role for interleukin-6 (IL-6) in malignant mesothelioma has been suggested by the clinically presenting symptoms of mesothelioma patients, which include fever, weight loss and thrombocytosis. A murine model of malignant mesothelioma was therefore used to examine the potential role of IL-6 in this cancer type and whether the effect of interferon alpha (IFN alpha) therapy on mesothelioma might be mediated, in part, by regulating IL-6 levels and/or IL-6-induced pathobiology. A panel of human and murine mesothelioma cell lines was assayed for endogenous IL-6 production in a bioassay, and for IL-6-mRNA expression. Four out of 5 human and 5 out of 15 murine mesothelioma cell lines produced moderate to high levels of bioactive IL-6 in vitro. This result was corroborated by mRNA detection. One of the representative murine cell lines, AB22, was chosen for further in vivo studies in the murine mesothelioma model. In AB22-inoculated mice detectable serum IL-6 levels were found to precede macroscopically detectable tumour growth, clinical signs (cachexia, abdominal distension, diarrhoea) and changes in the peripheral lymphoid organs (cell depletion and functional depression). Treatment with anti-IL-6 antibody curtailed the clinical symptoms (P < 0.001), as did treatment with recombinant human (rhu) IFN alpha (P < 0.001). Neither anti-IL-6 antibody nor rhuIFN alpha had a direct growth-inhibitory effect on the AB22 mesothelioma cell line in vitro, however, in vivo rhuIFN alpha treatment of mice inoculated with AB22 cells attenuated both IL-6 mRNA expression in the tumours and serum IL-6 levels, ameliorated the depression of lymphocyte activities, and enhanced the number of tumour-infiltrating lymphocytes and macrophages. On the basis of these results it is suggested that IL-6 mediates some of these effects, directly or indirectly, and that a combination therapy of rhuIFN alpha and anti-IL-6 antibody may be an improved palliative treatment for patients with malignant mesothelioma.

Animals↗
PubMed1995

Role of neutrophils in mediating human epithelial cell detachment from native basement membrane.

Epithelial cell detachment from underlying basement membrane is a feature of diseases of many organs. In the lungs it is seen in disorders as diverse as bronchiectasis, allograft rejection, and asthma. The potential for different leukocytes to induce this change is not clear. In asthma both eosinophils and neutrophils are found in affected tissues, but the capacity of each of these types of cells to induce detachment of native epithelial cells from basement membrane requires clarification. Although eosinophils damage rather than detach human epithelial cells, the effects of neutrophils on epithelial cells naturally attached to basement membrane have not previously been described. Using the human amnion in vitro model, we tested the hypothesis that neutrophils have the capacity to detach intact human epithelial cells from basement membrane. The data indicate that increasing concentrations of neutrophils are able to detach epithelial cells from their underlying basement membrane. Detachment was increased when the neutrophils were activated in situ with tetradecanoyl phorbol acetate and after longer incubation periods. Platelet activating factor and opsonized zymosan showed similar boosting effects, whereas activated complement and formyl-methyl-leucyl-phenylalanine did not. Physical contact of the neutrophils with the epithelial cells was required to induce detachment. Detachment could be inhibited by glutathione and by soybean trypsin inhibitor, an inhibition pattern similar to cathepsin G and trypsin, but not collagenase, in this system. We conclude that neutrophils are capable of detaching human epithelial cells from basement membrane, which in part involves the release of chymotrypsin-like serine proteases, probably in conjunction with oxidants, and that this detachment can be inhibited.

Amnion↗
PubMed1995

Expression and immune recognition of stress proteins in sarcoidosis and other chronic interstitial lung diseases.

Stress proteins (SP) are major immunogens in a number of microbial infections and have been implicated in some autoimmune diseases. The aetiology of sarcoidosis, a non-caseating granulomatous disease, remains unknown, but mycobacteria as well as autoimmunity have been considered. In the present study, patients diagnosed with sarcoidosis and other interstitial lung diseases (ILD), as well as healthy volunteers were studied to determine: (i) the level of expression of SP in alveolar macrophages and blood monocytes; (ii) the serum levels of antibodies specific for mycobacterial SP65 and SP70; and (iii) the reactivity of peripheral blood and alveolar lymphocytes to mycobacterial SP65. Our results suggest that SP are expressed constitutively at high levels in alveolar macrophages, retrieved by bronchoalveolar lavage, from all individuals regardless of health status. In contrast, freshly isolated blood monocytes express low levels of SP, which are, however, readily upregulated following exposure to IFN-gamma and TNF-alpha. Lymphocyte reactivity and presence of antibodies against mycobacterial SP may reflect the current state of in vivo inflammation rather than the cause of inflammation.

Antibodies, Monoclonal↗
PubMed1995

Potential for interferon-alpha-based therapy in mesothelioma: assessment in a murine model.

Malignant mesothelioma is an aggressive tumor, usually induced by asbestos exposure, that has a poor prognosis and is unresponsive to conventional therapy. The present study was aimed at assessing the potential for interferon-alpha (IFN-alpha)-based therapies in a murine model for malignant mesothelioma. The effect of recombinant human IFN-alpha B/D on tumor growth, alone and in combination with either of two immunomodulatory and antiproliferative agents beta-carotene or alpha-difluoromethylornithine (DFMO), was assessed. The data suggest that IFN-alpha treatment is most efficacious when commenced early in tumor development. Combination of IFN-alpha with either DFMO or dietary beta-carotene supplementation improved the effect of an otherwise suboptimal IFN-alpha therapy regimen. Both IFN-alpha and beta-carotene had in vivo stimulatory effects on immune cells, perhaps indirectly by inhibiting TGF-beta generation. The immunomodulatory effects may contribute, at least in part, to the positive antitumor and clinical activities of the treatments in this model.

Adjuvants, Immunologic↗
PubMed1995

Alveolar macrophages from humans and rodents selectively inhibit T-cell proliferation but permit T-cell activation and cytokine secretion.

Alveolar macrophages (AM) are thought to play a key role in the regulation of immune responses within the lung. While it is well established that AM inhibit T-cell proliferation in vitro, it is unclear whether other aspects of the T-cell activation process are also inhibited. The present study demonstrates that AM from rat, mouse and human differ markedly in the potency with which they inhibit mitogen-induced T-cell proliferation, although in humans the degree of inhibition approaches that observed in the animal systems, if antigen (as opposed to mitogen) is employed as the T-cell activating agent. Rodent and human AM also differ in the mechanisms employed to achieve this inhibition; rodent AM appear to utilize reactive nitrogen intermediates, while this does not appear to be the case for human AM. Despite these differences, T cells stimulated in the presence of AM display a similar phenotype in all species examined, i.e. CD3 down-modulation, up-regulation of interleukin-2 receptor (IL-2R) expression and IL-2 production, but inability to respond to IL-2. Thus, AM appear to allow T-cell activation and expression of T-cell effector function, while selectively inhibiting T-cell proliferation.

Adult↗