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Biomedical subjects

H Mellstedt

Publications and source records attributed to H Mellstedt.

At least 19 recordsLinked to original sources
PubMed1992

Cytotoxic functions of blood mononuclear cells in patients with colorectal carcinoma treated with mAb 17-1A and granulocyte/macrophage-colony-stimulating factor.

Unconjugated monoclonal antibodies (mAb) may induce tumour regression in patients. The mechanisms of action are complex. Antibody-dependent cellular cytotoxicity (ADCC) is considered one of the effector functions. Augmentation of the killing capacity of cytotoxic cells may thus be a way to increase the therapeutic potential of mAb. Granulocyte/macrophage-colony-stimulating factor (GM-CSF) has been shown to enhance this function in vitro. Eighteen patients with metastatic colorectal carcinoma received GM-CSF (250 micrograms m-2 day-1 s.c.) for 10 days and a single infusion of the anti-(colon carcinoma) mAb 17-1A (mouse IgG2A) (400 mg) on day 3 of the cycle. The cycles were repeated once a month four times. Neutrophils, eosinophils, monocytes and lymphocytes increased significantly in a biphasic way. However, at the fourth cycle the rise in white blood cells was significantly lower compared to the preceding courses. ADCC (SW948, a human CRC cell line,+mAb 17-1A) or peripheral blood mononuclear cells (PBMC) was significantly (P less than 0.05) augmented by day 6 of a cycle and then declined gradually and, at the end of a cycle, the ADCC activity had returned to the pretreatment level. The spontaneous cytotoxicity of PBMC against the natural-killer-resistant cell line, SW948, varied in a similar way. During GM-CSF treatment there was also a significant increase in FcRI+ (CD64), FcRII+ (CD32), FcRIII+ (CD16) and CD14+ cells but not of CD56+ cells.

Adolescent↗
PubMed1992

Diverse effect of cytokine treatment of tumor cells on specific versus non-specific cytotoxicity.

The effect of IFN-gamma and TNF-alpha treatment of an ovarian carcinoma line on the sensitivity to lysis by specific CTL clones and non-specific Tumor Associated Lymphocytes (TAL), isolated from the ascites fluid, was analyzed. The in vitro established TAL line displayed a non-specific lytic activity against the autologous tumor as well as against several allogeneic tumor lines. Pretreatment with IFN-gamma alone, or in combination with TNF-alpha, rendered the carcinoma line less susceptible to lysis by the autologous TAL line. Conversely, susceptibility to lysis by tumor specific T cell clones, isolated from the TAL line, was increased as a result of cytokine pretreatment. Several TCR-alpha/beta+, CD8+ T-cell clones showing a more specific pattern of lysis against the autologous tumor were isolated. Lysis of the autologous tumor by these clones involved the TCR-alpha/beta via a MHC-class I restricted mechanism dependent on the adhesion molecules ICAM-1 and LFA-3, as inferred from antibody blocking studies. The enhanced sensitivity to specific CTL clones seen after cytokine treatment may be related to the enhanced expression of ICAM-1 molecules on the ovarian carcinoma. These results have implications for cytokine based immunotherapy, where IFN-gamma may enhance the effects of tumor associated specific CTL while decreasing that of non-specific effector cells.

Ascitic Fluid↗
PubMed1992

Characterization of the colorectal antigen IOR-C2.

A colorectal antigen (IOR-C2) was characterized by a monoclonal antibody produced against the colon cancer cell line SW1116. By immunohistochemical staining the antigen was abundant and strongly expressed in epithelium of normal colon whereas colorectal carcinomas showed a more variable and heterogenous reactivity to the antibody (IOR-C2). Radioimmunoprecipitates of SW1116 cell homogenates showed a 160-200 kD band in SDS gels. Physicochemical characterization indicate that at least two IOR-C2 reactive sites are present on the antigen tested and that it is mainly an 0-linked glycoprotein carbohydrate chain which can also be N-linked to the protein. The expression of IOR-C2 mimics that of the colon associated antigen (CAA) and NCC-CO-450 antigen but is distinct from these with regard to its expression in carcinomas as well as its physicochemical characteristics.

Animals↗
PubMed1992

Chicken antibodies: a tool to avoid interference by human anti-mouse antibodies in ELISA after in vivo treatment with murine monoclonal antibodies.

Human anti-murine antibodies (HAMA) can be found in serum of many patients who have received murine monoclonal antibodies for diagnosis or therapy. These antibodies are known to give false positive results in sandwich-type assays (e.g. ELISA or RIA). This interference problem will increase in the future as more patients are treated with murine monoclonal antibodies in vivo. HAMA can also be found in sera from patients that has not been treated with monoclonal antibodies. In this work we have studied the interference of HAMA in sandwich ELISAs containing antibodies from different species. HAMA, present in the sample, may react both with the capture antibody and the detection antibody in these assays to give a false positive reaction. HAMA did not react with chicken IgG, and if one of (or both) the capture and detection antibody was of avian origin, the interference of HAMA in sandwich assays could be avoided.

Animals↗
PubMed1991

Anti-idiotypic immunity as a potential regulator in myeloma and related diseases.

In this paper some recent and partly preliminary results on anti-idiotypic immunity against clonal B cells in human monoclonal gammopathies are summarized. B cell lines producing antibodies to idiotypic determinants on autologous monoclonal immunoglobulin could be propagated after activation with Epstein-Barr virus of peripheral blood lymphocytes from patients with MGUS and MM clinical stage I but not from untreated persons with advanced MM. Blood T lymphocytes from patients with MGUS and Waldenström's macroglobulinemia were activated to DNA synthesis and production of interleukins by the autologous M protein. In another series of experiments T cell clones raised from patients with MM clinical stage I and MGUS bound F(ab')2 fragments of the autologous M protein and were stimulated to DNA synthesis by the idiotope-bearing protein. Control experiments demonstrated the specificity for idiotypic determinants. Ten of eleven clones were CD4-/CD8+. Finally, using a panel of 8 mAbs to alpha/beta V region epitopes, we noted a clonal expansion of CD4+ and CD8+ T cells in MGUS and MM patients.

Animals↗
PubMed1991

Establishment of idiotype bearing B-lymphocyte clones from a patient with monoclonal gammopathy.

B-lymphocyte clones bearing an idiotypic Ig structure, which could also be found on the serum M-component, have been isolated from peripheral blood of a patient with monoclonal gammopathy (MG) using an immune-rosetting technique and limiting dilution. The majority of the cells had the surface phenotype id+/CD19+/CD20+/CD21+ or id+/CD19+/CD20+/CD21-. Some of the clones originated from spontaneous outgrowth of lymphocytes and some were derived from in vitro Epstein-Barr virus-infected lymphocytes. Three of the B-lymphocyte clones and the patient's bone marrow plasma cells appeared to have clonal identity as shown by the same Ig heavy chain gene rearrangements in Southern blot analysis using a JH probe. The study further supports the notion that the peripheral blood of patients with MG contains B lymphocytes that belong to the tumor clone.

Antibodies, Monoclonal↗
PubMed1991

Lymphocyte abnormalities predicting a poor prognosis in Hodgkin's disease. A long-term follow-up.

Two hundred sixty-two adult patients with Hodgkin's disease (HD) were studied. Incorporation of carbon-14-thymidine was measured in unstimulated monocyte-depleted lymphocyte cultures, and in cultures activated by concanavalin A (Con-A) before institution of therapy in all patients. Total blood lymphocytes and T-cell subsets were enumerated in the last 108 patients. Patients had significantly decreased total (CD3+, CD4+, CD8+) and relative (CD3+, CD4+) T-cell counts compared with healthy controls. Stage IV patients tended to have lower total lymphocyte and subset counts than remaining patients. However, significantly reduced total lymphocyte and CD8+ counts were only observed in comparison to patients in clinical stage II. Thirty-three percent of patients had an increased spontaneous and a decreased Con-A-induced blood lymphocyte DNA synthesis. Functional lymphocyte abnormalities were related to advanced clinical stage, high age, mixed cellularity, and lymphocyte depletion histopathology and presence of B symptoms. The 10-year survival of patients in this group was 36%, compared with 62% for the remainder. In a multivariate analysis of the whole series lymphocyte DNA synthesis was besides age the strongest predictor of prognosis. In univariate analyses of the second patient series total lymphocyte, T-cell and subset counts were related to prognosis. These relatively simple lymphocyte functional tests may help to identify young HD patients for whom intensive cytoreductive therapy with or without autologous stem cell support may be the best therapeutic option.

Actuarial Analysis↗
PubMed1991

Patients treated with a monoclonal antibody (ab1) to the colorectal carcinoma antigen 17-1A develop a cellular response (DTH) to the "internal image of the antigen" (ab2).

The anti-tumor effector functions of unconjugated MAb in cancer therapy are not fully understood. Direct cytotoxic mechanisms have been demonstrated as well as induction of anti-idiotypic (ab2) and anti-anti-idiotypic (ab3) antibodies. If such a humoral response is induced, then an idiotypic cellular response would also be anticipated. Human monoclonal ab2s which mimic a tumor-associated antigen (TAA) (CO17-1A) of colorectal carcinoma (CRC) cells ("the internal image of the antigen") were produced. These ab2s were injected intradermally to patients with metastatic CRC who had been treated with the anti-colon carcinoma MAb 17-1A (ab1). Five out of 12 patients had a specific DTH (delayed-type hypersensitivity) reaction of the tuberculin type, which was proven by immunohistochemical analysis of skin biopsies. Serum ab3 was demonstrated in 4/4 tested DTH+ patients and also in 4 DTH patients. Control patients did not show any skin reactivity. Generation of an idiotypic response induced by the infused antibody (ab1) might be regarded as an active anti-tumor "vaccination". Induction of an idiotypic cellular and humoral cascade might be an important anti-tumor effector function of MAb and should be considered in future strategies for such therapy in cancer patients.

Antibodies, Anti-Idiotypic↗
PubMed1991

Clonality and methylation status of the Epstein-Barr virus (EBV) genomes in in vivo-infected EBV-carrying chronic lymphocytic leukemia (CLL) cell lines.

Directly growing Epstein-Barr virus (EBV)-carrying cell lines were established from a chronic lymphocytic leukemia (CLL) patient (PG) on repeated occasions. The lines carried the same ring chromosome 15 as the leukemia cells in vivo and were similarly trisomic for chromosome 12. They all showed the same JH rearrangement, indicating that they had arisen from the same B-cell progenitor. They also had the same single EBV-terminal repeat (TR), indicating that they had been generated by a single EBV infection event. It may be surmised that a single CLL cell had been infected by EBV in vivo and established itself subsequently as a subclone within the CLL population. This subpopulation persists in vivo but does not appear to expand with time. After explantation, it transforms into lymphoblastoid cells and proliferates selectively as immortalized lines. The leukemia-representative CLL lines were phenotypically indistinguishable from the B95-8 virus-transformed normal diploid cells of the patient, established in parallel by in vitro infection. They grew as typical LCL clusters and expressed the same B-cell activation markers. The methylation status of EBV-DNA was different in the CLL lines and the B95-8-virus-transformed LCLs. When Hpall- and Mspl- digested DNA was probed with BamHI C, E, H and W fragments, the CLL lines showed a mixture of methylated and unmethylated restriction fragments as in certain EBV-carrying Burkitt lymphoma (BL) lines. In contrast, the EBV-DNA of B95-8 virus-transformed normal diploid cells was completely unmethylated, as in other LCLs.

Antigens, CD↗
PubMed1991

Predominant T cell receptor V gene usage in patients with abnormal clones of B cells.

We have examined alpha/beta V gene segment usage of peripheral blood CD4+ and CD8+ T cells, respectively, from patients with multiple myeloma and monoclonal gammopathy of undetermined significance, by using T cell receptor (TCR) for antigen monoclonal antibodies (MoAbs). In 7 of 16 patients we found an increase in the usage of various TCR V gene segments. The expansion was confined to either the CD4+ or the CD8+ T-cell subset, except for one patient where an abnormal pattern was observed both within the CD4+ and CD8+ T-cell subsets. In one patient 47%, and in another patient 30% of the CD8+ lymphocytes reacted with alpha V12.1 and beta V6.7 antibodies, respectively. In two other patients 29% and 40% of the CD4+ lymphocytes reacted with beta V6.7 and beta V8.1 antibodies, respectively. We conclude that T cells with a predominant V gene usage is a frequent feature in patients with abnormal clonal B cells of malignant or benign types. T- and B-cell populations are normally clonally linked in regulatory circuits. An abnormal proliferation of B cells might therefore induce, or be regulated by, an expansion of clonal T cells, as suggested by the present results.

Antibodies, Monoclonal↗
PubMed1991

Induction of DNA fragmentation in chronic B-lymphocytic leukemia cells.

Chronic lymphocytic leukemia of B cell type (B-CLL) is a neoplastic disorder characterized by the accumulation of small resting lymphocytes in the periphery. The phenotype of these cells suggests that they are "frozen" at an early stage of maturation. Glucocorticoid hormones are commonly used to treat patients with B-CLL, resulting in a reduction in the peripheral lymphocyte count by an undefined mechanism. Here we report that glucocorticoids stimulate DNA fragmentation characteristic of a suicide process known as apoptosis or programmed cell death (PCD) in suspensions of cells from patients with B-CLL. The effects can be mimicked by Ca2+ ionophore and involve a sustained increase in the cytosolic Ca2+ concentration. Specific antibodies binding to membrane-associated IgM on the leukemic cells can also induce PCD by a similar mechanism. Phorbol esters block DNA fragmentation and cell killing in response to all of the agents, suggesting that activation of protein kinase C desensitizes the cells to PCD. Targeting the B-CLL cells with antibodies that induce an unbalanced, sustained Ca2+ increase may therefore represent a rational strategy for the destruction of leukemic cells.

Antibodies, Monoclonal↗
PubMed1991

Generation of T cell clones binding F(ab')2 fragments of the idiotypic immunoglobulin in patients with monoclonal gammopathy.

Lymphocytes from two patients with multiple myeloma stage I and one patient with monoclonal gammopathy of undetermined significance were found to proliferate specifically in response to low concentrations of F(ab')2 fragments of the autologous M component. T cell clones isolated from repeatedly stimulated cultures bound specifically the autologous idiotype and proliferated after addition of soluble idiotype and exogenous interleukin-2. The majority of clones were CD8+ and showed negligible staining for CD4. Idiotype-binding clones could not be isolated from cultures of lymphocytes from a healthy control stimulated under the same conditions. The study provides support for the existence of idiotype-reactive T cells in monoclonal gammopathies. Such cells might have a regulatory role on the tumor cell clone and may be important for a future therapeutic approach.

Cell Division↗
PubMed1991

Interleukin-4 augments the cytotoxic capacity of lymphocytes and monocytes in antibody-dependent cellular cytotoxicity.

Human peripheral blood mononuclear cells (lymphocytes and monocytes) (PBMC) were preincubated for 0-24 h with human recombinant interleukin-4 (IL-4) and used as effector cells in an 18 h antibody-dependent cellular cytotoxicity (ADCC) assay with mAb 17-1A (mouse IgG2A) against SW948 (a human colorectal carcinoma cell line). A statistically significant increase in the lytic capability was noted after 2-24 h of preactivation. IL-4 at 1 ng/ml induced the highest cell lysis while higher and lower concentrations were inferior or had no effect at all. Preactivation for 24 h induced a more effective lytic cell population than 2 h prestimulation: 63 LU (lytic units)/10(6) cells vs 42 LU/10(6) cells. Pretreatment with 1 ng/ml IL-4 for 2 h induced a statistically significant increase in the ADCC activity of PBMC (P less than 0.05), of monocytes (P less than 0.01) and E-rosette-negative cells (natural killer cells) (P less than 0.05) compared to non-activated cells. IL-4 did not induce lymphokine-activated killer activity of PBMC against SW948. The spontaneous cytotoxicity against K562 was, however, increased after stimulation with 1 ng/ml IL-4 for 2 h of E-rosette-negative non-adherent cells.

Antibodies, Monoclonal↗
PubMed1991

Chemotherapy and immunotherapy of colorectal cancer.

More than 50% of the patients with large bowel cancer develop disseminated disease and invariably succumb. Adjuvant chemotherapy with 5-FU and levamisole have been shown to be more efficient than 5-FU alone or in combination with cytostatics. The combination of 5-FU, leukovorin and methotrexate induces prolonged survival with a good quality of life in metastatic colorectal cancer (CRC). During the last decade tumor immunotherapy has been an alternative facilitated by isolation and large scale production of cytokines and monoclonal antibodies. The mouse monoclonal antibody (MAb) 17-1A recognizes a tumor-associated antigen (TAA), present in high concentrations on the surface of gastrointestinal tumor cells. Injections of MAb 17-1A in patients with metastatic CRC induced generation of anti-idiotypic (ab2) in 90% and anti-anti-idiotypic (ab3) antibodies in 47% of the treated patients. The development of ab3 correlated significantly with survival (mean 80 weeks) while ab3- patients survive only 38 weeks. One of 52 patients treated with MAb 17-1A is a complete remission after 66 months, 3 had minor regression and 6 had a stable disease (19% RR). Based on in vitro findings showing increased antibody-dependent cellular cytotoxicity (ADCC) by the combination of granulocyte-macrophage colony stimulating factor (GM-CSF) and MAb 17-1A, 16 CRC patients have been treated with subcutaneously injections of GM-CSF for 10 days and intravenous infusions of MAb 17-1A at day 3. Two of 16 are in CR, 1 in MR and 3 in SD (37.5% RR). Minor side-effects were registered. A further development of immunotherapy of CRC might imply vaccination by injection of specific human anti-idiotypic antibodies (ab2) which mimics the nominal antigen, in order to induce a specific immunity.

Antibodies, Monoclonal↗
PubMed1991

The leukemic B-cell population of patients with monoclonal lymphocytosis of undetermined significance (MLUS) are functionally distinct from the chronic lymphocytic leukemia (CLL) derived cell population.

Some patients with CLL survive for decades with a stable lymphocytosis without other signs of progression of the disease. This condition has been termed monoclonal lymphocytosis of undetermined significance (MLUS). The aim of the present study was to search for functional differences between the monoclonal B-cell population of CLL (n = 3) and MLUS (n = 5) patients. MLUS derived B-cell populations were susceptible to Epstein-Barr virus (EBV) infection measured as the production of EB nuclear antigen (EBNA) whereas CLL derived cells were resistant. In 4 out of 5 MLUS patients, lymphoblastoid cell line (LCL) like cell-clumps were formed, but not in CLL. The clonal B-cell population from 2 of 5 MLUS patients was immortalized by EBV (LCL restricted to the expression of one Ig light chain) while no cell line emerged from the CLL patients. Phorbol esters induced cell to cell adhesion of MLUS and normal B cells but not of CLL derived cells. This study further enlarges previous observations and strengthens the assumption that MLUS clonal B cells are functionally close to normal B cells while CLL B cells display various functional abnormalities.

Antigens, Surface↗
PubMed1991

Induction of anti-idiotypic (ab2) and anti-anti-idiotypic (ab3) antibodies in patients treated with the mouse monoclonal antibody 17-1A (ab1). Relation to the clinical outcome--an important antitumoral effector function?

Forty-three patients with metastatic colorectal carcinoma (CRC) were treated with the unconjugated mouse monoclonal antibody (MAb) 17-1A (ab1) only. The presence of antiidiotypic antibodies (ab2) and anti-antiidiotypic antibodies (ab3) were analyzed using an ELISA technique and a mixed hemadsorption assay respectively. Ninety-five percent (41/43) of the patients developed ab2 both of the IgM and the IgG classes. Forty-seven percent (20/43) of the patients had detectable ab3 after therapy, two of them also before administration of MAb 17-1A. Binding in vitro of ab3 (ab1) to CRC cells could be specifically inhibited by ab1. Ab3 bound to human monoclonal antiidiotypic antibodies and to a goat antiidiotypic antibody (ab2). Both these ab2 were directed against MAb 17-1A (ab1). There was a strong correlation between the presence of ab3 and the clinical outcome. Ab3+ patients survived significantly longer than those who did not develop ab3 antibodies, 80 weeks vs 38 weeks (p less than 0.001). A statistically significant correlation was found between the presence of ab3 and the anti-tumor response (CR + PR + MR + SD) (p = 0.01). Thus, induction of an antiidiotypic cascade seems to be an important antitumor effector function of MAb in the treatment of cancer patients.

Antibodies, Anti-Idiotypic↗