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Biomedical subjects

W H Fridman

Publications and source records attributed to W H Fridman.

At least 19 recordsLinked to original sources
PubMed1995

A transforming growth factor beta-like immunosuppressive factor in immunoglobulin G-binding factor.

Immunoglobulin G-binding factors (IgG-BF), which are produced by cells of the immune system, inhibit antibody production. In this paper, we show that transforming growth factor-beta (TGF-beta) suppresses secondary in vitro anti-sheep red blood cell responses of mouse splenocytes and lipopolysaccharide- or anti-IgM-stimulated mouse B cell responses in a way similar to, and with the same kinetics as, rodent IgG-BF. Moreover, the immunosuppressive activity of IgG-BF was totally neutralized by polyclonal and monoclonal anti-TGF-beta antibodies and it eluted with TGF-beta by gel exclusion chromatography, suggesting that a TGF-beta-like immunosuppressive factor is present in IgG-BF. We also show that TGF-beta behaves as an IgG-BF since it binds to insolubilized IgG, but not to insolubilized F(ab')2 or bovine serum albumin. Altogether, the data support the concept of a biological role for TGF-beta in the IgG-mediated negative feedback of antibody responses.

Animals↗
PubMed1995

Variable expression of CD3-zeta chain in tumor-infiltrating lymphocytes (TIL) derived from renal-cell carcinoma: relationship with TIL phenotype and function.

It has been reported that in mice and in humans, tumor-infiltrating lymphocytes (TIL) may exhibit a defect in CD3-zeta-chain expression. Therefore, the level of CD3-zeta was analyzed in TIL derived from patients with renal-cell carcinoma, and its correlation with TIL phenotype and function was assessed. We identified 4 out of 13 tumor-infiltrating lymphocytes derived from renal-cell carcinoma, with a significant decrease in CD3-zeta-chain expression as compared with control peripheral-blood lymphocytes. This defect was never found after culturing TIL with IL2. In one case, the low expression of zeta chain observed in TIL on day 0 was reversed when TIL were cultured with IL2. The zeta-chain level did not seem to predict the growth of TIL in response to IL2. All the TIL, irrespective of the level of zeta-chain expression, exhibited lower proliferative response when stimulated with PHA or anti-CD3 MAb in comparison with normal peripheral-blood mononuclear cells. Nevertheless, in this limited series of patients, a correlation was observed between the level of zeta-chain expression and T-cell infiltration (p = 0.02). After TIL stimulation with PHA or anti-CD3, in contrast to IL2 or IFN-gamma production, a trend towards a relationship between TNF alpha induction and the level of zeta-chain expression was observed.

CD3 Complex↗
PubMed1995

Membrane and soluble Fc gamma RII/III modulate the antigen-presenting capacity of murine dendritic epidermal Langerhans cells for IgG-complexed antigens.

Murine dendritic epidermal Langerhans cells (LC) are APC. This implies that LC take up, process, and present Ag to T cells. One way of doing so that could allow Ag internalization is provided by the low affinity receptors for the Fc region of IgG (Fc gamma R), which murine LC are known to express, although their isoform(s) and function(s) have not been defined. By using molecular biology and biochemical approaches, we demonstrated that LC expressed Fc gamma RIIb2 and Fc gamma RIII. Furthermore, LC internalized Fc gamma R by receptor-mediated endocytosis, as observed with gold-labeled anti-Fc gamma RII/III mAb or immune complexes. We demonstrated the biologic relevance of this process by observing that Fc gamma R-mediated Ag internalization improved by approximately 300-fold the Ag-presenting capacity of LC to T cells. Moreover, analysis of cell culture supernatants showed that two forms of soluble Fc gamma R (sFc gamma R) were released by LC: the first most probably was the secreted transmembrane-deleted Fc gamma RII isoform, Fc gamma RIIb3, and the second was a soluble receptor probably derived from the membrane-associated Fc gamma RII/III. The ability of two recombinant forms, corresponding to the two sFc gamma R released by LC, to inhibit Fc gamma R-mediated presentation enhancement was assayed. Preincubation of IgG-complexed Ag with either rsFc gamma R led to a dose-dependent decrease in the Ag-presenting capacity of LC. Taken together, our results suggest that, in vivo, LC express membrane Fc gamma R, which increase their Ag-presenting capacity for IgG-complexed Ag, and release sFc gamma R, which might be able to modulate this Ag presentation.

Animals↗
PubMed1995

In vitro killing of neuroblastoma cells by neutrophils derived from granulocyte colony-stimulating factor-treated cancer patients using an anti-disialoganglioside/anti-Fc gamma RI bispecific antibody.

Neutrophils isolated from cancer patients treated with granulocyte colony-stimulating factor (G-CSF) express high levels of Fc gamma RI. They exhibited an efficient killing of GD2+ neuroblastoma cells in the presence of an antidisialoganglioside (GD2) mouse monoclonal antibody (MoAb; 7A4, IgG3 kappa). However, this cytotoxicity was totally blocked by human monomeric IgG. In contrast, a bispecific antibody (7A4 bis 22/MDX-260), prepared by chemically linking an F(ab') fragment of 7A4 with an F(ab') fragment of an anti-Fc gamma RI MoAb, 22, which binds outside the Fc binding domain, triggered antibody-dependent cell cytotoxicity, even when neutrophils were preincubated with human monomeric IgG. F(ab')2 22 MoAb abrogated the MDX-260 killing without affecting that of 7A4. The 3G8 MoAb, directed against the Fc gamma RIII binding site, did not inhibit the cytotoxicity induced by either antibody. Thus, these results indicate that G-CSF-activated neutrophils exert their cytotoxic effect against neuroblastoma cells through Fc gamma RI and not Fc gamma RIII, and that the saturation of the high affinity Fc gamma RI by monomeric IgG can be overcome by the use of bispecific antibodies binding epitopes outside the IgG Fc gamma RI binding site. A combined administration of such bispecific antibodies and G-CSF may be, therefore, an efficient therapeutic approach to trigger tumor lysis by cytotoxic neutrophils in vivo.

Antibodies, Bispecific↗
PubMed1995

In vivo targeting of human neuroblastoma xenograft by anti-GD2/anti-Fc gamma RI (CD64) bispecific antibody.

Antidisialoganglioside (GD2) monoclonal antibodies can target in vitro and in vivo neuroblastoma cells. However, their in vivo use is limited by the presence of high levels of circulating IgG which hamper the recruitment of effector cells through the high affinity Fc gamma RI (CD64). A bispecific Fab' x Fab' antiGD2/antiFc gamma RI antibody (7A4 bis 22), which binds outside the IgG binding site of Fc gamma RI, was therefore developed. This antibody binds both human GD2+ neuroblastoma and Fc gamma RI+ activated macrophages in vitro. It can localise a GD2 positive neuroblastoma xenografted on Nu/Nu mice. Scintigraphy tumour/muscle ratios showed that targeting with this antibody has an excellent selectivity for the tumour over normal tissues. Furthermore, although its whole body clearance is more rapid than that of the 7A4 parental antibody over the first 48 h, its selective tumour uptake is similar, as shown by immunoscintigraphy imaging. Thus, such a bispecific antibody may represent an efficient tool for in vivo therapy of neuroblastoma through its ability to recruit Fc gamma RI+ effector cells even in presence of circulating IgG and to bind concomitantly GD2+ tumour cells.

Animals↗
PubMed1995

Role of B cell receptor Ig alpha and Ig beta subunits in MHC class II-restricted antigen presentation.

The ability of the B cell antigen receptors (BCRs) to enhance MHC class II-restricted antigen presentation was ascribed to mig-associated Ig alpha/Ig beta heterodimers. The relative role of Ig alpha and Ig beta subunits in antigen presentation was investigated by fusing their cytoplasmic tails to the extracellular and transmembrane domains of Fc receptors. Ig alpha and Ig beta chimera mediate antigen internalization and increase the efficiency of antigen presentation, but they drive antigens to different endosomal compartments. Furthermore, antigens internalized by either chimera are degraded and presented with different kinetics. The cytoplasmic tail of Ig alpha targets antigen towards a major population of newly synthesized MHC class II located in class II-rich compartments. In contrast, Ig beta targets antigen towards a minor population of recycling MHC class II molecules, located in transferrin receptor-containing endosomes. Altogether, our data indicate that the composition of BCR could be therefore an important way to modulate the immune response.

Animals↗
PubMed1995

The same tyrosine-based inhibition motif, in the intracytoplasmic domain of Fc gamma RIIB, regulates negatively BCR-, TCR-, and FcR-dependent cell activation.

The cell-triggering properties of BCR, TCR and FcR depend on structurally related immunoreceptor tyrosine-based activation motifs (ITAMs). Fc gamma RIIB have no ITAM and do not trigger cell activation. When coaggregated to BCR, they inhibit B cell activation. We show here that, when coaggregated to these receptors, Fc gamma RIIB inhibit Fc epsilon RI-, Fc gamma RIIA-, and TCR-dependent cell activation. Inhibition also affected cell activation by single ITAMs, in isolated FcR or TCR subunits. The same tyrosine-based inhibitory motif (ITIM), which is highly conserved in murine and human Fc gamma RIIB and that was previously shown to inhibit BCR-dependent B cell activation, was required to regulate TCR- and FcR-dependent cell activation. Our findings endow Fc gamma RIIB, and thus IgG antibodies, with general immunoregulatory properties susceptible to act on all ITAM-containing receptors.

Amino Acid Sequence↗
PubMed1995

Lack of efficacy of low-dose subcutaneous recombinant interleukin-2 and interferon-alpha in the treatment of metastatic renal cell carcinoma.

OBJECTIVE: To evaluate the efficacy and toxicity of subcutaneous immunotherapy using a combination of recombinant interleukin-2 (r-IL2) and interferon-alpha (IFN-alpha) for the treatment of patients with metastatic renal cell carcinoma (RCC). PATIENTS AND METHODS: Initially a maximum of 45 patients with advanced RCC were to be included in the study, according to a Fleming three-stage procedure. To be included patients had to have measurable metastasis. Of a potential 45 patients with advanced RCC, 15 patients were included in the study (10 men and five women, mean age 51 years, range 25-69). From the first week of treatment r-IL2 was given subcutaneously on day 1 to 5, at 18 x 10(6) units once a day and then 9 x 10(6) units once a day for the following 5 weeks. IFN-alpha was given three times a week for the last 5 weeks. Minimum follow-up was 6 months. RESULTS: All patients initially underwent radical nephrectomy. Seven patients were found to have metastases at the time of diagnosis. All patients received ambulatory therapy, except for the first 5 days of treatment. Overall, 80% of the patients received more than 75% of the complete dose of r-IL2. One patient suffered toxicity greater than the World Health Organization (WHO) grade 2 (neutropenia). No patient had a complete or partial response, two patients had a minor response, two patients had stable disease and 11 patients had disease progression. CONCLUSIONS: Subcutaneous r-IL2 and IFN-alpha had no beneficial effect on the first 15 patients and the study was discontinued, in accordance with the Fleming rules. The dose, administration and combination of r-IL2 and IFN-alpha may explain the lack of efficacy. Other studies have shown that low doses of r-IL2 are not effective and the superiority of the combination of r-IL2 and IFN-alpha has not been proven. Therefore, a high dose of r-IL2, in association with other cytokines, chemotherapy and adoptive immunotherapy, may be the only way to improve the response rate of metastatic RCC.

Adult↗
PubMed1995

Activation of effector functions by immune complexes of mouse IgG2a with isotype-specific autoantibodies.

Analysis of five monoclonal autoantibodies, rheumatoid factors produced by hybridomas generated from spleen cells of BALB/c mice repeatedly infected with A/PR/8/34 human influenza A virus, revealed that they recognized distinct but spatially related epitopes. The differing isoallotypic specificity of the IgM and IgA monoclonal antibodies correlated with the presence of Ile258 and Ala305, respectively. Although these data suggest that the epitopes recognized are within the CH2 domain, all antibodies failed to inhibit IgG antigen reactivity with Staphylococcus aureus protein A (SpA), C1q, mouse C3, human Fc gamma RI or mouse Fc gamma RII, activities known to be predominantly determined by CH2 domain structures. Reactivity of the IgA antibody, Z34, with IgG2b allowed further specificity studies using a panel of 26 mutant IgG2b proteins, each having single amino acid replacements over the surface of the CH2 domain. The only substitution that affected Z34 reactivity was Asn/Ala297, which destroyed the glycosylation sequon, resulting in secretion of an aglycosylated IgG molecule. The epitope recognized by Z34 therefore seems to be located outside of the Fc gamma R and C1q binding sites, but to be dependent on the presence of carbohydrate for expression. In contrast to the binding studies, complement activation by aggregated IgG2a, through classical or alternative pathways, was inhibited by the presence of autoantibodies. The functional significance of isotype-specific autoantibody in immune regulation is discussed.

Animals↗
PubMed1995

[Immunotherapy of malignant diseases].

Cancer immunotherapy has been carried out since the early fifties and first involved nonspecific system (BCG, Corynebacterium parvum, levamisole...). More recently, the production of cytokines as interferons or interleukin 2, the introduction of monoclonal antibodies have allowed a new development to cancer immunotherapy. Nevertheless, these new approaches have to be considered as a step in the biological therapy of cancer.

Animals↗
PubMed1994

Different patterns of calcium signaling triggered through two components of the B lymphocyte antigen receptor.

The engagement of the B cell antigen receptor is the first step of antigenic stimulation of B lymphocytes. This step is followed by a series of biochemical events, including the activation of protein-tyrosine kinases, phosphoinositide turnover, and multiple patterns of calcium mobilization, which lead to the regulation of gene transcription and cellular responses. The B cell antigen receptor complex is composed of membrane immunoglobulins (as antigen recognition subunits) and associated chains (Ig-alpha and Ig-beta) that couple the receptor to cytoplasmic protein kinases. To investigate independently the relative signaling capacity of Ig-alpha and Ig-beta, chimeric proteins containing their cytoplasmic domains were expressed in a B cell line. We found that Ig-alpha and Ig-beta activate two distinct intracellular signaling pathways. The engagement of Ig-alpha chimeras induces a complete release of calcium from intracellular stores, followed by transmembrane calcium influx and late cell activation signals, detected by lymphokine secretion. In contrast, Ig-beta chimeras do not induce lymphokine secretion or calcium influx, but induce short oscillatory release of calcium, dependent on the activity of the Ca-ATPase pump of the endoplasmic reticulum. These results provide a structural basis for the diversity of B cell responses.

B-Lymphocytes↗
PubMed1992

Induction of tumor necrosis factor-alpha production by mast cells via Fc gamma R. Role of the Fc gamma RIII gamma subunit.

Murine mast cells produce cytokines in response to cross-linking of high affinity receptors for IgE (Fc epsilon RI). Murine mast cells also express the two types of low-affinity receptors for IgG, murine (m)Fc gamma RII, and mFc gamma RIII. We examined the ability of mFc gamma R to trigger a cytokine response such as TNF-alpha production by mast cells. We found that the mFc gamma RII- and mFc gamma RIII-positive mouse mastocytoma cells MMC-1 released TNF-alpha when challenged with F(ab')2 fragments of the rat anti-mFc gamma RII/III 2.4G2 mAb and mouse anti-rat IgG F(ab')2. The release of TNF-alpha was preceded by an increase in TNF-alpha transcripts. mFc gamma RII and mFc gamma RIII have 95% homologous extracellular domains but unrelated transmembrane and intracytoplasmic (IC) domains. mFc gamma RII are single chain receptors whereas mFc gamma RIII associate with a homodimeric gamma-chain that also associates with Fc epsilon RI and TCR. In order to analyze the ability of mFc gamma RII and III to trigger the synthesis of TNF-alpha, we studied RBL-2H3 cells transfected with corresponding cDNA. Rat basophilic leukemia (RBL) transfectants expressing mFc gamma RIII produced TNF-alpha in response to 2.4G2 F(ab')2, but not transfectants expressing mFc gamma RII. Non-transfected RBL cells and mFc gamma RII- or mFc gamma RIII-expressing transfectants, however, released TNF-alpha in response to a rat IgG2a mAb. The respective roles of the alpha and gamma subunits of mFc gamma RIII were examined by studying the production of TNF-alpha by RBL cells expressing deletant and chimeric mFc gamma R. The deletion of intracellular amino acids of the Fc gamma RIII alpha subunit did not prevent 2.4G2 F(ab')2 from triggering the synthesis of TNF-alpha. The substitution of the IC domain of mFc gamma RII for that of mFc gamma RIII gamma, but not that of Fc gamma RIII alpha, enabled 2.4G2 F(ab')2 to trigger the release of TNF-alpha by RBL transfectants. A cytokine response can therefore be induced in mouse and rat mast cells through Fc gamma R. This response is triggered upon cross-linking of mFc gamma RIII but not mFc gamma RII. It depends on the IC sequences of the gamma but not of the alpha subunit of mFc gamma RIII.

Animals↗
PubMed1992

Murine recombinant Fc gamma RIII, but not Fc gamma RII, trigger serotonin release in rat basophilic leukemia cells.

Murine Fc gamma RII and Fc gamma RIII have highly homologous extracellular domains, but unrelated transmembrane and intracytoplasmic (IC) domains. Murine Fc gamma RIIb1 and b2 are two isoforms of single-chain receptors which differ only by 47 aa in their IC domain. Murine Fc gamma RIII are composed of an IgG-binding alpha-chain, the intracellular portion of which is unrelated to that of Fc gamma RII, and of a homodimeric gamma-chain which also associates with Fc epsilon RI. Murine mast cells express Fc gamma RII, Fc gamma RIII, and Fc epsilon RI. They can be induced to degranulate by murine IgG immune complexes or by F(ab')2 fragments of the rat anti-murine Fc gamma RII/III mAb 2.4G2, complexed to mouse anti-rat (MAR) F(ab')2. In order to determine which murine Fc gamma R can activate mast cells, cDNA encoding murine Fc gamma RIIb1, Fc gamma RIIb2 or Fc gamma RIII alpha were stably transfected into RBL-2H3 cells. Murine Fc gamma RIII but not Fc gamma RIIb1 or Fc gamma RIIb2 induced serotonin release when aggregated by (2.4G2-MAR) F(ab')2 complexes. The respective roles of the IC domains of murine Fc gamma RIII subunits in signal transduction were investigated by stably transfecting cDNA encoding IC-deleted or chimeric murine Fc gamma R into RBL-2H3 cells. The substitution of the IC domain of murine Fc gamma RII for that of murine Fc gamma RIII gamma, but not that of murine Fc gamma RIII alpha, conferred the ability to trigger serotonin release. The deletion of IC sequences of the alpha subunit did not alter the ability of murine Fc gamma RIII to trigger serotonin release. It follows that 1) murine Fc gamma RIII, but not Fc gamma RII, can induce RBL cells to release serotonin, 2) the aggregation of the IC domain of the murine Fc gamma RIII gamma subunit is sufficient, but 3) the IC domain of the murine Fc gamma RIII alpha subunit is neither sufficient nor necessary for triggering serotonin release.

Animals↗
PubMed1992

Tyrosine-containing motif that transduces cell activation signals also determines internalization and antigen presentation via type III receptors for IgG.

Type III receptors for IgG (Fc gamma RII; ref. 1), high-affinity IgE receptors (Fc epsilon RI; ref. 2), as well as the T- and B-cell antigen receptors, consist of multiple components with specialized ligand-binding and signal transduction functions. Fc gamma RII alpha (ligand-binding) and gamma (signal-transducing) subunits are expressed in macrophages, a cell type involved in the uptake of antigen, its processing and the presentation of the resulting peptides to major histocompatibility complex class II-restricted T lymphocytes. Here we show that murine Fc gamma RIII, transfected into Fc gamma R-negative antigen-presenting B-lymphoma cells, mediate rapid ligand internalization and strongly increase the efficiency of antigen presentation when antigen is complexed to IgG. Efficient internalization and antigen presentation via Fc gamma RIII did not require the cytoplasmic domain of the ligand-binding alpha-chain, but did require the gamma-subunit. Using chimaeric molecules, we show that gamma-chain contains a signal for receptor internalization and that the mutation of either of the two tyrosine residues present in its cytoplasmic domain prevents efficient internalization and antigen presentation of immune complexes. Thus, associated chains and their tyrosine-containing motif are not exclusively involved in cell activation, but also determine multimeric receptor internalization.

Amino Acid Sequence↗
PubMed1992

Cytoplasmic domain heterogeneity and functions of IgG Fc receptors in B lymphocytes.

B lymphocytes and macrophages express closely related immunoglobulin G (IgG) Fc receptors (Fc gamma RII) that differ only in the structures of their cytoplasmic domains. Because of cell type-specific alternative messenger RNA splicing, B-cell Fc gamma RII contains an insertion of 47 amino acids that participates in determining receptor function in these cells. Transfection of an Fc gamma RII-negative B-cell line with complementary DNA's encoding the two splice products and various receptor mutants indicated that the insertion was responsible for preventing both Fc gamma RII-mediated endocytosis and Fc gamma RII-mediated antigen presentation. The insertion was not required for Fc gamma RII to modulate surface immunoglobulin-triggered B-cell activation. Instead, regulation of activation involved a region of the cytoplasmic domain common to both the lymphocyte and macrophage receptor isoforms. In contrast, the insertion did contribute to the formation of caps in response to receptor cross-linking, consistent with suggestions that the lymphocyte but not macrophage form of the receptor can associate with the detergent-insoluble cytoskeleton.

Amino Acid Sequence↗
PubMed1992

Role of associated gamma-chain in tyrosine kinase activation via murine Fc gamma RIII.

Type III receptors for the Fc portion of IgG (Fc gamma RIII), initially characterized on macrophages and NK cells, are also expressed on several pre-B cell lines. Surface expression of Fc gamma RIII requires the association of the ligand binding alpha-chain with homodimeric gamma-chains. Type II Fc gamma R is homologous to Fc gamma RIII alpha-chain in the extracellular portion and differs in the transmembrane and cytoplasmic domains. The role of Fc gamma R in cell activation was investigated by expressing Fc gamma RIII and the lymphocyte-specific b1 isoform of Fc gamma RII (Fc gamma RIIb1) in an Fc gamma R-negative, sIgG-positive B-cell line. We found that, in contrast to Fc gamma RIIb1, Fc gamma RIII triggers the same events of cell activation as sIG i.e. Ca2+ mobilization, tyrosine phosphorylation and IL-2 secretion. By expressing cytoplasmic domain-lacking Fc gamma RIII alpha-chain in the absence or in the presence of gamma-chains, we demonstrated that cell activation via Fc gamma RIII requires the co-expression of gamma-chains, and is independent of the cytoplasmic portion of the alpha-chain. Furthermore, the cytoplasmic portion of the gamma-chain, fused to the extracellular and transmembrane domains of Fc gamma RII confers on the chimeric receptor the ability to trigger cell activation. Mutation of one tyrosine residue in the cytoplasmic domain of the gamma-chain prevented triggering of cytoplasmic signals. We therefore demonstrate that a tyrosine-containing motif, present in the cytoplasmic domain of the associated gamma-chain, is necessary and sufficient to trigger cell activation via Fc gamma RIII.

Animals↗