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Biomedical subjects

L Toujas

Publications and source records attributed to L Toujas.

At least 37 records · Page 2Linked to original sources
PubMed1989

Distribution of radiolabelled monoclonal antibody Po66 after intravenous injection into nude mice bearing human lung cancer grafts.

Monoclonal antibody Po66, produced by immunization against a patient's lung squamous cell carcinoma was found suitable for the scintigraphic detection of human tumours. Surprisingly, the cellular antigen recognized by Po66 was abundant in the cytoplasm of tumour cells but could not be detected on the surface membrane. In the present work the biodistribution of radiolabelled Po66 and of an unrelated immunoglobulin were studied comparatively after intravenous injection into nude mice bearing lung squamous cell carcinoma grafts. Radioactivity distribution among mouse organs and tumour was analysed by gamma counting and autohistoradiography. After injection, radiolabelled Po66 decreased rapidly from the blood in tumour-bearing animals whereas, in controls, it remained at a level comparable to that of the unrelated immunoglobulin. The antibody seemed slowly trapped by the tumour and, 12 days after its injection, distribution ratios between tumour and mouse organs reached values of 20-30 as against 1 in animals injected with the non-specific immunoglobulin. Autohistoradiographic investigations in the tumour confirmed the slow diffusion rate of the antibody, which remained in the vascular spaces up to the 24th hour after injection and diffused afterwards throughout the clusters of tumor cells. Furthermore, radioactivity was detected in cells which, unexpectedly, seemed morphologically unaltered. These cells, the viability of which remains to be determined, were predominant in the central area of the tumours. The results presented constitute new evidence of the ability of an in vivo injected monoclonal antibody to reach a cytoplasmic target inside non-necrotic cells and suggest that the cells permeable to the antibody might be in defective nutritional conditions.

Animals↗
PubMed1989

Macrophage antigens associated with adhesion: identification by a monoclonal antibody specific for Lewis lung carcinoma cells.

A monoclonal antibody specific for Lewis lung carcinoma (3LL) cells (Mab 5B5) was found to recognize antigens expressed on murine macrophages and on a macrophage hybridoma line upon cell adhesion on plastic surfaces. These antigens were also present on the surface of murine macrophage tumor M5076 cells which develop solid tumors and metastases. The M5076 tumor cells freshly isolated from the primary tumor and from hepatic metastases strongly bound Mab 5B5 but lost this capacity after adhesion. Freshly isolated thioglycolate-elicited peritoneal mouse macrophages were not labeled by Mab 5B5; however, after 1 h of adhesion, 50% of the adherent macrophages were directly incubated with Mab 5B5 prior to harvesting by scraping. Permeabilization of peritoneal macrophages by saponin showed that the antigens recognized by Mab 5B5 were present inside the cells before adhesion. Similar results were obtained with the 2C11-12 macrophage hybridoma cells. P388D1 cells (a weakly adherent macrophage tumor cell line), HL60 cells (a human promyelocytic cell line), and human monocytes were poorly labeled without permeabilization but were strongly labeled by Mab 5B5 upon permeabilization. The specificity of the monoclonal antibody in relation to the adherence capacity of these cells is discussed.

Animals↗
PubMed1988

Scintigraphic detection in mice of inflammatory lesions and tumours by an indium-labelled monoclonal antibody directed against Mac-1 antigen.

The monoclonal antibody, 3A33, directed against Mac-1 antigen which is expressed essentially on macrophages and polymorphonuclear cells, was injected i.v. into mice, as part of an attempt to visualize inflammatory lesions and tumours by external scintigraphy. The monoclonal antibody, a rat IgG2a, was conjugated with a bifunctional chelating agent, diethylenetriaminepentaacetic acid at a 1:1 molecular ratio and complexed with 111-indium, a procedure which apparently did not alter its binding to peritoneal macrophages and provided relatively stable cell labelling. An unrelated rat IgG2a of unknown specificity radiolabelled in the same manner as 3A33 served as a control. The uptake of i.v. injected 3A33 by peritoneal macrophages was up to 50 times that of unrelated IgG2a. After i.v. inoculation, the antibody accumulated in the liver, spleen, lung, in foot-pad inflammatory reactions induced by injection of Freund's adjuvant and in experimentally grafted tumours. The 3A33: non-specific IgG2a uptake ratio in inflammatory lesions and tumours, however, was much lower than for peritoneal macrophages and was generally close to 2. This was sufficient to obtain scintigraphic images of inflammations and tumours. The images obtained after injection of 3A33 were clearly of better quality than those given by the non-specific immunoglobulin. They could be improved by subtraction of the vascular images obtained after injection of 99m-technetium serum albumin. The labelling of Mac-1-positive blood mononuclear cells by in vitro incubation with radioactive 3A33 was not intense enough to allow scintigraphic imaging after in vivo re-infusion but seemed more selective than the injection of whole antibody in detecting inflammatory reactions. These results seem interesting in view of the potential human application to the detection inflammatory lesions and the appreciation of tumour inflammatory components. Possible improvements in the technique are discussed.

Animals↗
PubMed1987

Regulation of the expression on mouse T lymphocytes of the epitope identified by monoclonal antibody 3A35.

Monoclonal antibody 3A35 (MA 3A35) has previously been shown to be an activation marker of macrophages and T lymphocytes. It immunoprecipitated from macrophages a 200-kDa molecule belonging to the T200 family and from T cells a 85-kDa antigen. In the present work, the factors controlling the expression of the epitope identified by MA 3A35 on polyclonal activated T cells and T-cell clones, as well as the ability of 3A35 alone or together with complement to interfere with T-cell functions, were investigated. Corticoresistant thymocytes unreactive with MA 3A35 became fully reactive after 2 days of in vitro stimulation by PMA and IL-2 and the level of reactivity per cell declined to a low level thereafter. In helper and cytolytic T-cell clones, the expression of the epitope defined by MA 3A35 was also maximal soon after antigenic stimulation then declined. In helper-T-cell clones, the epitope remained detectable during the entire culture period, whereas in cytolytic clones its expression was markedly reduced at the end of the culture. The lineage of cytotoxic T lymphocytes (CTL) as studied in a bulk culture of spleen cells primed in vivo against a syngeneic tumor exhibited similar regulation by antigenic stimulation. The CTL precursors were resistant to lysis by MA 3A35 plus complement; after 3 days of culture with the stimulatory antigen, they became highly sensitive but their sensitivity then diminished and mature CTL were completely resistant. MA 3A35 plus complement also killed the activated T cells which responded to macrophage-presented antigens and were thought to be mainly Lyt-1+. Therefore, the epitope identified by MA 3A35 was expressed predominantly at an early stage of T-cell activation. At a late stage, it persisted almost exclusively on helper and Lyt-1+ cells. In addition, MA 3A35 plus complement lysed NK cells, AK cells, and their precursors present in normal spleen. In the absence of complement, MA 3A35 had no detectable effect on T-cell functions.

Animals↗
PubMed1987

A new epitope of the T200 molecule family defined by the 3A35 monoclonal antibody and expressed by macrophages and activated T lymphocytes.

A monoclonal antibody (mAb), 3A35, produced against mouse macrophages (M phi) was found to react against certain activated T cells. This mAb, a rat IgM, resulted from a cell fusion between a mouse plasmacytoma and rat lymphocytes immunized against mouse M phi. It bound more avidly to activated than to resident M phi. It did not react against B cells and resting T lymphocytes but recognized certain dividing T cells like EL4 lymphoma, concanavalin A-activated and interleukin 2-expanded spleen cells, and helper T cell hybridomas. By contrast, other T lymphocyte-derived cell lines such as YAC-1 and CTLL2 were unreactive. No clear relationship was found between the binding of 3A35 to cells and the expression of L3T4 and Lyt-2 antigens. The specific stimulation of T cell clones with antigen rapidly induced a strong reactivity with 3A35 mAb which declined thereafter to a low (helper clones) or non-reactivity (cytotoxic clones) after 10 days of culture. Immunoprecipitation experiments, performed with M phi derived from bone marrow cell cultures, surface iodinated with 125I or metabolically labeled with [35S]methionine, showed that 3A35 bound to a 200-kDa molecule, shifting to 175 kDa under reducing conditions. In peritoneal M phi activated in vivo, in addition to the 175-kDa band, new bands migrating at 140, 120 and 85 kDa were identified by 3A35 and could be absorbed on a commercial anti-T200 mAb bound to Sepharose beads. After strengthening the cell binding of 3A35 to EL4 lymphoma cells by a cross-linking agent, only a 85-kDa molecule was immunoprecipitated. Thus, 3A35 identifies a new epitope of the T200 molecule family which is expressed on M phi and activated T cells.

Animals↗
PubMed1987

A monoclonal antibody (Po66) directed against human lung squamous cell carcinoma immunolocalization of tumour xenografts in nude mice.

Po66, a mouse IgG1 monoclonal antibody, was produced by immunization against a patient lung squamous cell carcinoma. The tissue reactivity of the antibody was measured by a radioimmunological assay with enzymatically dissociated cells, by an immunofluorescence test on frozen tissue sections and by peroxidase-staining of paraffin sections. The antibody bound to lung squamous cell carcinoma, oesophagus carcinoma and, inconsistently to lung adenocarcinoma but not to the other tumours tested. Some normal tissues also reacted positively, in particular bronchial serous glands, oesophagus epithelium and renal distal and collecting tubules. In normal and malignant tissues showing epithelioid differentiation, Po66 bound to the intermediate maturation area. The antigen immunoprecipitated by Po66 from lung squamous cell carcinoma appeared as a single band with a molecular weight 47,000 to 50,000 daltons. Purified monoclonal antibody Po66 and an unrelated IgG1 immunoglobulin were labelled with radioactive iodine and injected i.v. into nude mice bearing subcutaneous xenografts of human lung squamous cell carcinoma. The localization index in the tumour was 3.3. Antibody labelled with 131I allowed gamma-scintigraphic imaging of the xenografts which were clearly outlined by days 9 to 11.

Animals↗
PubMed1986

A monoclonal antibody (3A33) that reacts with a mouse-specific epitope of Mac-1 antigen.

The 3A33 monoclonal antibody, obtained by fusing rat immune lymphocytes with mouse plasmacytoma cells, was directed against mouse macrophages. Antibody 3A33, a rat IgG2a, reacted with macrophages from all the mouse strains tested, with mouse blood monocytes and with 56% of bone marrow cells, but not with T lymphocytes. It immunoprecipitated an antigen with alpha and beta subunits, found to be identical to Mac-1 antigen after cross-absorption experiments with M1/70 monoclonal antibody. The two antigenic determinants of the Mac-1 molecule identified by the 3A33 and M1/70 antibodies both displayed reduced expression on inflammatory macrophages and comparable resistance to trypsin digestion. The sites of the determinants on this molecule seemed close together judging from the ability of both the 3A33 and M1/70 antibodies to block C3bi receptor sites and compete for cell binding. However, unlike antibody M1/70, 3A33 never reacted with human cells bearing Mac-1 antigen. Therefore, two closely related epitopes of the Mac-1 molecule - one specific for mouse and one common to mouse and man, were recognized by these monoclonal antibodies.

Animals↗
PubMed1985

Diminution of circulating polymorphonuclear leucocytes by administration of a monoclonal antibody reacting with granulocytes and monocytes.

The monoclonal antibody 3A35 which binds mouse polymorphonuclear leucocytes (PMN) and monocytes was injected intravenously (i.v.) into normal mice. A great diminution of circulating PMN was observed. The percentage of PMN passed through a minimum (2.5%) 20 min after antibody injection and returned to normal value (18.3%) within 24 h. After repeated daily injections, the ability of the antibody to induce granulopenia attenuated. Moreover, mice bearing the 3A35-producing hybridoma as an ascitic tumor had a normal percentage of blood PMN and a normal granulopoiesis as judged from bone marrow cytological examination. Thus, the monoclonal antibody produced a transitory diminution of PMN but could not induce a lasting granulopenia.

Animals↗
PubMed1985

Modulation of expression of mouse macrophage surface antigens by monoclonal antibodies.

Mouse macrophages from peritoneal cavity were exposed to monoclonal antibodies (MAbs) directed against cell surface antigens and the effect on antigen expression was investigated. The two Mabs used, 3A33 and 3A35, were produced by cell fusion between a mouse plasmacytoma and rat lymphocytes immunized against mouse macrophages. The binding of the MAbs to cell surface was measured by immunofluorescence and flow cytometry or by a radioimmunological technique. When injected i.p. the MAbs diminished the expression of the corresponding antigens but did not alter it when added to cultures of adherent macrophages. Antigenic modulation, however, could be produced in vitro either by inhibiting macrophage adherence during incubation with MAbs or by using a second antibody layer. MAb 3A33 (IgG2a) was more effective than 3A35 (IgM) in provoking modulation. The appearance of re-synthesized antigens on cell surface was not affected by macrophage adherence. The modulated antigens were found to internalize into cytoplasmic vacuoles.

Animals↗
PubMed1984

Red blood cell polyamines in mice bearing the Lewis lung carcinoma (3LL) and in patients with bronchopulmonary cancers.

Experimentally, during Lewis lung carcinoma (3LL) growth, the red blood cell (RBC) polyamine levels increase with tumor volume and are inversely correlated to tumoral concentrations of spermidine and spermine. The RBC level of spermidine is continually correlated to both the volume and the tumoral concentration of this polyamine. Clinically, high levels of RBC polyamine are observed in cases of squamous-cell carcinoma or anaplastic cancer, and not in cases of adenocarcinoma. RBC polyamine levels only permit the establishment of statistical differences between groups of patients. Therefore, clinical use of these molecules as tumor markers depends on an understanding of polyamine distribution within blood.

Adenocarcinoma↗
PubMed1984

An anti-mouse macrophage monoclonal antibody reacting with T-derived leukaemic cells.

Hybridomas secreting anti-mouse macrophage antibodies were obtained by fusing a murine plasmacytoma with lymphocytes of a rat immunized against mouse macrophages. An IgM, monoclonal antibody (3 A 35) reacted with mouse monocytes, macrophages and polymorphonuclear leucocytes. It did not bind appreciably to erythrocytes, platelets and unstimulated T or B lymphocytes. However, 3 A 35 bound to various murine T-derived leukaemic cells and to a small proportion of Con A-stimulated thymocytes. Cross absorption experiments confirmed the existence of a common antigenic determinant on macrophages and leukaemic cells. The possibility that 3 A 35 identified a previously described antigen common to macrophages and normal or leukaemic T cells was investigated. The antibody was tested against thymocytes and macrophages of various mouse strains, some congenic for H-2 or T1a. The 3 A 35-detected antigen was found to be different from Ly5, Tla and Qa and did not represent a I-J encoded allotypic specificity.

Animals↗
PubMed1984

Phase I study of immunotherapy by live Brucella abortus (strain 19 BA) in cancer patients.

Twenty-eight patients showing negative responses against Brucella antigens were included in a preliminary trial of immunotherapy by a live Brucella abortus vaccine. Seventeen patients had squamous cell lung carcinoma, eight had acute myeloid leukemia, and three were classified as "others." Brucella abortus strain 19 BA was administered sc in a single injection at doses ranging from 5 X 10(7) viable organisms to 10(10), ie, 40 times the usual vaccine dose. No important toxicity was noted. Edematous reactions at the injection site and febrile responses were infrequent and moderate, hemocultures were all negative, spleen volume did not vary significantly, and cbc showed an increase of polymorphonuclear cells and lymphocytes.

Blood Cell Count↗
PubMed1983

Differentiation of cytotoxic adherent cells from peroxidase positive cells after intraperitoneal injection of Brucella abortus organisms.

The relations between the cytotoxic adherent cells (CAC) and the peroxidase positive adherent cells (PPAC) which appeared after i.p. injection of Brucella abortus were investigated. A kinetic study showed that PPAC preceeded CAC. Twenty-four hours after bacterial injection, almost all adherent cells stained for peroxidase and no cytotoxic activity could be recorded. Cells sampled at this moment acquired cytotoxic properties by cultivation in LPS containing medium. The treatment of the bacterial organisms by HCl or chloroform: methanol (C:M) suppressed their ability of inducing CAC but not that of inducing LPS-activatable PPAC. The substances extracted by C:M could activate PPAC into CAC in vitro. The data presented suggest that CAC differentiate from PPAC, that the recruitment of PPAC is not always followed by their transformation into CAC and that different components of the bacterial organisms might be necessary to achieve the steps of cell recruitment and maturation.

Animals↗
PubMed1983

Antitumor activity of cell walls from Brucella abortus.

The ip inoculation of inactivated Brucella abortus, strain B19 R, protected mice against a subsequent graft of an ascites lymphoma. The bacterial components responsible for this effect were investigated. Centrifugation supernatants of sonicated bacteria supposed to contain mainly cytoplasmic products did not offer protection against the lymphoma. Cell walls (CW's) prepared by enzyme digestion of pellets of lysed bacteria and checked for purity by electron microscopy prolonged survival of mice and induced cytotoxic macrophages in their peritoneal cavities. CW peptidoglycan (PG) did not seem to play an important part in this effect. Enzyme digestion of CW, in particular by lysozyme, was found to reduce a PG characteristic component (diaminopimelic acid) without altering CW antitumor activity. Conversely, a purified PG preparation did not influence tumor growth. Extraction of CW by an ether:water mixture did not alter its antitumor activity, while incubation in NaOH abolished its activity almost completely. All CW preparations were found to elicit hypersensitivity reactions in Brucella-infected animals.

Animals↗
PubMed1980

Increased resistance to tumor graft in mice infected by vaccinal strains of Brucella abortus.

Kinetics of proliferation in vivo and the effect on murine tumors of the vaccinal strain Brucella abortus B19 and two derivatives, 19BA and B19R, were studied. Inocula of 5 x 10(6) organisms of each strain produced comparable infections peaking on day 8. Several protocols of Brucella treatment yielded favorable results in EL4 lymphoma and Lewis tumor. The treatment for EL4 lymphoma seemed optimal 8--14 days after infection with 5 x 10(6) -- 5 x 10(7) organisms. In comparison with BCG, Brucella grew faster in vivo and accumulated more in the spleen. The effects of BCG and Brucella were comparable on EL4 lymphoma, but BCG was less effective than Brucella on Lewis tumor. The results encourage trials using live Brucella vaccine as an antitumor agent in man.

Animals↗