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Biomedical subjects

L Dazord

Publications and source records attributed to L Dazord.

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

Antitumor activity of living or killed Brucella: modification of the non-specific cytotoxic effector cells.

At various times after injection of living or killed smooth (S) or rough (R) Brucella abortus mice received a graft of the semi-allogenic EL4 lymphoma and their survival was studied. In parallel, the NK activity of spleen and peritoneal cells, the level of serum interferon (IFN), and the cytotoxic activity of peritoneal macrophages were investigated. Protection against the lymphoma lasted longer after injection of R organisms than after S. The parallelism between the in vivo resistance to El4 lymphoma and the augmentation of NK and macrophage activity was satisfactory with R but not with S. IFN production did not seem to be correlated with R antitumor activity. The antitumor effect of Brucella cannot therefore be simply explained on the basis of modification of the non-specific cytotoxic effector mechanisms.

Animals↗
PubMed1983

Influence of the culture conditions of Brucella abortus on its antitumor properties.

A heat-inactivated rough mutant of B. abortus increased resistance to a transplantable lymphoma when cultured on solid agar (ag) but not when cultured on a fluid medium (fl). The ag organisms were smaller, more toxic and induced more interferon 2 h after injection than fl. They also contained a phospholipid (cardiolipin) absent from fl preparations.

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↗
PubMed1979

Resistance to tumor graft in mice treated with inactivated Brucella abortus cultured in smooth or rough phase.

Because killed Brucella abortus organisms cultured in smooth (S) or rough (R) phase were known to differentially influence humoral and cellular immune responses and to differ in their effects on T-dependent responses, the antitumor properties of killed B. abortus organisms, cultured in S- or R-phase and then inactivated, were compared in (C57BL/6 X DBA/2)F1 female mice with the use of 6 different transplantable tumors. In solid tumors, the antitumor effects produced by S-preparations were never improved by R-preparations. However, in ascites tumors, R-preparations gave the best antitumor results. These findings suggested that the defense mechanisms acrivated by immunostimulants may differ according to the site of tumor implantation. Among the other experimental factors studied, the route of B. abortus administration had a prominent role. Local injection at the site of tumor implantation before or after the graft gave better results than did systemic treatment. Systemic treatment could enhance the growth of Lewis tumor when applied 5 or 10 days before tumor graft but generally had an antitumor effect when given 1 day after the graft.

Animals↗
PubMed1978

Influence of the antigenicity of Brucella preparations on modulation of the immune response to sheep erythrocytes.

The relationship between the expression of surface antigenicity of inactivated Brucella and the immunostimulant properties on the sheep erythrocyte response was studied in mice. The agglutinogenic Brucella abortus B19S preparation was compared to two non-agglutinogenic preparations (B19R and PB), using the plaque-forming and rosette-forming cell tests. When Brucella and antigen were injected together, only non-agglutinogenic preparations, even used at low doses, were able to increase the plaque-forming and rosette-forming cell responses measured 4 days after immunization. When the interval between the previous injection of non-agglutinogenic preparations and that of the antigen increased or when they were injected 24 h after the antigen, the modification of those two responses was no longer observed. After day 4, for the simultaneous injection of Brucella and antigen, B19S and PB preparations induced the best responses; this effect was dose dependent. Thus, in the present experimental situation, the modification of the day 4 response appeared independent of those of the ensuing days.

Agglutination↗
PubMed1978

Modulation of immune response by killed Brucella abortus organisms: comparison of the effects of smooth and rough strains on T-dependent responses.

Inactivated Brucella abortus organisms of the smooth (S) or rough (R) strain were tested comparatively on two T-dependent immune responses: mixed-lymphocyte reaction and delayed-type hypersensitivity. The intravenous injection of S organisms depressed the two tests, whereas R organisms increased mixed-lymphocyte reaction and did not alter delayed-type hypersensitivity significantly. This observation may be helpful in understanding the differences in adjuvant properties of S and R brucellae.

Brucella abortus↗
PubMed1975

[Inhibition of antigenic competition by immunostimulants].

The diminution of immune response against SRBC induced in mice, by a prior injection of HRBC was counteracted by addition of certain immunostimulants to SRBC. The intensity of inhibition of antigenic competition was related to the quantity of immunostimulant added to SRBC. Some immunostimulants (B. abortus, lipopolysaccharide) were more active than others (C. parvum, Poly I : C). To inhibit antigenic competition immunostimulant had to be injected after or in mixture with SRBC never before.

Animals↗