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Biomedical subjects

D Gerlier

Publications and source records attributed to D Gerlier.

82 records · Page 5Linked to original sources
PubMed1979

Specific passive immunotherapy of experimental lymphoma. Effects of macrophage toxic drugs.

Sub-lethal irradiation experiments have indicated that undamaged host cells are necessary for efficiency of specific passive tumour immunotherapy. To further indentify these host cells, the effect of known macrophage toxic agents (silica, carrageenan, trypan blue) were tested on passive immunotherapy of a Gross virus induced C57BL/6 mouse lymphoma with specific W/Fu rat anti-Gross cell surface antigens serum. Median survival time of serum treated mice was significantly decreased when toxic drug was injected three hours before tumour cell injection and seven hours before the beginning of passive immunotherapy, only if silica (5 mg i.p./mouse) or carrageenan (2.5 mg i.p./mouse) but not if trypan blue (4 mg i.p./mouse) was used. Pretreatment by PVNO, a macrophage protecting agent, 24 hours before, inhibited silica effect but not carrageenan effect on the passive immunotherapy. These results indicate that host's phagocytic cells are likely to be involved in the efficiency of passive antibody mediated tumour cell destruction, possibly through opsonization. However, more than one phagocyte population may participate in such a mechanism.

AKR murine leukemia virus↗
PubMed1979

A potent inhibitor of cell proliferation in "middle molecules" isolated from the urine of uremic patients.

A potent inhibitor of cell proliferation was found in the urine of a patient with chronic renal failure. This substance included in "middle molecules" (MM) fraction, was obtained by chromatography. This factor was shown to inhibit noticeably the proliferation of various cells : lymphocytes stimulated by allogeneic cells, monolayer cell lines of normal or tumorous origin and leukemic cell lines derived from acute lymphoblastic leukemia. This effect was reversible and thus could not be related to a direct, rapid cytotoxic effect of MM. Such substances could play an important part in uremic symptoms, such as immunodeficiency, anemia, thrombopenia, gastrointestinal or skin manifestations.

Animals↗
PubMed1978

[Inclusion of Gross virus cell surface associated antigen in liposomes].

The Gross virus associated cell surface antigen GCSAa was extracted from (C58NT)D cells by solubilization of membranes with detergent and partially purified. This antigen was entraped in liposomes. Absorption experiments of the cytotoxic activity towards EmaleG2 cells of a W/Fu anti (C58NT)D serum showed the presence of the antigen at the surface of sensibilized liposomes.

AKR murine leukemia virus↗
PubMed1977

[Expression of an antigen associated with Gross virus on the surfaces of murine cells producing an oncornavirus from the radioleukemia of C57BL/6 mice].

A leukemogenic viral complex was demonstrated in cultures of 13-3 C cell line derived from a C57BL/6, radiation leukemia virus (RadLV-Rs) induced tumor. Both 13-3C and leukemic cells induced in C57BL/6 mice by 13-3C virus carry a cell surface antigen associated with Gross leukemia virus (GCSAa). These findings point to a close similarity between these antigens and those of murine endogenous ecotropic viruses.

AKR murine leukemia virus↗
PubMedDate not supplied

Chimeric CD46/DAF molecules reveal a cryptic functional role for SCR1 of DAF in regulating complement activation.

Chimeric proteins using membrane cofactor (CD46) and decay accelerating factor (DAF or CD55) were generated to further investigate the functional domains involved in the regulation of human serum complement. Following activation of the classical pathway, the isolated substitution of CD46 SCR III (x3DAF) exhibited a modest regulatory activity comparable to that of CD46. The isolated substitution of CD46 SCR IV (x4DAF), and the combined CD46 SCR III+IV substitutions (x3/4DAF) were essentially as efficient as DAF. No regulation of C3b deposition was observed with the combined CD46 SCR I+II substitutions (x1/2DAF). When tested after activation of the alternative pathway, both the x3DAF and x3/4DAF chimeras failed to regulate C3b deposition, while the x4DAF chimera still displayed some activity. In contrast to that observed following classical pathway activation, the x1/2DAF chimera exhibited a similar efficiency to wild type CD46 and DAF in controlling C3b deposition. Using SCR specific antibodies, the regulatory activity of the x1/2DAF chimera against the alternative pathway was mapped to the first three distal SCR (i.e. DAF 1, DAF 2 and CD46 III). These data demonstrate that several combinations of SCR domains from two related complement regulators can result in functional molecules, and reveal a novel and cryptic functional role for DAF SCR1.

Animals↗
PubMedDate not supplied

Localization of an entrapped item within unilamellar vesicle compartments: use of ultrasound disruption as a procedure to separate aqueous phase and lipidic lamellae.

A procedure has been carried out previously to separate the aqueous phase and the lipidic lamellae from multilamellar liposomes (Bakouche and Gerlier, Analyt. Biochem., 1983, 130, 379). This procedure consisted in multiple short bursts of sonication at a temperature below the transition temperature (Tm) of the lowest melting component followed by an ultracentrifugation. The aqueous phase and the lipidic lamellae were recovered in the supernatant and in the pellet respectively. This procedure was adapted for unilamellar vesicles by modifying the second step of the procedure. A suspension of unilamellar liposomes containing 5,6-carboxyfluorescein (5,6-CF) as a probe for the aqueous phase was disrupted by sonication at low temperature. After gel filtration on to a Sephadex G100 column, the phospholipid bilayers were readily separated from the aqueous probe 5,6-CF. Such a procedure should allow the localization of any item within the unilamellar liposome compartments.

Chromatography, Gel↗
PubMedDate not supplied

Substitution of peptide bond 53-54 of HEL(52-61) with an ethylene bond rather than reduced peptide bond is tolerated by an MHC-II restricted T cell.

To probe the interactions between major histocompatibility class-II molecules and the amide bonds of the antigenic peptide main chain, we synthesized ethylenic and reduced analogues of HEL(52-61), an immunogenic peptide for murine major histocompatibility class-II IA k restricted T-cell clones. The synthesis of the corresponding ethylenic analogue of HEL(52-61) in position 53-54 was performed by coupling the Fmoc-protected tripeptide Asp-Tyr-psi [E, CH = CH]Gly with HEL(55-61). Biological tests showed that the ethylenic peptide was presented by major histocompatibility class-II IA kappa molecule and recognized by HEL(52-61)-specific T-cell clones. The corresponding reduced peptide of HEL(52-61) at position 53-54 neither stimulated T-cell clones nor competed with the natural peptide. These results show that, while reduced pseudopeptides might not be appropriate, ethylenic pseudopeptides may be used as probes to dissect the role of hydrogen bonding between the peptide main chain and MHC residues and also help in the design of more stable immunogenic peptides.

Animals↗