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J Y Cesbron

Publications and source records attributed to J Y Cesbron.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Cutaneous changes induced by a dose of DEC in rodents with skin microfilaria: relevance of these phenomena for understanding the Mazzotti reaction and the pathogenesis of human onchocerciasis].

A single dose of DEC was given to Lemniscomys striatus parasitized by Monanema martini. The histopathological analysis of ear-lobe skin sections shows: a massive escape of microfilariae from the lymph capillaries, a major vascular exudative reaction with edema and diapedesis of blood cells. This inflammatory process leads to the destruction of the extralymphatic microfilariae and it induces a subacute and chronic dermatitis at the 7th day. These findings explain the pathogenesis of Mazzotti reaction during treatment of human onchocerciasis. The use of DEC produces precisely the factor that is responsible for the severity of the human disease: inflammatory reactions around the extralymphatic microfilariae.

Animals↗
PubMed1986

Role of specific IgE antibodies in peroxidase (EPO) release from human eosinophils.

After the demonstration of cytophilic IgE immunoglobulins (Ig) on human blood and lung eosinophils, their role in cell activation was studied by eosinophil peroxidase (EPO) assay. Hypodense human eosinophils from filariasis-infected patients were activated by anti-human Ig or various antigens. A selective release of EPO occurred after incubation with anti-human IgE, but not with anti-human IgG. The activation by antigens showed a strict antibody specificity of cytophilic IgE antibodies. The direct involvement of IgE antibodies in activation by the specific antigen was evidenced by inhibition experiments with aggregated human IgE myeloma protein. Circulating IgE antibodies exhibiting the same specificity and able to induce EPO release were detected in the sera from filariasis patients by a passive sensitization assay. Only the hypodense eosinophils were able to release EPO after IgE-dependent activation both in the direct assay and in the passive sensitization test, confirming the functional heterogeneity of human eosinophils. These results suggest that the interaction between IgE antibodies and human eosinophils can play a role both in protective immunity and pathology by releasing active pharmacologic mediators.

Antibodies, Anti-Idiotypic↗
PubMed1986

A suppressive lymphokine of platelet cytotoxic functions.

The in vitro stimulation of mononuclear cells from human peripheral blood with mitogens is known to induce the release of factors (monokines and lymphokines) that possess distinct biologic activities. The present data describe the presence in Con A- and antigen-stimulated T cell supernatants (of man or rat) of a factor able to inhibit, in a dose-dependent manner, the platelet cytotoxicity toward the young larvae of Schistosoma mansoni. The production of oxygen metabolites by IgE-coated platelets, stimulated by anti-IgE or the specific antigen, was, likewise, strongly inhibited by this lymphokine. The producing T lymphocyte subpopulation was identified as OKT 8+. This suppressive lymphokine of platelet functions had an m.w. of 15,000 to 20,000 and a pI of 4.6. It was heat- and acid-stable and sensitive to trypsin and proteinase K, but neuraminidase had no effect on its activity. This platelet suppressive activity was specifically absorbed by platelet membrane, suggesting its action through the binding to a receptor.

Binding, Competitive↗
PubMed1986

[A new ELISA method for the diagnosis of toxoplasmosis. Assay of serum IgM by immunocapture with an anti-Toxoplasma gondii monoclonal antibody].

The diagnosis of acute toxoplasmosis is based exclusively on the detection of IgM anti-Toxoplasma antibodies. The principal of the immunoenzymatic test reported here is the capture of serum IgM antibodies which are detected indirectly by the sequential addition of antigen and a monoclonal antibody directed against the immunodominant epitope at the surface of the tachyzoite. This test combines the sensitivity of enzyme-based assays and the specificity of monoclonal reagents and represents an important contribution to the diagnosis of Toxoplasma gondii infection.

Acute Disease↗
PubMed1986

Raised serum IgG4 levels in patients with atopy and filariasis: application of an automated particle-counting immunoassay using monoclonal antibody.

We show here an automated (50 samples/h) assay for serum IgG4 having a throughput time of 40 min per sample and a sensitivity of 10 micrograms/ml. The assay procedure is based on the inhibition by sample of the agglutination reaction between monoclonal anti-IgG4 antibodies and latex particles to which IgG4 myeloma protein has been coupled. Assay reliability was ascertained by testing for linearity, analytical recovery (96.4%), interassay precision (less than or equal to 8%), specificity and correlation between the results obtained with monoclonal and polyclonal anti-IgG4 antibodies (n = 84; rs = 0.97). Application of the assay to sera from various groups of patients indicated significantly (p less than 0.00005) higher geometrical means (Gx) in patients suffering from atopy (n = 87; Gx = 617 micrograms/ml), atopic dermatitis (n = 28; Gx = 1,043 micrograms/ml), filariasis with Onchocerca volvulus (n = 48; Gx = 1,681 micrograms/ml) and Brugia malayi (n = 20; Gx = 1,078 micrograms/ml) as compared to nonatopic subjects (n = 103; Gx = 302 micrograms/ml) and randomized paired maternal/cord sera (n = 41; Gx = 276 and 296 micrograms/ml, respectively). IgG4 in the paired maternal/cord sera correlated (r = 0.98; p less than 0.00005). There was no significant influence of age or sex on the IgG4 levels either among the nonatopics or the atopics even though low IgG4 (less than or equal to 30 micrograms/ml) was more common among women. The results suggest that IgG4 and IgE responses are somehow closely related in atopic and parasite-infested patients at the physiological, pathogenic or genetic level.

Adolescent↗
PubMed1985

[Homozygotic C5 deficiency disclosed by purulent Neisseria meningitidis meningitis].

The complement system functions to protect the individual against infectious agents. Deficiencies of the late-acting complement proteins C5-C8 are associated with an increased susceptibility to Neisseria infection. This paper describes a deficiency in C5 in a Caucasoid family from the north of France that was revealed by the occurrence of a N. meningitidis meningitis in the homozygous C5-deficient propositus.

Adult↗
PubMed1985

Use of a monoclonal antibody in a double-sandwich ELISA for detection of IgM antibodies to Toxoplasma gondii major surface protein (P30).

A double-sandwich ELISA, developed for detection of IgM antibodies to the major surface protein of Toxoplasma gondii (P30), is proposed for the diagnosis of acute acquired toxoplasmosis. The method is based on the capture of serum IgM antibodies, which are revealed indirectly by the sequential addition of a Toxoplasma extract and a beta-galactosidase-conjugated anti-P30 monoclonal antibody. All 57 patients tested with serological characteristics of recently acquired toxoplasmosis showed high levels of IgM anti-P30 antibodies. In addition, 5 out of the 24 patients with chronic toxoplasmosis and all 7 patients with a clinical acute infection in which the classical IgM serology was negative, also presented significant anti-P30 IgM antibodies. Patients with either rheumatoid factor or antinuclear antibodies were all negative. In view of its simplicity, specificity and sensitivity, this method is recommended for the current diagnosis of T. gondii infection.

Animals↗
PubMed1985

Serodiagnosis of toxoplasma infection using a purified parasite protein (P30).

The major surface protein (P30) of Toxoplasma gondii has been purified by immunoabsorption with anti-P30 monoclonal antibodies linked to a glutardialdehyde activated affinity absorbant. SDS-PAGE analysis of the eluted material followed by silver staining showed only a single band of 30,000 mol wt. Western blotting using antibodies from a rabbit immunized with purified P30 against the total Toxoplasma extract separated by SDS-PAGE again revealed an unique antigen of 30,000 daltons. The presence of repeated epitopes within P30 was confirmed by a two-site/one-antibody radiometric assay with the purified protein. Sandwich ELISA procedures with purified P30 clearly demonstrated that all 37 tested patients with acute toxoplasmosis presented significantly high levels of IgM anti-P30 antibodies. In addition, all 40 tested patients with chronic toxoplasma infection also showed high IgG anti-P30 antibody levels. These findings represent an essential step for the development of new reagents for the diagnosis of toxoplasmosis.

Antigens, Protozoan↗
PubMed1985

The use of monoclonal antibodies in studies of filarial parasite antigens.

The strength of the hybridoma technology in providing probes for the study of parasite immunology is obvious. The use of monoclonal antibodies should greatly expedite the task of the identification and the isolation of antigens which are relevant to host protection, of immunodiagnosis and of immunopathology. We have produced a series of monoclonal antibodies against Brugia malayi which causes lymphatic filariasis in man. One of these monoclonal antibodies (IgM isotype) can detect circulating antigens in the sera of individuals and of laboratory animals infected with B. malayi by radioimmunoprecipitation-PEG assay. This monoclonal antibody can bind to the relevant epitope of the circulating antigen or to the antigenic determinants of the immune complexes that remained exposed in the complex. A few monoclonal antibodies raised against B. malayi were selected, one of which gave positive fluorescence reaction on the surface of microfilariae. This particular monoclonal antibody showed such biological activities as conferring resistance to circulating microfilariae and inducing cell-mediated killing of microfilariae in vitro. The same monoclonal antibody was able to identify antigenic determinants (of mol. wt, 110 Kd) on the surface of B. malayi microfilariae which may be involved in effector mechanisms related to the development of transmission inhibiting immunity in lymphatic filariasis.

Animals↗
PubMedDate not supplied

Dose-dependent systemic human immunodeficiency virus infection of SCID-hu mice after intraperitoneal virus injection.

SCID mice were engrafted with human foetal liver, thymus and lung. Human cells were subsequently detected among peripheral blood leukocytes for 81% of tested animals and in tissue implants for 100% of tested animals. SCID-hu mice received intraperitoneal injections of human immunodeficiency virus type 1 (HIV1) at from 20 up to 20,000 median tissue culture infectious doses (TCID5). HIV1 infection was detected by means of cell culture and polymerase chain reaction both in blood and implants, up to 58 days after infection. The rate of infection was dependent upon the inoculated dose: the frequency of thymus infection ranged from 14% with 20-500 TCID50 up to 100% with 20,000 TCID50. HIV1 infection was detected less frequently in blood leukocytes than in thymus. Thymus virus load ranged from 40 to 50,000 HIV1 provirus copies per million cells and was not correlated with either infectious dose or viraemia. Thymus T-cell depletion was observed mainly in the CD1+4+8+ immature thymocyte compartment. The same rate of SCID-hu mouse infection was obtained using three different primary HIV1 isolates, suggesting that infection was not restricted to a few particular virus strains. The systemic infection of SCID-hu mice following intraperitoneal virus injection mimics some traits of human HIV infection and provides a promising, novel approach for future investigations in this field.

Animals↗
PubMedDate not supplied

Specific IgE antibodies to Leishmania braziliensis in patients with mucocutaneous leishmaniasis.

A total of 116 sera of patients suffering from South American mucocutaneous leishmaniasis were analysed using the RAST (L. braziliensis-specific) and RIST techniques. Results of total and specific IgE levels were correlated with different clinical stages of the disease. The level of total and specific IgE appeared to be higher among patients with cutaneous ulcers than among those presenting mucocutaneous lesions, i.e. espundia. Furthermore, non-treated patients presented higher concentrations of total and specific IgE than did treated ones.

Antibody Specificity↗
PubMedDate not supplied

Platelets mediate the action of diethylcarbamazine on microfilariae.

More than 400 million people in the world are infected by filarial parasites leading to a wide range of pathologies. Although introduced in 1947, the mainstay of the therapy and control of the filariases is diethylcarbamazine (N,N-diethyl-4-methyl-1-piperazine carboxamide; DEC), the mode of action of which still remains unknown despite widespread use and intensive laboratory investigations. The marked contrast between an extremely rapid action in vivo and the absence of any significant activity on microfilariae in vitro is unique among chemotherapeutic agents. DEC has been thought to modify the surface layer of the microfilariae and expose them to immunological cell-mediated lysis. This report provides the first evidence that the effect of DEC is mediated by blood platelets with the additional triggering of a filarial excretory antigen (FEA). The killing mechanism is antibody-independent and involves the participation of free radicals.

Animals↗
PubMedDate not supplied

Human IgE in severe combined immunodeficiency mice reconstituted with peripheral blood mononuclear cells from Dermatophagoides pteronyssinus-sensitive patients.

We studied conditions of human IgE formation in severe combined immunodeficiency (SCID) mice engrafted with peripheral blood mononuclear cells (PBMCs) from allergic patients sensitive to Dermatophagoides pteronyssinus (D.pt.). With 10 x 10(6) PBMCs injected intraperitoneally, the hu-SCID mice developed an IgE response, but only if experimental animals were immunized with the related allergen. Two routes of immunization were tested: intraperitoneal and inhalation. In these experimental conditions (allergen given at day 14 after reconstitution), a significant rise in total serum IgE but also in specific anti-D.pt. IgE was observed. No human IgE could be detected within 3-4 weeks after immunization with an unrelated allergen. Similarly, when mice were engrafted with PBMCs from nonallergic donors, even after D.pt. administration, no significant increase of serum IgE was detectable, while an IgG response was regularly found. Thus SCID mice could represent a useful model to analyze IgE production as well as the conditions of immunization required to obtain an optimal response.

Administration, Inhalation↗
PubMedDate not supplied

Introduction of Pneumocystis carinii in a colony of SCID mice.

Pneumocystis carinii-free SCID mice were housed closely exposed to corticosteroid-treated non-SCID mice in a conventional area of our laboratory animal facilities. A one-day exposure was sufficient for P. carinii transmission. The lung infection increased thereafter. Irradiation or splenectomy of SCID mice at the beginning of the exposure resulted in a marked increase of parasite multiplication. Extrapulmonary foci of pneumocystosis were detected in heart and spleen of SCID mice infected by P. carinii via air transmission.

Animals↗