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Biomedical subjects

M Van Hoegaerden

Publications and source records attributed to M Van Hoegaerden.

16 recordsLinked to original sources

A monoclonal antibody specific for conidia and mycelium wall layer of Penicillium and Aspergillus.

A monoclonal antibody was obtained from BALB/c mice immunized with Penicillium frequentans mycelium. The specificity of the antibody was evaluated by enzyme-linked immunosorbent and indirect immunofluorescence assays against the same mycelium. This IgM antibody cross-reacted with various strains of the Penicillium and Aspergillus genera. By indirect immunofluorescence assays, the antibody was able to stain about 10% of Penicillium and Aspergillus conidia, but major part of conidia did not absorb the fluorescence-labeled antibody before swelling. During germination of P. frequentans conidia, the germ tube wall which constitutes a continuation of an inner wall layer was also stained. During germination of P. griseofulvum, the protrusion of the germ tube wall was not always recognized by the antibody because the germ tube wall was constituted by a continuation of an outer spore wall layer. The study of the staining patterns of the spores and the protrusions suggests that the antibody specifically recognizes an antigen of the inner spore wall layer. The monoclonal antibody reacts with extracellular galactomannans produced by genera Aspergillus and Penicillium but is not directed against beta-(1,5)-linked galactofuranose units.

Animals↗

Rapid detection of members of the family Enterobacteriaceae by a monoclonal antibody.

Six monoclonal antibodies directed against enterobacteria were produced and characterized. The specificity of one of these antibodies (CX9/15; immunoglobulin G2a) was studied by indirect immunofluorescence against 259 enterobacterial strains and 125 other gram-negative bacteria. All of the enterobacteria were specifically recognized, the only exception being Erwinia chrysanthemi (one strain tested). Bacteria not belonging to members of the family Enterobacteriaceae were not detected, except for Plesiomonas shigelloides (two strains tested), Aeromonas hydrophila (five strains tested), and Aeromonas sobria (one strain tested). This recognition spectrum strongly suggested that CX9/15 recognized the enterobacterial common antigen. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) experiments, the six antienterobacteria antibodies presented similar specificities; they all revealed only one band with an apparent molecular weight of about 20,000 from the crude extract of an enterobacterium. The six monoclonal antibodies, and especially CX9/15, can be used to develop new tests for rapid and specific detection of enterobacteria.

Antibodies, Monoclonal↗

Monoclonal antibodies to barley alpha-amylase I: production, characterization, and application to a specific immunoassay.

Monoclonal antibodies (MAbs) to barley alpha-amylase I have been produced, purified and characterized. Six are specific for the alpha-amylase I isoform, while one also reacts with alpha-amylase II. All but one recognize the antigen in solution. Topology of the MAbs was investigated by additivity in ELISA, which led us to subdivide them into four groups. An immunoassay was developed using one of these MAbs, to measure alpha-amylase I activity in an extract containing both isoforms.

Animals↗

Immunological differentiation of Penicillium species.

Antisera were obtained from a rabbit immunized with Penicillium verrucosum var. verrucosum. These antisera were characterized by immunofluorescence and by indirect enzyme-linked immunosorbent assay for their reactivity with 44 strains of moulds. Antigenically, P. verrucosum var. verrucosum (subgenus Penicillium) appears to be similar to strains belonging to subgenus Furcatum, but strongly different from Penicillium frequentans (subgenus Aspergilloides). Specific absorption of antibodies to antigens confirmed the existence of similar biochemical structures on Penicillium frequentans, Aspergillus versicolor, and Aspergillus fumigatus. Immunological procedures may thus significantly contribute to refine the taxonomic classification of moulds.

Animals↗

Filariasis due to Loa loa and Mansonella perstans: distribution in the region of Okondja, Haut-Ogooué Province, Gabon, with parasitological and serological follow-up over one year.

The prevalence of Loa loa and Mansonella perstans filariasis has been determined in 6 rural villages in eastern Gabon. Between 18.9 and 27.2% of people carry L. loa microfilariae with an overall microfilarial rate of 25.1%. The microfilarial rate for M. perstans was more variable, between 33.3 and 62.2% (average 49.1%). No significant difference was seen in the microfilarial rate with age over 15 years for either parasite, but men were infected more frequently than women. Anti-L. loa antibody titres were measured, using a homologous microfilarial antigen in ELISA. Taking the parasitological and immunological evaluations together, only 10% of the sample population appear to be free of these filarial infections. L. loa and M. perstans microfilaraemia and corresponding serology were also investigated twice in 150 people at a one-year interval. 99.1% of the cases who had no circulating L. loa microfilaria in March 1984 still did not show any 12 months later. Similarly, 97.1% of the untreated, microfilaraemic cases still harboured this parasite a year later. The same was not observed for M. perstans, since microfilariae appeared or disappeared in 26.7% of the cases. This suggests different dynamics for the two filarial infections. Variation in individual anti-L. loa antibody titres was low. The possibility of a genetic influence on the expression of loiasis is discussed.

Adolescent↗

The use of mebendazole in the treatment of filariases due to Loa loa and Mansonella perstans.

Patients harbouring Loa loa and/or Mansonella perstans infections, or presenting typical filarial symptomatology, were treated with mebendazole, a drug shown to be efficient in other parasitoses. Of the patients who took the drug during 21 days and provided regular blood samples, 84% showed a significant decrease in their L. loa microfilaraemia and 100% in their M. perstans microfilaraemia, with a concomitant improvement in the clinical manifestations and no side reaction to drug administration. Additionally, the long-lasting effect of the drug (up to day 200 in some cases) may suggest a positive action on the adult worm. Mebendazole may consequently be regarded as a safer alternative to diethylcarbamazine for the treatment of these two parasitoses.

Adolescent↗

A rapid, simple method for isolation of viable microfilariae.

We describe a rapid, efficient method for purifying Loa loa microfilariae from blood that does not affect their longterm motility. It is based on the separation of microfilariae on a performed discontinuous Percoll gradient, followed by filtration on cellulose ester membranes. The parasite population, after isolation, is close to 100% pure, 100% viable and remains motile for at least 20 days. Recovery from original blood samples is typically around 90%. The method, because of its simplicity and minimal material requirements, could be used with up to 210 ml of blood. It also allows the isolation of Mansonella perstans microfilariae.

Animals↗

Lack of evidence for transplacental transfer of microfilarial antigens in filariasis due to Loa loa and Mansonella perstans.

The transplacental transfer of microfilarial antigens could induce prenatal tolerance, or conversely resistance, which would influence the development of filariasis after birth. The passage across the placenta of immunogens constitutive of a crude microfilarial Loa loa extract has been investigated by dosing specific IgG, IgM and IgE antibodies in 92 maternal and corresponding cord blood samples, IgG levels were shown to be identical in about half of the mother-cord paired samples while in the other half the cord serum had a lower titre. Specific IgM or IgE could not be evidenced in any of the cord blood samples, even from those mothers who where harbouring L. loa microfilariae and/or specific antibodies. It is concluded that prenatal sensitization to the immunogenic preparation used is unlikely to have occurred.

Animals↗

Treatment of recurrent, filarial, Calabar-type oedema with mebendazole.

A case of recurrent, severe filarial Calabar-type oedema, causing acute discomfort in the patient, is described in a male Caucasian. An adult Loa loa worm but no microfilariae were present while Dipetalonema perstans microfilaraemia was extremely low. Treatment with mebendazole (1.5 g per day) for 21 days led to the disappearance of the clinical symptoms and microfilariae, and to a decrease of eosinophilia to normal values.

Adult↗

Antigenic analysis of Trypanosoma cruzi strains by crossed immunoelectrophoresis: demonstration and isolation of antigens particular to some strains.

Antigenic differences among soluble extracts of Y, CL, SF, and Colombian strain epimastigotes of Trypanosoma cruzi have been demonstrated by crossed immunoelectrophoresis with an intermediate gel containing the heterologous antiserum. Using crossed immunoelectrophoresis with the homologous antiserum, over 30 precipitin lines could be demonstrated for each strain and, even though marked differences were observed in experimental infections, the strains shared a significant number of antigens. In addition, some strain-particular antigens were isolated using affinity chromatography. These antigens could be valuable in the study of biological, immunological, and pathological characteristics of experimental and natural T. cruzi infections.

Animals↗

Sequence of a rabbit anti-Micrococcus lysodeikticus antibody light chain.

The complete sequence of rabbit antibody light-chain L 120 has been elucidated. The antibody was raised against Micrococcus lysodeikticus bacteria and is specific for the external part of the cell wall. All protein used in this work was obtained from a single 50-mL bleeding. The variable region of L 120 is compared to 13 other sequences of chains of different specificities. The constant region of this b4 k chain is identical to that of two other constant regions published earlier. The general structure of the rabbit light chain is compatible with the three-dimensional folding proposed for human myeloma chains.

Amino Acid Sequence↗

[Evolution of the immune response against Micrococcus lysodeikticus].

The immune response of rabbits immunized with Micrococcus lysodeikticus freeze-dried bacteria was studied by following the variation of the affinity and the heterogeneity of the antibodies during immunization. Partial or complete amino acid sequences were determined on the isolated light and heavy chains, and comparative studies were initiated in litter mates. No relationship between the affinity and the restriction in heterogeneity was observed. Sequences are indistinguishable from those reported for antibodies of other specificities.

Animals↗