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Biomedical subjects

L Coetzee

Publications and source records attributed to L Coetzee.

11 recordsLinked to original sources
PubMed1992

Spontaneous hybridoma formation induced by immunization with Haemophilus paragallinarum: evidence for a lipopolysaccharide fusion inducer.

The phenomenon of spontaneous fusion between myeloma cells and splenocytes from mice immunized with formalin-inactivated Haemophilus paragallinarum cells, has been reported on recently (1). The identity and properties of the bacterial inducer of fusogenicity of splenocytes have been further investigated with the aid of a monoclonal antibody VF3 against H. paragallinarum (2), which has a bacterial strain specificity correlating with the ability of the strains to induce spontaneous fusion between splenocytes of immunized mice and myeloma cells. It was shown that the lipopolysaccharide fraction of the bacteria was required for the induction of fusogenicity. LPS involvement was clearly indicated by the parallel effects on VF3 antigenicity and fusogenic inductivity of various treatments such as proteolytic digestion, periodate oxidation and sensitivity towards alkali, acid or freezing.

Animals↗
PubMed1991

Isolation and identification of adenovirus 127, the causative agent of egg drop syndrome (EDS), from commercial laying hens in South Africa.

A drop in egg production associated with loss of pigment and soft-shelled eggs was experienced on a farm in the Western Cape. Investigations revealed high levels of antibodies against adenovirus 127, the causative agent of egg drop syndrome (EDS) in chickens which were not vaccinated against EDS. A cytopathic agent was subsequently isolated in chicken embryo liver cell cultures and identified as EDS virus by haemagglutination inhibition and neutralization tests.

Adenoviridae Infections↗
PubMed1990

Spontaneous fusion between splenocytes and myeloma cells induced by bacterial immunization.

Spontaneous fusion between lymphoid and carcinoma cells in vivo has been described previously. Splenocytes from mice treated with LPS or mitogen have been reported to fuse better with myeloma cells using PEG as fusion agent than splenocytes from untreated mice. We report a phenomenon where immunization of mice with formalin treated, whole Haemophilus paragallinarum bacteria induced spontaneous fusion of splenocytes with myeloma cells in vitro, without the aid of any fusion agent. Co-immunization of mice with H. paragallinarum and an unrelated antigen (hen's egg white lysozyme), followed by co-culturing of the immune splenocytes with SP2/0 myeloma cells, yielded stable hybridoma cell lines producing anti-lysozyme antibodies. H. paragallinarum may be used in adjuvants to simplify the production of monoclonal antibodies, and the discovery of a promotional activity of a gram negative bacterium on cell fusion and hybridoma formation may shed new light on spontaneous fusion as a natural immune phenomenon in cancer.

Animals↗
PubMed1978

The comparative antimicrobial sensitivity of Escherichia coli isolated from colisepticaemic broilers.

The standardisation of a method to perform antibiograms using Meuller Hinton agar routinely is described. It was found that from 1973 to 1975 the resistance of E. coli to oxytetracycline decreased from 49% to 32.5% and to sulphonamides from 49% to 42.5%. Resistance to furazolidone increased from 12% to 22%. No dramatic changes in the resistance to neomycin and chloramphenicol were found.

Animals↗
PubMedDate not supplied

Monoclonal antibody characterization of two field strains of Haemophilus paragallinarum isolated from vaccinated layer hens.

An oil-based bacterin, containing strains 083 and 0222 of Haemophilus paragallinarum, is commonly used in South Africa to vaccinate laying flocks against infectious coryza. Two strains of H. paragallinarum, designated M85 and SB86, were isolated from infected but vaccinated commercial laying flocks in two incidental outbreaks of coryza in 1985 and 1986. A panel of five monoclonal antibodies was established which clearly distinguished the vaccine strains from the field isolates. One of these reacted with only vaccine strains A and B, another reacted with only field strains M85 and SB86, and the remaining three cross-reacted to various degrees with all four strains or isolates. Immunoassays were performed by enzyme-linked immunosorbent assay using whole bacteria as solid-phase antigen. These monoclonal antibodies may aid in serotyping new field isolates of H. paragallinarum and in improved standardization of vaccine strains.

Animals↗