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Biomedical subjects

R O Thomson

Publications and source records attributed to R O Thomson.

At least 19 recordsLinked to original sources
PubMed1986

Cloning, nucleotide sequencing, and expression of tetanus toxin fragment C in Escherichia coli.

The amino acid sequence of the first 30 residues of fragment C of tetanus toxin was determined, and a mixture of 32 complementary oligonucleotides, each 17 bases long, was synthesized. A 2-kilobase (kb) EcoI fragment of Clostridium tetani DNA was identified by Southern blotting and was cloned into the Escherichia coli plasmid vector pAT153 with the 32P-labeled oligonucleotide mixture as a probe. A second 3.2-kb Bg/II fragment was identified and cloned with the 2-kb EcoRI fragment as a probe. The nucleotide sequence of 1.8 kb of this DNA was determined and was shown to encode the entire fragment C and a portion of fragment B of tetanus toxin. The tetanus DNA was expressed in E. coli with pWRL507, a plasmid vector containing the trp promoter and a portion of the trpE gene. The trpE-tetanus fusion proteins were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were shown to react with anti-fragment C antibody.

Base Sequence↗
PubMed1983

Active and passive immunization to protect against antibiotic associated caecitis in hamsters.

The administration of clindamycin to hamsters induces a lethal enterocolitis as a consequence of toxins produced in the alimentary tract by Clostridium difficile. The lethal and cytopathic effects of C. difficile toxins are neutralized in vitro by C. sordellii antitoxin and hamsters may be protected against clindamycin induction of caecitis by passive immunization using C. sordellii antitoxin. To examine active immunization using C. difficile and C. sordellii toxoids, groups of male and female Syrian hamsters were immunized on two occasions and challenged by parenteral clindamycin. A concentrated C. difficile toxoid protected 90% of females and 78% of males; the degree of protection per group decreased with dilution of the toxoid used for immunization. A similar degree of protection was observed in female hamsters immunized with a bivalent vaccine prepared from the partially purified toxins A and B of C. difficile. Immunization using a C. sordellii toxoid protected between 100 and 25% of females per group and between 50 and 12.5% of males per group.

Animals↗
PubMed1976

The relative potency of an oily adjuvant multicomponent vaccine in laboratory animals and sheep.

Oil emulsion vaccines differ considerably from conventional alum precipitated vaccines both in their method of application and immunological response. It is questionable whether the existing statutory tests provide meaningful evaluation of such vaccines. Attempts were therefore made to determine how far antigenicity tests of an oil emulsion vaccine in laboratory animals reflects the potency of this vaccine in the target species - sheep. The results that were obtained are presented and discussed and comparisons are made with similar results obtained with a multicomponent alum precipitated vaccine.

Adjuvants, Immunologic↗
PubMed1969

Bacterial immunoabsorbent columns.

Methods are described for the preparation of bacterial immunoabsorbents consisting of organisms dispersed in agar beads 50 to 200 mum in diameter. The concentration of organisms could be made extremely high and columns prepared had sufficient capacity to enable them to be used for a number of purposes, but particularly for the removal of cross-reacting agglutinins from production batches of type-specific antisera. The absorptive capacity of these columns was regenerated after absorption by the elution of agglutinins with low pH buffers. Results obtained from the use of these immunoabsorbents are presented.

Journal Article↗