Biphasic Occurrence of IgM-forming Cells in the Intestine after Oral Immunization

Werner, H; Lefèvre, Hans; Raettig, H

doi:10.1038/232119a0

Cited by 6 publications

(1 citation statement)

References 3 publications

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“…Since it is known that R factor plasmids code for changes in surface structure (Ferrazza & Levy 1980;Portnoy et al 1981), it is tempting to speculate that pJT4 codes for changes in the outer membrane that lessen immunogenicity or that enhance resistance to gut immune mechanisms. This is suggested because the decline in numbers of the isogenic recipient did not become substantial until 7 or 8 d after administration of the organism, a period which would correspond with the lag in onset of the gut immune response (Werner et al 1971).…”

Section: Discussionmentioning

confidence: 99%

Experimental ecological studies on H2 plasmids in the intestine and faeces of the calf

Timoney

Linton

1982

Journal of Applied Bacteriology

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In vivo transfer of a typical H2 plasmid (pJT4) was not detected in groups of calves experimentally given large numbers of donor and genetically marked recipient Escherichia coli strains when the calves were muzzled and so denied oral contact with their surroundings. Transfer to the marked recipient and to a number of other Esch. coli strains was, however, observed when muzzles were not used or were removed during an experiment. pJT4 was transferred in voided faeces at 30°C but not at 37°C. These results suggest that H2 plasmids do not transfer in the intestine and most probably are acquired by conjugations in the animal's environment. Experiments with calves using sets of isogenic strains of Esch. coli, with and without pJT4, showed that the presence of the plasmid greatly increased the persistence of the host organism in the intestine. Strains with the plasmid persisted for 20 d or longer; strains cured of the plasmid decreased rapidly in number after 7 days. This phenomenon may be an important factor in the epidemicity in the calf of strains of Salmonella typhimurium that carry H2 plasmids.

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Section: Discussionmentioning

confidence: 99%