Immunity to experimental fowl typhoid in chickens induced by a virulence plasmid-cured derivative of Salmonella gallinarum.
AUTOR(ES)
Barrow, P A
RESUMO
Chickens were immunized by two intramuscular inoculations at 1 and 14 days of age with virulence plasmid-cured derivatives of Salmonella gallinarum and were challenged 14 days later by oral inoculation of ca. 50 50% lethal doses (LD50) of fully virulent S. gallinarum 9. Mortality in the nonimmunized and immunized groups were 36 and 3%, respectively. This difference was highly significant (P less than 0.01). A significant reduction in mortality was also produced following oral challenge with 5,000 LD50 doses. The LD50 values by intramuscular inoculation of the challenge organism into nonimmunized and immunized chickens were log10 (0.13 +/- 1.57) and (9.74 +/- 2.72), respectively. Immunization was effective whether chickens were immunized at 1 and 14 days of age or at 21 and 35 days of age. Serum agglutinins were present in immunized chickens. Immunization with plasmid-cured Salmonella pullorum gave less protection, and immunization with Escherichia coli K-12 possessing the virulence plasmid of S. gallinarum gave none. The plasmid-cured S. gallinarum was made both rough by virulent bacteriophage activity and nalidixic acid resistant (Nalr) to produce a strain designated 9VP-phi rNalr. It was compared with a Nalr mutant of the rough 9R vaccine strain designated 9 Nalr for virulence and immunogenicity. 9VP-phi rNalr was slightly less protective and less virulent than was the 9R vaccine strain.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=258809Documentos Relacionados
- Contribution of Salmonella gallinarum large plasmid toward virulence in fowl typhoid.
- Plasmid-cured Salmonella enteritidis AL1192 as a candidate for a live vaccine.
- Utilization of Carbon Substrates, Electrophoretic Enzyme Patterns, and Symbiotic Performance of Plasmid-Cured Clover Rhizobia
- Host restriction phenotypes of Salmonella typhi and Salmonella gallinarum.
- Assessment of serological response of chickens to Salmonella Gallinarum and Salmonella Pullorum by Elisa