Assessment of immunity against avian colibacillosis induced by an aroA mutant containing increased serum survival gene in broilers
AUTOR(ES)
Salehi, Taghi Zahraei, Tabatabaei, Saeid, Karimi, Vahid, Fasaei, Bahar Nayeri, Derakhshandeh, Abdollah, Jahromi, Omid Ali Nekoui
FONTE
Brazilian Journal of Microbiology
DATA DE PUBLICAÇÃO
2012-03
RESUMO
Colibacillosis is an important disease in the poultry industry which causes serious economic damages. As it is suggested that vaccination is one of the means to control colibacillosis, we tried to investigate the vaccine potential of a ΔaroA derivative of an O78:K80 avian pathogenic Escherichia coli containing increased serum survival gene. 490 chicks were selected as follows: For assessment of virulence of ΔaroA mutant, 30 chicks were divided into three groups and injected with 0.5ml of PBS or bacterial suspension containing either10(7)colony forming units (CFU) of mutant or parent strains via subcutaneous route. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. For assessment of safety and immunogenicity of the ΔaroA mutant, three groups of 20 chicks were vaccinated by aerosol administration of 250 ml of suspension containing 10(8) CFU of mutant strain at days 1 and 14, while the two other groups received PBS or wild type strain. Macroscopic lesions and mortality rate were recorded in different groups until day 21. To determine whether the vaccination is protective against challenges or not, the chickens were vaccinated at days 1 and 14 and challenged intramuscularly with either a homologous or heterologous strains at day 21. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. The results revealed that the ΔaroA mutant was slightly virulent, however it was safe and did not cause mortality, lesions or weight loss after vaccination. Antibody responses were similar in the control and mutant groups and vaccination did not induce a significant humoral immunity. The mutant could not protect chickens against both homologous and heterologous challenges. This could be due to several factors such as the high amount of maternal antibodies in the first two weeks of life, and the vaccination procedure.
Documentos Relacionados
- Natural killer cells mediate protection induced by a Salmonella aroA mutant.
- Molecular Characterization of the Aeromonas hydrophila aroA Gene and Potential Use of an Auxotrophic aroA Mutant as a Live Attenuated Vaccine
- Molecular gene cloning and nucleotide sequencing and construction of an aroA mutant of Pasteurella haemolytica serotype A1.
- Protection against Fatal Pseudomonas aeruginosa Pneumonia in Mice after Nasal Immunization with a Live, Attenuated aroA Deletion Mutant
- Protective Immunity Conferred by Attenuated aroA Derivatives of Pasteurella multocida B:2 Strains in a Mouse Model of Hemorrhagic Septicemia