Resumo
ABSTRACT Pseudomonas aeruginosa is an etiologic agent of opportunistic infections mainly in immunocompromised patients. Its inherent feature of developing resistance to a wide range of antibacterial agents make it a critical point in infection control. In animals, problems with multidrug resistance occur in otitis, cystitis, uveo-conjunctivitis, endometritis and mastitis, and there is no commercially available vaccine. With the aim of improving its immunogenicity, the lipopolysaccharide (LPS) antigen was coupled to bovine serum albumin (BSA) with .-periodate as the reductive agent. The conjugation was evaluated by gel-permeation chromatography, by quantitating total sugar and protein, and both LPS and BSA were detected in similar proportions. The immunization of mice with LPS-BSA conjugate vaccine resulted in an agglutinating antibody response against P. aeruginosa lower than that obtained for a mixture of free LPS and BSA. They were 65% and 86% lower in the 6th and 10th weeks after the hyperimmunization procedure, respectively. This indicates that the conjugation reaction resulted in an immunogenic product, however its quality should be improved.
RESUMO A Pseudomonas aeruginosa é agente etiológico de infecções oportunistas, principalmente em pacientes imunocomprometidos. Suas características inerentes em desenvolver resistência aos mais variados tipos de antibacterianos a torna um ponto crítico no controle de infecções. Em animais, os problemas com multirresistência ocorrem principalmente em casos de otite, cistite, úveo-conjuntivite, endometrite e mastite, não havendo vacina comercialmente disponível. No intuito de melhorar a imunogenicidade desse antígeno, foi testada a técnica de conjugação do lipopolissacarídeo (LPS) de P. aeruginosa à albumina bovina (BSA) por aminação redutiva direta utilizando .-periodato de sódio. A conjugação foi avaliada por cromatografia de gel-permeação, dosando-se açúcar e proteína totais, e tanto o LPS quanto a BSA foram identificados em proporções semelhantes. A imunização de camundongos com a vacina conjugada LPS-BSA conferiu títulos de anticorpos aglutinantes contra P. aeruginosa inferiores aos obtidos com a mistura de LPS e BSA livres. Foram 65% e 86% menores na 6ª e na 10ª semanas após o procedimento de hiperimunização, respectivamente. Isto indica que a reação de conjugação resultou em um produto imunogênico, porém, sua qualidade precisará ser melhorada.
Resumo
Infectious bronchitis virus (IBV) of chickens is currently one of the main diseases associated with respiratory syndrome in domestic poultry, as well as with losses related to egg production. The etiological agent is a coronavirus, which presents structural differences in the field, mainly in the S1 spike protein. The immune response against this virus is complicated by the few similarities among serotypes. Environmental and management factors, as well as the high mutation rate of the virus, render it difficult to control the disease and compromise the efficacy of the available vaccines. Bird immune system capacity to respond to challenges depend on the integrity of the mucosae, as an innate compartment, and on the generation of humoral and cell-mediated adaptive responses, and may affect the health status of breeding stocks in the medium run. Vaccination of day-old chicks in the hatchery on aims at eliciting immune responses, particularly cell-mediated responses that are essential when birds are first challenged. Humoral response (IgY and IgA) are also important for virus clearance in subsequent challenges. The presence of antibodies against the S1 spike protein in 3- to 4-week-old birds is important both in broilers and for immunological memory in layers and breeders.
Resumo
Infectious bronchitis virus (IBV) of chickens is currently one of the main diseases associated with respiratory syndrome in domestic poultry, as well as with losses related to egg production. The etiological agent is a coronavirus, which presents structural differences in the field, mainly in the S1 spike protein. The immune response against this virus is complicated by the few similarities among serotypes. Environmental and management factors, as well as the high mutation rate of the virus, render it difficult to control the disease and compromise the efficacy of the available vaccines. Bird immune system capacity to respond to challenges depend on the integrity of the mucosae, as an innate compartment, and on the generation of humoral and cell-mediated adaptive responses, and may affect the health status of breeding stocks in the medium run. Vaccination of day-old chicks in the hatchery on aims at eliciting immune responses, particularly cell-mediated responses that are essential when birds are first challenged. Humoral response (IgY and IgA) are also important for virus clearance in subsequent challenges. The presence of antibodies against the S1 spike protein in 3- to 4-week-old birds is important both in broilers and for immunological memory in layers and breeders.