M.E. Rosales; G. Garza-Malacara; A. Fernández-Ramírez; G. Barcenas-Morales; J.A. Montaraz-Crespo
Lab. Inmunología, Posgrado, FES-C, UNAM. Av. Primero de Mayo S/N, Cuautitlán Izc. Edo. de México
Introduction: There are eleven species of B. bronchiseptica genus, B. pertussis and B. bronchiseptica have been considered as more virulent species, the first specie is the whooping cough etiologic agent, whilst the second specie is the etiologic agent of diverse respiratory diseases in animals and occasional in immunosuppressed humans. Both bacterial species show evenness among expression of their virulence factors, such as expression of pertactin (adhesin). The pertactin of B. pertussis has been used as immunogen in children against whooping cough; however, there are some reports that show genetic variability of pertactin in the same genus, this problematic has become partial or null protection against the disease. In animals, there are few studies about pertactin immunity against respiratory diseases, and nearly all works has been done in dogs. In the present work, was evaluate the protection of pertactin against B. bronchiseptica infection in cats; also was standardize extraction method of pertactin from this specie.
Methodology: B. bronchiseptica was isolate from nasal swab of cat and identified by biochemical and serologic tests, also some virulence factors (such as the pertactin expression) were identified by different assays. Extraction of pertactin was performance by acid method, corroborated the purification by polyacrylamide gel electrophoresis and western blot assays, using BB05 and BB07 monoclonal antibodies.
Cats of nearly two months of age and free of B. bronchiseptica were used, ten cats were gather in two groups: Group I, as control; Group II, immunized with 500 ug of pertactin in incomplete adjuvant at day cero; both groups were challenge with 107 CFU/ml intranasal via at eighteenth day. During seven days post-challenge were recorded corporal temperature, nasal and ocular secretion, at seven day post-challenge serum samples were collect and the cats sacrificed in order to re-isolate the strain from lungs.
Results: The preparation of pertactin obtained in this work was partial pure because the gel electrophoresis showed two more bands; and just one band (~45 kDa) was recognized by monoclonal antibodies.
There were no differences in the data temperature reports and nasal secretion between the cat groups; nevertheless, tearful was showed in the control group until the 5th day post-challenge whilst in the group II only two first days showed tearful. Also, the mean antibody title showed in the control cat group was 1:128 whilst in the immunized group the mean title antibody was 1:563. The strain was re-isolate from all cats belong to the control group and only one from immunized cat group (this cat showed the most low title antibody).
Conclusion: The results obtained in this work show the protective capacity of the pertactin in response to challenge of B. bronchiseptica infection; however, is necessary to increase the number of animals in order to test different immunization doses, and also will be interest to study pertactin protection from different B. bronchiseptica strains.
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