INVESTIGADORES
ZANETTI Flavia Adriana
congresos y reuniones científicas
Título:
Animal models of paratuberculosis for vaccine development
Autor/es:
COSTANZO GG; DELGADO F; FORT M; GIOFFRÉ A; ZANETTI FA; FUCHS L; BALDONE VN; CALAMANTE G; ROMANO MI
Lugar:
Zacatecas
Reunión:
Simposio; Vta Reunión de la Sociedad Latinoamericana de Tuberculosis (SLAMTB) y VI simposio ?Fronteras del conocimiento en Tuberculosis y otras Micobacteriosis, Dr. Joseph Corston.; 2010
Resumen:
Animal models of paratuberculosis for vaccine development Paratuberculosis (PTB) is a prevalent and economically important disease that affects cattle and thus impacts on the cattle industry. It is caused by Mycobacterium avium subsp. paratuberculosis. There are vaccines against PTB, but they only limit the clinical course of the disease and shedding of the bacteria in feces. The objectives of this work were to establish differences in relative pathogenicity between different MAP strains and to determine if rabbit can be used as a model of MAP infection to examine vaccine candidates. This study examined different MAP strains, using different doses and routes of infection. Gut lesions occurred in a large proportion of rabbit challenged with one dose of a low-passage-number laboratory culture of MAP (strain Perú). The optimal conditions necessary to produce Johne?s disease, in rabbits, resulted in an oral inoculation with one dose of 10exp8/CFU of MAP. This inoculation was consistent with gut histopathology at 4 months postchallenge. We evaluated in rabbits the use of heterologous prime boost strategies based on vaccination with culture filtrate proteins (CFP) of Mycobacterium avium and the mycolyl transferase Ag85A from M. tuberculosis expressed by a recombinant modified vaccinia virus Ankara (MVA85A). Four different vaccination schedules were tested: CFP followed by MVA85A (group 1); MVA85A (group 2); two dosis of MVA85A (group 3); CFP (group 4). Vaccine induced immunity were assessed. Animals inoculated with CFP (groups 1 and 4) resulted in significantly higher frequencies of antibody titer to these mix of proteins than the other groups. Besides, we tested the degree of protection after oral challenge with the virulent strain of MAP strain Perú. Finally, cell-mediated immune reaction and pathological and bacteriological examinations are carried on. The fecal samples or cultures are being examined by ZN staining and PCR analysis is being performed on DNA extracted from fecal cultures.