ICIVET-LITORAL   24728
INSTITUTO DE CIENCIAS VETERINARIAS DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
?Functional evaluation of the humoral response obtained with a multicomponent vaccine against bovine mastitis caused by Staphylococcus aureus?
Autor/es:
PUJATO N; CAMUSSONE MC; RENNA M.S; CALVINHO L.F; MARCIPAR I
Reunión:
Congreso; LIX Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC)- LXII Reunión Científica Anual de la Sociedad Argentina de Inmunología (SAI).; 2014
Resumen:
Bovine mastitis is the major cause of economical losses for dairy producers and industry, being Staphylococcus aureus the most prevalent pathogen causing mastitis in Argentina. A tempting strategy to fight against staphylococcal mastitis is cattle vaccination, but any of the numerous vaccines attempts could afford protection against new infections. Researchers have agreed that and effective staphylococcal vaccine would be a multicomponent one inducing IgG2 response in blood and milk. The aim of this study is to develop a vaccine against staphylococcal mastitis, based on different promising candidates involved in different phases of S. aureus infection, obtained by DNA recombinant technology: adhesins clumping factor A (ClfA) and fibronectina binding protein A (FnBPA) and the hemolysin β-toxin. The formulation of these antigens with ISCOMmatrixTM adjuvant was named VacR1. Dairy cattle were inoculated with two supra-mammary doses of VacR1 or PBS at days -45 and -15 before calving. ELISAs assays were performed to determine total IgG and IgG2 responses in serum and milk samples. Antibodies functionality was evaluated by β-toxin hemolysis assays, fibronectin and fibrinogen binding assays, phagocytosis and mammary epithelial cells (MAC-T) adherence. VacR1 induced a strong humoral response both in blood and milk (p< 0.05, compared with the control). IgG2 titers were also increased in blood in relation to control group (p< 0.05)). Serum samples inhibited 60% of β-toxin hemolysis (p< 0.05), 86% of Fn binding (p< 0.05), 80% Fg binding (p< 0.05) and contributed to bacteria phagocytosis by bovine PMN (p< 0.05). Finally, blood and milk antibodies decreased bacteria adherence to MAC-T in magnitudes of 20% and 80% respectively (p< 0.05). In conclusion, VacR1 provided a robust humoral response in dairy cattle being a promising vaccine candidate against S. aureus bovine mastitis. In vivo efficacy studies remain to be done to determine if VacR1 provide protection against bacteria.