Improvement of the immune response to foot and mouth disease virus vaccinein calves by using Avridine as adjuvant

The epidemiological analysis of the cattle population during the eradicatio n plan of foot and mouth disease (FMD) in Argentina clearly indicated a hig her incidence of the disease in animals within their first year of age. It is important to improve the efficacy of the vaccination in those animals. I n a previous report, we have shown the effect of an immunomodulator, Avridi ne (Avr), in the enhancement of the immune response elicited by FMD virus ( FMDV) vaccines in experimental hosts [Berinstein, A., Perez Filgueira, M., Schudel, A., Zamorano, P., Borca, M., Sadir, A.M., 1993. Avridine and LPS f rom Brucella ovis: effect on the memory induced by foot-and-mouth disease v irus vaccination in mice. Vaccine Il, 1295-1301]. In this report, we analyz e the effect of Avr in the improvement of the anti-FMDV immune response eli cited in young animals immunized with a tetravalent vaccine. The anti-FMDV antibody response was evaluated using a liquid-phase blocking sandwich ELIS A (LPBE) [Smitsaart, E.N., Zanelli, M., Rivera, I., Fondevila, N., Compaire d, D., Maradei, E., Bianchi, T., O'Donnell, V., Schudel, A.A., 1998. Assess ment using ELISA of the herd immunity levels induced in cattle by foot and mouth disease oil vaccines. Prev. Vet. Med 33, 283-296] while the cellular response was detected using an antigen specific lymphoproliferative test [Z amorano, P., Wigdorovitz, A., Chaher, M., Fernandez, E, Sadir, A., Borca, M ., 1994. Localization of B and T cell epitopes on a synthetic peptide conta ining the major immunogenic site of FMDV 01 Campos. Virology 201, 383-387]. The results show that, while no differences were detected in the cellular response, the anti-FMDV antibody reaction was significantly (<0.05) higher in animals immunized with the immunogen containing Avr. At 90 days post vac cination, 89-100% of the animals immunized with Avr presented predicted pro tection (PP) higher than 82% while just 50-61% of the animals immunized wit h vaccine without immunomodulator presented that characteristic. Also, it i s shown that the increase in the anti-FMDV antibody titre in animals immuni zed with the vaccine containing Avr was mediated by an increase in the leve ls of both IgG1 and IgG2 which presented a significative correlation with L PELISA antibodies titres. It is concluded that the addition of Avr in the F MDV vaccines improve the immune status of the calves, the cattle population chat suffers the highest epidemiological risk. (C) 1999 Elsevier Science B .V. All rights reserved.