|Ferman Ii, Geoffrey|
Submitted to: Keystone Symposia
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2006
Publication Date: 3/28/2006
Citation: Pacheco, J.M., Ferman Ii, G.S., Golde, W.T. 2006. Determination of antibody class and subclass following foot-and-mouth disease virus (fmdv) infection or vaccination with killed virus vaccine. Keystone Symposia. 2006. P.84 Interpretive Summary:
Technical Abstract: Foot-and-mouth disease virus (FMDV) continues to be a significant economic problem worldwide. Eradication of the disease involves the use of killed virus vaccines, a control measure developed decades ago. The primary site of replication of FMDV after natural infection seems to be the pharyngeal area, except in those situations when the virus gains direct entry into the skin or mucosa through cuts or abrasions. The humoral immune response to vaccination induces circulating antibodies that prevent the disease but will not prevent primary local infection. It has been shown previously that levels of FMDV specific antibodies in the oral and nasal secretions of infected cattle are primarily IgA and IgG1 isotypes. In contrast, when administered parenterally, killed FMDV vaccines do not induce secretory mucosal antibody in cattle. We have shown previously that pigs infected with FMDV made viral specific antibody of the IgM, IgG1 and IgA subclass in serum, but in animals vaccinated with a commercial, killed FMDV vaccine, IgA was not detected. Here the effects of infection and vaccination on the pattern of IgA, IgG1 and IgG2 antibody responses are described, using two different ELISAs. Specifically, we tested for antibody responses in serum and saliva, 7 or 21 days after vaccination with a single dose of vaccine. Only FMDV-specific IgG1 antibodies were detected in serum and saliva after vaccination and only with the indirect double antibody sandwich assay (IDAS-ELISA). After infection, FMDV-specific IgG1 and IgG2 were detected in serum with the IDAS-ELISA,while in saliva, IgA and IgG1 were detected. Using the antibody capture assay (ACA-ELISA), the same serum samples had readily detectable levels of FMDV-specific IgA antibodies, lower levels of FMDV-specific IgG1 and even less IgG2. When the ACA-ELISA was applied to saliva samples, only low levels of IgG1 were detected. Surprisingly, no FMDV-specific IgA antibodies were detected, indicating the limit of the assay given the previous results. Understanding the humoral response to vaccination and FMDV infection is complicated, requiring a comprehensive analysis using multiple assay methods. These data illustrate evidence of the limitation of parenterally administered vaccine. The development of alternative FMDV vaccines designed for more efficient mucosal delivery and the induction of a mucosal IgA response may yield a better control approach for FMD outbreaks.