DIFFERENCE OF ANTIBODY ISOTYPE (IGA) PRODUCTION AFTER FOOT-AND-MOUTH DISEASE VIRUS VACCINATION OR INFECTION IN PIGS

Authors: PACHECO, JUAN - UNIV CONNECTICUT; Ferman Ii, Geoffrey; Golde, William

Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2005
Publication Date: 6/18/2005
Citation: Pacheco, J.M., Ferman Ii, G.S., Golde, W.T. 2005. Difference of Antibody Isotype (IGA) Production after Foot-and-Mouth Disease Virus Vaccination or Infection in Pigs. American Society for Virology 24th Annual Meeting. P. P18-1.

Interpretive Summary:

Technical Abstract: Foot-and-mouth disease virus (FMDV) continues to be a significant economic problem worldwide. Eradication of the disease from endemic areas involves the use of killed virus vaccines, a control measure developed decades ago. The primary site of replication of FMDV after natural infection is the pharyngeal area, except in those situations when the virus gains direct entry into the skin or mucosa through cuts or abrasions. The humoral 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 were primarily IgA and IgG1 isotypes. In contrast, when administered parenterally, killed FMDV vaccines produced no 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 antibody response and the importance of two different ELISA methods for the detection of IgA are described. We studied local secretory and systemic IgA responses, induced by a double oil emulsion vaccine in naïve pigs as compared to pigs which were challenged with live virus. Specifically, we tested for IgA antibody responses in serum and saliva, 7 or 21 days after vaccination with a single dose of vaccine. Results were compared with IgA antibody responses after direct inoculation of pigs or following contact infection. In serum we detected IgA antibodies after infection, which was confirmed when we analyzed the saliva samples. Our results also show that there is no IgA production in serum or saliva after vaccination. However, IgA is detected after challenge of these vaccinated animals. In our study, anti-FMDV IgA was detected as early as 5 to 7 days post-infection. These data illuminate 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 is predicted to yield better control of FMDV during an outbreak.