Location: Foreign Animal Disease Research2013 Annual Report
1a. Objectives (from AD-416):
The objective of this collaboration is to demonstrate the use of computational algorithms to predict epitopes for T cells isolated from genetically defined swine. USDA-ARS and the University of Rhode Island (URI) will independently conduct analysis of the antigenic epitopes recognized by T cells that mediate adaptive immune responses to viruses and viral antigens utilizing different algorithmic techniques.
1b. Approach (from AD-416):
USDA-ARS has adapted an assay developed at University of Copenhagen (Denmark) for human proteins to swine, which involves expressing the major histocompatibility complex (MHC) proteins in vitro in E. coli, isolating and purifying the proteins and analyzing the capacity of these proteins to bind antigenic peptides derived from pathogenic viruses. This technology has been applied to predictions using an algorithm developed by the Danish collaborators and it has been shown that the algorithm for human proteins successfully predicts swine protein attributes. The University of Rhode Island has independently developed an algorithm for these predictions. Both algorithms will be tested utilizing recombinant proteins of swine and compared for relative accuracy and capacity to identify T cell epitopes in pigs.
3. Progress Report:
The current approach to administering Foot-and-Mouth Disease Virus (FMDV) vaccines, including the replication defective human Ad5-FMDV vaccines, is that they are not administered to mucosal surfaces and in general induce little or no mucosal immunity. We have addressed this problem by designing an Ad5-vectored mucosal adjuvant (LTR-72) and co-administered the adjuvant with the Ad5-FMDV vaccine via the intranasal (IN) route or combined intranasal/intramuscular (IM) routes. Our goal is to achieve a high level of parenteral immunity in combination with substantial mucosal immunity, raising the probably of inducing sterilizing immunity by protecting the mucosal epithelium, the site of initial infection and virus replication. Conducted proof-of-principle experiments that were performed in mice which showed very promising results. We also began testing a similar approach in pigs, with somewhat less promising results. We believe that part of the reason the mucosal/parenteral vaccine approach was less successful in pigs was due to an overwhelming challenge dose, so these studies may need to be repeated. The most significant accomplishment over the life of this research project to date are the results which showed that although all six groups of vaccinated swine developed clinical signs after FMDV challenge, the two groups receiving the Ad5-A24 vaccine, with or without the LTR-72 adjuvant administered first IN, followed by an IM boost, were the most protected. No technologies have been transferred to date. Publications for this reporting period include: Alejo DM, Moraes MP, Liao X, Dias CC, Tulman ER, Diaz-San Segundo F, Rood D, Grubman MJ, Silbart LK. An adenovirus vectored mucosal adjuvant augments protection of mice immunized intranasally with an adenovirus-vectored foot-and-mouth disease virus subunit vaccine. Vaccine. 2013 Apr 26;31(18):2302-9. doi: 10.1016/j.vaccine.2013.02.060. Epub 2013 Mar 13. PubMed PMID: 23499593.