Bioinformatics prediction for determining epitopes of porcine reproductive and respiratory syndrome virus (PRRSV)

Researchers of the CReSA have described for the first time (Vaccine) antigenic sites of PRRSV that are recognized by T cells, using bioinformatics tools and later immunological analysis. All these information is relevant for the design of newer and better vaccines.

PRRSV is one of the most challenging viruses in veterinary immunology since several aspects of the immunological response against this virus remain still unknown. Several papers emphasized the role of neutralizing antibodies as well as of the cell-mediated immunity. However, there is a limited knowledge about the location of T-cell epitopes. Development of new and more efficacious vaccines against this virus faces the fact that our understanding of the host's protective immune responses against the virus or about what parts of the virus induce protective responses is very far from being complete.

In this study, researchers of the CReSA selected 14 peptides with better scoring. T-cell epitopes of PRRSV glycoproteins 4 (GP4), 5 (GP5) and nucleocapsid (N) were predicted by researchers of the CReSA using bioinformatics and later tested by IFN-γ ELISPOT in pigs immunized with either a modified live vaccine (MLV) or DNA (open reading frames 4, 5 or 7).

The results obtained are summarized next:

  1. The methodology applied is useful; 8/14 synthesized peptides were recognized in the immunological assay (57%). Furthermore, the location of the ORF 5 epitopes was confirmed, as previously described by researchers of Illinois University using different strains and different methodology (Vashisht et al., 2008).
  2. New T-cell epitopes of N protein (ORF 7), GP4 (ORF 4) and GP5 (ORF 5) have been located in the virus.
  3. It has been demonstrated -using a wide virus sequence database, including genotype I (European) and genotype II (American) strains- that some epitopes described are common to all the strains, and subsequently, must be taken into consideration for the future development of third-generation vaccines.

This work has been recently published as “Díaz I, Pujols J, Ganges L, Gimeno M, Darwich L, Domingo M, Mateu E. In silico prediction and ex vivo evaluation of potential T-cell epitopes in glycoproteins 4 and 5 and nucleocapsid protein of genotype-I (European) of porcine reproductive and respiratory syndrome virus. Vaccine. 2009 Sep 18;27(41):5603-11”.

This is the first time that an in silico prediction and in vitro/in vivo confirmation has been used for evaluating cell mediated immunological responses against a pig disease and in particular for PRRSV.

To contact with the author of this article:

Iván Díaz Luque
Investigator
Immunology Unit (CReSA)
Email: ivan.diaz@cresa.uab.cat
Telephone no.: +34 93 581 10 46
Fax: +34 93 581 44 90
Edifici CReSA. Campus UAB
08193 Bellaterra (Barcelona) Spain

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