Possibility in creating specific antibody of GP5-ELP recombinant antigen of Porcine reproductive and respiratory syndrome virus (PRRSV) on experimental animals

Abstract

Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus has resulted
in huge economic losses to the livestock sector in many countries around the world. PRRSV
belongs to Arterivirus, Arteriviridae and Nidovirales. GP5 is an important PRRSV envelope
glycoprotein with molecular weight of 24-25 kDa, known as the stimulant for the production of   neutralizing antibodies in pigs, consequently to design the PRRS subunit vaccine. In order to have
a scientific evidence for the development of a PRRS-derived plant-derived subunit vaccine, GP5
was fused with ELP to create recombinant protein and accumulated in tobacco tree by transient
gene expression. The GP5-ELP protein from N. benthamiana leaf extract was purified by mITC and
recovered target protein, with 98% GP5-ELP protein recovery efficiency and 81.1% GP5-ELP purity
protein. Pure protein was used to induce immunity in 4-6 week BALB/C mice and blood samples
were collected at the times: before antigen injection and day 21, 35 after the first antigen injection.
IgG antigen-specific antibody to GP5-ELP antigen in mouse serum was detected by ELISA and
Western blot analysis. The studied results showed that GP5-ELP purified antigen was capable of
stimulating production of GP5-ELP-specific IgG antibody in mice. GP5-ELP-specific IgG production
was increased more than 2.4 times after three injections compared to two injections. Thus, it can be
concluded that GP5-ELP antigen synthesized in tobacco leaf tissue by transient gene expression
was capable of inducing immune responses in mice. This is an important scientific evidence for using
GP5-ELP as a candidate to develop a PRRS subunit vaccine.