RESUMEN
The NSP2 gene of porcine reproductive and respiratory syndrome virus (PRRSV)S1 strain was partly amplified and cloned into a prokaryotic expression vector pGEX-6P-1 and a fusion protein GST-tNSP2 with molecular weight of 50 kDa was expressed in E.coli. The purified GST-tNSP2 protein showed a strong reaction with the PRRSV-positive sera in Western blot assay. Balb/c mice were immunized with the purified protein, and the splenocytes of the immunized mice were fused with murine myeloma cells SP2/0. After subcloning by 3 times, two hybridoma clones which produced McAbs steadily were screened by ELISA, named 3H3 and 2B5. They all reacted strongly with the PRRSV S1 infected Marc-145 cells in IFA, but not with the PRRSV SY0608 strain. Both of the McAbs belong to IgG1 isotype, and their light chains belong ? type. The expressed GST-tNSP2 protein and McAbs could be used for identification of PRRSV isolates and functional analysis of NSP2.
RESUMEN
The M protein gene of porcine reproductive and respiratory syndrome virus amplified by PCR was tandem linked with its GP5 gene in shuttle vector in correct frame, resulting in shuttle vector pShuttle-CMV-M-GP5. The positive clone was identified by PCR and further confirmed by sequencing. The constructed plasmid was linearized with Pme I and co-transformed BJ5183 host bacteria with pAdEasy-1 to produce recombinant adenovirus DNA by homologous recombination. Then the adenovirus DNA was linearized with Pac I and transfected into HEK-293A cells to obtain recombinant adenovirus. The specific expression of target proteins by the recombinant adenovirus was verified by indirect immuno-fluorescence assay (IFA) with monoclonal antibodies against M and GP5.The results showed that the tandem linked M with GP5 could be co-expressed by adenovirus vector. Mice immunized with the constructed recombinant adenovirus induced strong humoral immunity (ELISA antibody and virus neutralizing antibody) and cellular immunity (lymphocyte proliferation and CTL responses). The results showed that the recombinant adenovirus has strong immunogenicity and provided the basis for the further experiments in pigs.