Recombinant foot-and-mouth disease virus (FMDV) non-structural protein 3A fused to enhanced green fluorescent protein (EGFP) as a candidate probe to identify FMDV-infected cattle in serosurveys

LOTUFO, CECILIA M.; BERGMANN, INGRID E.; MATTION, NORA M.; WILDA, MAXIMILIANO; GRIGERA, PABLO R.

ARCHIVES OF VIROLOGY

SPRINGER WIEN

Año: 2017

0304-8608

Recombinant protein 3A-EGFP, a fusion constructbetween foot-and-mouth disease virus (FMDV)non-structural protein 3A and the enhanced green fluorescentprotein (EGFP) was expressed in BL21-DE3 cells.The identity of the partially purified protein 3A-EGFPwas confirmed by its reactivity with sera from cattleinfected with FMDV and with a monoclonal antibodyspecific for FMDV-3ABC (MAb3H7) in Western blotassays. No reactivity was observed with sera from uninfectedvaccinated animals. The performance of 3A-EGFPas an antigen in an indirect enzyme-linked immunosorbentassay (ELISA) was assessed and compared with thatof a previously developed and validated capture ELISAthat uses a 3ABC recombinant antigen (3ABC ELISA)and has been widely applied for serological surveys inArgentina. Parallel analysis of strongly and weakly positivereference sera from infected animals and 329 serumsamples from uninfected vaccinated cattle showed that the3A-EGFP antigen unequivocally identifies sera fromFMDV-infected cattle with similar performance to its3ABC counterpart. The 3A-EGFP ELISA is simpler andfaster to perform than the 3ABC ELISA, since it does notrequire a capture step with a specific antibody. Moreover,the expression and storage of the recombinant 3A-EGFPis simplified by the absence of residual autoproteolyticactivity associated to the 3C sequence. We conclude thatthe 3A-EGFP ELISA constitutes a promising screeningmethod in serosurveys to determine whether or not animalsare infected with FMDV.