The Immune Modulation Of Auto Anti-Idiotypic Antibody Of PRRSV

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of auto-anti-idiotypic antibody (Aab2) in serum samples collected from pigs experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV) by coating ELISA plate with the IgG F(ab')2 fragments generated from monoclonal antibodies specific for the envelope glycoprotein GP5 and matrix (M) protein of PRRSV. From a total of 59 pig experimentally infected with PRRSV, the ELISA detected Aab2 specific against anti-GP5 and anti-M antibodies from 47 pigs from which eight pigs free of the virus at 98 days post infection (DPI) was from serum samples collected between 21 and 49 DPI with peak levels at 35 DPI; whereas Aab2 detected from remaining 39 pigs persistently infected with PRRSV were from serum sample collected between 63 and 98 DPI with peak levels at 77 DPI. Serological characterization revealed that portion of the Aab2 was internal image that recognized shared idiotype (IdX) on murine and swine antibodies to GP5 and M antigens of PRRSV. Further more, Aab2 from pigs free of the virus and that persistently infected with PRRSV had different binding affinity to the anti-PRRSV antibodies. The ELISA described herein was anticipated to be useful as a serodiagnostic tool for differentiation of pigs free of PRRSV and that become persistently infected with PRRSV. The further identification and characterization of auto-anti-idiotypic antibodies specific for antibodies against PRRSV-GP5 indicate that the Aab2 recognized the idiotype located within or near the antigen-combining sites of the anti-GP5 antibodies, whichwas shared by both mouse Mab anti-GP5 and swine polyclonal antibodies. The Aab2 inhibited the anti-GP5 antibodies from binding to PRRSV suggest that the Aab2 will play antigen-inter-image role in immunity go PRRSV infection. Inoculation of experimental pig with Aab2 resulted the development of neutralizing antibodies to PRRSV and indicated that the Aab2 could be a candidate vaccine against PRRSV in the future.