Date Full Report Received12/12/2017
Date Abstract Report Received12/12/2017
Neutralizing antibodies are useful predictors of immunity to viral infections, with many examples in animals and humans. In pigs and PRRSV, presence of neutralizing antibodies was shown to predict protection only for re-exposure to the same virus. Since PRRSV is enormously diverse, immunity needs to be cross-protective, but cross-neutralizing antibodies were not widely known to occur. Here, we showed widespread presence of high titers of antibodies with broad cross-neutralizing activity against PRRSV in sow herds. Passive transfer of neutralizing antibodies specifically provided cross-protection, with the amount of protection proportional to the level of neutralizing activity transferred. Herd-level prediction of protection in the field based on broadly neutralizing activity in serum was confounded by high variability among animals in the quality and characteristics of the neutralizing activity. An alternative approach to predict protection by assessing immune memory was initiated by development of a PRRSV-specific B cell tetramer. The reagent is designed to identify memory B cells that respond to PRRSV infection by producing antibodies, and is the technical basis by which vaccines work. Production of the tetramer will facilitate studies to assess its potential for predicting the protection status of pigs in a blood sample without a need for challenge studies.
Contact information: Michael Murtaugh, Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Avenue, St. Paul, MN 55108; office phone 612 625 6735; email email@example.com.