Preparation and evaluation of homologous IgG on canine parvovirus.

Background: Canine parvovirus, an important and highly pathogenic agent for puppies, is distributed worldwide. Despite the various vaccines being available, it is not easily prevented. Immunoglobulin therapy has been attempted as a supportive approach to cure affected puppies. Aims: In order to achieve a homologous immunoglobulin G (IgG) for the treatment of the fatal parvovirus, the purification of anti-parvovirus IgG from immunized dogs was assayed. Methods: IgG purification was conducted on the obtained immune sera using two-stage dialysis, in which various concentrations of ammonium sulfate with several incubations and centrifugations were applied in multiple steps. Results: Using SDS-PAGE electrophoresis, the correct band sizes of the purified IgGs were observed and its concentration was assessed to be >22 mg/ml. Also, using quantitative ELISA, the specific anti-parvovirus IgG titer of the purified dog IgG was calculated to be considerably above the protective threshold titer. To do so, 13 parvoviral diarrheic puppies were randomly categorized into 3 treatment groups for 5 consecutive days. Administration of 4, 8 and 16 mg/kg bw/d of purified IgG to these puppies significantly improved all clinical symptoms including diarrhea, dehydration, appetite, vomiting and white blood cell (WBC) in all affected puppies in dose-dependent manner, comparing with those in the placebo-controlled group (n=8) that experienced 2 deaths, too. Conclusion: This homologous anti-parvovirus IgG, which was purified through a novel, simple and inexpensive technology is expected to pass further clinical trials. Also, this IgG has the potential as a commercial product to reduce the burden of parvovirus infection in puppies.