Briefly, plates were incubated at room temperature for 60 min and then washed five times in washing solution. Then, 100 μL of peroxidase-conjugated goat antipig IgG (A100-104P) diluted 1:150,000, peroxidase-conjugated goat antipig IgM (A100-100P) diluted 1:40,000, or peroxidase-conjugated goat antipig IgA (A100-102P) diluted 1:100,000 in solution for samples was added to each well.