Antigenicity of the “a” determinant fused to MrNV capsid protein. Microtiter plate wells were coated with each protein diluted to 20, 10, 5, and 2 μg/ml. BSA was the negative control. NvC, MrNV capsid protein without the “a” determinant; NvC-aD, fusion protein of MrNV capsid protein and the “a” determinant. The error bars indicate standard deviations.