Radial Immunodiffusion Ab-containing gel Precipitin oo⊙⊙】 ring Ag/8 Ag/4 Ag/2 Ag/1 D2Ring Antigen ConcentrationRadial Immunodiffusion Ab-containing gel Ag/8 Ag/4 Ag/2 Ag/1 Precipitin ring Antigen Concentration D2 Ring