Neutralizing Antibody Complex of Infectious Bronchitis Virus

Abstract

The reaction between infectious bronchitis virus-42 (Beaudette) and neutralizing antibody, and dissociation of the antigen-antibody complex, was studied by the plaque technique using chicken embryo kidney cell cultures. Neutralization was a first-order reaction dependent upon time and concentration of antibody. When the complex was diluted, there was a slight but statistically significant dissociation. The complex clarified by centrifugation did not dissociate after dilution. Complexes were readily dissociated by acid with a direct relationship to H+ ion concentration. Maximum dissociation occurred within 1 min at pH 1.7 with a recovery of 60% of the original infectious virus. Virus and antibody dissociated at low pH could be reassociated at neutrality. The complexes adsorbed to cells. Brief acidification dissociated neutralizing antibody from the complexes allowing virus to infect the cells.