ANTIGENIC-N TO ANTIGENIC-H CONVERSION OF POLIOVIRUS BY A MONOCLONAL-ANTIBODY AT LOW IONIC-STRENGTH

Monoclonal antibody 35-1f4 at low ionic strength converted native virions (N antigen) to noninfectious H-antigenic, empty capsids. The reaction was stoichiometric, as the amount of N antigen that could be converted to H was limited to an average of 2 virions per molecule of antibody. The antibody remained associated with virus aggregates after antigenic conversion. Using antibody immobilized onto protein A-bearing staphylococci, it could be shown that the loss of antigen-converting power was concomitant with the loss of antigen-binding ability. Only a small amount of viral protein (equivalent to 0.02 empty capsid per molecule of antibody) remained attached to the antibody. Heating to 56° caused most of this material to be released and restored the antibody's antigen-binding and antigen-converting abilities. Several possible explanations for the heat-reversible inactivation of the antibody are discussed. © 1992.