PRODUCTION OF REASSORTANT VIRUSES CONTAINING HUMAN ROTAVIRUS VP4 AND SA11 VP7 FOR MEASURING NEUTRALIZING ANTIBODY FOLLOWING NATURAL INFECTION

The outer capsid proteins VP4 and VP7 of group A rotaviruses are both targets of neutralizing antibody produced following natural infection in humans. Of interest is the relative importance and immunodominance of each protein in the generation of a protective immune response, In order to measure neutralizing antibody responses to VP4 and VP7 separa tely, reassortants bearing VP4 of each of the major human rotavirus P types with VP7 of SA11 origin were successfully produced by neutralizi ng monoclonal antibody selection, The resulting reassortants, together with reassortants representing each of the major VP7 types, were anti genically characterized with serotype-specific neutralizing monoclonal antibodies and hyperimmune sera, The neutralization proteins of human rotavirus origin were found to be unaffected antigenically by reassor tment. The abilities of these reassortants to discriminate between VP4 and VP7 immune responses were evaluated with postinfection sera colle cted from three patients infected with either a P1A[8],G1, a P1B[4],G2 , or a P1A[8], G4 rotavirus strain, The reassortants were shown to be capable of separating the neutralizing antibody responses to VP4 and V P7, with each patient showing a different immune response with respect to VP4 or VP7 immunodominance. These reassortants can now be applied to analyses of individual immune responses to VP4 and VP7 proteins aft er primary rotavirus infections and reinfections in humans.