CHIMERAS FROM A HUMAN RHINOVIRUS 14-HUMAN IMMUNODEFICIENCY VIRUS TYPE-1 (HIV-1) V3 LOOP SEROPREVALENCE LIBRARY INDUCE NEUTRALIZING RESPONSES AGAINST HIV-1

A chimeric virus library was designed whereby sequences corresponding to the V3 loop of human immunodeficiency virus type 1 (HIV-1) were pre sented on the surface of human rhinovirus 14. The V3 loop sequences co nsisted of a relatively conserved segment of seven amino acids and fiv e adjacent residues that were allowed to vary in proportion to their s eroprevalence among HIV-1 isolates of North America and Europe. A tech nique called random systematic mutagenesis was used to incorporate the composite V3 loop sequences Banked by zero to two randomized amino ac ids. This library could contain 2.7 x 10(8) members having diverse seq uences and conformations. Immunoselection of a portion of this library by using two neutralizing V3 loop directed monoclonal antibodies foll owed by selection for desirable growth and purification characteristic s yielded a set of chimeric rhinoviruses, five of which are described. The inserted sequences in the five chimeras do not match those of any known isolate of HIV-1. Nonetheless, all five chimeras were neutraliz ed by antibodies directed against different strains of HIV-1 and were able to elicit the production of antibodies that bind V3 loop peptides from diverse HIV-1 isolates. Moreover, antisera derived from four of the five chimeras were capable of neutralizing one or more strains of HIV-1 in cell culture. This study demonstrates that random systematic mutagenesis in conjunction with antibody screening is a powerful and e fficient means to obtain antigenic chimeras with relevant immunogenic properties.