Short synthetic CDR-peptides forming the antibody combining site of the monoclonal antibody against RNA bacteriophage fr neutralize the phage activity

The construction of a mouse hybridoma FRS2 secreting neutralizing monoclonal antibody specific for RNA bacteriophages fr, MS2 and GA is reported. The genes encoding the variable domains of the monoclonal antibody FRS2 heavy and light chains were cloned and sequenced and the corresponding complementarity determining region (CDR) peptides were chemically synthesized. The CDR-peptides were tested for their ability to neutralize the activity of RNA phage fr and related RNA phages MS2 and GA. The CDR-derived peptides H2, L2 and L3 interacted with the fr phage particles and neutralized fr phage activity. Two of these peptides-H2 and L3 also had the ability to neutralize partly the activity of related bacteriophage MS2; butLJande-speciilll’y L3 neutralize the activity of the RNA phage GA. These results provide an excellent system for further antibodyantigen interaction studies and raise the possibility that simple CDR-peptides may serve as a new class of antiviral molecules. [Hum Antibod Hybridomas 1996; 7: 106-112].