EPITOPES AND HEMAGGLUTINATION BINDING DOMAIN ON SUBGENUS B-2 ADENOVIRUS FIBERS

The adenovirus fiber serves as a ligand between the virus and the host cell receptor and manifests hemagglutination (HA) activity and antige nic domains, We have screened both the antigenic and immunogenic epito pes on the adenovirus fibers of subgenus B:2 by using recombinant fibe r proteins (rfibers) expressed in Escherichia coli, synthesized peptid es (Pi to PS), and the corresponding antisera, The results indicated t hat P4 (amino acids [aa] 201 to 220), P5 (aa 231 to 250), and P7 (aa 2 75 to 295) presented both antigenic and immunogenic epitopes in adenov irus type 11 prototype (Ad11p), Ad34a, and Ad11a fibers. P6 (aa 251 to 270) presented both epitopes in Ad11a fiber but only an antigenic epi tope in other fibers. The C-terminal 20 amino acids of the fiber, corr esponding to P8, manifested an epitope of law-level immunogenicity, P5 , localized at the N-terminal aa 231 to 250, displayed an epitope that reacted with fibers of all the members of subgenus B analyzed, The rf ibers of Ad11p and Ad34a displayed HA activity with monkey erythrocyte s, though those of Adlla did not, Mutagenesis of the rfibers revealed that neither the fragment replacements, 11p20211a, 11p26011a, and 11a2 8011p, nor the Ad11p rfiber with the substitutions of Tyr-260-->H (Tyr 260H) and Arg279Q displayed HA activity, The Adlla fiber knob was sens itive to proteolytic digestion, whereas that of Ad11p was resistant, T he results demonstrated that the decisive HA binding domain was presen ted at aa 260 to 280 and was conformation dependent, Nearby amino acid s, aa 283 and 284, may also affect the HA function.