Engineering the filamentous phage surface to alter its immunogenicity
N.E. van Houten, K. Henry, G.P. Smith, J.K. Scott
Simon Fraser University, CA
Keywords: filamentous phage, peptide, carbohydrate, immunization, antibodies, cross-reactivity, immunogenicity
Abstract:We have altered the immunogenic properties of filamentous phage by altering the biochemical properties of its surface; this was accomplished by removing the outer domains of pIII and changing the amino-acid sequence of the N-terminal 10 residues of pVIII. Antibodies against wild-type phage did not cross-react with the altered phage, and vice versa. In addition, for two different peptide sequences, we prepared immunogen phage that display each sequence as a recombinant peptide fusion to pVIII, and as a synthetic peptide that is chemically conjugated to the phage surface in high copy number. We compared these conjugates, as immunogens, for their abilitiy to elicit anti-peptide antibodies, and to produce cross-reactivity with antigen that the peptides are supposed to “mimic”. In one case, the peptide was a “mimic” of a carbohydrate that was previously selected from a phage library; as an immunogen the phage-displayed recombinant peptide elicited strong cross-reactivity with the carbohydrate, as compared to its synthetic-peptide conjugate counterpart, and the removal of the outer domain of pIII increased the antibody response against the peptide and its cross-reactivity with the carbohydrate. Our results indicate that the antibody response against a phage-displayed peptide can be enhanced by removing immunodominant domains from the phage surface.