RESUMO
The new protein carrier was developed on the basis of recombinant RNA phage Qbeta capsid. C-terminal UGA extension of the short form of Qbeta coat, so-called A1 extension, served as a target for presentation of foreign peptides on the outer surface of mosaic Qbeta particles. In conditions of enhanced UGA suppression, the proportion of A1-extended to short coats in mosaic particles dropped from 48% to 14%, with an increase of the length of A1 extension. A model insertion, short preS1 epitope 31-DPAFR-35 of hepatitis B surface antigen, demonstrated superficial location on the mosaic Qbeta particles and ensured specific antigenicity and immunogenicity.
Assuntos
Allolevivirus/genética , Proteínas do Capsídeo , Capsídeo/genética , Allolevivirus/imunologia , Allolevivirus/ultraestrutura , Animais , Capsídeo/imunologia , Clonagem Molecular , Códon de Terminação , Vetores Genéticos , Camundongos , Camundongos Endogâmicos BALB C , Biblioteca de Peptídeos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Montagem de VírusRESUMO
The Q beta gene C has been proposed as a new carrier for the exposure of foreign peptide sequences. Contrary to well-known 'display vectors' on the basis of coat proteins of RNA phage group I, group III phage Q beta-based vectors suggested application of the 195-amino acid extension of coat protein (CP) within the so-called A1 protein for insertion of the appropriate immunological epitopes. 'Mosaic' capsids presenting model hepatitis B virus preS1 and HIV-1 gp120 epitopes and formed by Q beta CP together with A1-derived proteins were obtained as a result of (1) suppression of leaky UGA stop codon of the CP gene and (2) simultaneous expression of 'pure' CP and full-length A1-derived genes obtained after the changing of CP-terminating UGA to strong UAA stop codon or sense GGA codon, respectively.