An Escherichia coli CS31A fibrillum chimera capable of inducing memory antibodies in outbred mice following booster immunization with the entero-pathogenic coronavirus transmissible gastroenteritis virus

作者：Vartanian MD^*; Girardeau JP; Martin C; Rousset E; Chavarot M; Laude H; Contrepois M

来源：Vaccine, 1997, 15(2): 111-120.

• CS31A fibrillae
• TGEV coronavirus
• recombinant DNA
• carrier-delivery system
• immune responses

CS31A fibrillae are thin, flexible, heteropolymeric proteinaceous appendages exposed as a capsule-like material around the cell surface of certain Escherichia coli strains. Two antigenic peptides of the S spike glycoprotein (TGEV-S) amino acids (aa) 363-371 and 521-531 of the transmissible gastroenteritis virus (TGEV) were tandemly introduced in the loop-structured variable region an 202-218 of the major ClpG subunit protein composing the bulk of CS3IA. The resulting hybrid fibrillae with a 25 aa heterologous peptide were produced at the cell surface. Using a monoclonal antibody, (Mab) specific for the TGEV epitopes, purified hybrid fibrillae were analysed in Western blotting tinder native conditions, which showed that the two viral epitopes Mere recognized immunologically as an integral part of the hybrid fibrillae, and therefore that they were antigenically active. The immunogenicity, of the fusion construct was evaluated with live recombinant bacteria, purified hybrid ClpG monomers, and purified chimeric CS31A polymers. Whatever the form of hybrid used as antigen, intraperitoneally immunized outbred mice elicited serum anti-TGEV peptides antibodies (Abs) with significant titres and capable of recognizing native TGEV particles, indicating that the epitopes are exposed in an immunogenic conformation in all cases. However, virus neutralization titres were only obtained after immunization with either purified polymers or monomers. Furthermore, 4 months after an ultimate immunization with 20 mu g of hybrid fibrillae mice developed a strong anamnestic Ab response against the two TGEV peptides following booster inoculation with virions. We conclude that CS31A fibrillae carrying a combination of TGEV epitopes as insert can induce an immunological memory in outbred animals infected with TGEV, and therefore that hybrid CS31A fibrillae may prove efficient as components of a subunit vaccine.

• 出版日期1997-2