The serum albumin-binding region of streptococcal protein G: a bacterial fusion partner with carrier-related properties.
In this study, we have explored the use of the serum albumin-binding region (BB) from streptococcal protein G (SpG) as a bacterial fusion partner for production of peptide immunogens. The fusion protein BB-M3, containing BB and repeated structures from the Plasmodium falciparum malaria antigen Pf155/RESA, was efficiently purified from Escherichia coli culture supernatants by affinity chromatography using BB as an affinity tag. Rabbits immunized with BB-M3 in Freund's adjuvant produced high levels of antibodies which reacted with both M3 and BB in ELISA and stained intact Pf155/RESA in the membrane of infected erythrocytes. These antibody levels were sustained for more than 30 weeks. BB-M3 also induced antibody responses to M3, BB and intact Pf155/RESA in a number of mouse strains, including several strains which are non-responders to the malaria sequences. In the latter mice, however, BB-M3 only activated BB-specific T cells, suggesting that BB has ability to provide carrier-related T cell help for antibody production. Moreover, the minimal albumin-binding motif of SpG, containing only 46 amino acids, was immunogenic in both B10.BR, B10.D2 and C57BL/6 mice (H-2k, H-2d and H-2b, respectively). These results indicate that BB has both affinity tag and carrier-related properties and suggest that fusion proteins containing BB can be efficient tools for the generation of antibody responses to peptides which are weak immunogens.
Sjölander
A
A
Department of Immunology, Stockholm University, Sweden. sjolander@wehi.edu.au
Nygren
P A
PA
Stahl
S
S
Berzins
K
K
Uhlen
M
M
Perlmann
P
P
Andersson
R
R
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000737:chemistry*; D006239:Haplotypes; D008213:Lymphocyte Activation; D017780:Malaria Vaccines / Q000737:chemistry*; D051379:Mice; D008815:Mice, Inbred Strains / Q000276:immunology; D010455:Peptides / Q000276:immunology; D011485:Protein Binding; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D012709:Serum Albumin / Q000737:chemistry*; D013601:T-Lymphocytes / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*
D000913:Antibodies, Protozoan; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D017780:Malaria Vaccines; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012709:Serum Albumin; D014614:Vaccines, Synthetic