Dear Hoang

if the presence of Trx fused to your antigens affect the efficacy of immune response against the antigen is not so easy to predict.

Certainly the Trx itself is not a small peptide but a protein therefore it certanilly:

- will produce immuno-response and you will generate a lot of non specific antibodies.

- if interact with some of antigen region (especially if the linker beetwen the 2 proteins is short and flexible) can mask some epitopes.

If this will reduce the efficacy of the vaccine, it depends a lot from where are located the immunodominant epitopes of your protein and therefore i suspect that can change protein to protein also on the basis of the protein MW and properties.

If suggest to you to add on your plasmid a protease cleavage site (eg TEV) beetween the protein and the Trx and try to remove using a second subctactive imac purification step. You can find a tutorial about subctractive IMAC on my blog: http://proteocool.blogspot.com/ (ProteoCool n° 13 at PAGE 3).

If this not work you can try to immunize with the fusion but i'm scared about proteins for which tag cleavage do not work because generally this phenomena is associate to protein aggregation that mask the cleavage site and if you would produce a vaccine the quality and stability of your antigen is very important.

good luck

Manuele

As Manuele Martinelli pointed out above, it is hard to predict. It could be detrimental (see Manuele's excellent advice above) but it could also help, since the T-cell epitopes that bacterial thioredoxin bring into the picture may increase the immunogenicity of the fusion protein (it has been used for that purpose before; see e.g. Article A high-performance thioredoxin-based scaffold for peptide im...

Hope it helps!

My appreciation for the advises given by Mr. Manuele and Mr. Alejandro! I will try to use TEV cleavage and purify only the protein of interest then test for vaccine efficacy.