stable transfection - V5-tag antibody (Sep/21/2009 )

I had tranfected my cell line with a V5-tag vector with my gene of interest. My aim is to get stable clones. I did a western on 3 clones + my control cell line ( (cell line with no transfection). I got single bands of protein of interest (right size) but to my surprise I also got a v5tag-antibody expression in my control cell line ( the same size as the bands observed in the clones). Could this be a mix-up or is there any other explanation?

There is no antibody to my gene of interest so we added a tag to the gene contruct.

It could be that the antibody is non-specific. It sounds like you need to repeat this experiment.