Recombinant expression of protein variants cover rubeola e1 as fusion proteins chaperone, and use thereof in the detection of anti-rubella antibodies.

Soluble antigen Rubella E1 and variants of this peptide, wherein: (i) not present in the C-terminal at least the transmembrane region and the anchor segment as well as at least amino acids 143-168, and ( ii) it contains at least the region spanning the disulfide bridges Cys 349-Cys35 and Cys 368-Cys 401, and comprising at least amino acids 315-412 of the sequence rubella E1, wherein the rubella E1 antigen is fused with a FKBP chaperone.