Antigen mixVP1-BKV1, chimeric protein derived from capsid protein of mouse polyomavirus and and human BK virus, subtype I, for testing of specific antibodies
Abstract
The mixVP1-BKV1 antigen was developed for immunodetection BKV subtype I specific antibodies in blood serum and plasma. The mixVP1-BKV1 antigen is composed of a recombinant chimeric protein derived from the capsid protein, VP1, of murine polyomavirus (MPyV) and from VP1 protein of human polyomavirus BK, subtype I, BKV-Ia (Dunlop / Gardner strain).
The chimeric VP1 gene was designed from bioinformatic data of VP1 genes of MPyV VP1 gene (GenBank: AAL35610.1) and BKV subtype I VPI gene (GenBank: AEK21505.1)and chemically synthesized. Specifically, part of MPyV VP1 sequence was replaced with region of so called BC loop (encoding amino acid residues 55 to 105)from VP1 gene of BKV-I VP1 and therefore encoded the variable region of the VP1 protein of subtype BKV I which is responsible for interaction with neutralizing (subtype specific) antibodies.
The gene was used for production of recombinant baculovirus and for production of antigen in baculovirus expression system. The antigen mixVP1-BKV1 was isolated from insect cells by ultracentrifugation in a three-step sucrose gradient.