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Simultaneous expression of the S and L surface antigens of hepatitis B, and formation of mixed particles in the methylotrophic yeast, Hansenula polymorpha
Author(s) -
Janowicz Zbigniew A.,
Melber Karl,
Merckelbach Armin,
Jacobs Eric,
Harford Nigel,
Comberbach Martin,
Hollenberg Cornelis P.
Publication year - 1991
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320070502
Subject(s) - hbsag , biology , immunogenicity , antigen , microbiology and biotechnology , pichia pastoris , yeast , epitope , biochemistry , gene , virology , hepatitis b virus , virus , recombinant dna , genetics
An expression system has been developed for the methylotrophic yeast Hansenula polymorpha and used to co‐express both the L (preS1‐S2‐S) and S hepatitis B surface antigens (HBsAg) under the control of strong methanol‐inducible promoters derived from the methanol oxidase and from the formate dehydrogenase genes. A unique feature of this H. polymorpha expression system is the possibility of integrating up to 100 copies of an expression cassette via a multimeric integration mechanism. Several multimeric integrants containing various numbers of L and S expression cassettes were constructed to give a spectrum of strains characterized by different L to S ratios. The expression level of S antigen was 5–8% of the total soluble cell protein. Analysis by sucrose and CsCl density gradient centrifugation and by particle‐specific immunoassays demonstrated that the synthesized HBsAg spontaneously assembled into composite subviral particles containing both S and L proteins. Only a minor portion of the L protein was found to be glycosylated. These H. polymorpha ‐derived composite particles can be used for the production of a hepatitis B virus vaccine with the potential for improved immunogenicity due to the presence of a wider spectrum of epitopes and negligible glycosylation.