Hofmann, Irmgard, Ciferri, Claudio, Wen, Yingxia, Schulze, Axel, Fühner, Viola, Leong, Megan, Gerber, Andrea, Gerrein, Rachel, Nandi, Avishek, Lijla, Anders E. , Carfi, Andrea and Laux, Holger (2016) Expression of the Human Cytomegalovirus Pentamer Complex for vaccine use in a CHO system. Biotech Bioeng.

Abstract

Human cytomegalovirus (HCMV) causes significant disease worldwide. Multiple HCMV vaccines have been tested in man but only partial protection has been achieved. The HCMV gH/gL/UL128/UL130/UL131A complex (Pentamer) is the main target of neutralizing antibodies in HCMV seropositive individuals and immunization with Pentamer raises high titers of neutralizing antibodies in small animals and non-human primates (NHP). Thus, Pentamer is a promising candidate for a future HCMV vaccine. Development of a Pentamer-based subunit vaccine requires expression of high amounts of a functional and stable complex. We describe here the development of a mammalian expression system for large scale Pentamer production. Several approaches comprising three different CHO-originated cell lines and multiple vector as well as selection strategies were tested. Stable cell pools expressed the HCMV Pentamer at a titer of approximately 60 mg/L at laboratory scale. A FACS-based single cell sorting approach allowed selection of a high expressing clone producing Pentamer at levels of approximately 400 mg/L in a laboratory scale fed-batch culture. Expression in a 50L bioreactor led to the production of HCMV Pentamer at comparable titers indicating the feasibility of further scale-up to production scale. The CHO produced HCMV Pentamer complex bound to a panel of human neutralizing antibodies and raised potently neutralizing immune response in mice. Thus, we have generated an expression system for the large scale production of functional HCMV Pentamer at high titers suitable for future subunit vaccine production.

Item Type:	Article
Date Deposited:	03 May 2016 23:45
Last Modified:	03 May 2016 23:45
URI:	https://oak.novartis.com/id/eprint/25179