Recombinant Glycoprotein E of Varicella Zoster Virus Contains Glycan-Peptide Motifs That Modulate B Cell Epitopes into Discrete Immunological Signatures

Abstract

A recombinant subunit vaccine (Shingrix®) was recently licensed for use against herpes zoster. This vaccine is based on glycoprotein E (gE) of varicella zoster virus (VZV), the most abundantly expressed protein of VZV, harboring sites for N- and O-linked glycosylation. The subunit vaccine elicits stronger virus-specific CD4+ T cell response as well as antibody B cell response to gE, compared to the currently used live attenuated vaccine (Zostavax®). This situation is at variance with the current notion since a live vaccine, causing an active virus infection, should be far more efficient than a subunit vaccine based on only one single viral glycoprotein. We previously found gE to be heavily glycosylated, not least by numerous clustered O-linked glycans, when it was produced in human fibroblasts. However, in contrast to Zostavax®, which is produced in fibroblasts, the recombinant gE of Shingrix® is expressed in Chinese hamster ovary (CHO) cells. Hence, the glycan occupancy and glycan structures of gE may differ considerably between the two vaccine types. Here, we aimed at (i) defining the glycan structures and positions of recombinant gE and (ii) identifying possible features of the recombinant gE O-glycosylation pattern contributing to the vaccine efficacy of Shingrix®. Firstly, recombinant gE produced in CHO cells (“Shingrix situation”) is more scarcely decorated by O-linked glycans than gE from human fibroblasts (“Zostavax situation”), with respect to glycan site occupancy. Secondly, screening of immunodominant B cell epitopes of gE, using a synthetic peptide library against serum samples from VZV-seropositive individuals, revealed that the O-linked glycan signature promoted binding of IgG antibodies via a decreased number of interfering O-linked glycans, but also via specific O-linked glycans enhancing antibody binding. These findings may, in part, explain the higher protective efficacy of Shingrix®, and can also be of relevance for development of subunit vaccines to other enveloped viruses.

Acute retinal necrosis following recombinant subunit varicella-zoster virus vaccine

“… 4 This antigenic subunit is produced using genetically engineered Chinese hamster ovary cells and subsequently purified. 12 Importantly, varicella-zoster virus is not used in the manufacturing process and therefore eliminates the risk of iatrogenically induced zoster infection. The vaccine also includes the adjuvant AS01 B , which is formulated with liposomes and 2 immunostimulants.…”

“… 4 , 27 Additionally, there is significant interest in the recombinant vaccine's potential to benefit immunosuppressed patients in whom Zostavax is contraindicated, and the off-label use of Shingrix in these populations has been supported up to this point by studies demonstrating its relative safety in hematopoietic stem cell or solid organ transplant recipients. 12 , 13 , 28 Though post-vaccination VZV infection or reactivation appears to be rare, clinicians should be aware of this potential complication to the recombinant subunit vaccine.…”

Recombinant protein vaccines, a proven approach against coronavirus pandemics

“…Though more costly, mammalian systems are appreciated for their ability to express glycoproteins with their native structures and PTMs, and thus constitute the majority of the recently approved recombinant biologics [ 83 ]. A successful example for this class of vaccines is Shingrix®, the herpes zoster vaccine manufactured by GSK, which uses Chinese Hamster Ovary (CHO) cells to produce recombinant glycoprotein E from the virus as its antigen [ 84 ].…”

Glycomics and glycoproteomics of viruses: Mass spectrometry applications and insights toward structure–function relationships

“…Nordén et al (2019) used HCD and ETD to study the N‐ and O‐glycosylation of recombinant glycoprotein E (gE) from Varicella Zoster Virus. Precursors with the highest charge states and most intense ions triggered MS 2 HCD.…”