Cell surface expression of human cytomegalovirus (HCMV) gp55-116 (gB): use of HCMV-recombinant vaccinia virus-infected cells in analysis of the human neutralizing antibody response.

Human cytomegalovirus (HCMV) is known to evade extrinsic pro-apoptotic pathways not only by downregulating cell surface expression of the death receptors TNFR1, TRAIL receptor 1 (TNFRSF10A) and TRAIL receptor 2 (TNFRSF10B), but also by impeding downstream signalling events. Fas (CD95/APO-1/TNFRSF6) also plays a prominent role in apoptotic clearance of virus-infected cells, so its fate in HCMV-infected cells needs to be addressed. Here, we show that cell surface expression of Fas was suppressed in HCMV-infected fibroblasts from 24 h onwards through the late phase of productive infection, and was dependent on de novo virus-encoded gene expression but not virus DNA replication. Significant levels of the fully glycosylated (endoglycosidase-H-resistant) Fas were retained within HCMV-infected cells throughout the infection within intracellular membranous structures. HCMV infection provided cells with a high level of protection against Fas-mediated apoptosis. Downregulation of Fas was observed with HCMV strains AD169, FIX, Merlin and TB40.

Download Full-text

The serological detection of recombinant vaccinia virus encoded HIV-1 gag proteins in the cytoplasm of human B cells in the absence of cell surface expression

Serodiagnosis and Immunotherapy in Infectious Disease ◽

10.1016/0888-0786(89)90041-3 ◽

1989 ◽

Vol 3 (5) ◽

pp. 329-336 ◽

Cited By ~ 2

Author(s):

Carol M. O'Toole ◽

M.W. Lowdell

Keyword(s):

B Cells ◽

Cell Surface ◽

Surface Expression ◽

Recombinant Vaccinia Virus ◽

Cell Surface Expression ◽

Serological Detection ◽

Recombinant Vaccinia ◽

Gag Proteins ◽

Human B Cells ◽

Hiv 1

Download Full-text

Cell Surface Expression of the Vaccinia Virus Complement Control Protein Is Mediated by Interaction with the Viral A56 Protein and Protects Infected Cells from Complement Attack

Journal of Virology ◽

10.1128/jvi.02426-07 ◽

2008 ◽

Vol 82 (9) ◽

pp. 4205-4214 ◽

Cited By ~ 28

Author(s):

Natasha M. Girgis ◽

Brian C. DeHaven ◽

Xin Fan ◽

Kendra M. Viner ◽

Mohammad Shamim ◽

...

Keyword(s):

Membrane Protein ◽

Cell Surface ◽

Vaccinia Virus ◽

Transmembrane Domain ◽

Surface Expression ◽

Cell Surface Expression ◽

Major Protein ◽

Complement Control Protein ◽

Infected Cells ◽

Control Protein

ABSTRACT The vaccinia virus (VACV) complement control protein (VCP) is the major protein secreted from VACV-infected cells. It has been reported that VCP binds to the surfaces of uninfected cells by interacting with heparan sulfate proteoglycans (HSPGs). In this study, we show that VCP is also expressed on the surfaces of infected cells and demonstrate that surface localization occurs independently of HSPGs. Since VCP does not contain a transmembrane domain, we hypothesized that VCP interacts with a membrane protein that localizes to the infected-cell surface. We show that the VACV A56 membrane protein is necessary for the cell surface expression of VCP and demonstrate that VCP and A56 interact in VACV-infected cells. Since the surface expression of VCP was abrogated by reducing agents, we examined the contribution of an unpaired cysteine residue on VCP to VCP surface expression and VCP's interaction with A56. To do this, we mutated the unpaired cysteine in VCP and generated a recombinant virus expressing the altered form of VCP. Following the infection of cells with the mutant virus, VCP was neither expressed on the cell surface nor able to interact with A56. Importantly, the cell surface expression of VCP was found to protect infected cells from complement-mediated lysis. Our findings suggest a new function for VCP that may be important for poxvirus pathogenesis and impact immune responses to VACV-based vaccines.

Download Full-text