scholarly journals The Coxsackievirus and Adenovirus Receptor: Glycosylation and the Extracellular D2 Domain Are Not Required for Coxsackievirus B3 Infection

2016 ◽  
Vol 90 (12) ◽  
pp. 5601-5610 ◽  
Author(s):  
Sandra Pinkert ◽  
Carsten Röger ◽  
Jens Kurreck ◽  
Jeffrey M. Bergelson ◽  
Henry Fechner

ABSTRACTThe coxsackievirus and adenovirus receptor (CAR) is a member of the immunoglobulin superfamily (IgSF) and functions as a receptor for coxsackie B viruses (CVBs). The extracellular portion of CAR comprises two glycosylated immunoglobulin-like domains, D1 and D2. CAR-D1 binds to the virus and is essential for virus infection; however, it is not known whether D2 is also important for infection, and the role of glycosylation has not been explored. To understand the function of these structural components in CAR-mediated CVB3 infection, we generated a panel of human (h) CAR deletion and substitution mutants and analyzed their functionality as CVB receptors, examining both virus binding and replication. Lack of glycosylation of the CAR-D1 or -D2 domains did not adversely affect CVB3 binding or infection, indicating that the glycosylation of CAR is not required for its receptor functions. Deletion of the D2 domain reduced CVB3 binding, with a proportionate reduction in the efficiency of virus infection. Replacement of D2 with the homologous D2 domain from chicken CAR, or with the heterologous type C2 immunoglobulin-like domain from IgSF11, another IgSF member, fully restored receptor function; however, replacement of CAR-D2 with domains from CD155 or CD80 restored function only in part. These data indicate that glycosylation of the extracellular domain of hCAR plays no role in CVB3 receptor function and that CAR-D2 is not specifically required. The D2 domain may function largely as a spacer permitting virus access to D1; however, the data may also suggest that D2 affects virus binding by influencing the conformation of D1.IMPORTANCEAn important step in virus infection is the initial interaction of the virus with its cellular receptor. Although the role in infection of the extracellular CAR-D1, cytoplasmic, and transmembrane domains have been analyzed extensively, nothing is known about the function of CAR-D2 and the extracellular glycosylation of CAR. Our data indicate that glycosylation of the extracellular CAR domain has only minor importance for the function of CAR as CVB3 receptor and that the D2 domain is not essential per se but contributes to receptor function by promoting the exposure of the D1 domain on the cell surface. These results contribute to our understanding of the coxsackievirus-receptor interactions.

1999 ◽  
Vol 80 (12) ◽  
pp. 3153-3158 ◽  
Author(s):  
Andreas Pasch ◽  
Jan-Heiner Küpper ◽  
Antje Wolde ◽  
Reinhard Kandolf ◽  
Hans-Christoph Selinka

Decay-accelerating factor (DAF/CD55), and coxsackievirus–adenovirus receptor (CAR) have been identified as cellular receptors for coxsackie B viruses (CBV). To elucidate the interplay of DAF and CAR on the cell surface, virus–receptor interactions of two coxsackieviruses of serotype B3 (non-haemagglutinating CBV3 and haemagglutinating CBV3-HA strain) were analysed. Binding assays revealed clear differences between these viruses with regard to their interactions with DAF and CAR. However, only the combination of anti-DAF and anti-CAR antibodies resulted in complete inhibition of virus binding for both strains. In plaque-reduction assays, anti-DAF antibodies had no effect, whereas CAR-specific antibodies significantly reduced productive infection of HeLa cells by both viruses. Interestingly, a synergistic inhibitory effect of anti-DAF and anti-CAR antibodies was also observed with regard to infection. These findings support the model of preferential interactions of both strains of CBV3 with closely associated DAF and CAR proteins on HeLa cells, despite displaying clear differences in their binding phenotypes.


2007 ◽  
Vol 88 (11) ◽  
pp. 3031-3038 ◽  
Author(s):  
Steven D. Carson ◽  
Kyung-Soo Kim ◽  
Samuel J. Pirruccello ◽  
Steven Tracy ◽  
Nora M. Chapman

Cells in which the appropriate viral receptor cannot be detected may paradoxically act as a host to the virus. For example, RD cells are often considered to be non-permissive for infection with coxsackievirus and adenovirus receptor (CAR)-dependent group B coxsackieviruses (CVB), insofar as inoculated cell monolayers show little or no cytopathic effect (CPE) and immunohistological assays for CAR have been consistently negative. Supernatants recovered from RD cells exposed to CVB, however, contained more virus than was added in the initial inoculum, indicating that productive virus replication occurred in the monolayer. When infected with a recombinant CVB type 3 (CVB3) chimeric strain expressing S-Tag within the viral polyprotein, 4–11 % of RD cells expressed S-Tag over 48 h. CAR mRNA was detected in RD cells by RT-PCR, and CAR protein was detected on Western blots of RD lysates; both were detected at much lower levels than in HeLa cells. Receptor blockade by an anti-CAR antibody confirmed that CVB3 infection of RD cells was mediated by CAR. These results show that some RD cells in the culture population express CAR and can thereby be infected by CVB, which explains the replication of CAR-dependent CVB in cell types that show little or no CPE and in which CAR has not previously been detected. Cells within cultures of cell types that have been considered non-permissive may express receptor transiently, leading to persistent replication of virus within the cultured population.


2005 ◽  
Vol 79 (18) ◽  
pp. 12016-12024 ◽  
Author(s):  
Ian G. Goodfellow ◽  
David J. Evans ◽  
Anna M. Blom ◽  
Dave Kerrigan ◽  
J. Scott Miners ◽  
...  

ABSTRACT We previously reported that soluble decay-accelerating factor (DAF) and coxsackievirus-adenovirus receptor (CAR) blocked coxsackievirus B3 (CVB3) myocarditis in mice, but only soluble CAR blocked CVB3-mediated pancreatitis. Here, we report that the in vitro mechanisms of viral inhibition by these soluble receptors also differ. Soluble DAF inhibited virus infection through the formation of reversible complexes with CVB3, while binding of soluble CAR to CVB induced the formation of altered (A) particles with a resultant irreversible loss of infectivity. A-particle formation was characterized by loss of VP4 from the virions and required incubation of CVB3-CAR complexes at 37°C. Dimeric soluble DAF (DAF-Fc) was found to be 125-fold-more effective at inhibiting CVB3 than monomeric DAF, which corresponded to a 100-fold increase in binding affinity as determined by surface plasmon resonance analysis. Soluble CAR and soluble dimeric CAR (CAR-Fc) bound to CVB3 with 5,000- and 10,000-fold-higher affinities than the equivalent forms of DAF. While DAF-Fc was 125-fold-more effective at inhibiting virus than monomeric DAF, complement regulation by DAF-Fc was decreased 4 fold. Therefore, while the virus binding was a cooperative event, complement regulation was hindered by the molecular orientation of DAF-Fc, indicating that the regions responsible for complement regulation and virus binding do not completely overlap. Relative contributions of CVB binding affinity, receptor binding footprint on the virus capsid, and induction of capsid conformation alterations for the ability of cellular DAF and CAR to act as receptors are discussed.


2005 ◽  
Vol 79 (1) ◽  
pp. 655-660 ◽  
Author(s):  
Aaron M. Milstone ◽  
JenniElizabeth Petrella ◽  
Melissa D. Sanchez ◽  
Mariam Mahmud ◽  
J. Charles Whitbeck ◽  
...  

ABSTRACT Although many coxsackie B viruses interact with decay accelerating factor (DAF), attachment to DAF by itself is not sufficient to initiate infection. We examined the early events in infection that follow virus interaction with DAF, and with the coxsackievirus and adenovirus receptor (CAR). Interaction with soluble CAR in a cell-free system, or with CAR on the surfaces of transfected cells, induced the formation of A particles; interaction with soluble or cell surface DAF did not. The results suggest that CAR, but not DAF, is capable of initiating the conformational changes in the viral capsid that lead to release of viral nucleic acid.


1998 ◽  
Vol 72 (1) ◽  
pp. 415-419 ◽  
Author(s):  
Jeffrey M. Bergelson ◽  
Anita Krithivas ◽  
Leo Celi ◽  
Gustavo Droguett ◽  
Marshall S. Horwitz ◽  
...  

ABSTRACT Complementary DNA clones encoding the murine homolog (mCAR) of the human coxsackievirus and adenovirus receptor (CAR) were isolated. Nonpermissive CHO cells transfected with mCAR cDNA became susceptible to infection by coxsackieviruses B3 and B4 and showed increased susceptibility to adenovirus-mediated gene transfer. These results indicate that the same receptor is responsible for virus interactions with both murine and human cells. Analysis of receptor expression in human and murine tissues should be useful in defining factors governing virus tropism in vivo.


2004 ◽  
Vol 78 (24) ◽  
pp. 13743-13754 ◽  
Author(s):  
Florian Kühnel ◽  
Bernd Schulte ◽  
Thomas Wirth ◽  
Norman Woller ◽  
Sonja Schäfers ◽  
...  

ABSTRACT Expression of cellular receptors determines viral tropism and limits gene delivery by viral vectors. Protein transduction domains (PTDs) have been shown to deliver proteins, antisense oligonucleotides, liposomes, or plasmid DNA into cells. In our study, we investigated the role of several PTD motifs in adenoviral infection. When physiologically expressed, a PTD from human immunodeficiency virus transactivator of transcription (Tat) did not improve adenoviral infection. We therefore fused PTDs to the ectodomain of the coxsackievirus-adenovirus receptor (CARex) to attach PTDs to adenoviral fiber knobs. CARex-Tat and CARex-VP22 allowed efficient adenoviral infection in nonpermissive cells and significantly improved viral uptake rates in permissive cells. Dose-dependent competition of CARex-PTD-mediated infection using CARex and inhibition experiments with heparin showed that binding of CARex-PTD to both adenoviral fiber and cellular glycosaminoglycans is essential for the improvement of infection. CARex-PTD-treated adenoviruses retained their properties after density gradient ultracentrifugation, indicating stable binding of CARex-PTD to adenoviral particles. Consequently, the mechanism of CARex-PTD-mediated infection involves coating of the viral fiber knobs by CARex-PTD, rather than placement of CARex domains on cell surfaces. Expression of CARex-PTDs led to enhanced lysis of permissive and nonpermissive tumor cells by replicating adenoviruses, indicating that CARex-PTDs are valuable tools to improve the efficacy of oncolytic therapy. Together, our study shows that CARex-PTDs facilitate gene transfer in nonpermissive cells and improve viral uptake at reduced titers and infection times. The data suggest that PTDs fused to virus binding receptors may be a valuable tool to overcome natural tropism of vectors and could be of great interest for gene therapeutic approaches.


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