Epstein-Barr virus infection mechanisms

The structure of gp42 (green) bound to an HLA class II molecule, based on X-ray crystallography of the complex (30), is shown in side view (left) or from above (right). Clinical trials involving approximately 10, 000 patients (including patients from nongenital herpes studies, such as herpes zoster) have assessed the safety and efficacy of valacyclovir in the treatment of initial genital herpes outbreaks, episodic treatment of recurrent episodes and daily suppressive therapy. Many viruses use a single glycoprotein for both binding and membrane fusion. At 48 h post transfection, the cells were infected with identical dosages of a reporter HSV-1(gL86) virus and entry was measured at 6 h post infection. investigated the role of the second Ig-like domain of nectins in cis- and trans-interactions and cell adhesion by using a mouse nectin-2 second-domain deletion mutant. Cytoskeletons are intracellular fiber networks that fill the space between organelles within the cytoplasm.

Efficient entry of EBV into a B cell minimally requires 5 viral envelope glycoproteins and 3 cellular proteins[4]. This is particularly important since incoming capsids interact with the cellular dynein motor for transport along microtubules to the nuclear pore (5, 26, 30) where the viral genomic DNA is released into the nucleus. As with all herpesviruses, EBV enters cells as its envelope fuses with a membrane of the cell. Despite these differences, the structure of all herpesvirus virions is unique in virology and is remarkably similar. BPIV3 efficiently infected the airway epithelial cells using sialic acids on the apical surface as a receptor determinant for virus entry from the apical side. MHV-68 gB is therefore likely to play a major role in virion entry even though it lacks the RGD integrin binding motif (32) of Kaposi’s sarcoma-associated herpesvirus gB.

The integrin α3β1 (CD49c/29) has been shown to serve as a receptor for HHV-8 infection of vascular endothelial cells and human foreskin fibroblasts (8). In immunosuppressed transplant patients, HCMV infection can result in pneumonia, gastrointestinal disease, hepatitis, retinitis, and encephalitis. As with all herpesviruses, EBV enters cells as its envelope fuses with a membrane of the cell. Viral envelope fusion with the host cell membrane requires the additional interaction of the ternary EBV glycoprotein gp85-gp25-gp42 complex with its cellular ligand (6, 7). After initial binding of the virion via viral glycoprotein B (gB) or gC to heparan sulfate on the cell surface, nectin-1 or nectin-2 can mediate viral entry through interaction with viral gD, followed by fusion of the viral envelope with the cellular plasma membrane. However, a role for the proteasome in HSV entry has not been described.

That herpesvirus gB molecules serve as fusion proteins was also supported by studies showing that HSV gB associates with (dives into) liposomes, whereas gH/gL does not associate with membranes unless coexpressed with gB [15,16]. The host range of EBV in vitro is largely restricted to B cells. Altogether, HR-2 adds to the features typical of class 1 fusion glycoproteins exhibited by HSV-1 gH. The percentage inhibition of HSV-1 infection by mAbs was calculated. Nevertheless, each form contains the same DNA–protein core, with numerous enzymes and factors for early gene expression, that is surrounded by a lipid membrane with more than a dozen viral proteins, none of which are glycosylated (Moss, 2001). RPE cells grown (4 × 106 cells) in six-well dishes were challenged with β-galactosidase–expressing recombinant HSV-2(333)gJ- at 20 PFU/cell.

Another complex concept is that very different viruses may use identical receptors. Viral glycoproteins mediate entry of enveloped viruses into cells and thus play crucial roles in infection. In vitro and in vivo neutralization experiments using synthetic peptide contained WSSV binding domain (WBD) showed that the WBD peptide could inhibit WSSV infection in primary cultured hemocytes and delay the mortality in shrimps challenged with WSSV. In indirect immunofluorescence analysis, the antiserum labeled vesicular structures in PrV infected cells which also contained glycoprotein B. We show here that gp42 interacts directly with gH and that point mutations in the region of gH recognized by an antibody that differentially inhibits epithelial and B cell fusion significantly impact both the core fusion machinery and cell-specific events. These sequences represent the protein coding region of the PVRL2 gene which is encoded by the open reading frame (ORF) sequence.