Comparison of Levels of Nasal, Salivary, and Plasma Antibody to Severe Acute Respiratory Syndrome Coronavirus 2 During Natural Infection and After Vaccination.

BACKGROUND: Most studies of immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) measure antibody or cellular responses in blood; however, the virus infects mucosal surfaces in the nose and conjunctivae and infectious virus is rarely if ever present in the blood. METHODS: We used luciferase immunoprecipitation assays to measure SARS-CoV-2 antibody levels in the plasma, nose, and saliva of infected persons and vaccine recipients. These assays measure antibody that can precipitate the SAR-CoV-2 spike and nucleocapsid proteins. RESULTS: Levels of plasma anti-spike antibody declined less rapidly than levels of anti-nucleocapsid antibody in infected persons. SARS-CoV-2 anti-spike antibody levels in the nose declined more rapidly than antibody levels in the blood after vaccination of infected persons. Vaccination of previously infected persons boosted anti-spike antibody in plasma more than in the nose or saliva. Nasal and saliva anti-spike antibody levels were significantly correlated with plasma antibody in infected persons who had not been vaccinated and after vaccination of uninfected persons. CONCLUSIONS: Persistently elevated SARS-CoV-2 antibody in plasma may not indicate persistence of antibody at mucosal sites such as the nose. The strong correlation of SARS-CoV-2 antibody in the nose and saliva with that in the blood suggests that mucosal antibodies are derived primarily from transudation from the blood rather than local production. While SARS-CoV-2 vaccine given peripherally boosted mucosal immune responses in infected persons, the increase in antibody titers was higher in plasma than at mucosal sites. Taken together, these observations indicate the need for development of mucosal vaccines to induce potent immune responses at sites where SARS-CoV-2 infection occurs. CLINICAL TRIALS REGISTRATION: NCT01306084.

BTK inhibitors impair humoral and cellular responses to recombinant zoster vaccine in CLL.

Vaccinations effectively prevent infections; however, patients with chronic lymphocytic leukemia (CLL) have reduced antibody responses following vaccinations. Combined humoral and cellular immune responses to novel adjuvanted vaccines are not well characterized in CLL. In an open-label, single-arm clinical trial, we measured the humoral and cellular immunogenicity of the recombinant zoster vaccine (RZV) in CLL patients who were treatment naïve (TN) or receiving Bruton tyrosine kinase inhibitor (BTKi) therapy. The primary endpoint was antibody response to RZV (≥fourfold increase in anti-glycoprotein E [anti-gE]). Cellular response of gE-specific CD4+ T cells was assessed by flow cytometry for upregulation of ≥2 effector molecules. The antibody response rate was significantly higher in the TN cohort (76.8%; 95% confidence interval [CI], 65.7-87.8) compared with patients receiving a BTKi (40.0%; 95% CI, 26.4-53.6; P = .0002). The cellular response rate was also significantly higher in the TN cohort (70.0%; 95% CI, 57.3-82.7) compared with the BTKi group (41.3%; 95% CI, 27.1-55.5; P = .0072). A concordant positive humoral and cellular immune response was observed in 69.1% (95% CI, 56.9-81.3) of subjects with a humoral response, whereas 39.0% (95% CI, 24.1-54.0) of subjects without a humoral response attained a cellular immune response (P = .0033). Antibody titers and T-cell responses were not correlated with age, absolute B- and T-cell counts, or serum immunoglobulin levels (all P > .05). RZV induced both humoral and cellular immune responses in treated and untreated CLL patients, albeit with lower response rates in patients on BTKi therapy compared with TN patients. This trial was registered at www.clinicaltrials.gov as #NCT03702231.

Nectin-1 Is an Entry Mediator for Varicella-Zoster Virus Infection of Human Neurons.

Varicella-zoster virus (VZV) maintains lifelong latency in neurons following initial infection and can subsequently be reactivated to result in herpes zoster or severe neurological manifestations such as encephalitis. Mechanisms of VZV neuropathogenesis have been challenging to study due to the strict human tropism of the virus. Although neuronal entry mediators of other herpesviruses, including herpes simplex virus, have been identified, little is known regarding how VZV enters neurons. Here, we utilize a human stem cell-based neuronal model to characterize cellular factors that mediate entry. Through transcriptional profiling of infected cells, we identify the cell adhesion molecule nectin-1 as a candidate mediator of VZV entry. Nectin-1 is highly expressed in the cell bodies and axons of neurons. Either knockdown of endogenous nectin-1 or incubation with soluble forms of nectin-1 produced in mammalian cells results in a marked decrease in infectivity of neurons. Notably, while addition of soluble nectin-1 during viral infection inhibits infectivity, addition after infection has no effect on infectivity. Ectopic expression of human nectin-1 in a cell line resistant to productive VZV infection confers susceptibility to infection. In summary, we have identified nectin-1 as a neuronal entry mediator of VZV. IMPORTANCE Varicella-zoster virus (VZV) causes chickenpox, gains access to neurons during primary infection where it resides lifelong, and can later be reactivated. Reactivation is associated with shingles and postherpetic neuralgia, as well as with severe neurologic complications, including vasculitis and encephalitis. Although the varicella vaccine substantially decreases morbidity and mortality associated with primary infection, the vaccine cannot prevent the development of neuronal latency, and vaccinated populations are still at risk for reactivation. Furthermore, immunocompromised individuals are at higher risk for VZV reactivation and associated complications. Little is known regarding how VZV enters neurons. Here, we identify nectin-1 as an entry mediator of VZV in human neurons. Identification of nectin-1 as a neuronal VZV entry mediator could lead to improved treatments and preventative measures to reduce VZV related morbidity and mortality.

Serum and Cervicovaginal Fluid Antibody Profiling in Herpes Simplex Virus-Seronegative Recipients of the HSV529 Vaccine.

Previous herpes simplex virus type 2 (HSV-2) vaccines have not prevented genital herpes. Concerns have been raised about the choice of antigen, the type of antibody induced by the vaccine, and whether antibody is present in the genital tract where infection occurs. We reported results of a trial of an HSV-2 replication-defective vaccine, HSV529, that induced serum neutralizing antibody responses in 78% of HSV-1-/HSV-2- vaccine recipients. Here we show that HSV-1-/HSV-2- vaccine recipients developed antibodies to epitopes of several viral proteins; however, fewer antibody epitopes were detected in vaccine recipients compared with naturally infected persons. HSV529 induced antibodies that mediated HSV-2-specific natural killer (NK) cell activation. Depletion of glycoprotein D (gD)-binding antibody from sera reduced neutralizing titers by 62% and NK cell activation by 81%. HSV-2 gD antibody was detected in cervicovaginal fluid at about one-third the level of that in serum. A vaccine that induces potent serum antibodies transported to the genital tract might reduce HSV genital infection.

An integrated disease-specific graded prognostic assessment scale for melanoma: contributions of KPS, CITV, number of metastases, and BRAF mutation status.

BACKGROUND: Stereotactic radiosurgery (SRS) remains a mainstay therapy in the treatment of melanoma brain metastases (BM). While prognostic scales have been developed for melanoma patients who underwent SRS treatment for BM, the pertinence of these scales in the context of molecularly targeted therapies remains unclear. METHODS: Through a multi-institutional collaboration, we collated the survival patterns of 331 melanoma BM patients with known BRAF mutation status treated with SRS. We established a prognostic scale that was validated in an independent cohort of 174 patients. All patients with BRAF mutations in this series were treated with BRAF inhibitors. Prognostic utility was assessed using Net Reclassification Index (NRI > 0) and integrated discrimination improvement (IDI) metrics. RESULTS: In a multivariate Cox proportional hazards model, BRAF mutation status, KPS, number of metastases, and cumulative intracranial tumor volume (CITV) independently contributed to survival prognostication for melanoma patients with SRS-treated BM (P < .05 for all variables). These variables were incorporated into a prognostic scale using the disease-specific graded prognostic assessment (ds-GPA) framework. This integrated melanoma ds-GPA scale was validated in 2 independent cohorts collated through a multi-institutional collaboration. In terms of order of prognostic importance, BRAF mutation status exerted the greatest influence on survival, while KPS, the number of metastases, and CITV exhibited comparable, lesser impacts. CONCLUSIONS: Optimal survival prognostication for SRS-treated patients with melanoma BM requires an integrated assessment of patient characteristics (KPS), tumor characteristics (CITV and number of metastases), and the mutational profile of the melanoma (BRAF mutation status).

Effect of Bruton tyrosine kinase inhibitor on efficacy of adjuvanted recombinant hepatitis B and zoster vaccines.

Vaccinations are effective in preventing infections; however, it is unknown if patients with chronic lymphocytic leukemia (CLL) who are treatment naïve (TN) or receiving Bruton tyrosine kinase inhibitors (BTKi's) respond to novel adjuvanted vaccines. Understanding the effect of BTKi's on humoral immunity is timely because BTKi's are widely used and vaccination against coronavirus disease 2019 is urgently needed. In 2 open-label, single-arm clinical trials, we measured the effect of BTKi's on de novo immune response against recombinant hepatitis B vaccine (HepB-CpG) and recall response against recombinant zoster vaccine (RZV) in CLL patients who were TN or on BTKi. The primary end point was serologic response to HepB-CpG (anti-hepatitis B surface antibodies ≥10 mIU/mL) and RZV (≥fourfold increase in anti-glycoprotein E). The response rate to HepB-CpG was lower in patients on BTKi (3.8%; 95% confidence interval [CI], 0.7-18.9) than patients who were TN (28.1%; 95% CI, 15.6-45.4; P = .017). In contrast, the response rate to RZV did not differ significantly between the BTKi (41.5%; 95% CI, 27.8-56.6) and TN cohorts (59.1%; 95% CI, 38.7-76.7; P = .2). BTKi's were associated with a decreased de novo immune response following HepB-CpG, whereas recall immune response following RZV was not significantly affected by BTKi therapy. These trials were registered at www.clinicaltrials.gov as #NCT03685708 (Hep-CpG) and #NCT03702231 (RZV).

Notions of Preprocedural Patient Anxiety in the Realm of IR.

PURPOSE: To determine the views and current practice preferences of interventional radiologists and allied healthcare providers regarding management of preprocedural anxiety. MATERIALS AND METHODS: From March to April 2018, members of the Society of Interventional Radiology were surveyed regarding their opinions in the assessment and management of patient anxiety. Degree of responsibility for the management of anxiety was also queried through the use of a scale (1 = no responsibility; 2 = some responsibility; 3 = major responsibility). RESULTS: Of 1163 respondents (23.8% response rate), most described preprocedural anxiety as somewhat to very important in their practice (n = 961, 82.6%), somewhat to very important to the patients (n = 1087, 93.5%), and at least sometimes interfering with delivery of care (n = 815, 70.1%). Most respondents did not measure preprocedural anxiety directly (n = 953, 81.9%), but would address it if raised by the patient (n = 911, 82.9%). Patient education (n = 921, 79.1%), medications (n = 801, 68.8%), and therapeutic or empathetic interactions (n = 665, 56.4%) were most preferred to manage anxiety. Radiologists, nurses, patients, primary care providers, family members, and psychologists or psychiatrists were all allocated responsibility to reduce anxiety. CONCLUSIONS: Interventional radiologists and other providers are aware of the importance of preprocedural anxiety. Despite the notion that most radiologists did not address anxiety directly, most indicated a willingness to discuss the issue if raised by patients. Patient education, medications, and several other techniques are preferred to manage preprocedural anxiety. Responsibility to reduce anxiety is perceived to be shared among radiologists, nurses, patients, family members, and other health care providers.

Role of the JNK Pathway in Varicella-Zoster Virus Lytic Infection and Reactivation.

Mechanisms of neuronal infection by varicella-zoster virus (VZV) have been challenging to study due to the relatively strict human tropism of the virus and the paucity of tractable experimental models. Cellular mitogen-activated protein kinases (MAPKs) have been shown to play a role in VZV infection of nonneuronal cells, with distinct consequences for infectivity in different cell types. Here, we utilize several human neuronal culture systems to investigate the role of one such MAPK, the c-Jun N-terminal kinase (JNK), in VZV lytic infection and reactivation. We find that the JNK pathway is specifically activated following infection of human embryonic stem cell-derived neurons and that this activation of JNK is essential for efficient viral protein expression and replication. Inhibition of the JNK pathway blocked viral replication in a manner distinct from that of acyclovir, and an acyclovir-resistant VZV isolate was as sensitive to the effects of JNK inhibition as an acyclovir-sensitive VZV isolate in neurons. Moreover, in a microfluidic-based human neuronal model of viral latency and reactivation, we found that inhibition of the JNK pathway resulted in a marked reduction in reactivation of VZV. Finally, we utilized a novel technique to efficiently generate cells expressing markers of human sensory neurons from neural crest cells and established a critical role for the JNK pathway in infection of these cells. In summary, the JNK pathway plays an important role in lytic infection and reactivation of VZV in physiologically relevant cell types and may provide an alternative target for antiviral therapy.IMPORTANCE Varicella-zoster virus (VZV) has infected over 90% of people worldwide. While primary infection leads to the typically self-limiting condition of chickenpox, the virus can remain dormant in the nervous system and may reactivate later in life, leading to shingles or inflammatory diseases of the nervous system and eye with potentially severe consequences. Here, we take advantage of newer stem cell-based technologies to study the mechanisms by which VZV infects human neurons. We find that the c-Jun N-terminal kinase (JNK) pathway is activated by VZV infection and that blockade of this pathway limits lytic replication (as occurs during primary infection). In addition, JNK inhibition limits viral reactivation, exhibiting parallels with herpes simplex virus reactivation. The identification of the role of the JNK pathway in VZV infection of neurons reveals potential avenues for the development of alternate antiviral drugs.

Ganetespib, an HSP90 inhibitor, kills Epstein-Barr virus (EBV)-infected B and T cells and reduces the percentage of EBV-infected cells in the blood.

HSP90 inhibitors have been shown to kill Epstein-Barr virus (EBV)-infected cells by reducing the level of EBV EBNA-1 and/or LMP1. We treated virus-infected cells with ganetespib, an HSP90 inhibitor currently being evaluated in multiple clinical trials for cancer and found that the drug killed EBV-positive B and T cells and reduced the level of both EBV EBNA-1 and LMP1. Treatment of cells with ganetespib also reduced the level of pAkt. Ganetespib delayed the onset of EBV-positive lymphomas and prolonged survival in SCID mice inoculated with one EBV-transformed B-cell line, but not another B-cell line. The former cell line showed lower levels of EBNA-1 after treatment with ganetespib in vitro. Treatment of a patient with T-cell chronic active EBV with ganetespib reduced the percentage of EBV-positive cells in the peripheral blood. These data indicate that HSP90 inhibitors may have a role in the therapy of certain EBV-associated diseases.

Education and Communication in an Interprofessional Antimicrobial Stewardship Program.

CONTEXT: Interprofessional education/interprofessional practice (IPE/IPP) is an essential component in medical education and training. A collaborative interprofessional team environment ensures optimal patient-centered care. OBJECTIVE: To describe the implementation of 2 interprofessional antimicrobial stewardship program (ASP) teams using IPE/IPP and to assess the acceptance rate by the primary medical and surgical teams of ASP recommendations for antimicrobial interventions. METHODS: A business plan for the ASP was approved at 2 academic medical centers used for the present study. During a 3-year study period, 2 interprofessional ASP teams included an attending physician specializing in infectious disease (ID), an ID physician fellow, an ASP pharmacist, physician residents, medical students, pharmacy residents, and pharmacy students. Educational seminars were presented for all adult-admitting physicians to discuss the need for the ASP and the prospective audit and feedback process. Cases were presented for discussion during ASP/ID rounds and recommendations were agreed upon by the ASP team. A motivational interviewing face-to-face technique was frequently used to convey the ASP team recommendation to the primary medical or surgical team in a noncoercive and educational manner. The ASP team recommendations for ASP interventions were documented in the medical records. RESULTS: The overall acceptance rate of recommendations by the primary medical and surgical teams were greater than 90% (2051 of 2266). The most frequent interventions provided were streamline therapy (601), route of administration change (452), bug-drug mismatch (190), and discontinuation of therapy (179). Route of administration change was also the most frequently accepted intervention (96%). CONCLUSIONS: The motivational face-to-face communication technique was particularly useful in conveying ASP team member recommendations to the primary medical or surgical teams. Communicating recommendations as a multidisciplinary team in an educational manner seems to have resulted in to greater acceptance of recommendations.

Detection of antibodies to varicella-zoster virus in recipients of the varicella vaccine by using a luciferase immunoprecipitation system assay.

A high-throughput test to detect varicella-zoster virus (VZV) antibodies in varicella vaccine recipients is not currently available. One of the most sensitive tests for detecting VZV antibodies after vaccination is the fluorescent antibody to membrane antigen (FAMA) test. Unfortunately, this test is labor-intensive, somewhat subjective to read, and not commercially available. Therefore, we developed a highly quantitative and high-throughput luciferase immunoprecipitation system (LIPS) assay to detect antibody to VZV glycoprotein E (gE). Tests of children who received the varicella vaccine showed that the gE LIPS assay had 90% sensitivity and 70% specificity, a viral capsid antigen enzyme-linked immunosorbent assay (ELISA) had 67% and 87% specificity, and a glycoprotein ELISA (not commercially available in the United States) had 94% sensitivity and 74% specificity compared with the FAMA test. The rates of antibody detection by the gE LIPS and glycoprotein ELISA were not statistically different. Therefore, the gE LIPS assay may be useful for detecting VZV antibodies in varicella vaccine recipients. (This study has been registered at ClinicalTrials.gov under registration no. NCT00921999.).

Whole genome mapping of the first reported case of KPC-2-positive Klebsiella pneumoniae ST258 in Nebraska.

Three ertapenem-resistant Klebsiella pneumoniae carrying bla(KPC-2) were isolated from a single patient in Nebraska over a span of 5 months. A comparative analysis of the genetic relatedness of these isolates was investigated using pulsed-field gel electrophoresis, multilocus sequence typing, and whole genome mapping.

Activation of H2AX and ATM in varicella-zoster virus (VZV)-infected cells is associated with expression of specific VZV genes.

Mammalian cells activate DNA damage response pathways in response to virus infections. Activation of these pathways can enhance replication of many viruses, including herpesviruses. Activation of cellular ATM results in phosphorylation of H2AX and recruits proteins to sites of DNA damage. We found that varicella-zoster (VZV) infected cells had elevated levels of phosphorylated H2AX and phosphorylated ATM and that these levels increased in cells infected with VZV deleted for ORF61 or ORF63, but not deleted for ORF67. Expression of VZV ORF61, ORF62, or ORF63 alone did not result in phosphorylation of H2AX. While BGLF4, the Epstein-Barr virus homolog of VZV ORF47 protein kinase, phosphorylates H2AX and ATM, neither VZV ORF47 nor ORF66 protein kinase phosphorylated H2AX or ATM. Cells lacking ATM had no reduction in VZV replication. Thus, VZV induces phosphorylation of H2AX and ATM and this effect is associated with the presence of specific VZV genes in virus-infected cells.

Altered antibody profiles against common infectious agents in chronic disease.

Despite the important diagnostic value of evaluating antibody responses to individual human pathogens, antibody profiles against multiple infectious agents have not been used to explore health and disease mainly for technical reasons.  We hypothesized that the interplay between infection and chronic disease might be revealed by profiling antibodies against multiple agents. Here, the levels of antibodies against a panel of 13 common infectious agents were evaluated with the quantitative Luciferase Immunoprecipitation Systems (LIPS) in patients from three disease cohorts including those with pathogenic anti-interferon-γ autoantibodies (IFN-γ AAB), HIV and Sjögren's syndrome (SjS) to determine if their antibody profiles differed from control subjects.  The IFN-γ AAB patients compared to controls demonstrated statistically higher levels of antibodies against VZV (p=0.0003), EBV (p=0.002), CMV (p=0.003), and C. albicans (p=0.03), but lower antibody levels against poliovirus (p=0.04). Comparison of HIV patients with blood donor controls revealed that the patients had higher levels of antibodies against CMV (p=0.0008), HSV-2 (p=0.0008), EBV (p=0.001), and C. albicans (p=0.01), but showed decreased levels of antibodies against coxsackievirus B4 (p=0.0008), poliovirus (p=0.0005),   and HHV-6B (p=0.002). Lastly, SjS patients had higher levels of anti-EBV antibodies (p=0.03), but lower antibody levels against several enteroviruses including a newly identified picornavirus, HCoSV-A (p=0.004), coxsackievirus B4 (p=0.04), and poliovirus (p=0.02). For the IFN-γ AAB and HIV cohorts, principal component analysis revealed unique antibody clusters that showed the potential to discriminate patients from controls.  The results suggest that antibody profiles against these and likely other common infectious agents may yield insight into the interplay between exposure to infectious agents, dysbiosis, adaptive immunity and disease activity.

Detection of molluscum contagiosum virus (MCV) DNA in the plasma of an immunocompromised patient and possible reduction of MCV DNA with CMX-001.

Molluscum contagiosum virus (MCV) is a poxvirus that causes localized papules in healthy persons. We evaluated a woman with severe immunodeficiency and disseminated MCV. During treatment with CMX-001, an antiviral with activity against other poxviruses, MCV DNA was detected in 20% of plasma samples. When the patient was not receiving CMX-001, MCV DNA was detected in 50% of samples. We also noted improvement in warts on her fingers during CMX-001 therapy. Although MCV is caused by direct inoculation of virus into skin in healthy persons, in a severely immunocompromised person MCV DNA was present in blood and may spread by viremia.

Xenotropic murine leukemia virus-related virus is not associated with chronic fatigue syndrome in patients from different areas of the us in the 1990s.

BACKGROUND: In 2009, xenotropic murine leukemia virus-related virus (XMRV) was reported in 67% of patients with chronic fatigue syndrome (CFS) compared to 4% of controls. Since then numerous reports failed to detect XMRV in other cohorts of CFS patients, and some studies suggested that XMRV sequences in human samples might be due to contamination of these samples with mouse DNA. RESULTS: We determined the prevalence of XMRV in patients with CFS from similar areas in the United States as the original 2009 study, along with patients with chronic inflammatory disorders and healthy persons. Using quantitative PCR, we initially detected very low level signals for XMRV DNA in 15% of patients with CFS; however, the frequency of PCR positivity was no different between patients with CFS and controls. Repeated attempts to isolate PCR products from these reactions were unsuccessful. These findings were supported by our observations that PHA and IL-2 stimulation of peripheral blood mononuclear cells from patients with apparently low levels of XMRV, which induced virus replication in the 2009 report, resulted in the disappearance of the signal for XMRV DNA in the cells. Immunoprecipitation of XMRV-infected cell lysates using serum from patients from whom we initially detected low levels of XMRV DNA followed by immunoblotting with antibodies to XMRV gp70 protein failed to detect antibody in the patients, although one control had a weak level of reactivity. Diverse murine leukemia virus (MLV) sequences were obtained by nested PCR with a similar frequency in CFS patients and controls. Finally, we did not detect XMRV sequences in patients with several chronic inflammatory disorders including rheumatoid arthritis, Bechet's disease, and systemic lupus erythematosus. CONCLUSIONS: We found no definitive evidence for XMRV DNA sequences or antibody in our cohort of CFS patients, which like the original 2009 study, included patients from diverse regions of the United States. In addition, XMRV was not detected in a cohort of patients with chronic inflammatory disorders.

Insulin degrading enzyme induces a conformational change in varicella-zoster virus gE, and enhances virus infectivity and stability.

Varicella-zoster virus (VZV) glycoprotein E (gE) is essential for virus infectivity and binds to a cellular receptor, insulin-degrading enzyme (IDE), through its unique amino terminal extracellular domain. Previous work has shown IDE plays an important role in VZV infection and virus cell-to-cell spread, which is the sole route for VZV spread in vitro. Here we report that a recombinant soluble IDE (rIDE) enhances VZV infectivity at an early step of infection associated with an increase in virus internalization, and increases cell-to-cell spread. VZV mutants lacking the IDE binding domain of gE were impaired for syncytia formation and membrane fusion. Pre-treatment of cell-free VZV with rIDE markedly enhanced the stability of the virus over a range of conditions. rIDE interacted with gE to elicit a conformational change in gE and rendered it more susceptible to proteolysis. Co-incubation of rIDE with gE modified the size of gE. We propose that the conformational change in gE elicited by IDE enhances infectivity and stability of the virus and leads to increased fusogenicity during VZV infection. The ability of rIDE to enhance infectivity of cell-free VZV over a wide range of incubation times and temperatures suggests that rIDE may be useful for increasing the stability of varicella or zoster vaccines.

The insulin degrading enzyme binding domain of varicella-zoster virus (VZV) glycoprotein E is important for cell-to-cell spread and VZV infectivity, while a glycoprotein I binding domain is essential for infection.

Varicella-zoster virus (VZV) glycoprotein E (gE) interacts with glycoprotein I and with insulin degrading enzyme (IDE), which is a receptor for the virus. We found that a VZV gE deletion mutant could only be grown in cells expressing gE. Expression of VZV gE on the surface of cells did not interfere with VZV infection. HSV deleted for gE is impaired for cell-to-cell spread; VZV gE could not complement this activity in an HSV gE null mutant. VZV lacking the IDE binding domain of gE grew to peak titers nearly equivalent to parental virus; however, it was impaired for cell-to-cell spread and for infectivity with cell-free virus. VZV deleted for a region of gE that binds glycoprotein I could not replicate in cell culture unless grown in cells expressing gE. We conclude that the IDE binding domain is important for efficient cell-to-cell spread and infectivity of cell-free virus.