Intrabronchial Infection of Rhesus Macaques with Simian Varicella Virus Results in a Robust Immune Response in the Lungs

Abstract

Varicella-zoster virus (VZV) is the etiological agent of varicella (chickenpox) and herpes zoster (shingles). Primary VZV infection is believed to occur via the inhalation of virus either in respiratory droplets or from shedding varicella lesions or by direct contact with infectious vesicular fluid. However, the ensuing immune response in the lungs remains incompletely understood. We have shown that intrabronchial inoculation of rhesus macaques with simian varicella virus (SVV), a homolog of VZV, recapitulates the hallmarks of acute and latent VZV infection in humans. In this study, we performed an in-depth analysis of the host immune response to acute SVV infection in the lungs and peripheral blood. We report that acute SVV infection results in a robust innate immune response in the lungs, characterized by the production of inflammatory cytokines, chemokines, and growth factors as well as an increased frequency of plasmacytoid dendritic cells (DCs) that corresponded with alpha interferon (IFN-␣) production and a rapid decrease in viral loads in the lungs. This is followed by T and B cell proliferation, antibody production, T cell differentiation, and cytokine production, which correlate with the complete cessation of viral replication. Although terminally differentiated CD8 T cells became the predominant T cell population in bronchoalveolar lavage cells, a higher percentage of CD4 T cells were SVV specific, which suggests a critical role for these cells in the resolution of primary SVV infection in the lungs. Given the homology between SVV and VZV, our data provide insight into the immune response to VZV within the lung. IMPORTANCEAlthough primary VZV infection occurs primarily via the respiratory route, the host response in the lungs and its contribution to the cessation of viral replication and establishment of latency remain poorly understood. The difficulty in accessing lung tissue and washes from individuals infected with VZV has hampered efforts to address this knowledge gap. SVV infection of rhesus macaques is an important model of VZV infection of humans; therefore, we utilized this animal model to gain a comprehensive view of the kinetics of the immune response to SVV in the lung and its relationship to the resolution of acute infection in respiratory tissues. These data not only advance our understanding of host immunity to VZV, a critical step in developing new vaccines, but also provide additional insight into immunity to respiratory pathogens. P rimary infection with varicella-zoster virus (VZV), a neurotropic alphaherpesvirus, occurs primarily through the inhalation of virus-laden saliva droplets (1, 2) or airborne virions from varicella lesions (3) or by contact with infectious vesicular fluid (4). The incubation period of varicella can range from 10 to 21 days and usually results in a benign self-limiting disease characterized by the appearance of vesicular exanthem, fever, and malaise (5). Current evidence suggests VZV can infect and replicate within the respiratory mucosal epithelium....

Acute Simian Varicella Virus Infection Causes Robust and Sustained Changes in Gene Expression in the Sensory Ganglia

“…Previous studies have shown a role for T cells in VZV and SVV dissemination (14,28,29). To determine whether T cells infiltrate the ganglia early after SVV infection in rhesus macaques, we digested DRG-T, DRG-C, and DRG-LS collected 3, 7, 10, 14, and 100 dpi and analyzed the isolated lymphocytes using flow cytometry and antibodies directed against CD4, CD8, CD28, CD95, and CCR7 in order to delineate naive and memory T cell subsets as well as CD20, CD27, and IgD to delineate naive and memory B cell subsets as recently described (19). Both CD4 and CD8 T cells were detected 3 to 14 dpi (Fig.…”

“…Cells were pelleted at 2,000 rpm for 5 min and then resuspended in 30% Percoll gradient and spun for 15 min at 2,000 rpm to isolate mononuclear cells. Cells were then stained with antibodies directed against surface markers: CD4 (Tonbo Biosciences, San Diego, CA), CD8␤ (Beckman Coulter, Brea, CA), CD28 (Tonbo Biosciences), CD95 (BioLegend, San Diego, CA), and CCR7 (BD Pharmingen, San Diego, CA) to delineate naive and memory T cell subsets, as well as CD20 (Southern Biotech, Birmingham, AL), IgD (Southern Biotech, Birmingham, AL), and CD27 (BioLegend) to delineate B cell subsets as previously described (19). Samples were analyzed using the LSRII instrument (Becton, Dickinson and Company, San Jose, CA) and FlowJo software (TreeStar, Ashland, OR).…”

A Rhesus Macaque Model of Pulmonary Nontuberculous Mycobacterial Disease

“…IL-6, IL-12, and IFNg levels peaked at 28 (IL-6), 14 (IL-12), and 21 (IFNg) dpi (data not shown). Given the observed changes in cytokines and chemokines, we next determined changes in frequency of dendritic cells (DCs) and monocytes in BAL, as recently described (14). In the BAL, the highest (22060) and middle (28493) dose animals showed an increase in DCs at 42 dpi, and all three animals showed changes in monocyte frequency at 42-56 dpi ( Figures 1E and 1F).…”

“…Innate immune cell populations were identified as described previously (14). To measure T and B cell frequency and proliferation, peripheral blood mononuclear cells (PBMC) and BAL cells were first stained with anti-CD4 (Tonbo Biosciences, San Diego, CA), CD8b (Beckman Coulter, Brea, CA), CD20 (BioLegend, San Diego, CA), IgD (Southern Biotech, Birmingham, AL), and CD27 (Tonbo Biosciences), then fixed and permeabilized before staining with anti-Ki67 (BD Pharmingen, San Diego, CA).…”

Interferon Gamma Prolongs Survival of Varicella-Zoster Virus-Infected Human NeuronsIn Vitro

“…Nonhuman primates experimentally infected with simian varicella virus (SVV), the counterpart of VZV, produce IFN-␥ 7 to 11 days postinfection (dpi) (5,6). IFN-␥ also inhibits herpes simplex virus 1 (HSV-1) infection in vitro (7) and in vivo (8)(9)(10).…”