Wild-type measles virus infection of primary epithelial cells occurs via the basolateral surface without syncytium formation or release of infectious virus

100

The global increase in measles vaccination has resulted in a significant reduction of measles mortality. The standard route of administration for the live-attenuated measles virus (MV) vaccine is subcutaneous injection, although alternative needle-free routes, including aerosol delivery, are under investigation. In vitro, attenuated MV has a much wider tropism than clinical isolates, as it can use both CD46 and CD150 as cellular receptors. To compare the in vivo tropism of attenuated and pathogenic MV, we infected cynomolgus macaques with pathogenic or attenuated recombinant MV expressing enhanced green fluorescent protein (GFP) (strains IC323 and Edmonston, respectively) via the intratracheal or aerosol route. Surprisingly, viral loads and cellular tropism in the lungs were similar for the two viruses regardless of the route of administration, and CD11c-positive cells were identified as the major target population. However, only the pathogenic MV caused significant viremia, which resulted in massive virus replication in B and T lymphocytes in lymphoid tissues and viral dissemination to the skin and the submucosa of respiratory epithelia. Attenuated MV was rarely detected in lymphoid tissues, and when it was, only in isolated infected cells. Following aerosol inhalation, attenuated MV was detected at early time points in the upper respiratory tract, suggesting local virus replication. This contrasts with pathogenic MV, which invaded the upper respiratory tract only after the onset of viremia. This study shows that despite in vitro differences, attenuated and pathogenic MV show highly similar in vivo tropism in the lungs. However, systemic spread of attenuated MV is restricted.Measles virus (MV) is one of the most contagious human viruses and is transmitted via aerosols or by direct contact with contaminated respiratory secretions. Clinical symptoms appear approximately 2 weeks after infection and include fever, rash, cough, coryza, and conjunctivitis (20). Measles is associated with immunosuppression, resulting in increased susceptibility to opportunistic infections. While significant progress has been made in global control programs, 164,000 deaths were attributed to measles in 2008 (46).MV was first isolated in cell culture in 1954 (16). This Edmonston wild-type MV strain was passaged multiple times in primary human kidney and amnion cells and adapted to eggs and chicken embryo fibroblasts to produce the live-attenuated Edmonston-B vaccine virus (15), which was later replaced by the more attenuated MV strains (Edmonston-Zagreb, Moraten, and Schwarz) (34). These vaccines have been shown to be safe and effective, and high coverage in two-dose regimens has successfully interrupted endemic MV transmission in large geographic areas (6).For many years, laboratory-adapted MV-Edmonston strains were used as the prototype virus and were shown to display a wide cellular tropism in vitro. The virus efficiently infected epithelial cells, which were considered the target cells for primary MV infection in vivo (22). In 1993,...

Section: Discussionsupporting

confidence: 64%

In VivoTropism of Attenuated and Pathogenic Measles Virus Expressing Green Fluorescent Protein in Macaques

Vries

Lemon

Ludlow

et al. 2010

100

“…In addition to being lymphotropic, in its natural host species CDV readily infects epithelial and neuronal cells (2,3,26). The epitheliotropic nature has also been described for MV in nonhuman primates (22,25,35) although CDV infects higher percentages of epithelial cells in carnivores than MV does in primates. Morbillivirus entry into epithelial cells requires the cellular receptor PVRL4.…”

Section: Discussionmentioning

confidence: 98%

“…We have previously used recombinant MV (rMV) expressing enhanced green fluorescent protein (EGFP) in conjunction with macroscopic and microscopic imaging techniques to detect virusinfected cells and study measles pathogenesis in the macaque model (22)(23)(24)(25). Here, we show that cynomolgus macaques are susceptible to infection with non-primate-adapted rCDV strains that express EGFP, resulting in virus replication in CD150 ϩ lymphocytes and DC.…”

Section: Anine Distemper Virus (Cdv) Is a Member Of The Familymentioning

confidence: 96%

“…Undifferentiated NMBE cells were grown in type 1 collagen and fibronectin-coated T75 flasks, trypsinized at 60 to 80% confluence, and seeded into 6.5-mm transwell inserts with a 0.4-m pore size at 5 ϫ 10 4 cells per insert as described previously (32). After the NMBE cells had polarized and developed cilia, the monolayers on filters were wounded by scratching with the tip of a pipette (25) and subsequently infected apically with 2 ϫ 10 5 TCID 50 of either rMV KS EGFP(3), rCDV SH EGFP(6), or rCDV R252 EGFP(6). The inoculum was removed 90 min after infection.…”

Section: Bronchoalveolar Lavage (Bal)mentioning

confidence: 99%

See 1 more Smart Citation

Measles Vaccination of Nonhuman Primates Provides Partial Protection against Infection with Canine Distemper Virus

Vries

Ludlow

Verburgh

et al. 2014

Measles virus (MV) is being considered for global eradication, which would likely reduce compliance with MV vaccination. As a result, children will grow up without MV-specific immunity, creating a potential niche for closely related animal morbilliviruses such as canine distemper virus (CDV). Natural CDV infection causing clinical signs has never been reported in humans, but recent outbreaks in captive macaques have shown that CDV can cause disease in primates. We studied the virulence and tropism of recombinant CDV expressing enhanced green fluorescent protein in naive and measles-vaccinated cynomolgus macaques. In naive animals CDV caused viremia and fever and predominantly infected CD150 ؉ lymphocytes and dendritic cells. Virus was reisolated from the upper and lower respiratory tracts, but infection of epithelial or neuronal cells was not detectable at the time points examined, and the infections were self-limiting. This demonstrates that CDV readily infects nonhuman primates but suggests that additional mutations are necessary to achieve full virulence in nonnatural hosts. Partial protection against CDV was observed in measles-vaccinated macaques, as demonstrated by accelerated control of virus replication and limited shedding from the upper respiratory tract. While neither CDV infection nor MV vaccination induced detectable cross-reactive neutralizing antibodies, MV-specific neutralizing antibody levels of MV-vaccinated macaques were boosted by CDV challenge infection, suggesting that cross-reactive VN epitopes exist. Rapid increases in white blood cell counts in MV-vaccinated macaques following CDV challenge suggested that cross-reactive cellular immune responses were also present. This study demonstrates that zoonotic morbillivirus infections can be controlled by measles vaccination. IMPORTANCEThroughout history viral zoonoses have had a substantial impact on human health. Given the drive toward global eradication of measles, it is essential to understand the zoonotic potential of animal morbilliviruses. Morbilliviruses are thought to have evolved from a common ancestral virus that jumped species and adapted to new hosts. Recently, canine distemper virus (CDV), a morbillivirus normally restricted to carnivores, caused disease outbreaks in nonhuman primates. Here, we report that experimental CDV infection of monkeys resulted in fever and leukopenia. The virus replicated to high levels in lymphocytes but did not spread to epithelial cells or the central nervous system. Importantly, like measles virus in macaques, the infections were selflimiting. In measles-vaccinated macaques CDV was cleared more rapidly, resulting in limited virus shedding from the upper respiratory tract. These studies demonstrate that although CDV can readily infect primates, measles immunity is protective, and CDV infection is self-limiting.

“…MeV replicated vigorously in primary and secondary lymphatic organs of cynomolgus macaques 3 to 5 days after inoculation (14). A few days later, most infected cells in the upper airways were of lymphoid or myeloid origin (15). MeV replication in airway epithelial cells was not observed until the second week following infection (16,17).…”

mentioning

confidence: 99%

Cell-to-Cell Contact and Nectin-4 Govern Spread of Measles Virus from Primary Human Myeloid Cells to Primary Human Airway Epithelial Cells

Singh

Mark

et al. 2016

Measles is a highly contagious, acute viral illness. Immune cells within the airways are likely first targets of infection, and these cells traffic measles virus (MeV) to lymph nodes for amplification and subsequent systemic dissemination. Infected immune cells are thought to return MeV to the airways; however, the mechanisms responsible for virus transfer to pulmonary epithelial cells are poorly understood. To investigate this process, we collected blood from human donors and generated primary myeloid cells, specifically, monocyte-derived macrophages ( IMPORTANCEMeasles virus spreads rapidly and efficiently in human airway epithelial cells. This rapid spread is based on cell-to-cell contact rather than on particle release and reentry. Here we posit that MeV transfer from infected immune cells to epithelial cells also occurs by cell-to-cell contact rather than through cell-free particles. In addition, we sought to determine which immune cells transfer MeV infectivity to the human airway epithelium. Our studies are based on two types of human primary cells: (i) myeloid cells generated from donated blood and (ii) well-differentiated airway epithelial cells derived from donor lungs. We show that different types of myeloid cells, i.e., monocyte-derived macrophages and dendritic cells, transfer infection to airway epithelial cells. Furthermore, cell-to-cell contact is an important component of successful MeV transfer. Our studies elucidate a mechanism by which the most contagious human respiratory virus is delivered to the airway epithelium. M easles virus (MeV) is extremely contagious and infects its human host via the respiratory route. For many years, MeV was thought to enter through the apical surface of airway epithelial cells (1), a misconception based on studies performed with polarized immortalized cell lines (2, 3). Using well-differentiated primary cultures of airway epithelial cells from human donors (HAE), we demonstrated that MeV has a clear preference for basolateral entry (4). HAE differentiate into a pseudostratified columnar epithelium sheet comprised of ciliated, nonciliated, basal, and goblet cells. This model system is highly representative of the in vivo airways (5). MeV infection of HAE results in the formation of infectious centers that, unlike syncytia, retain intact plasma membranes (4, 6, 7). MeV-mediated infectious-center formation in HAE differs from that of most paramyxoviruses (7) and may result from the unique receptor specificity of the Morbillivirus genus (8-11). Indeed, we have shown that infectious-center formation in HAE results from direct cell-to-cell spread and is facilitated by the nectin-4/afadin complex (7). These studies highlight the importance of using an appropriate model system to study MeV entry and spread.How MeV eventually reaches the airway epithelium during a natural infection is less clear. Initially, the infection may be ferried through the epithelium by myeloid cells that sample the airway lumen and express the primary MeV receptor signaling lymphocyte a...