Measles virus blind to its epithelial cell receptor remains virulent in rhesus monkeys but cannot cross the airway epithelium and is not shed
Vincent H.J. Leonard, … , Michael B. McChesney, Roberto Cattaneo
Vincent H.J. Leonard, … , Michael B. McChesney, Roberto Cattaneo
Published June 20, 2008
Citation Information: J Clin Invest. 2008;118(7):2448-2458. https://doi.org/10.1172/JCI35454.
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Research Article

Measles virus blind to its epithelial cell receptor remains virulent in rhesus monkeys but cannot cross the airway epithelium and is not shed

Abstract

The current model of measles virus (MV) pathogenesis implies that apical infection of airway epithelial cells precedes systemic spread. An alternative model suggests that primarily infected lymphatic cells carry MV to the basolateral surface of epithelial cells, supporting MV shedding into the airway lumen and contagion. This model predicts that a mutant MV, unable to enter cells through the unidentified epithelial cell receptor (EpR), would remain virulent but not be shed. To test this model, we identified residues of the MV attachment protein sustaining EpR-mediated cell fusion. These nonpolar or uncharged polar residues defined an area located near the binding site of the signaling lymphocytic activation molecule (SLAM), the receptor for MV on lymphatic cells. We then generated an EpR-blind virus maintaining SLAM-dependent cell entry and inoculated rhesus monkeys intranasally. Hosts infected with the selectively EpR-blind MV developed rash and anorexia while averaging slightly lower viremia than hosts infected with wild-type MV but did not shed virus in the airways. The mechanism restricting shedding was characterized using primary well-differentiated human airway epithelial cells. Wild-type MV infected columnar epithelial cells bearing tight junctions only when applied basolaterally, while the EpR-blind virus did not infect these cells. Thus, EpR is probably a basolateral protein, and infection of the airway epithelium is not essential for systemic spread and virulence of MV.

Authors

Vincent H.J. Leonard, Patrick L. Sinn, Gregory Hodge, Tanner Miest, Patricia Devaux, Numan Oezguen, Werner Braun, Paul B. McCray Jr., Michael B. McChesney, Roberto Cattaneo

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Figure 2

H protein residues relevant for EpR-dependent fusion.

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H protein residues relevant for EpR-dependent fusion. (A) Amino acid seq...
(A) Amino acid sequence 382–617 of the wild-type MV H protein. Homology of MV to CDV and rinderpest virus (RV) H proteins (NCBI protein sequence database accession numbers NP_056923, AAD18008, and AAD25093) is indicated as follows: asterisks (*), identical residues; colons (:), conserved residues; periods (.), semiconserved residues. The letters above the alignment denote mutants produced as single (individual letter) or double substitutions (contiguous residues; only the double mutant 442–444 is not contiguous) to alanine (A, polar residues) or serine (S, nonpolar residues). The H protein secondary structure is shown below the MV H sequence, with arrows indicating β-strands and boxes indicating α-helixes. Cyan, pink, blue, and green indicate the predicted propeller sheets 3–6, respectively. (B) Fusion efficiency of the H protein mutants in Vero/hSLAM or H358 cells. Each mutant is represented as a rectangle located at the appropriate position. Filled rectangles indicate full fusion activity; white rectangles, no fusion activity; partially filled rectangles, intermediate fusion levels. Mutants with unaltered SLAM-mediated fusion and no EpR-mediated fusion are indicated by asterisks. (C) Top view of the H protein crystal structure (25) in a ribbon plot (left) and space-filling (right) representation. The structure is color coded as in A; β-sheets 1 and 2 are indicated in yellow and red, respectively. Red: residues whose mutation abolished EpR-dependent fusion while completely retaining SLAM-dependent fusion; yellow: residues whose mutation abolished EpR-dependent fusion while strongly or moderately impairing SLAM-dependent fusion function; purple: residues important for SLAM-induced fusion.