Monoclonal antibodies targeting nonstructural viral antigens can activate ADCC against human cytomegalovirus
Virginia-Maria Vlahava, … , Eddie C.Y. Wang, Richard J. Stanton
Virginia-Maria Vlahava, … , Eddie C.Y. Wang, Richard J. Stanton
Published February 15, 2021
Citation Information: J Clin Invest. 2021;131(4):e139296. https://doi.org/10.1172/JCI139296.
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Research Article Immunology Virology

Monoclonal antibodies targeting nonstructural viral antigens can activate ADCC against human cytomegalovirus

Abstract

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that causes severe disease following congenital infection and in immunocompromised individuals. No vaccines are licensed, and there are limited treatment options. We now show that the addition of anti-HCMV antibodies (Abs) can activate NK cells prior to the production of new virions, through Ab-dependent cellular cytotoxicity (ADCC), overcoming viral immune evasins. Quantitative proteomics defined the most abundant HCMV proteins on the cell surface, and we screened these targets to identify the viral antigens responsible for activating ADCC. Surprisingly, these were not structural glycoproteins; instead, the immune evasins US28, RL11, UL5, UL141, and UL16 each individually primed ADCC. We isolated human monoclonal Abs (mAbs) specific for UL16 or UL141 from a seropositive donor and optimized them for ADCC. Cloned Abs targeting a single antigen (UL141) were sufficient to mediate ADCC against HCMV-infected cells, even at low concentrations. Collectively, these findings validated an unbiased methodological approach to the identification of immunodominant viral antigens, providing a pathway toward an immunotherapeutic strategy against HCMV and potentially other pathogens.

Authors

Virginia-Maria Vlahava, Isa Murrell, Lihui Zhuang, Rebecca J. Aicheler, Eleanor Lim, Kelly L. Miners, Kristin Ladell, Nicolás M. Suárez, David A. Price, Andrew J. Davison, Gavin W.G. Wilkinson, Mark R. Wills, Michael P. Weekes, Eddie C.Y. Wang, Richard J. Stanton

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Figure 3

Anti-UL16 and anti-UL141 mAbs can be isolated and cloned from seropositive donors.

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Anti-UL16 and anti-UL141 mAbs can be isolated and cloned from seropositi...
(A) IgG+ B cells from a HCMV-seropositive donor were stained with fluorescently labeled UL16 or UL141 proteins to sort B cells expressing specific mAbs. FSC, forward scatter; SSC, side scatter. (B and C) HFFF-hCARs were transduced with RAds expressing UL141 or UL16 lacking their ER retention signals. Cells were stained with the cloned human anti-UL141 or anti-UL16 mAbs and analyzed by flow cytometry. Cytotect was used as a positive control. (D) HFFF-hCARs were transduced with RAds lacking a transgene, or RAds expressing wild-type forms of UL141 or UL16. Samples were lysed, separated by SDS-PAGE, and analyzed by immunoblotting using human anti-UL16 or anti-UL141 mAbs. As a positive control, the UL16 lysate was stained with an anti-V5 Ab, and the UL141 lysate was stained with a murine anti-UL141 Ab. (E and F) HFFF-hCARs were transduced with RAds expressing wild-type forms of UL141 or UL16. Forty-eight hours later, they were stained with human anti-UL141 or anti-UL16 mAbs or Cytotect and then analyzed by flow cytometry.