Human cytomegalovirus infection of M1 and M2 macrophages triggers inflammation and autologous T-cell proliferation

C Bayer, S Varani, L Wang, P Walther, S Zhou… - Journal of …, 2013 - Am Soc Microbiol
C Bayer, S Varani, L Wang, P Walther, S Zhou, S Straschewski, M Bachem…
Journal of virology, 2013Am Soc Microbiol
Macrophages (Mϕ) are first targets during human cytomegalovirus (HCMV) infection and are
thought to be crucial for viral persistence and dissemination. However, since Mϕ are also a
first line of defense and key modulators of the immune response, these cells are at the
crossroad between protection and viral pathogenesis. To date, the Mϕ-specific contribution
to the immune response against HCMV is still poorly understood. In view of the opposite
roles of M1 and M2 Mϕ during initiation and resolution of the immune response, we …
Abstract
Macrophages (Mϕ) are first targets during human cytomegalovirus (HCMV) infection and are thought to be crucial for viral persistence and dissemination. However, since Mϕ are also a first line of defense and key modulators of the immune response, these cells are at the crossroad between protection and viral pathogenesis. To date, the Mϕ-specific contribution to the immune response against HCMV is still poorly understood. In view of the opposite roles of M1 and M2 Mϕ during initiation and resolution of the immune response, we characterized the effects of HCMV infection on classically activated M1 Mϕ and alternatively activated M2 Mϕ. Although HCMV susceptibility was higher in M2 Mϕ, HCMV established a productive and persistent infection in both types of Mϕ. Upon HCMV encounter, both types of Mϕ acquired similar features of classical activation and secreted high levels of proinflammatory cytokines and chemokines. As a functional consequence, conditioned media obtained from HCMV-infected M1 and M2 Mϕ potently activated freshly isolated monocytes. Finally, compared to HCMV-infected monocyte-derived dendritic cells, infected M1 and M2 Mϕ were more efficient in stimulating proliferation of autologous T cells from HCMV-seropositive donors at early times (24 h) postinfection, while the Mϕ immunostimulatory properties were reduced, but not abrogated, at later times (72 h postinfection). In summary, our findings indicate that Mϕ preserve proper antigen presentation capacity upon HCMV infection while enhancing inflammation, thus suggesting that Mϕ play a role in the maintenance of the large HCMV-specific T-cell repertoire in seropositive individuals.
American Society for Microbiology