Dynamics of Human Cytomegalovirus Infection in CD34⁺Hematopoietic Cells and Derived Langerhans-Type Dendritic Cells

Abstract

Acquisition of human cytomegalovirus (CMV) usually occurs by contact between contaminated bodily fluids, such as urine and saliva, and host mucosal cells. Langerhans-type dendritic cells (LC) are the only type of immune cells found in the outermost layers of the oral mucosae, where they not only provide a first line of defense against CMV but can easily be targeted by orally administered vaccines, while their bone marrow resident progenitors are important sites of virus latency. In this work, we tracked the progress of infection in CD34 ؉ progenitor cells, immature LC (iLC), and mature LC (mLC) exposed to the clinicallike strain TB40-BAC4 or to the vaccine strain AD169varATCC, prior to their long-term maintenance under either immature or mature conditions. We show that the genomes of both strains are efficiently maintained in CD34؉ cells during their differentiation into iLC, although this requires the presence of larger amounts of input AD169varATCC DNA. Lipopolysaccharide-and CD40 ligand-induced maturation of iLC derived from latently infected progenitors was not associated with robust viral genome replication and progeny production, while maturation of directly infected iLC increased and prolonged expression of the viral immediate early proteins. While effective replication of viral genomes from both strains occurred only in mLC, both iLC and mLC produced viral progeny, suggesting that both types of LC may contribute to CMV horizontal transmission in vivo. H uman cytomegalovirus (CMV), a major cause of disease and death in immunocompromised and in congenitally infected individuals, is normally acquired by contact between infected bodily fluids such as urine and saliva and host mucosal surfaces, particularly those lining the oral and nasal cavities. IMPORTANCE Human CMV is usually acquired via the oral and nasal mucosae. Langerhans-type dendritic cells (LC) are the only type of immune cells found in the outermost layers of these tissues. Understanding how CMV interacts with LC and their hematopoietic progenitors is thus essential to develop innovative means of defense against this virus. Here we show that the genomes of a viru-From these peripheral sites, CMV is thought to reach the circulation and hence the bone marrow, where latency is established in myeloid cells, including CD34 ϩ hematopoietic progenitors (1-5). Reactivation from latency in the myeloid progeny of these cells is then believed to be the source of newly produced viral particles, which upon amplification in oral epithelial cells are released in the saliva and contribute to CMV horizontal transmission in vivo (6-8).Immature Langerhans-type dendritic cells (iLC) are the only professional antigen-presenting cells located in the outermost layers of the oral mucosa (9-14). As such, iLC are bound to be the first immune cells to encounter invading pathogens that access their hosts via the oral cavity, such as CMV. Upon contact with "danger" signals, iLC migrate toward the draining lymph nodes and begin the process of maturation, which culmina...

Human Cytomegalovirus miR-UL148D Facilitates Latent Viral Infection by Targeting Host Cell Immediate Early Response Gene 5

“…Previous work has demonstrated that HCMV can establish latency in primary hematopoietic cells [6, 9, 38–47] as well as in Kasumi-3 cells [48–50]. Here, we first determined whether the NR-1 clinical strain can achieve latent infection in CD34 + hematopoietic progenitor cells (HPCs) and Kasumi-3 cells.…”

Human Cytomegalovirus Latency: Approaching the Gordian Knot

“…A further complication to understanding the latent program has been the multitude of culture systems used to study latency. One broadly used yet nonstandardized approach with regards to media and cytokine composition is stromal-free culture systems with exogenously supplied cytokine cocktails designed to either maintain CD34 + phenotypes or promote differentiation down a particular lineage (37–41). While the ease of this approach is appealing, cytokine concentrations and combinations can result in aberrant differentiation or expansion of cells that have little physiological relevance to function in vivo .…”

“…The capacity of laboratory strains to establish latency is controversial. Previous reports (60, 72, 81) and well as more recent publications (37, 41, 68, 114) have carried out latency studies using laboratory-adapted strain (AD169 or Town var RIT 3 ) infection in HPCs (CD34 + or CD33 + GMPs). While few side-by-side comparisons have been made, the baseline replication of a laboratory-adapted strain (in the absence of a reactivation stimulus) is 10- to 100-fold greater than that of low-passage strains in THP-1 (68) and CD34 + HPCs (47), respectively.…”

Latent human cytomegalovirus enhances HIV-1 infection in CD34+ progenitor cells

“…Thus, HCMV can establish latent infection in PB-CD34 cells and appears to modulate immune molecules. 42,44 HCMV latently infected PB-CD34 cells are more susceptible to HIV-1 infection Because AIDS progresses faster in HCMV-seropositive individuals, we next examined if latently infected PB-CD34 cells can favor HIV-1 infection. HCMV or mock infection of PB-CD34 cells at day 5 PI were infected by HIV-1 NL4-3 (X4-tropic; X4-HIV).…”