T-helper Cell-Mediated Proliferation and Cytokine Responses against Recombinant Merkel Cell Polyomavirus-Like Particles

The newly discovered Merkel Cell Polyomavirus (MCPyV) resides in approximately 80% of Merkel cell carcinomas (MCC). Causal role of MCPyV for this rare and aggressive skin cancer is suggested by monoclonal integration and truncation of large T (LT) viral antigen in MCC cells. The mutated MCPyV has recently been found in highly purified leukemic cells from patients with chronic lymphocytic leukemia (CLL), suggesting a pathogenic role also in CLL. About 50–80% of adults display MCPyVspecific antibodies. The humoral immunity does not protect against the development of MCC, as neutralizing MCPyV antibodies occur in higher levels among MCC patients than healthy controls. Impaired T-cell immunity has been linked with aggressive MCC behavior. Therefore, cellular immunity appears to be important in MCPyV infection surveillance. In order to elucidate the role of MCPyV-specific Th-cell immunity, peripheral blood mononuclear cells (PBMC) of healthy adults were stimulated with MCPyV VP1 virus-like particles (VLPs), using human bocavirus (HBoV) VLPs and Candida albicans antigen as positive controls. Proliferation, IFN-c, IL-13 and IL-10 responses were examined in 15 MCPyV-seropositive and 15 seronegative volunteers. With the MCPyV antigen, significantly stronger Th-cell responses were found in MCPyVseropositive than MCPyV-seronegative subjects, whereas with the control antigens, the responses were statistically similar. The most readily detectable cytokine was IFN-c. The MCPyV antigen tended to induce stronger IFN-c responses than HBoV VLP antigen. Taken together, MCPyV-specific Th-cells elicit vigorous IFN-c responses. IFN-c being a cytokine with major antiviral and tumor suppressing functions, Th-cells are suggested to be important mediators of MCPyV-specific immune surveillance.Peer reviewe

Trichodysplasia spinulosa-Associated Polyomavirus (TSV) and Merkel Cell Polyomavirus: Correlation between Humoral and Cellular Immunity Stronger with TSV

WOS:000309554700071Peer reviewe

Erythroid Progenitor Cells Expanded from Peripheral Blood without Mobilization or Preselection: Molecular Characteristics and Functional Competence

Peer reviewe

Epidemiology of two human protoparvoviruses, bufavirus and tusavirus

Two human parvoviruses were recently discovered by metagenomics in Africa, bufavirus (BuV) in 2012 and tusavirus (TuV) in 2014. These viruses have been studied exclusively by PCR in stool and detected only in patients with diarrhoea, although at low prevalence. Three genotypes of BuV have been identified. We detected, by in-house EIA, BuV1-3 IgG antibodies in 7/228 children (3.1%) and 10/180 adults (5.6%), whereas TuV IgG was found in one child (0.4%). All children and 91% of the adults were Finnish, yet interestingly 3/6 adults of Indian origin were BuV-IgG positive. By competition EIA, no cross-reactivity between the BuVs was detected, indicating that the BuV genotypes represent distinct serotypes. Furthermore, we analysed by BuV qPCR stool and nasal swab samples from 955 children with gastroenteritis, respiratory illness, or both, and found BuV DNA in three stools (0.3%) and for the first time in a nasal swab (0.1%). This is the first study documenting the presence of BuV and TuV antibodies in humans. Although the seroprevalences of both viruses were low in Finland, our results indicate that BuV infections might be widespread in Asia. The BuV-specific humoral immune responses appeared to be strong and long-lasting, pointing to systemic infection in humans.Peer reviewe

Expansion of EPC directly from peripheral blood.

<p>Rows 1–3: Fold increase of cells expressing erythroid markers CD36, CD71 and glycophorin on day 10 of culture; the values are based on CD34⁺ fraction (%) on day 0 (0.22%) and on the expansion factor of 150, expressed as an average fold increase throughout the culture (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009496#pone-0009496-g001" target="_blank">Fig. 1C</a>). The first column indicates the values obtained during the flow cytometry analysis of the three markers (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009496#pone-0009496-g002" target="_blank">Fig. 2B</a>).</p><p>Row 4: Fold increase of B19 virus permissive cells (row 4); the values are based on CD34⁺ fraction (%) on day 0 (0.22%) and on the expansion factor of 150, expressed as an average fold increase throughout the culture (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009496#pone-0009496-g001" target="_blank">Fig. 1C</a>). The first column indicates the percentage of cells expressing capsid proteins (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009496#pone-0009496-g004" target="_blank">Fig. 4A</a>).</p><p>EPC represents erythroid progenitor cells.</p

Phenotypic changes during cell culture from peripheral blood.

<p>(A) PBMC were isolated and cultured with growth factors favouring erythroid expansion and observed with an optical inverted microscope (Olympus IX71). Photographs were taken at 10× magnification with a Hamamatsu C8484-05G digital camera. (B) PBMC cultured as in panel A, but without the growth factors. (C) Numbers of cells cultured with or without the growth factors. Error bars indicate standard deviation.</p