DNA and seroprevalence study of MW and STL polyomaviruses.

The clinical importance and the pathogenesis of the MW and STL polyomaviruses (PyVs) remain unclear. Our aim was to study the seroprevalence of MWPyV and STLPyV, and to examine the prevalence of viral DNA in respiratory samples and secondary lymphoid tissues. In total, 618 serum samples (0.8-90 years) were analyzed for seroprevalence. For the DNA prevalence study, 146 patients (2.5-37.5 years) were sampled for adenoids (n = 100), tonsils (n = 100), throat swabs (n = 146), and middle ear discharge (n = 15) in study Group 1. In Group 2, we analyzed 1130 nasopharyngeal samples from patients (0.8-92 years) tested for SARS-CoV-2 infection. The adult seropositivity was 54% for MWPyV, and 81.2% for STLPyV. Both seroprevalence rates increased with age; however, the majority of STLPyV primary infections appeared to occur in children. MWPyV was detected in 2.7%-4.9% of respiratory samples, and in a middle ear discharge. STLPyV DNA prevalence was 1.4%-3.4% in swab samples, and it was detected in an adenoid and in a middle ear discharge. The prevalence of both viruses was significantly higher in the children. Noncoding control regions of both viruses and the complete genomes of STLPyV were sequenced. MWPyV and STLPyV are widespread viruses, and respiratory transmission may be possible.

Artificial Intelligence-Based Counting Algorithm Enables Accurate and Detailed Analysis of the Broad Spectrum of Spot Morphologies Observed in Antigen-Specific B-Cell ELISPOT and FluoroSpot Assays.

Antigen-specific B-cell ELISPOT and multicolor FluoroSpot assays, in which the membrane-bound antigen itself serves as the capture reagent for the antibodies that B cells secrete, inherently result in a broad range of spot sizes and intensities. The diversity of secretory footprint morphologies reflects the polyclonal nature of the antigen-specific B cell repertoire, with individual antibody-secreting B cells in the test sample differing in their affinity for the antigen, fine epitope specificity, and activation/secretion kinetics. To account for these heterogeneous spot morphologies, and to eliminate the need for setting up subjective counting parameters well-by-well, CTL introduces here its cutting-edge deep learning-based IntelliCount™ algorithm within the ImmunoSpot® Studio Software Suite, which integrates CTL's proprietary deep neural network. Here, we report detailed analyses of spots with a broad range of morphologies that were challenging to analyze using standard parameter-based counting approaches. IntelliCount™, especially in conjunction with high dynamic range (HDR) imaging, permits the extraction of accurate, high-content information of such spots, as required for assessing the affinity distribution of an antigen-specific memory B-cell repertoire ex vivo. IntelliCount™ also extends the range in which the number of antibody-secreting B cells plated and spots detected follow a linear function; that is, in which the frequencies of antigen-specific B cells can be accurately established. Introducing high-content analysis of secretory footprints in B-cell ELISPOT/FluoroSpot assays, therefore, fundamentally enhances the depth in which an antigen-specific B-cell repertoire can be studied using freshly isolated or cryopreserved primary cell material, such as peripheral blood mononuclear cells.