SUMMARYHybridomas were developed that secreted antibodies to soybean mosaic (SMV), lettuce mosaic (LMV) viruses, and to maize dwarf mosaic (MDMV) virus, strains Ap and B. All hybridomas produced antibodies specific to the homologous virus except for one to LMV, which produced antibodies that reacted at a low level with SMV and MDMV. Monoclonal antibodies against SMV were used in a double-antibody sandwich radioimmunoassay. The assay using only one type of monoclonal antibody lacked sensitivity because, presumably, limited epitopes were available. Results obtained using two monoclonal antibodies that bound to different epitopes were comparable to those using polyclonal antibodies. A competitive radioimmunoassay, using a single monoclonal antibody, was developed to detect successfully SMV, LMV and MDMV.

SUMMARYTwo monoclonal antibodies (M-Ab) specific for different epitopes on particles of soybean mosaic virus (SMV) were used in a double-antibody sandwich ELISA (M-Ab ELISA). The non-isotopic immunoassay, which used a biotinylated second antibody and an avidin-alkaline phosphatase detection system to detect SMV in soybean seed extracts, was compared with a polyclonal antibody-based solid-phase radioimmunoassay (SPRIA). M-Ab ELISA detected less than l0 ng of SMV/ml and was more sensitive than the SPRIA which detected 25 ng SMV/ml. Furthermore, M-Ab. ELISA required less than 36 h for seed sample assays and only 5.5 h for assays involving purified virus, whereas SPRIA required 3 or 4 days. When seeds from 33 field plots, in which 0~, 30~ and 50~o of the soybean plants had been inoculated with SMV, were assayed by both systems, results of the two tests correlated for 31 of 33 (94~) seed samples. This suggests that dual-site biotin-avidin M-Ab ELISA systems have potential utility for routine screening of seed samples.

We have demonstrated a postural effect on cardiac repolarization independent of heart rate using two individualized correction methods, as well as QTc-F and QTc-LR, and the bin method. Characterization of postural differences in QT/QTc (other than QTc-B) may provide a safe and inexpensive physiological control to validate the ECG methodology used in clinical trials to assess potential drug-induced QT interval changes.

The novel coronavirus SARS-CoV-2 was identified as the causative agent of the ongoing pandemic COVID 19. COVID-19-associated deaths are mainly attributed to severe pneumonia and respiratory failure. Recent work demonstrated that SARS-CoV-2 binds to angiotensin converting enzyme 2 (ACE2) in the lung. To better understand ACE2 abundance and expression patterns in the lung we interrogated our in-house single-cell RNA-sequencing dataset containing 70,085 EPCAM+ lung epithelial cells from paired normal and lung adenocarcinoma tissues. Transcriptomic analysis revealed a diverse repertoire of airway lineages that included alveolar type I and II, bronchioalveolar, club/secretory, quiescent and proliferating basal, ciliated and malignant cells as well as rare populations such as ionocytes. While the fraction of lung epithelial cells expressing ACE2 was low (1.7% overall), alveolar type II (AT2, 2.2% ACE2+) cells exhibited highest levels of ACE2 expression among all cell subsets. Further analysis of the AT2 compartment (n = 27,235 cells) revealed a number of genes co-expressed with ACE2 that are important for lung pathobiology including those associated with chronic obstructive pulmonary disease (COPD; HHIP), pneumonia and infection (FGG and C4BPA) as well as malarial/bacterial (CD36) and viral (DMBT1) scavenging which, for the most part, were increased in smoker versus light or non-smoker cells. Notably, DMBT1 was highly expressed in AT2 cells relative to other lung epithelial subsets and its expression positively correlated with ACE2.We describe a population of ACE2-positive AT2 cells that co-express pathogen (including viral) receptors (e.g. DMBT1) with crucial roles in host defense thus comprising plausible phenotypic targets for treatment of COVID-19.

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