Coxsackievirus B3 elicits a sex-specific CD8+ T cell response which protects female mice.

Sex is a significant contributor to the outcome of human infections. Males are frequently more susceptible to viral, bacterial, and fungal infections, often attributed to weaker immune responses. In contrast, a heightened immune response in females enables better pathogen elimination but leaves females more predisposed to autoimmune diseases. Unfortunately, the underlying basis for sex-specific immune responses remains poorly understood. Here, we show a sex difference in the CD8+ T cell response to an enteric virus, Coxsackievirus B3 (CVB3). We found that CVB3 induced expansion of CD8+ T cells in female mice but not in male mice. CVB3 also increased the proportion and number of CD11ahiCD62Llo CD8+ T cells in female mice, indicative of activation. This response was independent of the inoculation route and type I interferon. Using a recombinant CVB3 virus expressing a model CD8+ T cell epitope, we found that the expansion of CD8+ T cells in females is viral-specific and not due to bystander activation. Finally, the depletion of CD8+ T cells, prior to infection, led to enhanced mortality, indicating that CD8+ T cells are protective against CVB3 in female mice. These data demonstrate that CVB3 induces a CD8+ T cell response in female mice and highlight the importance of sex-specific immune responses to viral pathogens.

Testosterone Promotes the Intestinal Replication and Dissemination of Coxsackievirus B3 in an Oral Inoculation Mouse Model.

Enteroviruses initiate infection in the gastrointestinal tract, and sex is often a biological variable that impacts pathogenesis. Previous data suggest that sex hormones can influence the intestinal replication of Coxsackievirus B3 (CVB3), an enterovirus in the Picornaviridae family. However, the specific sex hormone(s) that regulates intestinal CVB3 replication is poorly understood. To determine if testosterone promotes intestinal CVB3 replication, we orally inoculated male and female Ifnar-/- mice that were treated with either placebo or testosterone-filled capsules. Following oral inoculation, we found that the testosterone-treated male and female mice shed significantly more CVB3 in their feces than did the placebo-treated mice, indicating that testosterone enhances intestinal replication. Similarly, testosterone enhanced viral dissemination in both sexes, as we observed higher viral loads in peripheral tissues following infection. Further, the testosterone-treated male mice also had a higher mortality rate than did the testosterone-depleted male mice. Finally, we observed that testosterone significantly affected the immune response to CVB3. We found that testosterone broadly increased proinflammatory cytokines and chemokines while decreasing the number of splenic B cells and dendritic cells following CVB3 infection. Moreover, while testosterone did not affect the early CD4 T cell response to CVB3, testosterone reduced the activation of CD8 T cells. These data indicate that testosterone can promote intestinal CVB3 replication and dissemination while also impacting the subsequent viral immune response. IMPORTANCE Biological sex plays a significant role in the outcomes of various infections and diseases. The impact of sex hormones on the intestinal replication and dissemination of Coxsackievirus B3 remains poorly understood. Using an oral inoculation model, we found that testosterone enhances CVB3 shedding and dissemination in male and female mice. Further, testosterone can alter the immune response to CVB3. This work highlights the role of testosterone in CVB3 pathogenesis and suggests that sex hormones can impact the replication and dissemination of enteric viruses.

Specific Bacterial Cell Wall Components Influence the Stability of Coxsackievirus B3.

Enteric viruses infect the mammalian gastrointestinal tract and lead to significant morbidity and mortality worldwide. Data indicate that enteric viruses can utilize intestinal bacteria to promote viral replication and pathogenesis. However, the precise interactions between enteric viruses and bacteria are unknown. Here, we examined the interaction between bacteria and coxsackievirus B3, an enteric virus from the picornavirus family. We found that bacteria enhance the infectivity of coxsackievirus B3 (CVB3) in vitro. Notably, specific bacteria are required, as Gram-negative Salmonella enterica, but not Escherichia coli, enhanced CVB3 infectivity and stability. Investigating the cell wall components of both S. enterica and E. coli revealed that structures in the O-antigen or core of lipopolysaccharide, a major component of the Gram-negative bacterial cell wall, were required for S. enterica to enhance CVB3. To determine if these requirements were necessary for similar enteric viruses, we investigated if S. enterica and E. coli enhanced infectivity of poliovirus, another enteric virus in the picornavirus family. We found that while E. coli did not enhance the infectivity of CVB3, E. coli enhanced poliovirus infectivity. Overall, these data indicate that distinct bacteria enhance CVB3 infectivity and stability, and specific enteric viruses may have differing requirements for their interactions with specific bacterial species. IMPORTANCE Previous data indicate that several enteric viruses utilize bacteria to promote intestinal infection and viral stability. Here, we show that specific bacteria and bacterial cell wall components are required to enhance infectivity and stability of coxsackievirus B3 in vitro. These requirements are likely enteric virus specific, as the bacteria for CVB3 differ from poliovirus, a closely related virus. Therefore, these data indicate that specific bacteria and their cell wall components dictate the interaction with various enteric viruses in distinct mechanisms.

Functional outcomes and complications following combined locking plate and tunneled suspensory device fixation of lateral-end clavicle nonunions.

BACKGROUND: Lateral-end clavicle fractures have a high rate of nonunion that can lead to ongoing pain and loss of shoulder function. The operative techniques used to manage such nonunions vary, and data on postoperative functional outcomes and complications are limited, with no consensus on the optimal surgical treatment. Our goal was to present the outcomes and complications of a new indication for combined locking plate and tunneled suspensory device fixation in the operative management of lateral-end clavicle fracture nonunions. METHODS: A consecutive series of 38 patients (mean age, 46 years; age range, 24-76 years) with symptomatic lateral-end clavicle nonunions underwent operative treatment using a new technique of anatomic locking plate combined with open reduction and tunneled suspensory device fixation between March 2011 and September 2019. Patients were assessed at a minimum of 1-year postoperative follow-up for patient-reported outcomes, range of motion, and complications. RESULTS: All patients (N = 38) achieved bony union after operative treatment. Functional outcomes were available for 34 patients. The mean Oxford Shoulder Score was 44 (standard error of the mean [SEM], 0.7), and the mean EQ-5D-3L index score was 0.784 (SEM, 0.033). Mean forward flexion was 176° (SEM, 3°); mean extension, 53° (SEM, 3°); mean combined abduction, 171° (SEM, 4°); mean internal rotation, 57° (SEM, 2°); and mean external rotation, 83° (SEM, 4°). In 2 patients (5.3%), metalwork (plate) removal was performed owing to plate prominence. CONCLUSIONS: Nonunion of lateral-end clavicle fractures can be effectively managed by combined plate and open reduction-tunneled suspensory device fixation. Excellent union rates and functional outcomes, as well as low complication rates, can be expected. The most significant complication of this technique is subsequent metalwork removal.

Traumatic Glenohumeral Dislocation in Pediatric Patients Is Associated With a High Risk of Recurrent Instability.

BACKGROUND: The natural history of traumatic glenohumeral dislocation is well-established in young adults, but it is less clear in pediatric patients. We aimed to determine the rate of recurrent instability and medium-term functional outcome following shoulder dislocation in patients aged 14 years or younger. METHODS: All patients aged 14 years or younger who sustained a glenohumeral dislocation from 2008 to 2019 presenting to our regional health-board were identified. Patients who had subluxations associated with generalized laxity were excluded. Data was collected regarding further dislocations, stabilization surgery, sporting activity and patient-reported outcomes using the Western Ontario Shoulder Instability (WOSI) Index and Quick Disabilities of the Arm, Shoulder, and Hand score. RESULTS: Forty-one patients with a radiologically confirmed traumatic glenohumeral dislocation were suitable for study inclusion [mean age at injury 12.3 y (range: 7.2 to 14.0 y), male sex 29 (70.7%), median 7.9 y follow-up]. The incidence rate of pediatric glenohumeral dislocation was 2.5 cases per 100,000 population (aged 0 to 14 y) per year. Recurrent dislocation occurred in 43.9% (n=18/41) at a median time of 14.7 months postinjury (range: 1 to 54 mo). Skeletal maturity was associated with significantly higher proportion of recurrent instability (immature 6/24 vs. mature 12/17, P=0.01). One in 5 patients required surgical intervention for recurrent instability [mean 8 (range: 1 to 14) dislocations before surgery]. Twenty-eight patients had completed outcome questionnaires. The median modified WOSI score was 87.1% [270 (interquartile range: 65 to 795)] and the median Quick Disabilities of the Arm, Shoulder, and Hand score was 3.4 (interquartile range: 0 to 9.7). Recurrent shoulder instability was significantly associated with poorer WOSI score (unstable 71.4% vs. stable 94.3%, 95% confidence interval of the difference 6.2-36.9, P=0.04). CONCLUSIONS: Traumatic glenohumeral dislocation in patients aged 14 years or younger occurs rarely but is not a benign event. One in 2 patients experienced recurrent dislocation and 1 in 5 ultimately underwent surgical stabilization. LEVEL OF EVIDENCE: Level IV.

Related Enteric Viruses Have Different Requirements for Host Microbiota in Mice.

Accumulating evidence suggests that intestinal bacteria promote enteric virus infection in mice. For example, previous work demonstrated that antibiotic treatment of mice prior to oral infection with poliovirus reduced viral replication and pathogenesis. Here, we examined the effect of antibiotic treatment on infection with coxsackievirus B3 (CVB3), a picornavirus closely related to poliovirus. We treated mice with a mixture of five antibiotics to deplete host microbiota and examined CVB3 replication and pathogenesis following oral inoculation. We found that, as seen with poliovirus, CVB3 shedding and pathogenesis were reduced in antibiotic-treated mice. While treatment with just two antibiotics, vancomycin and ampicillin, was sufficient to reduce CVB3 replication and pathogenesis, this treatment had no effect on poliovirus. The quantity and composition of bacterial communities were altered by treatment with the five-antibiotic cocktail and by treatment with vancomycin and ampicillin. To determine whether more-subtle changes in bacterial populations impact viral replication, we examined viral infection in mice treated with milder antibiotic regimens. Mice treated with one-tenth the standard concentration of the normal antibiotic cocktail supported replication of poliovirus but not CVB3. Importantly, a single dose of one antibiotic, streptomycin, was sufficient to reduce CVB3 shedding and pathogenesis while having no effect on poliovirus shedding and pathogenesis. Overall, replication and pathogenesis of CVB3 are more sensitive to antibiotic treatment than poliovirus, indicating that closely related viruses may differ with respect to their reliance on microbiota.IMPORTANCE Recent data indicate that intestinal bacteria promote intestinal infection of several enteric viruses. Here, we show that coxsackievirus, an enteric virus in the picornavirus family, also relies on microbiota for intestinal replication and pathogenesis. Relatively minor depletion of the microbiota was sufficient to decrease coxsackievirus infection, while poliovirus infection was unaffected. Surprisingly, a single dose of one antibiotic was sufficient to reduce coxsackievirus infection. Therefore, these data indicate that closely related viruses may differ with respect to their reliance on microbiota.

Sex-Dependent Intestinal Replication of an Enteric Virus.

Coxsackievirus is an enteric virus that initiates infection in the gastrointestinal tract before disseminating to peripheral tissues to cause disease, but intestinal factors that influence viral replication are understudied. Furthermore, a sex bias for severe sequelae from coxsackievirus infections has been observed in humans. While mouse models mimicking human pathogenesis have been well characterized, many of these experiments use intraperitoneal injection of coxsackievirus to infect mice, bypassing the intestine. In light of recent studies identifying intestinal factors, such as the microbiota, that alter enteric viral replication, we sought to investigate coxsackievirus replication within the intestine. Here, we orally infected mice with coxsackievirus B3 (CVB3) and found that CVB3 replication in the intestine is sex dependent. CVB3 replicated efficiently in the intestine of male mice but not female mice. Additionally, we found that the type I interferon response and sex hormones can alter both viral replication and lethality. Overall, these data suggest that sex and the immune response play a vital role in CVB3 replication in the intestine and should be considered in light of the sex bias observed in human disease.IMPORTANCE Sex bias in severe sequelae from enteric viral infections has been observed. Since viruses have evolved to achieve optimal levels of fitness in their environmental niches, it is imperative to study viruses at the site of initial replication. Here, we used an oral inoculation system for CVB3, which follows the natural route of infection in the gastrointestinal tract. We found that sex can influence the replication of CVB3 in the intestine. Additionally, the type I interferon response and sex hormones alter both CVB3 intestinal replication and lethality. Overall this work highlights the fact that sex should be considered in investigations of enteric viral replication and pathogenesis.

Homologous recombination in E3 genes of human adenovirus species D.

Genes within the E3 transcription unit of human adenoviruses modulate host immune responses to infection. A comprehensive genomics and bioinformatics analysis of the E3 transcription unit for 38 viruses within human adenovirus species D (HAdV-D) revealed distinct and surprising patterns of homologous recombination. Homologous recombination was identified in open reading frames for E3 CR1α, CR1ß, and CR1γ, similar to that previously observed with genes encoding the three major structural capsid proteins, the penton base, hexon, and fiber.

Determination of the cycle threshold value of the Xpert Xpress SARS-CoV-2/Flu/RSV test that corresponds to the presence of infectious SARS-CoV-2 in anterior nasal swabs.

Despite having high analytical sensitivities and specificities, qualitative SARS-CoV-2 nucleic acid amplification tests (NAATs) cannot distinguish infectious from non-infectious virus in clinical samples. In this study, we determined the highest cycle threshold (Ct) value of the SARS-CoV-2 targets in the Xpert Xpress SARS-CoV-2/Flu/RSV (Xpert 4plex) test that corresponded to the presence of detectable infectious SARS-CoV-2 in anterior nasal swab samples. A total of 111 individuals with nasopharyngeal swab specimens that were initially tested by the Xpert Xpress SARS-CoV-2 test were enrolled. A healthcare worker subsequently collected anterior nasal swabs from all SARS-CoV-2-positive individuals, and those specimens were tested by the Xpert 4plex test, viral culture, and laboratory-developed assays for SARS-CoV-2 replication intermediates. SARS-CoV-2 Ct values from the Xpert 4plex test were correlated with data from culture and replication intermediate testing to determine the Xpert 4plex assay Ct value that corresponded to the presence of infectious virus. Ninety-eight of the 111 (88.3%) individuals initially tested positive by the Xpert Xpress SARS-CoV-2 test. An anterior nasal swab specimen collected from positive individuals a median of 2 days later (range, 0-9 days) tested positive for SARS-CoV-2 by the Xpert 4plex test in 39.8% (39/98) of cases. Of these samples, 13 (33.3%) were considered to contain infectious virus based on the presence of cultivable virus and replication intermediates, and the highest Ct value observed for the Xpert 4plex test in these instances was 26.3. Specimens that yielded Ct values of ≤26.3 when tested by the Xpert 4plex test had a likelihood of containing infectious SARS-CoV-2; however, no infectious virus was detected in specimens with higher Ct values.IMPORTANCEUnderstanding the correlation between real-time PCR test results and the presence of infectious SARS-CoV-2 may be useful for informing patient management and workforce return-to-work or -duty. Further studies in different patient populations are needed to correlate Ct values or other biomarkers of viral replication along with the presence of infectious virus in clinical samples.

Overreliance on the hexon gene, leading to misclassification of human adenoviruses.

The genome of human adenovirus (HAdV) D30 was sequenced in depth. Sequence assembly and analysis revealed two distinct viral sequences with identical hexon genes, which were the same as the one previously reported for HAdV-D30. However, one of the two viruses was found to be a recombinant of HAdV-D29. Exclusive reliance on serum neutralization can lead to mischaracterization of adenoviruses and miss coinfections. Whole-genome sequencing remains the gold standard for proper classification of HAdVs.

Maintaining a healthy balance: How endothelial AHR signaling helps regulate tissue homeostasis and protection.

Two recent Nature papers reveal that aryl hydrocarbon receptor (AHR) signaling in endothelial cells plays a vital role in cellular quiescence and tissue homeostasis. These studies highlight the important role endothelial cells of the vasculature system play in maintaining a healthy barrier that limits inflammation and protects against invading pathogens.

Viral-Bacterial Interactions That Impact Viral Thermostability and Transmission.

Enteric viruses are significant human pathogens that commonly cause foodborne illnesses worldwide. These viruses initiate infection in the gastrointestinal tract, home to a diverse population of intestinal bacteria. In a novel paradigm, data indicate that enteric viruses utilize intestinal bacteria to promote viral replication and pathogenesis. While mechanisms underlying these observations are not fully understood, data suggest that some enteric viruses bind directly to bacteria, stabilizing the virion to retain infectivity. Here, we discuss the current knowledge of these viral-bacterial interactions and examine the impact of these interactions on viral transmission.

A viral-specific CD4 + T cell response protects female mice from Coxsackievirus B3 infection.

Biological sex plays an integral role in the immune response to various pathogens. The underlying basis for these sex differences is still not well defined. Here, we show that Coxsackievirus B3 (CVB3) induces a viral-specific CD4 + T cell response that can protect female mice from mortality. We found that CVB3 can induce expansion of CD62L lo CD4 + T cells in the mesenteric lymph node and spleen of female but not male mice as early as 5 days post-inoculation, indicative of activation. Using a recombinant CVB3 virus expressing a model CD4 + T cell epitope, we found that this response is due to viral antigen and not bystander activation. Finally, the depletion of CD4 + T cells before infection increased mortality in female mice, indicating that CD4 + T cells play a protective role against CVB3 in our model. Overall, these data demonstrated that CVB3 can induce an early CD4 response in female but not male mice and further emphasize how sex differences in immune responses to pathogens affect disease outcomes.

A viral-specific CD4+ T cell response protects female mice from Coxsackievirus B3 infection.

Background: Biological sex plays an integral role in the immune response to various pathogens. The underlying basis for these sex differences is still not well defined. Here, we show that Coxsackievirus B3 (CVB3) induces a viral-specific CD4+ T cell response that can protect female mice from mortality. Methods: We inoculated C57BL/6 Ifnar-/- mice with CVB3. We investigated the T cell response in the spleen and mesenteric lymph nodes in male and female mice following infection. Results: We found that CVB3 can induce expansion of CD62Llo CD4+ T cells in the mesenteric lymph node and spleen of female but not male mice as early as 5 days post-inoculation, indicative of activation. Using a recombinant CVB3 virus expressing a model CD4+ T cell epitope, we found that this response is due to viral antigen and not bystander activation. Finally, the depletion of CD4+ T cells before infection increased mortality in female mice, indicating that CD4+ T cells play a protective role against CVB3 in our model. Conclusions: Overall, these data demonstrated that CVB3 can induce an early CD4 response in female but not male mice and further emphasize how sex differences in immune responses to pathogens affect disease.

Standardization of SARS-CoV-2 Cycle Threshold Values: Multisite Investigation Evaluating Viral Quantitation across Multiple Commercial COVID-19 Detection Platforms.

The demand for testing during the coronavirus disease 2019 (COVID-19) pandemic has resulted in the production of several different commercial platforms and laboratory-developed assays for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This has created several challenges, including, but not limited to, the standardization of diagnostic testing, utilization of cycle threshold (CT) values for quantitation and clinical interpretation, and data harmonization. Using reference standards consisting of a linear range of SARS-CoV-2 concentrations quantitated by viral culture-based methods and droplet digital PCR, we investigated the commutability and standardization of SARS-CoV-2 quantitation across different laboratories in the United States. We assessed SARS-CoV-2 CT values generated on multiple reverse transcription-PCR (RT-PCR) platforms and analyzed PCR efficiencies, linearity, gene targets, and CT value agreement. Our results demonstrate the inappropriateness of using SARS-CoV-2 CT values without established standards for viral quantitation. Further, we emphasize the importance of using reference standards and controls validated to independent assays, to compare results across different testing platforms and move toward better harmonization of COVID-19 quantitative test results. IMPORTANCE From the onset of the COVID-19 pandemic, the demand for SARS-CoV-2 testing has resulted in an explosion of analytical tests with very different approaches and designs. The variability in testing modalities, compounded by the lack of available commercial reference materials for standardization early in the pandemic, has led to several challenges regarding data harmonization for viral quantitation. In this study, we assessed multiple commercially available RT-PCR platforms across different laboratories within the United States using standardized reference materials characterized by viral culture methods and droplet digital PCR. We observed variability in the results generated by different instruments and laboratories, further emphasizing the importance of utilizing validated reference standards for quantitation, to better harmonize SARS-CoV-2 test results.

Complete genome sequence of human adenovirus prototype 17.

As one of the first five human adenoviruses (HAdVs) to be sequenced, type 17 was important as a reference tool for comparative genomics of recently isolated HAdV pathogens in species D. HAdV-D17 was the first species D adenovirus to be sequenced and was deposited in GenBank in 1999. These genome data were not of high quality, and a redetermination of the same stock virus provides corrected data; among the differences are a length of 35,139 bp versus 35,100 bp in the original, and 160 mismatches to the original genome were found. Annotation of the coding sequences reveals 39 as opposed to 8, a finding which is important for phylogenomic studies.

Osteoclast-mediated bone loss observed in a COVID-19 mouse model.

The consequences of SARS-CoV-2 infection on the musculoskeletal system represent a dangerous knowledge gap. Aging patients are at added risk for SARS-CoV-2 infection; therefore, a greater understanding of the resulting musculoskeletal sequelae of SARS-CoV-2 infection may help guide clinical strategies. This study examined fundamental bone parameters among mice treated with escalating viral loads. Male C57BL/6J (WT, n = 17) and B6.Cg-Tg(K18-ACE2)2Prlmn/J mice (K18-hACE2 transgenic mice, n = 21) expressing human ACE2 (TG) were divided into eight groups (n = 4-6/group) and subjected to intranasal dosing of 0, 1 × 103, 1 × 104, and 1 × 105 PFU (plaque forming units) of human SARS-CoV-2. Animal health was assessed daily by veterinary staff using established and validated scoring criteria (activity, posture, body condition scores and body weight). We report here that mock and WT infected mice were healthy and completed the study, surviving until 12-14 days post infection (dpi). In contrast, the TG mice infected with 1 × 105 PFU all experienced severe health declines that necessitated early euthanasia (6-7 dpi). For TG mice infected with 1 × 104 PFU, 2 mice were also euthanized after 7 dpi, while 3 mice showed signs of moderate disease at day 6 dpi, but recovered fully by day 11 dpi. Four of the 5 TG mice that were infected with 1 × 103 PFU remained healthy throughout the study. This suggests that our study mimics what is seen during human disease, where some patients develop severe disease resulting in death, while others have moderate to severe disease but recover, and others are asymptomatic. At necropsy, femurs were extracted and analyzed by µCT. No difference was found in µCT determined bone parameters among the WT groups. There was, however, a significant 24.4% decrease in trabecular bone volume fraction (p = 0.0009), 19.0% decrease in trabecular number (p = 0.004), 6.2% decrease in trabecular thickness (p = 0.04), and a 9.8% increase in trabecular separation (p = 0.04) among surviving TG mice receiving any viral load compared to non-infected controls. No differences in cortical bone parameters were detected. TRAP staining revealed surviving infected mice had a significant 64% increase in osteoclast number, a 27% increase in osteoclast surface, and a 38% increase in osteoclasts per bone surface. While more studies are needed to investigate the long-term consequences of SARS-CoV-2 infection on skeletal health, this study demonstrates a significant reduction in several bone parameters and corresponding robust increases in osteoclast number observed within 2 weeks post-infection in surviving asymptomatic and moderately affected mice.

A Treatment to Eliminate SARS-CoV-2 Replication in Human Airway Epithelial Cells Is Safe for Inhalation as an Aerosol in Healthy Human Subjects.

BACKGROUND: Low airway surface pH is associated with many airway diseases, impairs antimicrobial host defense, and worsens airway inflammation. Inhaled Optate is designed to safely raise airway surface pH and is well tolerated in humans. Raising intracellular pH partially prevents activation of SARS-CoV-2 in primary normal human airway epithelial (NHAE) cells, decreasing viral replication by several mechanisms. METHODS: We grew primary NHAE cells from healthy subjects, infected them with SARS-CoV-2 (isolate USA-WA1/2020), and used clinical Optate at concentrations used in humans in vivo to determine whether Optate would prevent viral infection and replication. Cells were pretreated with Optate or placebo prior to infection (multiplicity of infection = 1), and viral replication was determined with plaque assay and nucleocapsid (N) protein levels. Healthy human subjects also inhaled Optate as part of a Phase 2a safety trial. RESULTS: Optate almost completely prevented viral replication at each time point between 24 h and 120 h, relative to placebo, on both plaque assay and N protein expression (P < .001). Mechanistically, Optate inhibited expression of major endosomal trafficking genes and raised NHAE intracellular pH. Optate had no effect on NHAE cell viability at any time point. Inhaled Optate was well tolerated in 10 normal subjects, with no change in lung function, vital signs, or oxygenation. CONCLUSIONS: Inhaled Optate may be well suited for a clinical trial in patients with pulmonary SARS-CoV-2 infection. However, it is vitally important for patient safety that formulations designed for inhalation with regard to pH, isotonicity, and osmolality be used. An inhalational treatment that safely prevents SARS-CoV-2 viral replication could be helpful for treating patients with pulmonary SARS-CoV-2 infection.

Computational analysis of human adenovirus type 22 provides evidence for recombination among species D human adenoviruses in the penton base gene.

Recombination in human adenoviruses (HAdV) may confer virulence upon an otherwise nonvirulent strain. The genome sequence of species D HAdV type 22 (HAdV-D22) revealed evidence for recombination with HAdV-D19 and HAdV-D37 within the capsid penton base gene. Bootscan analysis demonstrated that recombination sites within the penton base gene frame the coding sequences for the two external hypervariable loops in the protein. A similar pattern of recombination was evident within other HAdV-D types but not other HAdV species. Further study of recombination among HAdVs is needed to better predict possible recombination events among wild-type viruses and adenoviral gene therapy vectors.

Human adenovirus type 19: genomic and bioinformatics analysis of a keratoconjunctivitis isolate.

Human adenovirus type 19 (HAdV-19) is a major etiologic agent of epidemic keratoconjunctivitis (EKC), a common and severe eye infection associated with long-term visual morbidity due to persistent corneal inflammation. Ironically, while the prototype strain of HAdV-19 does not cause eye infections, other isolates of the serotype have caused major outbreaks of EKC. Here we have sequenced a clinical isolate of HAdV-19 (HAdV-19 strain C) from a human patient with EKC. Global pairwise alignment of HAdV-19C to other HAdV species D serotypes identified areas of sequence divergence in the penton base (host cell internalization signal), hexon (principal viral capsid structural protein), E3 (site of immunomodulatory genes), and fiber (host cell-binding ligand) regions. Comparison of HAdV-19 strain C to the recently sequenced HAdV-37, another EKC causing serotype, identified sequence diversity in the penton base and hexon, but sequence conservation in the E3 and fiber regions. Elucidation of the HAdV-19C genome will facilitate future studies into the pathogenesis of EKC, and may shed light on the genetic determinants of corneal tropism.