High transferability of neutralizing antibodies against SARS-CoV-2 to umbilical cord blood in pregnant women with BNT162b2 XBB.1.5 vaccine - a retrospective cohort study (preprint)

Coronavirus disease 2019 (COVID-19), when contracted by pregnant women, can lead to severe respiratory illness, rapid disease progression, and higher rates of intensive care unit admission. COVID-19 infection during pregnancy is associated with an increased risk of preterm delivery, cesarean section, fetal dysfunction, preeclampsia, and perinatal death. Additionally, vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from pregnant women to their fetuses has been observed. While severe infections in neonates and infants are rare, newborns can experience serious consequences from COVID-19, despite their suboptimal humoral immune system protection. The amino acids in the structural proteins of SARS-CoV-2 are subjected to constant mutation. Since around January 2023, COVID-19, caused by infection with omicron-type SARS-CoV-2 variants, has been prevalent globally. Omicron-type SARS-CoV-2 variants can evade the immune response triggered by traditional mRNA-based COVID-19 vaccines, such as BNT162b2. Therefore, vaccination with a vaccine (BNT162b2 XBB.1.5) that can provide protection against omicron-type SARS-CoV-2 variants is recommended. Therefore, we examined the titers of anti-spike glycoprotein of SARS-CoV-2 IgG and IgA in the blood and umbilical cord blood obtained from pregnant women vaccinated with BNT162b2 XBB.1.5. The results showed that anti-spike glycoprotein of SARS-CoV-2 IgG and IgA titers were highest in the blood and cord blood obtained from pregnant women vaccinated with BNT162b2 XBB.1.5 at late gestational age (28-34 weeks). No serious side effects or adverse events caused by vaccination of pregnant women with BNT162b2 XBB.1.5 were observed in either pregnant women or newborns. In the future, to validate our findings, large cohort clinical studies involving numerous pregnant women must be conducted.

Pathological Evidence for Residual SARS-CoV-2 in the Micrometastatic Niche of a Patient with Ovarian Cancer (preprint)

In previous clinical studies, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with cancer has a high risk of aggravation and mortality than in healthy infected individuals. The inoculation with the COVID-19 vaccine reduces the risk of SARS-CoV-2 infection and COVID- 19 severity. However, vaccination-induced production of anti-SARS-CoV-2 antibodies is said to be lower in patients with cancer than in healthy individuals. Additionally, the rationale for why patients with cancer become more severe with COVID-19 is not well understood. Therefore, we examined the infection status of SARS-CoV-2 in primary tumor and micrometastasis tissues of patients with cancer and COVID-19. In this study, angiotensin-converting enzyme 2 (ACE2) expression was observed, and SARS-CoV-2 particles were detected in ovarian tissue cells in contact with the micrometastatic niche of high-grade serous ovarian cancer. We believe that more severe COVID-19 cases in patients with cancer may be attributed to these pathological features.

Spontaneous myocarditis in mice predisposed to autoimmune disease: Including Vaccination-induced onset (preprint)

Non-obese diabetic (NOD)/ShiLtJ mice, like biobreeding rats, are used as an animal model for type 1 diabetes. Diabetes develops in NOD mice as a result of insulitis, a leukocytic infiltrate of the pancreatic islets. The onset of diabetes is associated with a moderate glycosuria and a non-fasting hyperglycemia. Previously, in non-obese diabetic (NOD)/ShiLtJ mice spontaneously developing type 1 diabetes, the possible involvement of decreased expression of LMP2/β1i, an immunoproteasome β subunit, and associated decreased expression of NF-κB1 (also called as p50) in the development of type 1 diabetes was argued between our research team and other research groups. In response to these arguments, we created NOD mice in which NF-κB1 expression is not consistently observed. Unexpectedly, most NOD Nfκb1 homozygote mice were found to die by the 8th week of age due to the development of severe myocarditis. Furthermore, in all NOD Nfκb1 heterozygote mice, the onset of Insulitis was observed from 4 months of age. In addition, in NOD Nfκb1 heterozygote mice, an increase in cTnT due to vaccination with influenza or HBV vaccine was observed without gender difference. Now, we found a direct involvement of decreased expression of NF-κB1 in the development of autoimmune diseases in NOD/ShiLtJ mice. Therefore, we would like to introduce new research results on autoimmune diseases, including findings on important risk factors for the development of myocarditis observed after vaccination with mRNA-based COVID-19 vaccine.

Possibility of SARS-CoV-2 infection in metastatic microenvironment of cancer (preprint)

According to a report from the World Health Organization, the mortality and severity rates among patients with cancer infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are significantly higher than those of individuals infected with SARS-CoV-2 without complications. Common and cancer-specific risk factors may be involved in the mortality and severity rates of coronavirus disease 2019 (COVID-19). Various factors have been determined to contribute to the aggravation of COVID-19 in patients with cancer. However, on the basis of current research, the factors involved in the aggravation of COVID-19 in patients with cancer have not been fully investigated. In the general course of treatment for patients with cancer, the detection of the formation of metastases in other organs is common. Therefore, the present study investigates the association between lung metastatic lesion formation and SARS-CoV-2 infectivity. On the basis of the results obtained, in the pulmonary micrometastatic niche of patients with ovarian cancer, alveolar epithelial stem-like cells adjacent to the ovarian cancer were observed. Moreover, it was revealed that angiotensin-converting enzyme 2, a host-side receptor for SARS-CoV-2, was expressed in alveolar epithelial stem-like cells adjacent to the ovarian cancer in the pulmonary micrometastatic niche. Furthermore, it was also observed that the SARS-CoV-2 spike glycoprotein receptor-binding domain binds to alveolar epithelial stem-like cells. In other words, it was suggested that patients with cancer and pulmonary micrometastases may be more susceptible to SARS-CoV-2. The prevention of de novo niche formation in metastatic disease may be a new strategy for the clinical treatment of COVID-19 for patients with cancer.

Neutralizing response against E484K variant after original SARS-CoV-2 infection (preprint)

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) variants, which are spreading in the United Kingdom (UK) and elsewhere, have been found in infected individuals in Japan. The virus mutates, to facilitate its life in the host, during the process of repeated proliferation in the body of the host, including humans. In other words, it is natural that a human-compatible mutant strain always predominates in infection and proliferation. As a result, the viral mutants acquire strong proliferative potential in the host and are highly pathogenic. The number of people infected with the mutated SARS-CoV-2 variant E484K, which is different from the SARS-CoV-2 variants that are spreading in the UK, South Africa, and Brazil, is increasing in Tokyo. It has been pointed out that the effects of immunity and vaccines may be reduced against the Tokyo-type SARS-CoV-2 variant E484K. We have investigated the neutralization response to various mutations in the spike glycoprotein using the serum of people already infected with the original SARS-CoV-2. The results showed that SARS-CoV-2 variants with Y543F or N501Y mutations in the spike glycoprotein affect the neutralization reaction. However, single E484K mutations within the spiked glycoprotein of the Tokyo-type SARS-CoV-2 variant are unlikely to have a significant effect on the affinity of the host antibody for the virus.

Effect of RBD mutations in spike glycoprotein of SARS-CoV-2 on neutralizing IgG affinity (preprint)

Background: Certain mutant strains of SARS-CoV-2 are known to spread widely among humans, including the receptor binding domain (RBD) mutant, Y453F, from farmed minks, and the RBD mutant, N501Y, a mutation common to three major SARS-CoV-2 subspecies (B.1.1.7, B.1.351, and B.1.1.248). Methods: We investigated the characteristics of the RBD mutants, Y453F and N501Y, using three-dimensional structural analysis. We also investigated the effect of Y453F and N501Y on neutralizing antibodies in serum derived from COVID-19-positive patients. Results: Our results suggest that SARS-CoV-2 subspecies with the RBD mutations Y453F or N501Y partially escaped detection by 4 neutralizing monoclonal antibodies and 21 neutralizing antibodies in serums derived from COVID-19-positive patients. Conclusions: Infection with SARS-CoV-2 subspecies that cause serious symptoms in humans may spread globally.

Effect of RBD (Y453F) mutation in spike glycoprotein of SARS-CoV-2 on neutralizing IgG affinity. (preprint)

Background: Infection with receptor binding domain (RBD) mutant (Y453F) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from farmed minks is known to widely spread among humans. Methods: We investigated the characteristics of SARS-CoV-2 RBD Y453F mutant using three-dimensional structural analysis. We investigated the effect of the RBD Y453F mutant of SARS-CoV-2 on neutralizing antibodies in serum derived from Corona virus Disease 2019 (COVID-19) positive patients. Results: Our studies suggest that virus variants with RBD Y453F mutation partially escaped detection by four neutralizing monoclonal antibodies and neutralizing antibodies in serum. Conclusions: Consequently, raising a concern that infection of SARS-CoV-2 mutants that cause serious symptoms in humans may spread globally.

Effect of RBD mutation (Y453F) in spike glycoprotein of SARS-CoV-2 on neutralizing antibody affinity (preprint)

Natural selection adaptation in the coronavirus can occur during coronavirus amplification in vivo in farmed minks. Natural selection in such viruses is observed by introduction of mutations in SARS-CoV-2 that are not observed during the growth process in humans. Infection with a mutant (Y453F) of SARS-CoV-2 from farmed minks is known to widely spread among humans. We investigated the virological characteristics of this SARS-CoV-2 mutant (Y453F) using three-dimensional protein structural analysis. Our experimental study suggests that virus variants with the Y453F mutation partially escaped detection by four neutralizing monoclonal antibodies. The spread of SARS-CoV-2 variants mediated by millions of infected farmed minks is uncontrolled; consequently, raising a concern that infection of SARS-CoV-2 mutants that cause serious symptoms in humans may spread globally.

Impact of COVID-19: Decrease in the Number of Fledging Barn Swallow Chicks in Tokyo (preprint)

Barn swallows that have crossed the sea from Southeast Asia usually appear in the Kyushu Region of Japan around March after passing through Okinawa Prefecture. When the climate becomes warmer, these birds then move further north, nesting and raising their chicks in various parts of Japan. It is worth noting that barn swallows typically nest on man-made objects, for example, the roofs of houses and barns. It is believed that this is because barn swallows protect their eggs and chicks from foreign enemies such as sparrows and crows so they build their nests in populated areas. The barn swallows behavior of using the presence of people to keep foreign enemies away shows that barn swallows are quite wise. However, it has been reported that from the spring to summer of 2020, barn swallows, nesting and raising their chicks, which were seen every year, were not found in various parts of Japan. Therefore, we investigated the relationship between peoples self-restraint from going out and the fledging of barn swallow chicks in Tokyo metropolitan during the corona virus disease 2019 (COVID-19) era. The results of the survey showed a link between peoples refraining from going out and the fledging of barn swallow chicks. Next spring of 2021, the termination of COVID-19 is an important environment for swallow chick fledging.

COVID-19 era, Preventive effect of no going out against co-infection of the seasonal influenza virus and SARS-CoV-2 (preprint)

In the situation where expansion of coronavirus infectious disease-2019 (COVID-19) does not stop, there is concern about co-infection of people with the seasonal influenza infections from late autumn to winter 2020. Therefore, the importance of supplying vaccines against the seasonal influenza has been pointed out all over the world. As an example in Japan, the number of people infected with the seasonal influenza, hand-foot-and-mouth disease (HFMD), epidemic keratoconjunctivitis, and pharyngoconjunctival fever (PCF), which are the seasonal infectious diseases in the 2020 season, has decreased remarkably compared to the number of people infected each year. It is believed that the significant reduction in the number of people infected with these seasonal infectious diseases is a result of the pervasive hand washing, wearing masks and maintaining social distance in COVID-19 rea. To examine the correlation between the three factors of the number of people with each seasonal infectious disease, the mask wearing rate, and the outing rate, we created a three-dimensional scatter plot based on these three factors using principal component analysis. Our research findings demonstrated preventive effect of no going out against co-infection with the seasonal influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Molecular analysis of binding region of an ACE2 as a receptor for SARS-CoV-2 between humans and mammals (preprint)

In June 2020, a second wave of coronavirus disease-2019 (COVID-19) infections raised concern in Beijing, where salmon sold a fresh fish wholesale market was suspected of being the source of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. It has raised questions in the press and elsewhere about the scientific basis of salmon as a source of infection. With the number of cases growing, the surface of a salmon chopping board in the market was examined for the presence of SARS-CoV-2 and a positive reaction was observed. Following these test results, there has been debate over whether salmon can be infected with SARS-CoV-2. To find assess this, we investigated the structural homology of angiotensin-converting enzyme 2 (ACE2), a host-side receptor for SARS-CoV-2, between humans and other species including salmon and mink. As a result, a high structural homology between ACE2 and mink, which has reportedly transmitted SARS-CoV-2 to humans, was confirmed. However, a non-high structural homology of ACE2 between salmon and humans was observed. Further experiments are needed to find the source of SARS-CoV-2 transmission to the salmon.

New Coronavirus Disease (COVID-19): Clinical Symptoms Other Than Pneumonia with Emphasis on Thrombosis (preprint)

The main manifestation of new coronavirus disease 2019 (COVID-19) is respiratory disease. The new coronavirus (SARS-CoV-2) attacks the lungs and may result in severe acute respiratory syndrome. In such cases, the infected person has difficulty breathing, which impairs oxygen uptake in the body. If pneumonia or another respiratory illness develops, and the host immune system is unable to combat SARS-CoV-2, the infected person may eventually die. Meanwhile, reports on unexpected symptoms in organs other than the nasal cavity, throat, and lungs are emerging. To elucidate the causes of such symptoms, we analyzed the expression status of angiotensin-converting enzyme 2 (ACE2), the host receptor used by SARS-CoV-2, in various tissues. This study confirmed that alveolar macrophages appear to be involved in pneumonitis and thrombus formation. In this report, we introduce some new symptoms.