Epitope profiling of monoclonal antibodies to the immunodominant antigen BmGPI12 of the human pathogen Babesia microti

The significant rise in the number of tick-borne diseases represents a major threat to public health worldwide. One such emerging disease is human babesiosis, which is caused by several protozoan parasites of the Babesia genus of which B. microti is responsible for most clinical cases reported to date. Recent studies have shown that during its intraerythrocytic life cycle, B. microti exports several antigens into the mammalian host using a novel vesicular-mediated secretion mechanism. One of these secreted proteins is the immunodominant antigen BmGPI12, which has been demonstrated to be a reliable biomarker of active B. microti infection. The major immunogenic determinants of this antigen remain unknown. Here we provide a comprehensive molecular and serological characterization of a set of eighteen monoclonal antibodies developed against BmGPI12 and a detailed profile of their binding specificity and suitability in the detection of active B. microti infection. Serological profiling and competition assays using synthetic peptides identified five unique epitopes on the surface of BmGPI12 which are recognized by a set of eight monoclonal antibodies. ELISA-based antigen detection assays identified five antibody combinations that specifically detect the secreted form of BmGPI12 in plasma samples from B. microti-infected mice and humans but not from other Babesia species or P. falciparum.

Specific and Sensitive Diagnosis of Babesia microti Active Infection Using Monoclonal Antibodies to the Immunodominant Antigen BmGPI12

The apicomplexan pathogen Babesia microti is responsible for most cases of human babesiosis worldwide. The disease, which presents as a malaria-like illness, is potentially fatal in immunocompromised or elderly patients, making the need for its accurate and early diagnosis an urgent public health concern. B. microti is transmitted primarily by Ixodes ticks but can also be transmitted via blood transfusion. The parasite completes its asexual reproduction in the host red blood cell, where each invading merozoite develops and multiplies to produce four daughter parasites. While various techniques, such as microscopy, PCR, and indirect fluorescence, have been used over the years for babesiosis diagnosis, detection of the secreted B. microti immunodominant antigen BmGPI12 using specific polyclonal antibodies was found to be the most effective method for the diagnosis of active infection and for evaluation of clearance following drug treatment. Here, we report the development of a panel of 16 monoclonal antibodies against BmGPI12. These antibodies detected secreted BmGPI12 in the plasma of infected humans. Antigen capture assays identified a combination of two monoclonal antibodies, 4C8 and 1E11, as a basis for a monoclonal antibody-based BmGPI12 capture assay (mGPAC) to detect active B. microti infection. Using a collection of 105 previously characterized human plasma samples, the mGPAC assay showed 97.1% correlation with RNA-based PCR (transcription-mediated amplification [TMA]) for positive and negative samples. The mGPAC assay also detected BmGPI12 in the plasma of six babesiosis patients at the time of diagnosis but not in three matched posttreatment samples. The mGPAC assay could thus be used alone or in combination with other assays for accurate detection of active B. microti infection.

A mitochondrial contribution to anti-inflammatory shear stress signaling in vascular endothelial cells

Atherosclerosis, the major cause of myocardial infarction and stroke, results from converging inflammatory, metabolic, and biomechanical factors. Arterial lesions form at sites of low and disturbed blood flow but are suppressed by high laminar shear stress (LSS) mainly via transcriptional induction of the anti-inflammatory transcription factor, Kruppel-like factor 2 (Klf2). We therefore performed a whole genome CRISPR-Cas9 screen to identify genes required for LSS induction of Klf2. Subsequent mechanistic investigation revealed that LSS induces Klf2 via activation of both a MEKK2/3-MEK5-ERK5 kinase module and mitochondrial metabolism. Mitochondrial calcium and ROS signaling regulate assembly of a mitophagy- and p62-dependent scaffolding complex that amplifies MEKK-MEK5-ERK5 signaling. Blocking the mitochondrial pathway in vivo reduces expression of KLF2-dependent genes such as eNOS and inhibits vascular remodeling. Failure to activate the mitochondrial pathway limits Klf2 expression in regions of disturbed flow. This work thus defines a connection between metabolism and vascular inflammation that provides a new framework for understanding and developing treatments for vascular disease.

Evidence for SARS-CoV-2 Spike Protein in the Urine of COVID-19 Patients

Background

SARS-CoV-2 infection has, as of April 2021, affected >133 million people worldwide, causing >2.5 million deaths. Because the large majority of individuals infected with SARS-CoV-2 are asymptomatic, major concerns have been raised about possible long-term consequences of the infection.

Methods

Wedeveloped an antigen capture assay to detect SARS-CoV-2 spike protein in urine samples from patients with COVID-19whose diagnosis was confirmed by positive PCR results from nasopharyngeal swabs (NP-PCR+) forSARS-CoV-2. We used a collection of 233 urine samples from 132 participants from Yale New Haven Hospital and the Children's Hospital of Philadelphia that were obtained during the pandemic (106 NP-PCR+ and 26 NP-PCR-), and a collection of 20 urine samples from 20 individuals collected before the pandemic.

Results

Our analysis identified 23 out of 91 (25%) NP-PCR+ adult participants with SARS-CoV-2 spike S1 protein in urine (Ur-S+). Interestingly, although all NP-PCR+ children were Ur-S-, one child who was NP-PCR- was found to be positive for spike protein in their urine. Of the 23 adults who were Ur-S+, only one individual showed detectable viral RNA in urine. Our analysis further showed that 24% and 21% of adults who were NP-PCR+ had high levels of albumin and cystatin C, respectively, in their urine. Among individuals with albuminuria (>0.3 mg/mg of creatinine), statistical correlation could be found between albumin and spike protein in urine.

Conclusions

Together, our data showed that one of four individuals infected with SARS-CoV-2 develop renal abnormalities, such as albuminuria. Awareness about the long-term effect of these findings is warranted.

Online Learning in the Face of COVID-19 Pandemic: Assessment of Students' Satisfaction at Chitwan Medical College of Nepal

Background Online learning can play a vital role in the process of teaching and learning during Corona Virus Disease 2019 (COVID-19) pandemic. However, learners' satisfaction is extremely important in effective implementation of the online learning, especially at institutions where it is newly adopted. Objective To assess satisfaction towards online learning and its predictors among students at Chitwan Medical College, Bharatpur. Method A web-based cross-sectional survey was undertaken among 434 undergraduate and postgraduate students from various academic programs who had participated in the online classes started during this COVID-19 pandemic. A structured questionnaire consisting of 31 items (5-point Likert scale) covering four major student satisfaction domains (learners' dimensions, technological characteristics, instructors' characteristics and course management and coordination) was distributed to the students using Google Form. Result More than half (53.5%) of the students were satisfied with the online learning, while 29.7% gave neutral views. Bivariate analyses found that all four domains scores were positively correlated with each other as well as with the students' overall satisfaction towards learning. In multivariate analysis, female gender [aOR: 2.72, p = 0.013], WiFi as internet modality for learning [aOR: 3.36, p = 0.001) and learners' dimension score [aOR: 1.27, p<0.001] were the significant predictors of students' satisfaction. Conclusion Although recently adopted, the satisfaction of the students towards online classes appears good, and prioritizing the identified predictors and working on the weak links could assist in enhancing students' satisfaction and better outcomes.

Early events in endothelial flow sensing

Responses of vascular and lymphatic endothelial cells (ECs) to fluid shear stress (FSS) from blood or lymphatic fluid flow govern the development, physiology, and diseases of these structures. Extensive research has characterized the signaling, gene expression and cytoskeletal pathways that mediate effects on EC phenotype and vascular morphogenesis. But the primary mechanisms by which ECs transduce the weak forces from flow into biochemical signals are less well understood. This review covers recent advances in our understanding of the immediate mechanisms of FSS mechanotransduction, integrating results from different disciplines, addressing their roles in development, physiology and disease, and suggesting important questions for future work.

Post operative diagnosis of early gastric cancer in a low risk population and the possibility of risk stratified screening

BACKGROUND

Gastric cancer is the second commonest cause of cancer related mortality worldwide. Though its incidence is more in Eastern Asia, it is increasing in the South Asian subcontinent. The diagnosis of early gastric cancer (EGC) confined to the mucosa or submucosa, is an important concern due to a better outcome at this stage where five year survival rates could increase by 90 percent. Though mass screening is done in few countries, it has not been applied in developing countries like Nepal. Preoperative diagnosis of EGC is rare in Nepal. The aim of this study is to analyze the clinicopathological features of postoperative cases of gastric cancer managed in a tertiary care university hospital of Nepal.

METHODS

All patients with histological diagnosis of gastric cancer admitted in the Department of Surgery, Tribhuvan University Teaching Hospital, Kathmandu, Nepal during the three year period (September 2010 to August 2013) were analyzed retrospectively.

RESULTS

Ninety two patients with endoscopic diagnosis of gastric cancers were admitted during the past three years. The mean age was 60 years ranging from 28 years to 85 years with the male to female ratio of 2.8:1. Five patients were younger than 40 years and all were in advanced stage. Thirty five percent of the patients belonged to Janajatis (Hill) community though they comprise only 23% of the population and about 65% of them belonged to an area involving 25% of the country. Seventy six cases were operated. Out of 92 patients, 4 patients were diagnosed as early gastric cancer postoperatively. All patients with early gastric cancer were above 50 years with CT Scan abdomen revealing focal thickening without lymphadenopathy.

CONCLUSION

Over the years, the incidence of gastric cancer is increasing in Nepal. Though 92% are advance gastric cancers, few have been diagnosed and treated early. A screening program in a country like Nepal with diverse ethnicity and difficult terrain might be helpful if it targets high risk people in high risk areas.

Cardiovascular health risk behavior among medical students in a teaching hospital

BACKGROUND

Medical students are the health care providers of tomorrow. The health behaviors that are acquired in early life and in medical school will influence their future acceptance and practice of preventive strategies including their interaction with patients. The main objective of our study was to assess the health behavior and perceptions of medical students in relation to cardiovascular diseases.

METHODS

A cross sectional descriptive study was done among 159 medical students of Institute of Medicine, Tribhuvan University Teaching Hospital in Kathmandu, Nepal from September 2010 to December 2010. Data collection was done using a self administered questionnaire.

RESULTS

The mean age was 22.9±2.5 yrs and a male:female ratio of 2.1:1. Thirty Five (22%) were current smokers, 56 (35%) indulged in episodic heavy drinking, 25 (15.7%) were overweight, 34 (21%) engaged in recommended amount of physical activitiy,58 (33%) regulated fat consumption and 46 (28%) regulated salt consumption. Regarding developing cardiovascular disease in the future, 85(53%) showed concern but only 33 (38%) of these adopted preventive practices. 101 (64%) believed that their medical school life had a harmful effect on their health.

CONCLUSIONS

Our study shows a high prevalence of cardiovascular risk behaviours among the medical students. This highlights the urgency that we must take to promote preventive knowledge and practices among medical students. This will help them to become prevention oriented clinicians in future to counter the increasing burden of cardiovascular diseases in this part of the world.