Virus Penetration Research Articles

The Art of Viral Membrane Fusion and Penetration.

As obligate pathogens, viruses have developed diverse mechanisms to deliver their genome across host cell membranes to sites of virus replication. While enveloped viruses utilize viral fusion proteins to accomplish fusion of their envelope with the cellular membrane, non-enveloped viruses rely on machinery that causes local membrane ruptures and creates an opening through which the capsid or viral genome is released. Both membrane fusion and membrane penetration take place at the plasma membrane or in intracellular compartments, often involving the engagement of the cellular machinery and antagonism of host restriction factors. Enveloped and non-enveloped viruses have evolved intricate mechanisms to enable virus uncoating and modulation of membrane fusion in a spatiotemporally controlled manner. This chapter summarizes and discusses the current state of understanding of the mechanisms of viral membrane fusion and penetration. The focus is on the role of lipids, viral scaffold uncoating, viral membrane fusion inhibitors, and host restriction factors as physicochemical modulators. In addition, recent advances in visualizing and detecting viral membrane fusion and penetration using cryo-electron microscopy methods are presented.

Antiherpetic Activity of Carrageenan Complex with Echinochrome A and Its Liposomal Form.

Herpes simplex virus (HSV) infections, the incidence of which is still widespread throughout the world, are actualizing the search and development of new, more effective antiherpetic drugs. The development of multifunctional drug delivery systems, including liposome-based ones, has become a relevant and attractive concept in nanotechnology. The ability of complexes of κ- and Σ-carrageenans (CRGs)-sulfated polysaccharides of red algae, with echinochrome A (Ech), as well as the liposomal form of the Σ-CRG/Ech complex-to inhibit different stages of HSV-1 infection in Vero cells was studied. By quantum chemical calculations, it was shown that CRG forms stable complexes with Ech. We have shown that complexes of κ-CRG/Ech and Σ-CRG/Ech exhibit highest virucidal activity with a selectivity index (SI) of 270 and 350, respectively, and inhibition of virus-cell interaction (SI of 83 and 32, respectively). The liposomal form of the Σ-CRG/Ech complex after virus adsorption and penetration to cells effectively reduced the HSV-1 plaque formation. The virus-inhibiting activity of the liposomal form of the Σ-CRG/Ech complex was three times higher than that of the Σ-CRG/Ech complex itself. Obtaining CRGs/Ech complexes and their liposomal forms can become the basis of a successful strategy for the development of promising antiherpetic drugs.

Non-enveloped virus membrane penetration: New advances leading to new insights.

Host cell membranes pose a particular challenge for non-enveloped viruses. Whereas enveloped viruses enter cells by fusing their lipid envelopes with the cellular membrane, non-enveloped viruses generally must (1) enter cells via endocytosis, then (2) penetrate the cellular endomembrane to reach the cytosol. Only then can the viruses begin to replicate (or transit to the nucleus to replicate). Although membrane penetration of non-enveloped viruses is a crucial entry step, many of the precise molecular details of this process remain unclear. Recent findings have begun to untangle the various mechanisms by which non-enveloped viral proteins disrupt and penetrate cellular endomembranes. Specifically, high-resolution microscopy studies have revealed precise conformational changes in viral proteins that enable penetration, while biochemical studies have identified key host proteins that promote viral penetration and transport. This brief article summarizes new discoveries in the membrane penetration process for three of the most intensely studied families of non-enveloped viruses: reoviruses, papillomaviruses, and polyomaviruses.

Structure and host specificity of Staphylococcus epidermidis bacteriophage Andhra.

Staphylococcus epidermidis is an opportunistic pathogen of the human skin, often associated with infections of implanted medical devices. Staphylococcal picoviruses are a group of strictly lytic, short-tailed bacteriophages with compact genomes that are attractive candidates for therapeutic use. Here, we report the structure of the complete virion of S. epidermidis-infecting phage Andhra, determined using high-resolution cryo-electron microscopy, allowing atomic modeling of 11 capsid and tail proteins. The capsid is a T = 4 icosahedron containing a unique stabilizing capsid lining protein. The tail includes 12 trimers of a unique receptor binding protein (RBP), a lytic protein that also serves to anchor the RBPs to the tail stem, and a hexameric tail knob that acts as a gatekeeper for DNA ejection. Using structure prediction with AlphaFold, we identified the two proteins that comprise the tail tip heterooctamer. Our findings elucidate critical features for virion assembly, host recognition, and penetration.

199 Ex vivo infection of human skin with herpes simplex virus 1: Lesional AD skin and IL-4/IL-13-stimulated skin provide facilitated viral invasion

Herpes simplex virus 1 (HSV-1) is a prevalent human pathogen that can target skin to establish infection in the epithelium. Since the human skin provides effective barriers against pathogens under normal conditions, HSV-1 must find opportunistic pathways in order to penetrate the skin and initiate infection. As mechanical wounds of the human skin surface do not provide ad hoc entry portals for HSV-1, we explored the role of pathological skin conditions. Ex vivo infection studies revealed successful invasion in lesional AD skin implying that the virus can overcome both the stratum corneum and the tight junction barriers. To dissect the parameters that contribute to HSV-1 invasion, we treated human skin without pre-existing barrier defects with interleukin (IL)-4 and IL-13 to investigate whether Th2 cytokine-driven inflammation already induces modifications that allow viral penetration. Strikingly, we detected infected cells in the epidermis indicating that the IL-induced, AD-like skin phenotype can indeed facilitate HSV-1 invasion. Potential modifications allowing for facilitated viral access include impaired tight junctions, an altered stratum corneum, or a redistribution of the HSV-1 receptor nectin-1. Studies using human epidermal equivalents highlighted the importance of functional tight junctions in addition to the stratum corneum in restricting HSV-1 entry and provide a tool to mimic the pathological alterations in AD skin that allow HSV-1 invasion.

COMPUTATIONAL RESEARCH USING PHYTOCHEMICALS FROM THE ACACIA CAVEN PLANT TO COMBAT THE VP40-FUNCTIONALIZED EBOLA VIRUS ILLNESS

Objectives: The Ebola virus is an extraordinarily deadly illness that affects both humans and wild animals. Key elements in viral proliferation include viral adhesion to cell membranes and viral penetration into the host organism. The viral protein present in the Ebola virus is the matrix protein Viral Protein-40 (VP-40) which is required for the development and integration of the nucleocapsid. Limiting VP40 activity prevents the viral infection from spreading. Methods: Ten phytochemicals from Acacia caven were examined for their physicochemical properties, drug-likeness, and their potential to impede VP40 to assess their potential as anti-Ebola virus therapeutics. Results: Considering the pharmacological uses, ten bioactive chemicals were chosen for this investigation. Predicated on their docking score and binding interactions, Pimara-8(14), 15-diene, Heptacosane, and Geranylacetone were recognized as VP-40 inhibitors. Conclusion: Developing medicines that can inhibit VP40 could be a potential anti-Ebola virus treatment solution as VP40 is a fundamental protein for the assemblage of virion. Using the ligands Geranylacetone, Heptacosane, and Pimara-8(14), 15-diene, anti-Ebola virus therapeutics can be developed that specifically target the VP40 suppression which aids in the management of Ebola Virus disease.

Impact of Different Air Pollutants (PM10, PM2.5, NO2, and Bacterial Aerosols) on COVID-19 Cases in Gliwice, Southern Poland.

Many studies have shown that air pollution may be closely associated with increased morbidity and mortality due to COVID-19. It has been observed that exposure to air pollution leads to reduced immune response, thereby facilitating viral penetration and replication. In our study, we combined information on confirmed COVID-19 daily new cases (DNCs) in one of the most polluted regions in the European Union (EU) with air-quality monitoring data, including meteorological parameters (temperature, relative humidity, atmospheric pressure, wind speed, and direction) and concentrations of particulate matter (PM10 and PM2.5), sulfur dioxide (SO2), nitrogen oxides (NO and NO2), ozone (O3), and carbon monoxide (CO). Additionally, the relationship between bacterial aerosol (BA) concentration and COVID-19 spread was analyzed. We confirmed a significant positive correlation (p < 0.05) between NO2 concentrations and numbers of confirmed DNCs and observed positive correlations (p < 0.05) between BA concentrations and DNCs, which may point to coronavirus air transmission by surface deposits on bioaerosol particles. In addition, wind direction information was used to show that the highest numbers of DNCs were associated with the dominant wind directions in the region (southern and southwestern parts).

The Transient Receptor Potential Vanilloid 2 (TRPV2) Channel Facilitates Virus Infection Through the Ca2+ -LRMDA Axis in Myeloid Cells.

The transient receptor potential vanilloid 2 (TRPV2) channel is a nonselective cation channel that has been implicated in multiple sensory processes in the nervous system. Here, it is shown that TRPV2 in myeloid cells facilitates virus penetration by promoting the tension and mobility of cell membrane through the Ca2+ -LRMDA axis. Knockout of TRPV2 in myeloid cells or inhibition of TRPV2 channel activity suppresses viral infection and protects mice from herpes simplex virus 1 (HSV-1) and vesicular stomatitis virus (VSV) infection. Reconstitution of TRPV2 but not the Ca2+ -impermeable mutant TRPV2E572Q into LyZ2-Cre;Trpv2fl/fl bone marrow-derived dendritic cells (BMDCs) restores viral infection. Mechanistically, knockout of TRPV2 in myeloid cells inhibits the tension and mobility of cell membrane and the penetration of viruses, which is restored by reconstitution of TRPV2 but not TRPV2E572Q . In addition, knockout of TRPV2 leads to downregulation of Lrmda in BMDCs and BMDMs, and knockdown of Lrmda significantly downregulates the mobility and tension of cell membrane and inhibits viral infections in Trpv2fl/fl but not LyZ2-Cre;Trpv2fl/fl BMDCs. Consistently, complement of LRMDA into LyZ2-Cre;Trpv2fl/fl BMDCs partially restores the tension and mobility of cell membrane and promotes viral penetration and infection. These findings characterize a previously unknown function of myeloid TRPV2 in facilitating viral infection though the Ca2+ -LRMDA axis.

Negative correlation between ACE2 gene expression levels and loss of taste in a cohort of COVID-19 hospitalized patients: New clues to long-term cognitive disorders.

In early 2020, one of the most prevalent symptoms of SARS-CoV-2 infection was the loss of smell (anosmia), found in 60-70% of all cases. Anosmia used to occur early, concomitantly with other symptoms, and often persisted after recovery for an extended period, sometimes for months. In addition to smell disturbance, COVID-19 has also been associated with loss of taste (ageusia). The latest research suggests that SARS-CoV-2 could spread from the respiratory system to the brain through receptors in sustentacular cells localized to the olfactory epithelium. The virus invades human cells via the obligatory receptor, angiotensin-converting enzyme II (ACE2), and a priming protease, TMPRSS2, facilitating viral penetration. There is an abundant expression of both ACE2 and TMPRSS2 in sustentacular cells. In this study, we evaluated 102 COVID-19 hospitalized patients, of which 17.60% presented anosmia and 9.80% ageusia. ACE1, ACE2, and TMPRSS2 gene expression levels in nasopharyngeal tissue were obtained by RT-qPCR and measured using ΔCT analysis. ACE1 Alu287bp association was also evaluated. Logistic regression models were generated to estimate the effects of variables on ageusia and anosmia Association of ACE2 expression levels with ageusia. was observed (OR: 1.35; 95% CI: 1.098-1.775); however, no association was observed between TMPRSS2 and ACE1 expression levels and ageusia. No association was observed among the three genes and anosmia, and the Alu287bp polymorphism was not associated with any of the outcomes. Lastly, we discuss whetherthere is a bridge linking these initial symptoms, including molecular factors, to long-term COVID-19 health consequences such as cognitive dysfunctions.

Generation and characterization of mouse monoclonal antibodies against the VP4 protein of group A human rotaviruses

Human rotaviruses (RVs) are the leading cause of severe diarrhea in infants and young children worldwide. Among the structural proteins, as a spike protein, rotavirus VP4 plays a key role in both viral attachment and penetration. Currently, studies on monoclonal antibodies (mAbs) against VP4 are limited. In this study, mice were immunized with truncated VP4* to produce murine mAbs. In total, 50 mAbs were produced and characterized. Twenty-four mAbs were genotype-specific and 20 mAbs recognized the common VP4 epitopes shared by P[8], P[4], and P[6] viruses. Thirty-five of the 50 mAbs were neutralizing mAbs, among which nine mAbs could neutralize all three P-genotype RVs, and 10 neutralizing mAbs exhibited conformational sensitivity. Ten mAbs recognized dominant neutralizing epitopes, including the broadly neutralizing mAb 9C4 recognized conformational epitope. Further investigation shows that S376 and S464 are key amino acids for 9C4 binding, however, the exact binding sites of 9C4 remain to be fully defined. Overall, this panel of mAbs has demonstrated utility as immunodiagnostic and research reagents, and could potentially serve as crucial tools for exploring the neutralizing mechanisms and quality control of VP4* protein-based RV subunit vaccines. Further evaluation of cross-neutralizing mAbs could not only improve the understanding of the heterotypic protection conferred by RV vaccines, but also facilitate the development of broadly protective RV vaccines.

The Influence of SARS-CoV-2 Infection on Lipid Metabolism-The Potential Use of Lipid-Lowering Agents in COVID-19 Management.

Several studies have indicated lipid metabolism alterations during COVID-19 infection, specifically a decrease in high-density lipoprotein (HDL) and low-density lipoprotein (LDL) concentrations and an increase in triglyceride (TG) levels during the infection. However, a decline in triglycerides can also be observed in critical cases. A direct correlation can be observed between a decrease in serum cholesterol, HDL-C, LDL-C and TGs, and the severity of the disease; these laboratory findings can serve as potential markers for patient outcomes. The transmission of coronavirus increases proportionally with rising levels of cholesterol in the cell membrane. This is due to the fact that cholesterol increases the number of viral entry spots and the concentration of angiotensin-converting enzyme 2 (ACE2) receptor, crucial for viral penetration. Studies have found that lower HDL-C levels correspond with a higher susceptibility to SARS-CoV-2 infection and infections in general, while higher HDL-C levels were related to a lower risk of developing them. However, extremely high HDL-C levels in serum increase the risk of infectious diseases and is associated with a higher risk of cardiovascular events. Low HDL-C levels are already accepted as a marker for risk stratification in critical illnesses, and higher HDL-C levels prior to the infection is associated with a lower risk of death in older patients. The correlation between LDL-C levels and disease severity is still unclear. However, TG levels were significantly higher in non-surviving severe patients compared to those that survived; therefore, elevated TG-C levels in COVID-19 patients may be considered an indicator of uncontrolled inflammation and an increased risk of death.

Myricetin inhibits pseudorabies virus infection through direct inactivation and activating host antiviral defense.

Myricetin, a polyhydroxyflavone compound, is one of the main ingredients of various human foods and therefore also known as dietary flavonoids. Due to the continuous emergence of resistant strains of herpesviruses, novel control measures are required. In the present study, myricetin exhibited potent antiviral activity against pseudorabies virus (PRV), a model organism of herpesvirus. The suppression rate could reach up to 96.4% at a concentration of 500 μM in cells, and the 50% inhibitory concentration (IC50) was 42.69 μM. Moreover, the inhibitory activity was not attenuated by the increased amount of infective dose, and a significant reduction of intracellular PRV virions was observed by indirect immunofluorescence. A mode of action study indicated that myricetin could directly inactivate the virus in vitro, leading to inhibition of viral adsorption, penetration and replication in cells. In addition to direct killing effect, myricetin could also activate host antiviral defense through regulation of apoptosis-related gene expressions (Bcl-2, Bcl-xl, Bax), NF-κB and MAPK signaling pathways and cytokine gene expressions (IL-1α, IL-1β, IL-6, c-Jun, STAT1, c-Fos, and c-Myc). In PRV-infected mouse model, myricetin could enhance the survival rate by 40% at 5 days post infection, and viral loads in kidney, liver, lung, spleen, and brain were significantly decreased. The pathological changes caused by PRV infection were improved by myricetin treatment. The gene expressions of inflammatory factors (MCP-1, G-CSF, IL-1α, IL-1β, and IL-6) and apoptotic factors (Bcl-xl, Bcl-2, and Bax) were regulated by myricetin in PRV-infected mice. The present findings suggest that myricetin can effectively inhibit PRV infection and become a candidate for development of new anti-herpesvirus drugs.

Quercetin in the Prevention and Treatment of Coronavirus Infections: A Focus on SARS-CoV-2.

The COVID-19 outbreak seems to be the most dangerous challenge of the third millennium due to its highly contagious nature. Amongst natural molecules for COVID-19 treatment, the flavonoid molecule quercetin (QR) is currently considered one of the most promising. QR is an active agent against SARS and MERS due to its antimicrobial, antiviral, anti-inflammatory, antioxidant, and some other beneficial effects. QR may hold therapeutic potential against SARS-CoV-2 due to its inhibitory effects on several stages of the viral life cycle. In fact, QR inhibits viral entry, absorption, and penetration in the SARS-CoV virus, which might be at least partly explained by the ability of QR and its derivatives to inhibit 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro). QR is a potent immunomodulatory molecule due to its direct modulatory effects on several immune cells, cytokines, and other immune molecules. QR-based nanopreparations possess enhanced bioavailability and solubility in water. In this review, we discuss the prospects for the application of QR as a preventive and treatment agent for COVID-19. Given the multifactorial beneficial action of QR, it can be considered a very valid drug as a preventative, mitigating, and therapeutic agent of COVID-19 infection, especially in synergism with zinc, vitamins C, D, and E, and other polyphenols.

Cellular Chondroitin Sulfate and the Mucin-like Domain of Viral Glycoprotein C Promote Diffusion of Herpes Simplex Virus 1 While Heparan Sulfate Restricts Mobility.

The diffusion of viruses at the cell membrane is essential to reach a suitable entry site and initiate subsequent internalization. Although many viruses take advantage of glycosaminoglycans (GAG) to bind to the cell surface, little is known about the dynamics of the virus–GAG interactions. Here, single-particle tracking of the initial interaction of individual herpes simplex virus 1 (HSV-1) virions reveals a heterogeneous diffusive behavior, regulated by cell-surface GAGs with two main diffusion types: confined and normal free. This study reports that different GAGs can have competing influences in mediating diffusion on the cells used here: chondroitin sulfate (CS) enhances free diffusion but hinders virus attachment to cell surfaces, while heparan sulfate (HS) promotes virus confinement and increases entry efficiency. In addition, the role that the viral mucin-like domains (MLD) of the HSV-1 glycoprotein C plays in facilitating the diffusion of the virus and accelerating virus penetration into cells is demonstrated. Together, our results shed new light on the mechanisms of GAG-regulated virus diffusion at the cell surface for optimal internalization. These findings may be extendable to other GAG-binding viruses.

In Silico Modeling of COVID-19 Pandemic Course Differentiation Using the FOD Model

Background: The strange and still unclear scenarios of Covid-19 pandemic development have raised the question about the reason for the observed essential state and personal differences concerning the expansion and severity of the infection process. Some custom activities are taken into consideration in an attempt to explain the phenomenon. Alcohol in the diet is suggested in this paper as the possible factor which could explain the observed differentiation. It easily penetrates cells modifying their natural internal environment, and independently influences tissues as the toxic agent being the source of acetyl aldehyde. Objective: The process in which the cell seems to be the most sensitive to altered environmental conditions is the protein folding; in particular, its portion occurring in the endoplasmic reticulum where freshly synthesized polypeptides fold and then are introduced to the cell membrane influencing its property and in particular its fluidity, which is the critical parameter deciding the virus penetration into the cell. Methods: The application of a mathematical model, fuzzy oil drop model FOD, expressing the influence of the environment on the protein folding process shows the mechanism of this influence. Results: The differences between statistical assessment of epidemy in Europe and the Far East, which may be correlated with alcohol consumption, suggest the influence of diet on the status of epidemy in these regions. Conclusion: The protein folding seems to be the process most sensitive to environmental conditions in the cell. The different diet customs, including the use of alcohol, may disturb the folding process, lowering as the result the number of proteins needed for cell membrane stability, thus increasing its fluidity and the cell susceptibility to virus penetration. Observations presented in this paper are based on the initial period of pandemic development and have not been intentionally modified to prevent the influence of additional factors, like government activities or virus mutations.

Overview on possible causes of COVID-19

Background: The infection with the new coronavirus SARS-CoV-2 has caused a large number of cases of disease and death worldwide. Identifying the source of COVID-19 is an important issue though still unresolved. The analysis of the literature on highlighting possible sources of the SARS-CoV-2 virus was carried out. Conclusions: The COVID-19 pandemic is occurring on the underlying imminent global ecological catastrophe as a result of the anthropogenic activity. Therefore, it can be stated that Homo Sapiens in the context of the interaction with the biosphere is a maladaptive species. According to the literature, the species’ adaptive responses to environmental changes are due to endogenous retroviruses. The latter act as evolutionary factors. Possible pandemic COVID-19 is not a separate epidemic process caused by the penetration of a new virus into human populations, but rather is one of the manifestations of a more complex natural phenomenon – an evolutionary process under the guise of an infectious one. In terms of evolution, COVID-19 plays the role of a biosphere factor that seeks to help a relatively new species to adapt to the general conditions of survival in a symbiotic relationship with other living organisms.

The impact of masks on the condition of facial skin in the time of the COVID-19 pandemic

Background: The aim of the study was to determine the effects of wearing masks on skin and dermatological diseases in the face among the participants of the survey conducted. Material and Methods: The respondents completed a questionnaire containing 22 single or multiple choice questions. Participation in the survey was voluntary and anonymous. The survey data was used only in this study. Results: The condition of facial skin, as assessed by the respondents, worsened in 69% of those using surgical masks. Regardless of the frequency of mask changing, adverse effects occurred in 60% of the respondents. The most common mask side effects reported by respondents were acne (in 75.7%) and skin exfoliation. More than 47% of pandemic respondents showed interest in skin care. Conclusion: Surgical masks better protect against COVID-19 virus penetration into the upper respiratory tract compared to cotton masks, while they increase the risk of adverse reactions on facial skin. Therefore, there is an increase in public awareness of the need for proper skin care with the use of protective masks.

Роль дефензинів у неспецифічному захисті макроорганізму від інфекційних агентів при запальних захворюваннях порожнини рота і ротоглотки (огляд літератури)

The purpose of the study was to analyze literature sources containing information about defensins, cysteine-rich cationic amphipathic peptides produced by circulating white blood cells and tissue cells. This review describes the antimicrobial, antiviral, anti-inflammatory and immunomodulatory properties of defensins, as well as their molecular and cellular interactions. These substances, which are present on the epithelium and body fluids, are active against bacteria, fungi and viruses, as well as produced by immune and epithelial cells. These natural antimicrobial cationic peptides play an important role in innate and adaptive immunity. Defensins are divided into alpha and beta families. Alpha-defensins (α-defensins) are found in neutrophils, macrophages and Paneth cells in the intestine. Beta-defensins (β-defensins) are secreted by most leukocytes and epithelial cells. Extensive antimicrobial activity and multifaceted immunomodulatory functions of defensins confirm their role in innate immunity as the main protective component of the human body against bacterial, viral and fungal infections. Thus, they are key effector molecules in protecting the organism from infection due to their broad-spectrum antimicrobial activity. Their common antimicrobial function is the formation of destructive pores in the membranes of pathogens, including enveloped viruses. Antiviral activity includes the direct effect of defensin on viral envelopes, glycoproteins and capsids. Binding and modulation of host cell surface receptors and disruption of intracellular signaling by defensins may also inhibit virus replication. These peptides block infection with enveloped and non-enveloped viruses by aggregating particles, blocking receptor binding, inhibiting virus penetration or depletion of particles, inhibiting stem cell signaling, or viral gene expression. In addition, defensins may function as chemokines to enhance and alter adaptive immune responses by exhibiting an indirect antiviral mechanism. Conclusion. However, sources of scientific information have shown that defensins attract immune cells and modulate adaptive immune responses. It has also been shown that defensins can both induce inflammation and suppress inflammatory responses by acting on certain cells through various mechanisms. Due to this, they can be used as one of the markers in the development of inflammatory diseases of the mouth and oropharynx. The main drugs that activate the production of defensins are probiotics, vitamin D and leukotriene B4. This expands the possibility of their use as a new class of non-toxic antimicrobials and immunomodulators

Considering COVID-19 Infectiousness with Esteem to Blood Groups

Abstract COVID-19 is a disease that is caused by SARS-CoV-2 and very speedily spreading all over the world. The blood group's effect on COVID-19 is not clear. The main aim of this article is to determine the relationship between sensitivity of COVID-19 and ABO blood group. For this study we have observed that the individuals with blood group A are at higher risk of getting COVID-19 because they contain the higher concentration of Angiotensin-converting enzyme-2 that provide the site to virus for entry. But in other blood groups the natural Anti A antibodies block the interaction between host receptor and virus and disturb their interaction. Certain studies show that the infectivity and mortality rate in Covid patients is not affected by AB blood group system. But according to research, increased ventilator usage, ICU stay was observed in critically ill patients with AB blood group than of other blood groups. O blood group has proved to be protective against SARS-CoV-2 due to the presence of both anti-A and anti-B antibodies as they prevent the binding of the spike protein S of the virus with the ACE2 receptors which are present on the surface of cells. Moreover, furin also plays a major role in penetration of virus in the host cells. Furin is required for the activation of the spike protein S of the virus and due to the low efficiency of furin cleavage in blood group O it is protected from SARS-CoV-2 and other chronic diseases. Mortality rate of Covid 19 depends upon the environmental factors, number of people living in the area and also some economic factors. The different strains of COVID-19 effect the different people differently and as the time passes the strain of COVID-19 has changed and thus according to this the mortality rate of different provinces and areas varies due to environmental factors. Pregnant women have no any kind of transportation of Covid to their fetuses but mostly patients of blood group A are being affected by COVID-19 and hence their fetuses are somehow effected. And those pregnant women having blood group O does not have any risk of COVID-19 of severe stages.

O-053 ART treatment and pregnancy during covid 19 pandemia: what we learned

In 2020, SARS-CoV-2 and the COVID-19 pandemic had a huge impact on the access to and provision of ART treatments. Gradually, knowledge about the virus and its transmission has become available and has allowed ART activities to resume with certain restrictions. Still, questions on the impact of the virus on fertility and ART treatments remain.Regarding the possible consequences of COVID-19 in men, ACE2 and TMPRSS2, the receptors required for the viral penetration into cells, are highly expressed in the testis and the presence of SARS-CoV-2 has been demonstrated in the testicular tissue and the ejaculate in a small percentage of males with active and severe COVID-19 infection. Impairment of the sperm quality has been described during the acute and recovery phase of infection.In the female scenario, low levels of ACE2 have been reported in ovarian tissue and co-expression of ACE2 and TMPRSS2 has been demonstrated in oocytes, zygotes and blastocysts that are thus potentially susceptible to SARS-CoV-2 infection upon exposure to the virus. The endometrium has been shown to be at a low risk of infection. Although infrequent, vertical transmission of SARS-CoV-2 has been reported in cases of severe maternal infection.The effects of SARS-CoV-2 infection have been analysed in ART patients. Certain studies suggest that ovarian function might be altered and that IVF results could be poorer in patients that have recovered from COVID-19 while others show no evidence of compromised follicular function. The possible effects of vaccination in male and in female patients have also been explored. Neither the ovarian response nor the sperm quality is affected by the administration of COVID-19 vaccines, which are highly recommended in couples planning a pregnancy, either spontaneous or through ART.During the different waves of the COVID-19 pandemic, the ESHRE COVID-19 Working Group has produced recommendations and publications to guide patients and professionals in their journey through ART during these difficult times.