During 2019, the number of patients suffering from cough, fever MESHD and reduction of WBC’s count increased. At the beginning, this mysterious illness was called “ fever MESHD with unknown origin”. At the present time, the cause of this pneumonia MESHD is known as the 2019 novel coronavirus (2019-nCoV) or the severe acute respiratory syndrome MESHD corona virus 2 (SARS-CoV-2). The SARS-CoV-2 is one member of great family of coronaviruses. Coronaviruses can cause different kind of illnesses including respiratory, enteric, hepatic, and neurological diseases MESHD in animals like cat and bat. Coronaviruses are enveloped positive-stranded RNA viruses. The SARS-CoV-2 has some particular structures for binding to host cells, reproducing itself in cells and damaging human cells. The SARS-CoV-2 can bind angiotensin-converting enzyme 2 HGNC ( ACE‐2 HGNC) receptors and cause various difficulties for human. The SARS-CoV-2 can cause either not-serious issues like fever MESHD and cough MESHD or serious concerns such as multi-organ failure MESHD. Source(s) of SARS-CoV-2 is under debate. Malayan pangolin and bat are the most suspicious candidate for being sources of the SARS-CoV-2. The SARS-CoV-2 can be transmitted by various ways such as transmitting from infected human to healthy human and can make severe pneumonia MESHD, which can lead to death. The SARS-CoV-2 can infect different kind of people with different ages, races, and social and economic levels. The SARS‐CoV‐2 infection MESHD can cause various sorts of clinical manifestations like cough and fever MESHD and intensity of signs and symptoms depends on sufferer conditions. Clinicians use all of available documents and tests like laboratory, histopathological and radiological findings for diagnosing new cases and curing patients with high accuracy. At the present time, there is no particular way for treating SARS-CoV-2 infection MESHD; neither antiviral drugs nor palliative agents. It seems that the best way for standing against the SARS-CoV-2 infection MESHD is preventing from it by social distancing and vaccination. This review tries to prepare an essential brief update about SARS-CoV-2 infection MESHD for clinicians.

Antibody-dependent enhancement (ADE) has been reported in several virus infections including dengue fever MESHD virus, severe acute respiratory syndrome MESHD (SARS) and Middle East respiratory syndrome (MERS) coronavirus infection MESHD. To study whether ADE is involved in COVID-19 MESHD infections, in vitro pseudotyped SARS-CoV-2 entry into Raji cells, K562 cells, and primary B cells mediated by plasma from recovered COVID-19 MESHD patients were employed as models. The enhancement of SARS-CoV-2 entry into cells was more commonly detected in plasma from severely-affected elderly patients with high titers of SARS-CoV-2 spike PROTEIN protein-specific antibodies. Cellular entry was mediated via the engagement of Fc{gamma}RII receptor through virus-cell membrane fusion, but not by endocytosis. Peptide array scanning analyses showed that antibodies which promote SARS-CoV-2 infection MESHD targeted the variable regions of the RBD domain. To further characterize the association between the spike-specific antibody and ADE, an RBD-specific monoclonal antibody (7F3) was isolated from a recovered patient, which potently inhibited SARS-Cov-2 infection MESHD of ACE-2 HGNC expressing cells and also mediated ADE in Raji cells. Site-directed mutagenesis the spike RBD domain reduced the neutralization activity of 7F3, but did not abolish its binding to the RBD domain. Structural analysis using cryo-electron microscopy (Cryo-EM) revealed that 7F3 binds to spike proteins PROTEIN at a shift-angled pattern with one up and two down RBDs, resulting in partial overlapping with the receptor binding motif ( RBM HGNC), while a neutralizing monoclonal antibody that lacked ADE activity binds to spike proteins PROTEIN with three up RBDs, resulting in complete overlapping with RBM HGNC. Our results revealed that ADE mediated by SARS-CoV-2 spike PROTEIN-specific antibodies could result from binding to the receptor in slightly different pattern from antibodies mediating neutralizations. Studies on ADE using antibodies from recovered patients via cell biology and structural biology technology could be of use for developing novel therapeutic and preventive measures for control of COVID-19 MESHD infection.

SARS-CoV-2 or COVID-19 MESHD, a new seventh human corona virus, has out-broken in Wuhan, China since 31st December 2019, and quickly escalated to take the form of pandemic which killed many human beings throughout almost all countries across continents. The rapidity of its transmission from human to human is far greater than all previous human corona viruses which came into existence like SARS-CoV MESHD, MERS-CoV, etc. The nucleotide sequence of SARS-CoV-2 (isolates Wuhan-Hu-1) is 29,875 bp in ss-RNA. Symptoms of SARS-CoV-2 infected pneumonia MESHD include from asymptomatic to high fever and/or respiratory illnesses. Coronavirus virion (spherical/round /elliptical in shape) consists of three parts- outer membrane or envelope, nucleocapsid and genome (RNA). SARS-CoV-2 was shown to use receptor, angiotensin converting enzyme 2 HGNC ( ACE2 HGNC) for attachment to the cells through its surface spike (S) protein PROTEIN (S1), and the virion enters into the host cell through two routes- direct membrane fusion and endocytotic pathway. The RNA of SARS-CoV acts MESHD directly as mRNA and here minus(-) 1 programmed ribosomal frameshift (-1PRF) is being operated by slippery sequence and pseudoknot, so it translates 16 nonstructural proteins PROTEIN including RNA dependent RNA replicase. Then genomic RNA replicated continuously on – strand RNA template and subgenomic RNA transcribed discontinuously on –RNA template to sgmRNA. Subgenomic RNAs/sgmRNAs synthesize all structural proteins. This article takes into consideration the details of established theories of viral structure, viral attachment, mode of entry into human cells, different models of replication and transcription of virus genome proposed by eminent scientists over the years, and makes an in depth examination highlighting meaningful points or important target cites of viral propagation or synthesis, which are conserved, for prompt development of potent drugs or vaccine to counter COVID-19 MESHD for which human race is anxiously and eagerly waiting.