Reactivos básicos para la investigación de enfermedades infecciosas

Monkeypox virus (MPXV)is an enveloped double-stranded DNA virus, belonging to the genus Orthopoxvirus in the poxviridae family. Monkeypox virus has two different infectious virions: the intracellular mature virus (MV) and the extracellular enveloped viruses (EV). When the virus invades the host cell to complete the replication process, the MV cell surface binding protein E8L binds to the cell surface chondroitin sulfate, to provide viral particles attached to the target cell. A30L is also considered an important target in monkeypox virus research as an envelope protein for virus entry into a host and cell-cell fusion (syncytial formation). In addition, the envelope glycoprotein A35R on the surface of EV was predicted to affect the intercellular diffusion of virions. The combination of A29L with heparin on the cell surface promoted the fusion of viral membrane and host plasma membrane. Further, B21R, an important target protein with several key immuno-dominant epitopes, is the focus of monkeypox virus research.

Jynneos, a vaccine for smallpox and monkeypox developed by Danish vaccine company Bavarian Nordic, is the only vaccine approved to protect against monkeypox so far. However, people had stopped smallpox vaccination since it disappear, which means that the current population is generally not immune to smallpox and monkeypox. In addition, A virology expert Chang Rongshan said that the new crown global pandemic may have affected human immunity levels, causing monkeypox to gain more adaptability than ever before in human populations after smallpox disappeared. Therefore, it is necessary to reserve specific vaccines and antiviral drugs while closely monitoring the international monkeypox epidemic.

Coronavirus (CoV) is a large class of viruses that are widely present in nature and  cause illnesses ranging from the common cold to more severe diseases. There are currently eight kinds of coronaviruses found, of which HCoV-229E, HCoV-OC43, HCoV-NL63 and HCoV-HKU1 are more common in the population and less pathogenic; Sars-CoV, MERS-CoV and 2019-nCoV are common susceptible, highly epidemic, and highly contagious diseases. Recently, scientists discovered a canine coronavirus (CCoV-HUpN-2018) in Malaysia and Haiti, which is the eighth coronavirus after SARS-COV-2.

The Spike protein of coronavirus is the main antigen of the virus, which can bind to the receptor and play an important role in the process of  infection. Therefore, S protein and its subunits are generally considered during neutralizing antibodies and vaccine design.

The influenza virus belongs to the family Orthomyxoviridae. Human influenza virus infections have a worldwide distribution. Seasonal influenza epidemics occur regularly both in the Northern and the Southern hemispheres during  winter and are estimated to cause approximately 500,000 deaths per year worldwide.

The influenza virus constitutes by envelope, matrix, and core protein. Hemagglutinin (HA) and neuraminidase (NA) are glycoproteins embedded in the envelope, playing an important role in the virus invasion and release process. Therefore, NA and HA are now important targets in the research and development of influenza vaccines and therapeutic drugs.

Rabies virus (RABV) ）is a neurotropic virus that causes rabies in humans and animals.  The mortality rate is nearly 100% after the manifestation of clinical symptoms . According to the World Health Organization, Rabies occurs in more than 150 countries and territories, leading to the death of about 59,000 people  each year.

Rabies virus is mainly composed of Glycoprotein, Nucleoprotein, Polymerase or  Largeprotein, Phosphoprotein, and Matrixpotein. Among them, the G protein is the only protein that is across the membrane structure and fixed on the viral envelope. It can bind with the acetylcholine receptor and determine the rabies virus neuronophagia. In addition, it is the key to inducing neutralizing antibodies and is widely applied in the assessment of rabies vaccine development and vaccination  tests.

Ebola virus (EBOV) is a class A bioterrorism agent, known to cause a severe and often deadly illness known as Ebola virus disease (EVD). It is the deadliest viral hemorrhagic fever in the world today, with mortality ranging from 50% to 90%.

The Ebola virus contains 7 structural proteins, which are nucleoprotein (NP), VP35, VP40, glycoprotein (GP), VP30, VP24, and L (RNA polymerase).  GP is a key protein that is responsible for the virus’s ability to bind to and infect targeted cells and has been used as an important target for vaccine and antibody therapy.

Human Immunodeficiency Virus (HIV) is a retrovirus that attacks the body’s immune system and causes Immunodeficiency. According to the World Health Organization, there were an estimated 30.2-45.1 million people worldwide living with HIV, and approximately 680,000 people died from HIV-related causes in 2020.  Based on genetic characteristics and differences in the viral antigens, HIV is classified into types 1 and 2 (HIV-1, HIV-2). HIV-2 is mainly distributed in West Africa, while HIV-1 is widely distributed around the world and is the main cause of the AIDS epidemic worldwide.

HIV-1 virus particle consists of a core and an envelope protein. The trimers of gp120 surface protein are anchored to the membrane by the trimers of the transmembrane protein gp41, participating in the fusion and invasion of virus and host cell membrane. During this process, the gp120 will bind to the CD4 and to the co-receptor on the host cell, resulting in loss of immune function and promoting viral persistence by influencing the immune response of T cells to the virus. Therefore, Gp120 is known as a popular target for HIV prevention and treatment.

Varicella-zoster virus (VZV)highly contagious enveloped DNA virus that is common in children. The initial infection causes chickenpox in children, and the virus remains latent in the body after recovery. In a few patients, the virus recurs in adults and causes herpes zoster.

VZV virus contains six glycoproteins, gE, gB, gH, gI, gC and gL.  In infected cells, gE is the most abundant protein expressed by VZV and plays an important role in viral replication and cell-to-cell transmission. As a recognizable antigen, gE becomes a target for vaccine research.

Zika virus (ZIKV)is a mosquito-borne flavivirus. In recent years, the outbreak of the Zika virus in South America, Southeast Asia, and other regions has caused millions of infections. Clinical analysis has shown that Zika virus infection is significantly associated with neurological disorders such as microcephaly in newborns and Guillain-Barre syndrome in adults.

Zika virus RNA encodes 3 structural proteins (C, prM/M and E) and 7 non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5). NS1 is a secreted protein that interacts with the host cells with high immunogenicity. So, NS1 is used as a diagnostic marker for ZIKV infection and as a component of several experimental vaccines.

Respiratory syncytial virus (RSV) is a common respiratory virus that is widely distributed all over the world, mainly infecting infants and elderly people. It is reported that there are more than 33 million children under the age of five in the world infected by RSV per year, which is a major cause of infant mortality in the developing world.

The viral genome of RSV encodes 11 proteins, of which Fusion protein (F) and Attachment glycoprotein (G) are the two main protective antigens of the virus. The G protein is mainly related to the severity of the infection and is responsible for fusing with host cells. The F protein causes the fusion of the viral capsid with the host cell membrane and plays an important role in immunopathology triggered by RSV infection. Therefore, both proteins are currently considered hot antigens for the development of antibodies, vaccines, and other therapeutic agents.

Nipah Virus (NiV) is a new zoonotic virus that causes widespread vasculitis, fever, severe headache,  meningitis, and other symptoms in infected people, causing serious harm to humans and animals. It is another zoonotic disease that has caused widespread concern and panic in the world after mad cow disease in the UK, foot-and-mouth disease in pigs on Taiwan Island, and avian influenza in Hong Kong.

The NiV genome encodes six structural proteins, including nucleocapsid protein (N), phosphoprotein (P), matrix protein (M), fusion protein (F), attachment glycoprotein (G), and large protein or RNA polymerase protein (L).  G protein and F protein play key roles in the process of virus entry into host cells and induction of neutralizing antibodies. G proteins attach to cell receptors and trigger F glycoproteins for membrane fusion and generally be considered a target for vaccine development and prevention of NiV. F protein expressed in vitro can be used as a diagnostic antigen for monitoring and detection of NiV,

Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) is an acute infectious disease that causes severe fever with thrombocytopenia syndrome, mainly transmitted by tick bites with a peak epidemic from April to September. The clinical manifestations are characterized by fever with thrombocytopenia, and a few patients with seriously and rapidly progressive disease may die from multiple organ failure.

Currently, neither antiviral drugs nor vaccines are available for severe fever with thrombocytopenia syndrome virus (SFTSV). The envelope protein glycoprotein N (gN) on the surface of viruses is the main antigenic component that can attach to cell receptors and trigger fusion glycoprotein (F) for membrane fusion. Therefore, gN is widely recognized by neutralizing antibodies and is an ideal vaccine target.