|
Antibody-dependent Enhancement
Antibody-dependent enhancement (ADE), sometimes less precisely called immune enhancement or disease enhancement, is a phenomenon in which binding of a virus to suboptimal antibodies enhances its entry into host cells, followed by its replication. The suboptimal antibodies can result from natural infection or from vaccination. ADE may cause enhanced respiratory disease, but is not limited to respiratory disease. It has been observed in HIV, RSV virus and Dengue virus and is monitored for in vaccine development. Technical description In ADE, antiviral antibodies promote viral infection of target immune cells by exploiting the phagocytic FcγR or complement pathway. After interaction with a virus, the antibodies bind Fc receptors (FcR) expressed on certain immune cells or complement proteins. FcγRs bind antibodies via their fragment crystallizable region (Fc). The process of phagocytosis is accompanied by virus degradation, but if the virus is not neutralized (either due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virulence
Virulence is a pathogen's or microorganism's ability to cause damage to a host. In most, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its host. The pathogenicity of an organism—its ability to cause disease—is determined by its virulence factors. In the specific context of gene for gene systems, often in plants, virulence refers to a pathogen's ability to infect a resistant host. The noun ''virulence'' derives from the adjective ''virulent'', meaning disease severity. The word ''virulent'' derives from the Latin word ''virulentus'', meaning "a poisoned wound" or "full of poison." From an ecological standpoint, virulence is the loss of fitness induced by a parasite upon its host. Virulence can be understood in terms of proximate causes—those specific traits of the pathogen that help make the host ill—and ultimate causes—the evolutionary pressures that lead to virulent traits occurring in a pathogen strain. Virulent ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FcγRII
CD32 (cluster of differentiation 32), also known as FcγRII or FCGR2, is a surface receptor glycoprotein belonging to the Ig gene superfamily. CD32 can be found on the surface of a variety of immune cells. CD32 has a low-affinity for the Fc region of IgG antibodies in monomeric form, but high affinity for IgG immune complexes. CD32 has two major functions: cellular response regulation, and the uptake of immune complexes. Cellular responses regulated by CD32 include phagocytosis, cytokine stimulation, and endocytic transport. Dysregulated CD32 is associated with different forms of autoimmunity, including systemic lupus erythematosus. In humans, there are three major CD32 subtypes: CD32A, CD32B, and CD32C. While CD32A and CD32C are involved in activating cellular responses, CD32B is inhibitory. Structure and signaling CD32 is a type I transmembrane protein with a helical transmembrane region. Whereas the extracellular region consists of three immunoglobulin domains (roughly 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Orthopneumovirus
Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a common, contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. Its name is derived from the large cells known as '' syncytia'' that form when infected cells fuse. RSV is the single most common cause of respiratory hospitalization in infants, and reinfection remains common in later life: it is a notable pathogen in all age groups. Infection rates are typically higher during the cold winter months, causing bronchiolitis in infants, common colds in adults, and more serious respiratory illnesses such as pneumonia in the elderly and immunocompromised. RSV can cause outbreaks both in the community and in hospital settings. Following initial infection via the eyes or nose, the virus infects the epithelial cells of the upper and lower airway, causing inflammation, cell damage, and airway obstruction. A vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthopneumovirus
The genus ''Orthopneumovirus'' consists of pathogens that target the upper respiratory tract within their specific hosts. Every orthopneumovirus is characterized as host-specific, and has a range of diseases involved with respiratory illness. Orthopneumoviruses can cause diseases that range from a less-severe upper-respiratory illness to severe bronchiolitis or pneumonia. Orthopneumoviruses are found among sheep, cows, and most importantly humans. In humans, the orthopneumovirus that specifically impacts infants and small children is known as human respiratory syncytial virus. Taxonomy Other viruses in this taxon include canine pneumovirus. Characteristics The genus ''Orthopneumovirus'' is included in the family ''Pneumoviridae''. Orthopneumoviruses are found specifically in the members of the species ''Homo sapiens'', ''Ovis aries'', '' Capra aegagrus hircus'', ''Bos primigenius'', and the order Rodentia. The most common pneumoviruses are as follows: •''Homo sapiens'': hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrovirus
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. Once inside the host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus ''retro'' (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Although retroviruses have different subfamilies, they have three basic groups: the oncoretroviruses (oncogenic retroviruses), the lentiviruses (slow retroviruses) and the spumaviruses (foamy viruses). The oncoretroviruses are able to cause cancer in some species, the lentiviru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Influenza
Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin from one to four days after exposure to the virus (typically two days) and last for about 2–8 days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia, which can be caused by the virus or by a subsequent bacterial infection. Other complications of infection include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease. There are four types of influenza virus, termed influenza viruses A, B, C, and D. Aquatic birds are the primary source of Influenza A virus (IAV), which is also widespread in various mammals, including humans and pigs. Influenza B virus (IBV) and Influenza C virus (ICV) pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthomyxoviridae
''Orthomyxoviridae'' (from Greek language, Greek ὀρθός, ''orthós'' 'straight' + μύξα, ''mýxa'' 'mucus') is a family of negative-sense single-stranded RNA virus, negative-sense RNA viruses. It includes seven genus, genera: ''Influenza A virus, Alphainfluenzavirus'', ''Influenza B virus, Betainfluenzavirus'', ''Influenza C virus, Gammainfluenzavirus'', ''Influenza D virus, Deltainfluenzavirus'', ''Isavirus'', ''Thogotovirus'', and ''Quaranjavirus''. The first four genera contain viruses that cause influenza in birds (see also avian influenza) and mammals, including humans. Isaviruses infect salmon; the thogotoviruses are arboviruses, infecting vertebrates and invertebrates (such as ticks and mosquitoes). The Quaranjaviruses are also arboviruses, infecting vertebrates (birds) and invertebrates (arthropods). The four genera of Influenza virus that infect vertebrates, which are identified by antigenic differences in their nucleoprotein and matrix protein, are as follows: * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betacoronavirus
''Betacoronavirus'' (β-CoVs or Beta-CoVs) is one of four genera (''Alpha''-, ''Beta-'', '' Gamma-'', and '' Delta-'') of coronaviruses. Member viruses are enveloped, positive-strand RNA viruses that infect mammals (of which humans are part). The natural reservoir for betacoronaviruses are bats and rodents. Rodents are the reservoir for the subgenus ''Embecovirus'', while bats are the reservoir for the other subgenera. The coronavirus genera are each composed of varying viral lineages with the betacoronavirus genus containing four such lineages: A, B, C, D. In older literature, this genus is also known as "group 2 coronaviruses". The genus is in the subfamily ''Orthocoronavirinae'' in the family ''Coronaviridae'', of the order '' Nidovirales''. The betacoronaviruses of the greatest clinical importance concerning humans are OC43 and HKU1 (which can cause the common cold) of lineage A, SARS-CoV and SARS-CoV-2 (which has caused the disease COVID-19) of lineage B, and MERS-CoV ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphacoronavirus
Alphacoronaviruses (Alpha-CoV) are members of the first of the four genera (''Alpha''-, '' Beta-'', '' Gamma-'', and '' Delta-'') of coronaviruses. They are positive-sense, single-stranded RNA viruses that infect mammals, including humans. They have spherical virions with club-shaped surface projections formed by trimers of the spike protein, and a viral envelope. Alphacoronaviruses are in the subfamily ''Orthocoronavirinae'' of the family ''Coronaviridae''. Both the ''Alpha''- and ''Betacoronavirus'' lineages descend from the bat viral gene pool. Alphacoronaviruses were previously known as "phylogroup 1 coronaviruses". The Alphacoronavirus genus is very diverse, particularly in bats. Most bat originating strains haven't been successfully isolated and cultured in laboratory. Alphacoronaviruses infecting other mammal species have been much better studied, see List of Coronavirus live isolates. Etymology The name alphacoronavirus is derived from Ancient Greek ἄλφα ( álp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zika Virus
''Zika virus'' (ZIKV; pronounced or ) is a member of the virus family ''Flaviviridae''. It is spread by daytime-active ''Aedes'' mosquitoes, such as '' A. aegypti'' and '' A. albopictus''. Its name comes from the Ziika Forest of Uganda, where the virus was first isolated in 1947. ''Zika virus'' shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to , the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–2016 Zika virus epidemic. The infection, known as Zika fever or ''Zika virus'' disease, often causes no or only mild symptoms, similar to a very mild form of dengue fever. While there is no specific treatment, paracetamol (acetaminophen) and rest may help with the symptoms. Zika can spread from a pregnant woman to her baby. This can result in microcephaly, severe brain malformations, and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellow Fever
Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased. The disease is caused by the yellow fever virus and is spread by the bite of an infected mosquito. It infects humans, other primates, and several types of mosquitoes. In cities, it is spread primarily by ''Aedes aegypti'', a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus ''Flavivirus''. The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood-sample testing with polymerase chain reaction is required. A saf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.png "Click for more on -> Zika Virus")
