AntibodyAn antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision.
VaccineA vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified.
COVID-19 vaccineA COVID19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID19). Prior to the COVID19 pandemic, an established body of knowledge existed about the structure and function of coronaviruses causing diseases like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). This knowledge accelerated the development of various vaccine platforms during early 2020.
Vaccine hesitancyVaccine hesitancy is a delay in acceptance, or refusal, of vaccines despite the availability of vaccine services and supporting evidence. The term covers refusals to vaccinate, delaying vaccines, accepting vaccines but remaining uncertain about their use, or using certain vaccines but not others. The scientific consensus that vaccines are generally safe and effective is overwhelming. Vaccine hesitancy often results in disease outbreaks and deaths from vaccine-preventable diseases.
Envelope glycoprotein GP120Envelope glycoprotein GP120 (or gp120) is a glycoprotein exposed on the surface of the HIV envelope. It was discovered by Professors Tun-Hou Lee and Myron "Max" Essex of the Harvard School of Public Health in 1988. The 120 in its name comes from its molecular weight of 120 kDa. Gp120 is essential for virus entry into cells as it plays a vital role in attachment to specific cell surface receptors. These receptors are DC-SIGN, Heparan Sulfate Proteoglycan and a specific interaction with the CD4 receptor, particularly on helper T-cells.
Viral envelopeA viral envelope is the outermost layer of many types of viruses. It protects the genetic material in their life cycle when traveling between host cells. Not all viruses have envelopes. A viral envelope protein or E protein is a protein in the envelope, which may be acquired by the capsid from an infected host cell. Numerous human pathogenic viruses in circulation are encased in lipid bilayers, and they infect their target cells by causing the viral envelope and cell membrane to fuse.
Polio vaccinePolio vaccines are vaccines used to prevent poliomyelitis (polio). Two types are used: an inactivated poliovirus given by injection (IPV) and a weakened poliovirus given by mouth (OPV). The World Health Organization (WHO) recommends all children be fully vaccinated against polio. The two vaccines have eliminated polio from most of the world, and reduced the number of cases reported each year from an estimated 350,000 in 1988 to 33 in 2018. The inactivated polio vaccines are very safe.
Humoral immunityHumoral immunity is the aspect of immunity that is mediated by macromolecules - including secreted antibodies, complement proteins, and certain antimicrobial peptides - located in extracellular fluids. Humoral immunity is named so because it involves substances found in the humors, or body fluids. It contrasts with cell-mediated immunity. Humoral immunity is also referred to as antibody-mediated immunity. The study of the molecular and cellular components that form the immune system, including their function and interaction, is the central science of immunology.
DNA vaccineA DNA vaccine is a type of vaccine that transfects a specific antigen-coding DNA sequence into the cells of an organism as a mechanism to induce an immune response. DNA vaccines work by injecting genetically engineered plasmid containing the DNA sequence encoding the antigen(s) against which an immune response is sought, so the cells directly produce the antigen, thus causing a protective immunological response. DNA vaccines have theoretical advantages over conventional vaccines, including the "ability to induce a wider range of types of immune response".
Hib vaccineThe Haemophilus influenzae type B vaccine, also known as Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis. It is recommended by both the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). Two or three doses should be given before six months of age.
MRNA vaccineAn mRNA vaccine is a type of vaccine that uses a copy of a molecule called messenger RNA (mRNA) to produce an immune response. The vaccine delivers molecules of antigen-encoding mRNA into immune cells, which use the designed mRNA as a blueprint to build foreign protein that would normally be produced by a pathogen (such as a virus) or by a cancer cell. These protein molecules stimulate an adaptive immune response that teaches the body to identify and destroy the corresponding pathogen or cancer cells.
Immune systemThe immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli.
Respiratory syncytial virusRespiratory 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 a common cause of respiratory hospitalization in infants, and reinfection remains common in later life: it is a notable pathogen in all age groups.
Antibody-dependent enhancementAntibody-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.
Coronavirus spike proteinSpike (S) glycoprotein (sometimes also called spike protein, formerly known as E2) is the largest of the four major structural proteins found in coronaviruses. The spike protein assembles into trimers that form large structures, called spikes or peplomers, that project from the surface of the virion. The distinctive appearance of these spikes when visualized using negative stain transmission electron microscopy, "recalling the solar corona", gives the virus family its main name.
Viral diseaseA viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Basic structural characteristics, such as genome type, virion shape and replication site, generally share the same features among virus species within the same family. Double-stranded DNA families: three are non-enveloped (Adenoviridae, Papillomaviridae and Polyomaviridae) and two are enveloped (Herpesviridae and Poxviridae).
Subunit vaccineA subunit vaccine is a vaccine that contains purified parts of the pathogen that are antigenic, or necessary to elicit a protective immune response. Subunit vaccine can be made from dissembled viral particles in cell culture or recombinant DNA expression, in which case it is a recombinant subunit vaccine. A "subunit" vaccine doesn't contain the whole pathogen, unlike live attenuated or inactivated vaccine, but contains only the antigenic parts such as proteins, polysaccharides or peptides.
Monoclonal antibodyA monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodies can have monovalent affinity, binding only to the same epitope (the part of an antigen that is recognized by the antibody). In contrast, polyclonal antibodies bind to multiple epitopes and are usually made by several different antibody-secreting plasma cell lineages.
Adaptive immune systemThe adaptive immune system, also known as the acquired immune system, or specific immune system is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system is one of the two main immunity strategies found in vertebrates (the other being the innate immune system). Like the innate system, the adaptive immune system includes both humoral immunity components and cell-mediated immunity components and destroys invading pathogens.
InfectionAn infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently bacteria and viruses. Hosts can fight infections using their immune systems. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response.
