subunit vaccine

Examples of subunit vaccine in the following topics:

• Genetically Engineered Vaccines

  • Genetically engineered subunit vaccines are more costly to manufacture than conventional vaccines, since the antigen must be purified to a higher standard than was demanded of older, conventional vaccines.
  • Although recombinant subunit vaccines hold great promise, they do present some potential limitations.
  • In addition to being less reactogenic, recombinant subunit vaccines have a tendency to be less immunogenic than their conventional counterparts.
  • This can be attributed to these vaccines being held to a higher degree of purity than was traditionally done for an earlier generation of licensed subunit vaccines.
  • Recombinant subunit vaccines may also suffer from being too well-defined, because they are composed of a single antigen.

• Vaccines and Immunity

  • Vaccinations prevent viruses from spreading by building immunity to the virus.
  • Vaccines may be prepared using live viruses, killed viruses, or molecular subunits of the virus.
  • The killed viral vaccines and subunit viruses are both incapable of causing disease.
  • Polio was one disease that represented a milestone in the use of vaccines.
  • The success of the polio vaccine paved the way for the routine dispensation of childhood vaccines against measles, mumps, rubella, chickenpox, and other diseases.

• Adherence

  • The Bordetella pertussis adhesins FHA and pertactin are components of 3 of the 4 acellular pertussis vaccines currently licensed for use in the U.S.
  • Most fimbriae of Gram-negative bacteria function as adhesins, but in many cases the actual adhesin is a minor subunit protein at the tip of the fimbriae.
  • Adhesins are attractive vaccine candidates because they are often essential to infection and are surface-located, making them readily accessible to antibodies.
  • In animal models, passive immunization with anti FimH-antibodies and vaccination with the protein significantly reduced colonization by UPEC.
  • Moreover, the Bordetella pertussis adhesins FHA and pertactin are components of 3 of the 4 acellular pertussis vaccines currently licensed for use in the U.S.

• Diphtheria

  • Historically quite common, diphtheria has largely been eradicated in industrialized nations through widespread vaccination.
  • In the United States, for example, there were 52 reported cases of diphtheria between 1980 and 2000; between 2000 and 2007, there were only three cases as the diphtheria–pertussis–tetanus (DPT) vaccine is recommended for all school-age children.
  • Boosters of the vaccine are recommended for adults, since the benefits of the vaccine decrease with age without constant re-exposure; they are particularly recommended for those traveling to areas where the disease has not been eradicated.
  • Fragment B is a recognition subunit that gains the toxin entry into the host cell by binding to the EGF-like domain of heparin-binding EGF-like growth factor (HB-EGF) on the cell surface.

• Vaccine Safety

  • Vaccines carry risks, ranging from rashes or tenderness at the site of injection to fever-associated seizures.
  • Vaccines are biological products with biological effects.
  • Some speculate that children with metabolic disorders might be prone to vaccine side effects.
  • Safer vaccines and manufacturing processes are also in the works.
  • These include current smallpox vaccines that cannot safely be given to immunocompromised people; the tuberculosis vaccine, which is not recommended for HIV-positive infants; and the yellow-fever vaccine, which puts elderly people at particular risk of a yellow-fever-like illness.

• Tetanus

  • The B subunit binds to the receptors on motor neurons, while the A subunit induces endocytosis to enter the neuron.
  • This is due to the extreme potency of the tetanospasmin toxin; even a lethal dose of tetanospasmin is insufficient to provoke an immune response.Tetanus can be prevented by vaccination with tetanus toxoid.
  • The CDC recommends that adults receive a booster vaccine every ten years, and standard care practice in many places is to give the booster to any patient with a puncture wound who is uncertain of when he or she was last vaccinated, or if he or she has had fewer than three lifetime doses of the vaccine.

• Vaccination

  • Vaccination is a proven way to prevent and even eradicate widespread outbreaks of life-threatening infectious diseases.
  • Global mass vaccination drives have met with enormous success in reducing the incidence of many diseases.
  • Another consideration is that the newer vaccination programs also protect older age groups.
  • By these vaccinated children not contracting these diseases, their parents, grandparents, friends and relatives (not vaccinated against these diseases themselves) will also be protected.
  • Describe how active immunity to diseases can be acquired by natural exposure or by vaccination

• Development of New Vaccines

  • New vaccines are being developed to control recent infectious disease epidemics and cancers.
  • A number of new vaccines with major potential for controlling infectious diseases have just been licensed or are at advanced stages of development.
  • Continuing intensive efforts are under way to develop effective vaccines for AIDS, malaria, tuberculosis, dengue, leishmaniasis, and enteric diseases, among others and to adapt new technologies to improve formulation and delivery.
  • Gardasil is a human papillomavirus vaccine on the market and it protects against HPV-16 and HPV-18 which cause 70% of cervical cancers, 80% of anal cancers, 60% of vaginal cancers, and 40% of vulvar cancers.
  • Describe how new vaccines are being developed to help eradicate several infectious global diseases

• Initiation of Transcription in Prokaryotes

  • Four of these subunits, denoted α, α, β, and β', comprise the polymerase core enzyme.
  • Each subunit has a unique role: the two α-subunits are necessary to assemble the polymerase on the DNA; the β-subunit binds to the ribonucleoside triphosphate that will become part of the nascent "recently-born" mRNA molecule; and the β' binds the DNA template strand.
  • The fifth subunit, σ, is involved only in transcription initiation.
  • The polymerase comprised of all five subunits is called the holoenzyme.
  • Once this interaction is made, the subunits of the core enzyme bind to the site.

• The Salk Vaccine Field Trial

  • The Salk polio vaccine field trial incorporated a double blind placebo control methodolgy to determine the effectiveness of the vaccine.
  • The Salk polio vaccine field trials constitute one of the most famous and one of the largest statistical studies ever conducted.
  • The Salk vaccine, or inactivated poliovirus vaccine (IPV), is based on three wild, virulent reference strains:
  • Soon after Salk's vaccine was licensed in 1955, children's vaccination campaigns were launched.
  • Jonas Salk administers his polio vaccine on February 26, 1957 in the Commons Room of the Cathedral of Learning at the University of Pittsburgh where the vaccine was created by Salk and his team.