Synthesis of pox viruses can be potentially useful in developing new and safer smallpox vaccines, as well as in the treatment of cancer.
Highlights:
Scientists
have synthesized a horsepox virus which could effectively replace the current
vaccinia virus in the smallpox vaccine. The study was published in PLOS ONE.
The
current smallpox vaccine that contains the vaccinia virus is used only in first
responders and military personnel, given the fact that the infection has been
eradicated.
The side effects of the vaccine include mild reactions like fever, soreness in
the arm, enlarged lymph nodes in the armpit, or more serious reactions like
allergic reaction, serious rash or even inflammation of the brain (encephalitis)
or heart /pericardium (myocarditis/pericarditis or both) in rare cases. Serious
adverse effects may be particularly noted in immunocompromised individuals,
patients with chronic skin diseases or active skin breaks at the time of the
vaccination. - Synthetic horsepox virus has been developed, which has the potential to be used in a smallpox vaccine instead of the vaccinia virus
- It appears to be a safer alternative to the vaccinia virus
- It provided mice protection against vaccinia virus infection.
New Light on the Historical Origin of Smallpox Vaccine
The smallpox vaccine can have potentially fatal side effects, so only the people who are at high risk of exposure get the vaccine.
The smallpox vaccine can have potentially fatal side effects, so only the people who are at high risk of exposure get the vaccine.
‘Synthesis of pox viruses can be potentially useful in developing new and safer smallpox vaccines, as well as in the treatment of cancer.’
Scientists
felt that another pox virus, the horsepox virus that does not cause infection
in humans, could be a safer alternative to the vaccinia virus in the smallpox
vaccine.
The horsepox virus appears to have a common ancestry with the modern vaccinia
virus strains, which are used to develop the smallpox vaccine. However, since
the horsepox virus is not easily available, the scientists decided to use
large-scale gene synthesis to produce the virus. Despite several challenges, the scientists were able to synthesize the horsepox virus in cells infected with Shope fibroma virus (SFV). The replicating synthetic-chimeric horsepox virus (scHPXV):
- Produced smaller plaques and less secondary plaque formation in vitro testing, which indicates the reduced virulence of the virus
- Was less virulent in mice as compared to a strain of vaccinia virus used in vaccines
- Provided protection against infection from the vaccinia virus
The scientists have also suggested another possible positive implication of their study in a totally unrelated condition, cancer. Ongoing research has used viruses to boost the immune system to fight against cancer cells. Thus, a similar approach as used in the current study could be employed to develop other pox viruses like orthopoxviruses, which could be used in cancer treatment. The synthesis of viral DNA in the laboratory can also help scientists to study some features of the viral genome that have not been completely understood as yet.
About Vaccines
Vaccines contain live attenuated or killed organisms (or sometimes toxins) that stimulate the immune response and protect the individual against the particular infection. In rare cases, especially in patients with reduced immunity, live attenuated vaccines can cause the infection they were meant to protect against.
Smallpox-Not an Ancient Disease?
Smallpox which was once though of as an ancient disease, may have emerged in more recent times.
Smallpox which was once though of as an ancient disease, may have emerged in more recent times.
- Noyce RS, Lederman S, Evans DH (2018) Construction of an infectious horsepox virus vaccine from chemically synthesized DNA fragments. PLOS ONE 13(1): e0188453.(https://doi.org/10.1371/journal.pone.0188453)
Source-Medindia
New Small Pox Vaccine Approved by FDA
US Food and Drug Administration has announced the approval of a new vaccine against smallpox. It said the shots could be made quickly if the virtually extinct virus reappears.
US Food and Drug Administration has announced the approval of a new vaccine against smallpox. It said the shots could be made quickly if the virtually extinct virus reappears.
Researchers Identify Alternative to Existing Smallpox Vaccine
Researchers at the University of California, Irvine have identified a potential alternative to the existing smallpox vaccine that can replace the current biodefense stockpile for this lethal virus.
Researchers at the University of California, Irvine have identified a potential alternative to the existing smallpox vaccine that can replace the current biodefense stockpile for this lethal virus.
