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Adenovirus antibodies reduce vector vaccine efficacy

  • Posted By
    10Pointer
  • Categories
    Science & Technology
  • Published
    15th Mar, 2021

Context

  • Studies have shown that using the same adenovirus subtypes for repeated vaccination might result in reduced efficacy.

What is an Adenovirus antibody?

  • Adenoviruses(family Adenoviridae) are medium-sized (90–100 nm)viruses.
  • They are-enveloped (without an outer lipid bilayer) viruses.
  • They are icosahedral nucleocapsid containing a double-stranded DNA genome.

  • Adenoviruses: These are a group of common viruses that infect the lining of the eyes, airways, and lungs, intestines, urinary tract, and nervous system.
    • They're common causes of fever, coughs, sore throats, diarrhea, and pink eye.
    • The immune system generated against the adenovirus infection causes the antibodies formation.

How these antibodies illicit response action against vector-based vaccine?

  • Pre-existing antibodies cause the relatively low efficacy of the adenovirus-based vaccine in some people.
    • It affects the development of antibodies against the new target.
    • Pre-existing antibodies against adenoviruses will stop the adenovirus particles from getting into cells and making the SARS-CoV-2 spike protein they carry the code for.

Adenovirus as Vector

  • Adenoviruses are excellent vectors for delivering genes or vaccine antigens. Adenovirus-based vectors offer several advantages over other viral vectors such as:
    • a broad range of tissue tropism
    • well-characterized genome
    • ease of genetic manipulation including acceptance of large transgene DNA insertions
    • inherent adjuvant properties
    • ability to induce robust transgene-specific T cell and antibody responses
    • non-replicative nature in host
    • ease of production at large scale

Vector-based Vaccines

  • Viral vectors are tools commonly used to deliver genetic material into cells.
    • This process can be performed inside a living organism (in vivo) or in cell culture (in vitro). 
    • As a medium of transport: Viruses have evolved specialized molecular mechanisms to efficiently transport their genomes inside the cells they infect. 
    • Functioning: They are then inserted into the genome of a non-pathogenic organism, where they are expressed on the organism's surface and can elicit an immune response.

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