New Vaccine Technologies

On this page

Nucleic Acid Vaccines - Genetic Code Shots

  • Delivers genetic material (DNA or mRNA) encoding specific antigen(s) into host cells.
  • Host cells transcribe (DNA) and translate (mRNA/DNA) the genetic material to produce the antigen.
  • This in-situ antigen production mimics natural infection, eliciting robust cellular (T-cell) and humoral (B-cell) immunity.
  • Types:
    • DNA Vaccines:
      • Plasmid DNA containing antigen gene.
      • Requires entry into nucleus for transcription.
      • Good stability; elicits strong Th1 responses.
    • mRNA Vaccines:
      • In vitro transcribed mRNA encoding antigen.
      • Direct translation in cytoplasm; no nuclear entry needed.
      • Rapid development, potent immunogenicity (e.g., COVID-19 vaccines).
      • Often encapsulated in Lipid Nanoparticles (LNPs) for delivery & stability.

mRNA and DNA Vaccine Mechanisms

⭐ mRNA vaccines (e.g., Pfizer-BioNTech, Moderna for COVID-19) are known for their rapid development and ability to elicit strong neutralizing antibody responses and T-cell immunity. They bypass the need for nuclear entry, leading to faster antigen expression compared to DNA vaccines.

  • Advantages: Rapid development, scalability, safety (non-infectious, no integration risk for mRNA), induces broad immunity.
  • Challenges: Delivery systems (especially for DNA), stability (mRNA more labile than DNA), potential for anti-DNA antibodies (theoretical for DNA vaccines).

Viral Vector Vaccines - Trojan Horse Tactics

  • Harmless virus (vector) delivers pathogen's genetic material (DNA/RNA) into host cells. 📌 Viral Vans Deliver Genes.
  • Host cells produce pathogen antigens, triggering robust immune response (cellular & humoral).
    • "Trojan Horse" delivery of antigen-coding genes.
  • Vector Types:
    • Replicating: e.g., Measles, VSV. ↑Antigen, stronger immunity.
    • Non-replicating: e.g., Adenovirus (Ad26, ChAdOx1), AAV. Safer; may need boosters.
  • Pros: Strong T & B-cell response; good stability.
  • Cons: Pre-existing vector immunity can ↓ efficacy; manufacturing complexity.
  • Examples:
    • COVID-19: J&J (Ad26), AstraZeneca (ChAdOx1).
    • Ebola: rVSV-ZEBOV. Viral Vector Vaccine Mechanism and Immune Response

⭐ Pre-existing adenovirus immunity can ↓ vector vaccine efficacy.

Subunit & Particle Vaccines - Protein Power-Ups

  • Uses purified antigens (proteins, polysaccharides) or Virus-Like Particles (VLPs). No whole organisms.
  • Pros: ↑ Safety (no infection risk), defined composition.
  • Cons: Often need adjuvants; immunity may be less broad/durable.
  • Examples:
    • Protein Subunit: Hepatitis B (HBsAg), Acellular pertussis.
    • Polysaccharide: Pneumococcal (PPSV23), Meningococcal. Conjugation (e.g., Hib, PCV13) vital for infant T-dependent response.
    • Virus-Like Particles (VLPs): HPV, Hepatitis B. Self-assembling viral proteins; mimic virus, highly immunogenic, non-infectious.

⭐ HPV vaccine, a VLP type, shows high efficacy by mimicking viral structure, inducing robust protective immunity against specific oncogenic HPV types.

Emerging Vaccine Tech & Adjuvants - Frontier Technologies

  • Nanoparticle Vaccines: VLPs, liposomes. ↑ immunogenicity.
    • Virus-Like Particles (VLPs): Non-infectious, mimic native pathogen structures (e.g., HPV, HBV).
    • Outer Membrane Vesicles (OMVs): From Gram-negative bacteria, potent immunogens (e.g., MenB).
  • Reverse Vaccinology 2.0: Genomic/proteomic antigen discovery.
  • Structural Vaccinology: Structure-based rational antigen design.
  • Self-amplifying RNA (saRNA): Lower dose, prolonged antigen expression than mRNA.
  • Modern Adjuvants: Enhance magnitude & duration of immune response.
    • TLR Agonists: CpG ODN (TLR9), MPLA (TLR4).
    • Saponins: QS-21 (potent saponin from Quillaja saponaria).
    • Emulsions: MF59, AS03 (oil-in-water).
    • STING Agonists: Potent innate immune activation via STING. Novel Vaccine Platforms: VLP, mRNA, and DNA Vaccines

⭐ AS04 adjuvant combines MPLA (TLR4 agonist) and alum, used in HPV (Cervarix) and HBV (Fendrix) vaccines.

High‑Yield Points - ⚡ Biggest Takeaways

  • mRNA vaccines (e.g., Pfizer, Moderna) use mRNA for antigen synthesis; rapid development, no infection risk.
  • Viral vector vaccines (e.g., Covishield) use a modified virus to deliver antigen genes.
  • DNA vaccines (e.g., ZyCoV-D) use plasmid DNA; stable, elicit cellular and humoral immunity.
  • Recombinant protein vaccines (e.g., Novavax) use purified antigens; fewer side effects.
  • Virus-Like Particles (VLPs) (e.g., HPV) are non-infectious, highly immunogenic structural mimics.
  • Modern adjuvants enhance immunogenicity and response duration.

Practice Questions: New Vaccine Technologies

Test your understanding with these related questions

Two viral vaccines are expected to reduce the incidence of cancers. Which vaccines are these?

1 of 5

Flashcards: New Vaccine Technologies

1/10

Which part of embryonated egg is used for making vaccine of Vaccinia, Variola, HSV 1 and HSV 2?_____

TAP TO REVEAL ANSWER

Which part of embryonated egg is used for making vaccine of Vaccinia, Variola, HSV 1 and HSV 2?_____

Chorioallantoic membrane

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial