Antigenic drift

Definition

Antigenic drift is a gradual process of genetic mutation in viruses, leading to minor changes in the surface proteins (antigens) that can help the virus evade the immune system. It is commonly seen in RNA viruses such as influenza.

5 Must Know Facts For Your Next Test

1. Antigenic drift results from small, random mutations in viral RNA.
2. It leads to new strains of viruses, requiring periodic updates to vaccines.
3. This process allows viruses to partially escape immunity developed from previous infections or vaccinations.
4. Influenza A and B viruses undergo antigenic drift frequently, contributing to seasonal flu outbreaks.
5. Antigenic drift is different from antigenic shift, which involves major changes due to reassortment of viral genes.

Review Questions

• What is antigenic drift and how does it affect viral evolution?
• How does antigenic drift contribute to the need for annual flu vaccinations?
• Compare and contrast antigenic drift with antigenic shift.

Related terms

Antigenic Shift:

A sudden, major change in a virus's antigens due to gene reassortment.

RNA Virus: A virus that uses RNA as its genetic material, often prone to high mutation rates.

Viral Pathogenicity: The ability of a virus to cause disease by overcoming host defenses and causing cellular damage.