key term - Envelope Glycoproteins

Definition

Envelope glycoproteins are proteins embedded within the viral envelope, the outermost layer of certain viruses. These glycoproteins play a crucial role in the attachment and entry of viruses into host cells, making them essential for viral infection and transmission.

5 Must Know Facts For Your Next Test

1. Envelope glycoproteins are responsible for the initial attachment of viruses to host cells, a critical step in the viral infection process.
2. The specific receptors that envelope glycoproteins bind to on host cells can determine the tissue tropism and host range of a virus.
3. Envelope glycoproteins often undergo conformational changes that facilitate the fusion of the viral envelope with the host cell membrane, enabling viral entry.
4. Antibodies targeting envelope glycoproteins can neutralize viral infectivity, making them a key target for vaccine development.
5. Mutations in envelope glycoproteins can alter viral tropism, transmissibility, and evasion of the host immune response.

Review Questions

• Explain the role of envelope glycoproteins in the attachment and entry of viruses into host cells.
  • Envelope glycoproteins are essential for the initial attachment of viruses to host cells, as they bind to specific receptors on the cell surface. This receptor binding triggers conformational changes in the envelope glycoproteins, which then facilitates the fusion of the viral envelope with the host cell membrane. This fusion event allows the viral genetic material to be delivered into the host cell, enabling the virus to hijack the cell's machinery and replicate. The specific receptors that envelope glycoproteins bind to can determine the tissue tropism and host range of a virus, making them a critical factor in viral infectivity and transmission.
• Describe how antibodies targeting envelope glycoproteins can neutralize viral infectivity and their importance in vaccine development.
  • Antibodies that bind to viral envelope glycoproteins can neutralize the infectivity of viruses by preventing them from attaching to and entering host cells. This is because the antibodies block the receptor-binding sites on the envelope glycoproteins, interfering with the initial attachment step. Antibodies targeting envelope glycoproteins are a key focus of vaccine development, as inducing the production of these neutralizing antibodies can provide protection against viral infections. Vaccines that elicit a robust immune response against envelope glycoproteins are often effective in preventing viral diseases, as they prevent the virus from establishing a successful infection within the host.
• Analyze how mutations in envelope glycoproteins can impact viral tropism, transmissibility, and evasion of the host immune response.
  • Mutations in the genes encoding viral envelope glycoproteins can have significant consequences for the virus. These mutations can alter the binding specificity of the glycoproteins, allowing the virus to target different cell types or even jump between host species, changing its tissue tropism and host range. Mutations can also affect the fusogenic properties of the envelope glycoproteins, impacting the virus's ability to enter and infect host cells, which can influence its transmissibility. Furthermore, changes in the envelope glycoproteins can enable the virus to evade recognition by the host's immune system, as antibodies may no longer be able to effectively bind and neutralize the altered glycoproteins. This immune evasion can allow the virus to persist and continue to spread within the host population. Understanding how envelope glycoprotein mutations can impact viral characteristics is crucial for predicting and mitigating the emergence of new viral strains with enhanced pathogenicity or pandemic potential.

Related terms

Viral Envelope:

The outermost layer of certain viruses, derived from the host cell membrane and containing embedded viral glycoproteins.

Viral Attachment: The process by which viral envelope glycoproteins bind to specific receptors on the host cell surface, facilitating viral entry.

Viral Fusion: The merging of the viral envelope with the host cell membrane, allowing the viral genetic material to be delivered into the host cell.