One of the way that a virus can avoid being detected by the immune system is to egress from the host cell by:
a. lysis
b. Excocytosis
c. Direct cell cell spread
d. budding
To determine how a virus can avoid being detected by the immune system when egressing from a host cell, we need to understand how each of the options listed - lysis, exocytosis, direct cell-cell spread, and budding - work.
a. Lysis: Lysis is a process where the virus causes the host cell to burst, releasing the newly formed viruses into the extracellular environment. While effective for viral release, lysis can often trigger an immune response as it causes the release of cell debris and other molecules that can be recognized by the immune system. Therefore, this is not an ideal mechanism for a virus to avoid detection by the immune system.
b. Exocytosis: Exocytosis is a process that involves the release of viruses from the host cell by fusing the viral-containing vesicles with the cell membrane, allowing the viruses to be released outside the cell without causing cell damage. While this mechanism is less likely to trigger an immediate immune response, it does not necessarily prevent the immune system from recognizing the released viruses once they are in the extracellular environment.
c. Direct cell-cell spread: Some viruses can spread directly from one cell to another without being exposed to the extracellular environment. This type of spread can occur through specialized junctions between cells, such as gap junctions. By bypassing the extracellular environment, viruses can potentially avoid detection by certain components of the immune system that primarily function in the extracellular space.
d. Budding: Budding involves the virus forming a new viral envelope using host cell components, allowing it to be released from the host cell without causing cell lysis. This method of viral egress is often used by enveloped viruses. The newly formed virus acquires a protective envelope derived from the host cell membrane, camouflaging it and making it harder for the immune system to detect. While not foolproof, this mechanism can help the virus evade immune surveillance to some extent.
In summary, among the options listed, the most effective way for a virus to avoid detection by the immune system when egressing from a host cell is likely d. budding, as it provides a means for the virus to acquire a protective envelope that can camouflage it from the immune system.