Some viruses, especially animal viruses, have an envelope surrounding their nucleocapsid. This envelope may have viral proteins embedded in it. Why are the viral proteins more readily recognized and targeted by the immune system than the envelope?
1) Enveloped viruses are often coated with animal cell membrane as they leave the cell. This membrane is a major component of the viral envelope. The viral proteins are more readily recognized by the immune system, as they are more distinct from the materials normally found in and on the cells. However, the envelope can contain several types of viral components as well.
2) The envelope is not capable of stimulating an immune response because of its make up.
3) Only proteins can stimulate the immune system, so the phospholipids and glycoproteins of the envelope are not immunogenic.
4) Viral proteins are highly immunogenic in order to facilitate uptake by host cells, while the envelope is not important in uptake by host cells.