HIV is an enveloped virus. This makes it different from many other retroviruses. It doesn’t just have a protein coat. Instead, when HIV leaves a host cell, it takes away part of the cell’s plasma membrane. That membrane became the HIV envelope. However, the HIV envelope is not only composed of host components. It is also composed of HIV envelope proteins.
HIV envelope proteins include gp41, gp120, and gp160. GP stands for “glycoprotein”. Glycoproteins have carbohydrate or sugar components and a protein backbone. The number after gp refers to the length of the protein.
Note: Not all glycoproteins are associated with viruses. Many of the most important proteins in the immune system are also glycoproteins. The same goes for many other proteins found in the human body.
The protein gp120 is probably the best known HIV envelope protein. Several HIV vaccines try to target it. It is very important in the binding of HIV to CD4 cells. Many researchers believe that if they can effectively interfere with gp120 binding, they will be able to reduce HIV transmission.
In addition to gp120, gp41 is also important in helping HIV enter host cells. It helps the fusion of viral and cell membranes. This is a critical part of the infection process. Fusion of the two membranes is the first step in releasing viral RNA into the cell for replication.In fact, fusion inhibitors Enfuvirtide Actually works by interfering with gp41. Gp41 is also the protein that attaches gp120 to the viral envelope. It is located in the membrane and binds to gp120. Gp120 is not attached directly to envelopes.
Gp160 is not actually a third HIV envelope protein. Instead, gp160 is the precursor of gp120 and gp41.The larger protein gp160 is produced by environment (Envelope) Genes. It is then cut into two small pieces by enzymes in the host cell, producing gp120 and gp41.
Role in HIV entry and infectivity
The HIV envelope protein plays an important role in HIV entry and infection. They can also be very important in prevention and treatment. Interestingly, however, the topic of HIV envelope proteins also frequently comes up in discussions of HIV testing.For example, Western Blot is not considered a definitive diagnosis of HIV unless a person has antibodies against both HIV envelope Protein and HIV nuclear protein.
There are also concerns about how HIV vaccine trials might affect routine HIV testing. The growing number of people participating in these trials may lead to more false-positive HIV antibody tests. Vaccines are usually designed to make the body produce antibodies against specific proteins, such as the HIV envelope protein. Because these antibodies are exactly what standard HIV tests look for, they can lead to false positives. After participating in an HIV vaccine trial, it is important to continue with the correct test; a way to look for the virus itself, not antibodies.
If you do participate in an HIV vaccine trial, tell your healthcare provider that you may decide to decline standard HIV testing. You should also carefully document your participation in any vaccine trials.