1. HIV structure

The human immunodeficiency virus (HIV):

HIV belongs to a group of retroviruses called lentiviruses. The genome of retroviruses is made of RNA (ribonucleic acid), and each virus has two single chains of RNA; for replication, the virus needs a host cell, and the RNA must first be transcribed into DNA (deoxyribonucleic acid), which is done with the enzyme reverse transcriptase.

HIV infects mainly the CD4+ lymphocytes (T cells), but also to a lesser degree monocytes, macrophages, and dendritic cells (these cells are also CD4+ cells). Once infected, the cell turns into an HIV-replicating cell and loses its function in the human immune system.

HIV structure:

An HIV virus particle is spherical and has a diameter of about 1/10,000 mm.

Like other viruses, HIV does not have a cell wall or a nucleus.


The basic structure of the virus is as follows:

- The viral envelope, the outer coat of the virus, consists of two layers of lipids; different proteins are embedded in the viral envelope, forming "spikes" consisting of the outer glycoprotein (gp) 120 and the transmembrane gp41. The lipid membrane is borrowed from the host cell during the budding process (formation of new particles). gp120 is needed to attach to the host cell, and gp41 is critical for the cell fusion process.

- The HIV matrix proteins (consisting of the p17 protein), lie between the envelope and core.

- The viral core, contains the viral capsule protein p24 which surrounds two single strands of HIV RNA and the enzymes needed for HIV replication, such as reverse transcriptase, protease, ribonuclease, and integrase; out of the nine virus genes, there are three, namely gag, pol and env, that contain the information needed to make structural proteins for new virus particles.


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In which context can p24 be used?