HIV is the causative agent of AIDS (Acquired Immunodeficiency Syndrome). The Human Immunodeficiency Virus (HIV) is a retrovirus. Retroviruses contain ribonucleic acid (RNA) in an enveloping protein capsule.
RNA is a carrier of genetic information, which differs from DNA by certain structural features. In cells, DNA is usually present as a double strand, while RNA is single-stranded. In addition to this RNA, retroviruses contain an enzyme called reverse transcriptase.
This enzyme forms an opposite, i.e. complementary, i.e. mirror-inverted DNA strand. This is then incorporated into the DNA of the body cell with the help of other enzymes produced by the virus, which means that the cell now produces the virus’ building blocks in the service of the virus.
Thus new viruses are formed at the expense of the host cell, which finally leave the cell to infect other cells. HIV (HI virus) has the special feature of only attacking certain cells of the immune system. It is a subclass of the white blood cells, the so-called T-lymphocytes, more precisely the T-helper cells.
They are an important part of the specific defence that uses certain recognition structures on foreign viruses and bacteria to specifically combat them. In this process, T cells have a mediating function between other important defence cells. However, they themselves carry a recognition structure on their cell surface that allows the virus to dock and enter the cell.
To a lesser extent, other cells of the immune system are also affected. However, the decrease in the number of T cells seems to be decisive for the course of the disease, since the counting of T cells allows conclusions to be drawn about the status of the disease.