When a virus or an
infectious bacterium penetrates in our body, a whole machinery gets under way to
eliminate it. This machinery, the immune system, acts through many types of
cells, called white globules. Certain viruses take the immune system for target.
Thus, the HIV (virus of the human immunodeficiency) attacks two kinds of white
globules: the macrophages, which intervene precociously, while
phagocyte
then by digesting the foreign bodies, and certain lymphocytes (lymphocytes T
CD4), which intervene more tardily in the immunizing answer. The HIV accumulates
in the infected macrophages, genuine viral tanks difficult to reach to the
antiviral treatments. On the other hand, the multiplication of the virus in the
lymphocytes T CD4 causes their destruction.
At the Institute Curie,
Philippe Benaroch, Director of research CNRS, and its intracellular Transport
team and immunity of the laboratory of Inserm, are interested in the immune
system and her failures. These researchers studied the proliferation of the HIV
in the macrophages, in collaboration with their colleagues of the Virus
laboratory and immunity of the Pasteur Institute associated with CNRS. They
showed that the viral particles accumulate in certain compartments of the
infected macrophages. However, these compartments have an acid pH normally where
the HIV should not survive. But the measurements of pH carried out by the
researchers revealed a defect of acidification in these compartments: the HIV
manages to modify this hostile environment and to create an environment
favorable to its survival and its storage. In these compartments, the enzymes of
degradation, which need an acid pH to function and degrade the virus, are put
except race. By controlling its environment, the HIV can multiply within the
infected macrophages. Within the same infected macrophages, the compartments
deprived of particles or viral proteins seem to function normally.
This study brings new
knowledge on the persistence of the HIV at the contaminated people.