Roll of Mycobacterium Tubercolosis Bacteria (TB) in HIV positive Person

Roll of Mycobacterium Tubercolosis Bacteria (TB) in HIV positive Person

When person has both HIV & TB , each disease speeds up the progress of other.

HIV positive person have weak immune system & therefore they are more prone to TB infection because TB bacteria get a conducive environment for their activation (its replication & growth). Generally TB does not affect normal person due to strong immune system of body.

Viruses do not have own enzymes which is necessary for protein & nucleic acid synthesis. For this reason virus depend upon synthetic machinery of host cells where they use host cell’s enzymes for their replication. When HIV positive person received TB cause bacteria, HIV found a new host cell in body for their replication.

Viruses that infect animal cells generally use cell-surface receptor that is found on those cell types in which the virus can replicate. Usually many viruses use a single type of receptor & some viruses can use several different receptor. Moreover, different viruses that infect the same cell type may each use a different receptor.  

However HIV requires both a primary receptor as a CD4 & a secondary co-receptor as a CCR5 OR CXCR4(a receptor for α-chemokines) depending on the particular variant of the virus for attachment & entry in to host cells. CD4 are protein involved in immune recognition which is found on the surface of many T-cells & macrophages. Macrophages are susceptible only to HIV variants that use CCR5 for entry, whereas T cells are most efficiently infected by variants that use CXCR4. The viruses that are found within the first few months after HIV infection almost invariably require CCR5, which presumably explains why individuals who carry a defective ccr5 gene are not susceptible to HIV infection. In the later stages of infection, viruses may either switch to use the CXCR4 co-receptor or adapt to use both co-receptors; in this way, the virus can change the cell types it infects as the disease progresses. 

After recognition and attachment to the host cell surface, the virus must next enter the host cell and release its nucleic acid genome from its protective protein coat or lipid envelope within so that the host's genetic coding can be altered to produce other HIV virions.