A HIV particle approaches and attaches to a lymphocyte. (Lymphocytes, which include helper T cells and killer T cells, are small white blood cells that are critical in immune defense and are HIV’s principal target.)
In order to replicate itself, an HIV particle must get its RNA, which is the genetic blueprint for a new particle, inside the host cell. To do that, the viral particle must first bind to two chief receptors on the outside of the host cell, much like a key fitting into a lock. If even one of those receptors, which are known as CD4 and CCR5 receptors, is missing, the viral core containing the RNA will not get into the cell. (Researchers have found that some AIDS patients, known as long-term non-progressors because they are HIV-positive yet show few or no symptoms of the disease, are missing the gene for one of these receptors.) The binding process is facilitated by a molecule on the surface of the HIV particle called gp120 (for glycoprotein with a molecular weight of 120).
Once the viral particle has successfully binded to the host cell, its core can pass through the cell wall into the cell’s cytoplasm. The core then dissolves, leaving the RNA and catalyzing enzymes ready to begin the process of replication.
The Essay on Aids Vaccine Cells Immune Hiv
HIV vaccine is possible. When HIV was identified as the cause of AIDS in 1984, researchers famously predicted that a preventive vaccine was right around the corner. Of course, it turned out that the task was not so easy, as in the early days of the epidemic, very little was understood about the virus. Yet in the time since, we have learned much more. In fact, we know now more about HIV/AIDS than ...
Viral RNA transforms itself into double-stranded DNA, and then integrats into the host cell’s DNA in order to produce new viral RNA.
Once inside the host cell, the viral RNA migrates toward the nucleus through the cell’s cytoplasm and eventually through the nuclear membrane. A series of steps that ultimately ends in a new HIV particle follows. First, through a process known as reverse transcription, the enzyme known as reverse transcriptase catalyzes the formation of double-stranded viral DNA using the single-stranded viral RNA as a template. Employing other enzymes such as integrase (shown by the starburst in step 4 and in the graphic at right above), the new viral DNA then breaks open the host cell’s DNA and integrates itself into it. This leads to the formation of a new viral RNA strand, which migrates out of the host’s DNA. The new viral RNA moves into the cytoplasm, where new viral proteins are built using the viral RNA as a blueprint.
A new viral particle is assembled and then migrates out of the host cell to infect new cells.
Once the viral protein parts have been built, they are assembled into a new HIV particle. This particle is an exact duplicate of the HIV particle from which it sprung, complete with two copies of viral RNA and the enzymes needed for reverse transcription. The new HIV particle moves out of the cell, where it heads off to infect another cell and perpetuate the life cycle.
This process repeats itself continuously, with many thousands of HIV particles produced simultaneously in the body. After repeated assaults by viral particles, host cells die, having exhausted their energy and molecular building supplies while generating HIV viruses. This suppresses a patient’s immune system and leaves him or her open to infection by other infectious agents, including bacteria, fungi, and other viruses.