Viruses AIDS acquired immune

AIDS, acquired immune deficiency syndrome HIV, human immunodeficiency virus. (Adapted from the DHHS Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents, April 7, 2005.)... 

Kalyanaraman, D. Mann, G. D. Sidhu, R. E. Stahl, S. Zolla-Prazner, J. Leibowitch, and M. Popovic, Isolation of human T-cell leukemia virus in acquired immune deficiency syndrome (AIDS), Science 220 865 (1983). 

AIDS, acquired immune deficiency syndrome HIV, human immunodeficiency virus PGL, persistent generalized lymphadenopathy. 

The human immunodeficiency virus (HIV) causes the immunodeficiency disease known as AIDS (acquired immune deficiency syndrome). The structure of this virus is similar to that of the influenza virus (A). 

When AIDS (Acquired Immune Deficiency Syndrome) first came into the news in the 1980s it was a horror story of mysterious deaths from normally harmless diseases after the patient s immune system had been weakened and eventually destroyed. The cause was identified by biologists as a new virus HIV (Human Immunodeficiency Virus) and antiviral drugs, notably AZT (Chapter 49), were used with some success. These drugs imitate natural nucleosides (AZT imitates deoxythymidine) and inhibit the virus from copying its RNA into DNA inside human cells by inhibiting the enzyme reverse transcriptase . 

Figure 4.29. DNA Sequence Yields the Amino Acid Sequence. The complete nucleotide sequence of HIV-1 (human immunodeficiency virus), the cause of AIDS (acquired immune deficiency syndrome), was determined within a year after the isolation of the virus. A part of the DNA sequence specified by the RNA genome of the virus is shown here with the corresponding amino acid sequence (deduced from a knowledge of the genetic code).

Viruses are species consisting of nucleic acids, usually ssRNA, encased in a protein coat and require a host organism for their replication. Once a virus invades a host cell, it uses its own reverse transcriptase enzyme to encode its genome into the host DNA thereby ensuring its survival. AIDS, acquired immune deficiency syndrome, is produced by a retrovirus that attacks the immune system. 

When a foreign substance - a virus, a bacterium, or even a foreign protein-invades the tissues of a higher vertebrate (like a human), the organism defends itself by what is called the immune response. The immune response is a first line of defense against infection and probably against cancer cells as well. Crippling of the immune system by the HIV virus makes AIDS (acquired immune deficiency syndrome) a disease that has so far proved to be almost invariably fatal. The immune response has two facets ... 

AIDS (acquired immune deficiency syndrome) is a disease of the immune system. It is caused by the human immunodeficiency virus, or HIV, which attacks a number of kinds of cells but is particularly virulent toward a class of helper T cells. The virus wages a long battle with rapidly replicating T cells, but eventually the rate of cell destruction exceeds the rate of replication. The consequence is a deterioration of the whole immune response, in particular the ability of B cells to proliferate in response to antigen stimulation. In addition, there is a general failure in T-cell activation. Most AIDS patients succumb either to diseases they could have easily resisted before contracting AIDS or to certain kinds of cancer. AIDS is so deadly because it attacks our most fundamental defenses against all disease. 

Isolation of human T-cell leukemia virus in acquired immune deficiency syndrome (AIDS). Science 4599 865-867. 

Viruses are infectious, parasitic small particles containing either DNA or RNA (but not both) encapsulated by a protein overcoat. Viruses are at the borderline of life since they neither reproduce nor carry out metabolism. Viruses are unable to reproduce or synthesize proteins because they lack some or most of the apparatus (amino acids, nucleotides, and enzymes) for replication, transcription, and translation. Viruses are responsible for a wide range of diseases—influenza, poliomyelitis, leukemia, hepatitis, smallpox, chicken pox, tumors (including cancer), and AIDS (acquired immune deficiency syndrome). 

AIDS Acquired immune deficiency syndrome CNT 3 -C-cyano-3 -deoxythymidine HIV Human immunodeficiency virus... 

AIDS (Acquired Immune Deficiency Syndrome) An infectious disease caused by the human immunodeficiency virus that destroys the individual s immune system. 

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