100
AIDS/HIV, Molecular and Cell Biology
Keywords
HIV (Human Immunodefciency Virus)
A retrovirus of the lentivirus family responsible for AIDS.
AIDS (Acquired Immune Defciency Syndrome)
A clinical state of profound susceptibility to infection with low pathogenicity
(opportunistic) infectious agent and unusual malignancies.
Retrovirus
A virus characterized by a diploid RNA genome converted to a DNA provirus by its
reverse transcriptase enzyme and integrated into the target cell DNA.
Provirus
The integrated DNA form of the virus.
Antiretroviral Drugs
Pharmacological agents targeting virus-speciFc processes used in the treatment
of AIDS.
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This article describes the basic molecular biology of the viruses causing AIDS and
the nature of the disease in causes, summarizing the immune response, antiviral
therapy and varrine prospects.
1
Origins of HIV
HIV is a retrovirus of the lentivirus
family. Closely related viruses have been
discovered in many groups of African
primates and sequence comparison would
suggest that there has been more than one
transspecies transmission of these viruses
from monkeys into humans within the last
80 years. In the simian population, these
viruses are transmitted by blood contact
during biting and Fghting. The butchering
of monkeys for sale as bush meat is
a highly plausible route of transmission
of these viruses into humans through
monkey blood contamination of cuts and
scratches on human hands. Hypotheses
surrounding contaminated polio vaccine
have been comprehensively disproved.
There are two major divisions of HIV
that have infected humans, HIV-1 and
HIV-2. HIV-1 is phylogenetically closely
related to SIV
cpz
, a lentivirus of chim-
panzees. HIV-2 is different in sequence
from both of these and more closely re-
lated to the sooty mangabey lentivirus,
SIV
smm
. HIV-1 is divided into a num-
ber of different groups, the main (M) and
the out (O) and new (N) groups within
each of which are clades. The M group
is estimated to have entered the human
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