Genes, vif
Gene Products, vif
Retrovirally encoded accessary proteins that play an essential role VIRUS REPLICATION. They are found in the cytoplasm of host cells and associate with a variety of host cell proteins. Vif stands for "virion infectivity factor".
vif Gene Products, Human Immunodeficiency Virus
HIV-1
HIV Infections
Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).
Simian immunodeficiency virus
Species of the genus LENTIVIRUS, subgenus primate immunodeficiency viruses (IMMUNODEFICIENCY VIRUSES, PRIMATE), that induces acquired immunodeficiency syndrome in monkeys and apes (SAIDS). The genetic organization of SIV is virtually identical to HIV.
HIV
Human immunodeficiency virus. A non-taxonomic and historical term referring to any of two species, specifically HIV-1 and/or HIV-2. Prior to 1986, this was called human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV). From 1986-1990, it was an official species called HIV. Since 1991, HIV was no longer considered an official species name; the two species were designated HIV-1 and HIV-2.
Virus Replication
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Acquired Immunodeficiency Syndrome
An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.
tat Gene Products, Human Immunodeficiency Virus
HIV Envelope Protein gp120
External envelope protein of the human immunodeficiency virus which is encoded by the HIV env gene. It has a molecular weight of 120 kDa and contains numerous glycosylation sites. Gp120 binds to cells expressing CD4 cell-surface antigens, most notably T4-lymphocytes and monocytes/macrophages. Gp120 has been shown to interfere with the normal function of CD4 and is at least partly responsible for the cytopathic effect of HIV.
HIV-2
An HIV species related to HIV-1 but carrying different antigenic components and with differing nucleic acid composition. It shares serologic reactivity and sequence homology with the simian Lentivirus SIMIAN IMMUNODEFICIENCY VIRUS and infects only T4-lymphocytes expressing the CD4 phenotypic marker.
HIV Antibodies
Antibodies reactive with HIV ANTIGENS.
Anti-HIV Agents
Agents used to treat AIDS and/or stop the spread of the HIV infection. These do not include drugs used to treat symptoms or opportunistic infections associated with AIDS.
Amino Acid Sequence
Gene Products, gag
Proteins coded by the retroviral gag gene. The products are usually synthesized as protein precursors or POLYPROTEINS, which are then cleaved by viral proteases to yield the final products. Many of the final products are associated with the nucleoprotein core of the virion. gag is short for group-specific antigen.
HIV Reverse Transcriptase
A reverse transcriptase encoded by the POL GENE of HIV. It is a heterodimer of 66 kDa and 51 kDa subunits that are derived from a common precursor protein. The heterodimer also includes an RNAse H activity (RIBONUCLEASE H, HUMAN IMMUNODEFICIENCY VIRUS) that plays an essential role the viral replication process.
Immunodeficiency Virus, Feline
A species of LENTIVIRUS, subgenus feline lentiviruses (LENTIVIRUSES, FELINE) isolated from cats with a chronic wasting syndrome, presumed to be immune deficiency. There are 3 strains: Petaluma (FIP-P), Oma (FIP-O) and Puma lentivirus (PLV). There is no antigenic relationship between FIV and HIV, nor does FIV grow in human T-cells.
HIV Core Protein p24
A major core protein of the human immunodeficiency virus encoded by the HIV gag gene. HIV-seropositive individuals mount a significant immune response to p24 and thus detection of antibodies to p24 is one basis for determining HIV infection by ELISA and Western blot assays. The protein is also being investigated as a potential HIV immunogen in vaccines.
Base Sequence
gag Gene Products, Human Immunodeficiency Virus
HIV Seropositivity
nef Gene Products, Human Immunodeficiency Virus
Simian Acquired Immunodeficiency Syndrome
Acquired defect of cellular immunity that occurs naturally in macaques infected with SRV serotypes, experimentally in monkeys inoculated with SRV or MASON-PFIZER MONKEY VIRUS; (MPMV), or in monkeys infected with SIMIAN IMMUNODEFICIENCY VIRUS.
Antigens, CD4
55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.
rev Gene Products, Human Immunodeficiency Virus
Gene Products, env
Retroviral proteins, often glycosylated, coded by the envelope (env) gene. They are usually synthesized as protein precursors (POLYPROTEINS) and later cleaved into the final viral envelope glycoproteins by a viral protease.
HIV Long Terminal Repeat
Regulatory sequences important for viral replication that are located on each end of the HIV genome. The LTR includes the HIV ENHANCER, promoter, and other sequences. Specific regions in the LTR include the negative regulatory element (NRE), NF-kappa B binding sites , Sp1 binding sites, TATA BOX, and trans-acting responsive element (TAR). The binding of both cellular and viral proteins to these regions regulates HIV transcription.
Zidovudine
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by an azido group. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA during reverse transcription. It improves immunologic function, partially reverses the HIV-induced neurological dysfunction, and improves certain other clinical abnormalities associated with AIDS. Its principal toxic effect is dose-dependent suppression of bone marrow, resulting in anemia and leukopenia.
HIV Antigens
Antigens associated with specific proteins of the human adult T-cell immunodeficiency virus (HIV); also called HTLV-III-associated and lymphadenopathy-associated virus (LAV) antigens.
Gene Products, tat
Trans-acting transcription factors produced by retroviruses such as HIV. They are nuclear proteins whose expression is required for viral replication. The tat protein stimulates LONG TERMINAL REPEAT-driven RNA synthesis for both viral regulatory and viral structural proteins. tat stands for trans-activation of transcription.
CD4 Lymphocyte Count
The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.
Reverse Transcriptase Inhibitors
Inhibitors of reverse transcriptase (RNA-DIRECTED DNA POLYMERASE), an enzyme that synthesizes DNA on an RNA template.
Viral Load
The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a SURROGATE MARKER in disease progression.
HIV Envelope Protein gp41
Transmembrane envelope protein of the HUMAN IMMUNODEFICIENCY VIRUS which is encoded by the HIV env gene. It has a molecular weight of 41,000 and is glycosylated. The N-terminal part of gp41 is thought to be involved in CELL FUSION with the CD4 ANTIGENS of T4 LYMPHOCYTES, leading to syncytial formation. Gp41 is one of the most common HIV antigens detected by IMMUNOBLOTTING.
HIV Protease
Enzyme of the human immunodeficiency virus that is required for post-translational cleavage of gag and gag-pol precursor polyproteins into functional products needed for viral assembly. HIV protease is an aspartic protease encoded by the amino terminus of the pol gene.
vpr Gene Products, Human Immunodeficiency Virus
Human Immunodeficiency Virus Proteins
HIV Protease Inhibitors
Inhibitors of HIV PROTEASE, an enzyme required for production of proteins needed for viral assembly.
Receptors, CCR5
CCR receptors with specificity for CHEMOKINE CCL3; CHEMOKINE CCL4; and CHEMOKINE CCL5. They are expressed at high levels in T-LYMPHOCYTES; B-LYMPHOCYTES; MACROPHAGES; MAST CELLS; and NK CELLS. The CCR5 receptor is used by the HUMAN IMMUNODEFICIENCY VIRUS to infect cells.
Virion
The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.
Genes, env
DNA sequences that form the coding region for the viral envelope (env) proteins in retroviruses. The env genes contain a cis-acting RNA target sequence for the rev protein (= GENE PRODUCTS, REV), termed the rev-responsive element (RRE).
AIDS-Related Opportunistic Infections
Opportunistic infections found in patients who test positive for human immunodeficiency virus (HIV). The most common include PNEUMOCYSTIS PNEUMONIA, Kaposi's sarcoma, cryptosporidiosis, herpes simplex, toxoplasmosis, cryptococcosis, and infections with Mycobacterium avium complex, Microsporidium, and Cytomegalovirus.
HIV Envelope Protein gp160
An envelope protein of the human immunodeficiency virus that is encoded by the HIV env gene. It has a molecular weight of 160,000 kDa and contains numerous glycosylation sites. It serves as a precursor for both the HIV ENVELOPE PROTEIN GP120 and the HIV ENVELOPE PROTEIN GP41.
RNA-Directed DNA Polymerase
AIDS Vaccines
Vaccines or candidate vaccines containing inactivated HIV or some of its component antigens and designed to prevent or treat AIDS. Some vaccines containing antigens are recombinantly produced.
CD4-Positive T-Lymphocytes
A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.
Gene Products, nef
Products of the retroviral NEF GENE. They play a role as accessory proteins that influence the rate of viral infectivity and the destruction of the host immune system. nef gene products were originally found as factors that trans-suppress viral replication and function as negative regulators of transcription. nef stands for negative factor.
env Gene Products, Human Immunodeficiency Virus
Proviruses
Duplex DNA sequences in eukaryotic chromosomes, corresponding to the genome of a virus, that are transmitted from one cell generation to the next without causing lysis of the host. Proviruses are often associated with neoplastic cell transformation and are key features of retrovirus biology.
Neutralization Tests
The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).
Genes, gag
Arthritis-Encephalitis Virus, Caprine
HIV Seronegativity
Immune status consisting of non-production of HIV antibodies, as determined by various serological tests.
Gene Products, rev
Trans-acting nuclear proteins whose functional expression are required for retroviral replication. Specifically, the rev gene products are required for processing and translation of the gag and env mRNAs, and thus rev regulates the expression of the viral structural proteins. rev can also regulate viral regulatory proteins. A cis-acting antirepression sequence (CAR) in env, also known as the rev-responsive element (RRE), is responsive to the rev gene product. rev is short for regulator of virion.
Macaca mulatta
A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.
Mutation
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
HeLa Cells
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Antiretroviral Therapy, Highly Active
Drug regimens, for patients with HIV INFECTIONS, that aggressively suppress HIV replication. The regimens usually involve administration of three or more different drugs including a protease inhibitor.
Leukocytes, Mononuclear
Mature LYMPHOCYTES and MONOCYTES transported by the blood to the body's extravascular space. They are morphologically distinguishable from mature granulocytic leukocytes by their large, non-lobed nuclei and lack of coarse, heavily stained cytoplasmic granules.
Polymerase Chain Reaction
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Virus Assembly
Receptors, CXCR4
Gene Products, vpr
Trans-acting proteins which accelerate retroviral virus replication. The vpr proteins act in trans to increase the levels of specified proteins. vpr is short for viral protein R, where R is undefined.
Feline Acquired Immunodeficiency Syndrome
Gene Expression Regulation, Viral
Antiviral Agents
Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.
Virus Integration
Drug Resistance, Viral
The ability of viruses to resist or to become tolerant to chemotherapeutic agents or antiviral agents. This resistance is acquired through gene mutation.
Genes, tat
DNA sequences that form the coding region for the protein responsible for trans-activation of transcription (tat) in human immunodeficiency virus (HIV).
Receptors, HIV
Cellular receptors that bind the human immunodeficiency virus that causes AIDS. Included are CD4 ANTIGENS, found on T4 lymphocytes, and monocytes/macrophages, which bind to the HIV ENVELOPE PROTEIN GP120.
Cells, Cultured
Retroviridae Proteins
Infectious Disease Transmission, Vertical
Giant Cells
Multinucleated masses produced by the fusion of many cells; often associated with viral infections. In AIDS, they are induced when the envelope glycoprotein of the HIV virus binds to the CD4 antigen of uninfected neighboring T4 cells. The resulting syncytium leads to cell death and thus may account for the cytopathic effect of the virus.
Didanosine
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by a hydrogen. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. Didanosine is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA by binding to reverse transcriptase; ddI is then metabolized to dideoxyadenosine triphosphate, its putative active metabolite.
T-Lymphocytes
Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
Genes, nef
DNA sequences that form the coding region for a protein that down-regulates the expression of human immunodeficiency virus (HIV). nef is short for negative factor.
Genes, pol
Genes, rev
Vaccinia virus
The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.
AIDS-Related Complex
A prodromal phase of infection with the human immunodeficiency virus (HIV). Laboratory criteria separating AIDS-related complex (ARC) from AIDS include elevated or hyperactive B-cell humoral immune responses, compared to depressed or normal antibody reactivity in AIDS; follicular or mixed hyperplasia in ARC lymph nodes, leading to lymphocyte degeneration and depletion more typical of AIDS; evolving succession of histopathological lesions such as localization of Kaposi's sarcoma, signaling the transition to the full-blown AIDS.
DNA Primers
Zalcitabine
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by a hydrogen. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication at low concentrations, acting as a chain-terminator of viral DNA by binding to reverse transcriptase. Its principal toxic side effect is axonal degeneration resulting in peripheral neuropathy.
Viral Regulatory and Accessory Proteins
A broad category of viral proteins that play indirect roles in the biological processes and activities of viruses. Included here are proteins that either regulate the expression of viral genes or are involved in modifying host cell functions. Many of the proteins in this category serve multiple functions.
Gene Products, pol
Retroviral proteins coded by the pol gene. They are usually synthesized as a protein precursor (POLYPROTEINS) and later cleaved into final products that include reverse transcriptase, endonuclease/integrase, and viral protease. Sometimes they are synthesized as a gag-pol fusion protein (FUSION PROTEINS, GAG-POL). pol is short for polymerase, the enzyme class of reverse transcriptase.
HIV Integrase
Enzyme of the HUMAN IMMUNODEFICIENCY VIRUS that is required to integrate viral DNA into cellular DNA in the nucleus of a host cell. HIV integrase is a DNA nucleotidyltransferase encoded by the pol gene.
Fusion Proteins, gag-pol
Receptors, Virus
Transcription, Genetic
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Genetic Vectors
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
Cytidine Deaminase
Transfection
Indinavir
A potent and specific HIV protease inhibitor that appears to have good oral bioavailability.
Macaca nemestrina
Protein Precursors
Virus Shedding
The expelling of virus particles from the body. Important routes include the respiratory tract, genital tract, and intestinal tract. Virus shedding is an important means of vertical transmission (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).
Lentivirus Infections
AIDS Dementia Complex
A neurologic condition associated with the ACQUIRED IMMUNODEFICIENCY SYNDROME and characterized by impaired concentration and memory, slowness of hand movements, ATAXIA, incontinence, apathy, and gait difficulties associated with HIV-1 viral infection of the central nervous system. Pathologic examination of the brain reveals white matter rarefaction, perivascular infiltrates of lymphocytes, foamy macrophages, and multinucleated giant cells. (From Adams et al., Principles of Neurology, 6th ed, pp760-1; N Engl J Med, 1995 Apr 6;332(14):934-40)
Cloning, Molecular
Binding Sites
Dideoxynucleotides
The phosphate esters of DIDEOXYNUCLEOSIDES.
CD8-Positive T-Lymphocytes
A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.
pol Gene Products, Human Immunodeficiency Virus
Plasmids
Sequence Analysis, DNA
Dideoxynucleosides
Nucleosides that have two hydroxy groups removed from the sugar moiety. The majority of these compounds have broad-spectrum antiretroviral activity due to their action as antimetabolites. The nucleosides are phosphorylated intracellularly to their 5'-triphosphates and act as chain-terminating inhibitors of viral reverse transcription.
Cytopathogenic Effect, Viral
Visible morphologic changes in cells infected with viruses. It includes shutdown of cellular RNA and protein synthesis, cell fusion, release of lysosomal enzymes, changes in cell membrane permeability, diffuse changes in intracellular structures, presence of viral inclusion bodies, and chromosomal aberrations. It excludes malignant transformation, which is CELL TRANSFORMATION, VIRAL. Viral cytopathogenic effects provide a valuable method for identifying and classifying the infecting viruses.
Defective Viruses
Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.
Viral Envelope Proteins
Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.
Pregnancy Complications, Infectious
Lamivudine
A reverse transcriptase inhibitor and ZALCITABINE analog in which a sulfur atom replaces the 3' carbon of the pentose ring. It is used to treat HIV disease.
Protein Binding
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
AIDS Serodiagnosis
Immunologic tests for identification of HIV (HTLV-III/LAV) antibodies. They include assays for HIV SEROPOSITIVITY and HIV SERONEGATIVITY that have been developed for screening persons carrying the viral antibody from patients with overt symptoms of AIDS or AIDS-RELATED COMPLEX.
Peptide Fragments
Virus Activation
The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.
Macaca
Immunodeficiency Virus, Bovine
The type species of LENTIVIRUS, subgenus bovine lentiviruses (LENTIVIRUSES, BOVINE), found in cattle and causing lymphadenopathy, LYMPHOCYTOSIS, central nervous system lesions, progressive weakness, and emaciation. It has immunological cross-reactivity with other lentiviruses including HIV.
Saquinavir
An HIV protease inhibitor which acts as an analog of an HIV protease cleavage site. It is a highly specific inhibitor of HIV-1 and HIV-2 proteases, and also inhibits CYTOCHROME P-450 CYP3A.
Hepatitis C
INFLAMMATION of the LIVER in humans caused by HEPATITIS C VIRUS, a single-stranded RNA virus. Its incubation period is 30-90 days. Hepatitis C is transmitted primarily by contaminated blood parenterally, and is often associated with transfusion and intravenous drug abuse. However, in a significant number of cases, the source of hepatitis C infection is unknown.
Mutagenesis, Site-Directed
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
RNA, Transfer, Lys
Genes, vpr
DNA sequences that form the coding region for a trans-activator protein that specifies rapid growth in human immunodeficiency virus (HIV). vpr is short for viral protein R, where R is undefined.
Cercopithecus aethiops
A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.
Drug Resistance, Microbial
Structure-Activity Relationship
Organophosphonates
Macrophages
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
Cell Fusion
Ritonavir
An HIV protease inhibitor that works by interfering with the reproductive cycle of HIV. It also inhibits CYTOCHROME P-450 CYP3A.
Recombinant Fusion Proteins
Enzyme-Linked Immunosorbent Assay
An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.
Nelfinavir
A potent HIV protease inhibitor. It is used in combination with other antiviral drugs in the treatment of HIV in both adults and children.
Amino Acid Substitution
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
Sequence Homology, Amino Acid
Recombination, Genetic
Severe Combined Immunodeficiency
Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).
HIV Long-Term Survivors
Persons who have experienced prolonged survival of HIV infection. This includes the full spectrum of untreated, HIV-infected long-term asymptomatics to those with AIDS who have survived due to successful treatment.
SAIDS Vaccines
Vaccines or candidate vaccines designed to prevent SAIDS; (SIMIAN ACQUIRED IMMUNODEFICIENCY SYNDROME); and containing inactivated SIMIAN IMMUNODEFICIENCY VIRUS or type D retroviruses or some of their component antigens.
Stavudine
A dideoxynucleoside analog that inhibits reverse transcriptase and has in vitro activity against HIV.
Drug Therapy, Combination
Jurkat Cells
A CELL LINE derived from human T-CELL LEUKEMIA and used to determine the mechanism of differential susceptibility to anti-cancer drugs and radiation.
Genotype
Cytosine Deaminase
T-Lymphocytes, Cytotoxic
Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.
Membrane Fusion
Nevirapine
A potent, non-nucleoside reverse transcriptase inhibitor used in combination with nucleoside analogues for treatment of HIV INFECTIONS and AIDS.
Phenotype
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
Virus Latency
The ability of a pathogenic virus to lie dormant within a cell (latent infection). In eukaryotes, subsequent activation and viral replication is thought to be caused by extracellular stimulation of cellular transcription factors. Latency in bacteriophage is maintained by the expression of virally encoded repressors.
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
HIV Seroprevalence
Studies of the number of cases where human immunodeficiency virus (HIV) is present in a specific population at a designated time. The presence in a given individual is determined by the finding of HIV antibodies in the serum (HIV SEROPOSITIVITY).
Cats
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Mutagenesis
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
Sequence Alignment
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Lymphocytes
White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.
HIV Integrase Inhibitors
Inhibitors of HIV INTEGRASE, an enzyme required for integration of viral DNA into cellular DNA.
Monocytes
HIV Fusion Inhibitors
Inhibitors of the fusion of HIV to host cells, preventing viral entry. This includes compounds that block attachment of HIV ENVELOPE PROTEIN GP120 to CD4 RECEPTORS.
Genes, vpu
DNA sequences that form the coding region for the HIV-1 regulatory protein vpu (viral protein U) that greatly increases the export of virus particles from infected cells. The vpu genes are not present in HIV-2 or SIMIAN IMMUNODEFICIENCY VIRUS.
Flow Cytometry
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
Lymphocyte Activation
Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.
Adenine
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
CD4-CD8 Ratio
Ratio of T-LYMPHOCYTES that express the CD4 ANTIGEN to those that express the CD8 ANTIGEN. This value is commonly assessed in the diagnosis and staging of diseases affecting the IMMUNE SYSTEM including HIV INFECTIONS.
Coinfection
Simultaneous infection of a host organism by two or more pathogens. In virology, coinfection commonly refers to simultaneous infection of a single cell by two or more different viruses.
Sensitivity and Specificity
Cohort Studies
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
Ribonuclease H
Disease Progression
Candidiasis, Oral
Species Specificity
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.