Biomaterial Database

Competition between zidovudine-sensitive and zidovudine-resistant strains of HIV. 1992

A R McLean, and M A Nowak

Zoology Department, Oxford, UK.

OBJECTIVE To investigate competitive interactions between zidovudine-sensitive and resistant strains of HIV within the context of host-parasite population dynamic interactions between CD4+ cells and HIV. METHODS A mathematical model of the population dynamics of CD4+ cells, sensitive HIV and resistant HIV is developed. METHODS The model is analysed numerically and analytically and model predictions are compared with previously published data on population dynamics of HIV and CD4+ cells in patients receiving zidovudine. A threshold result describing the critical dose of zidovudine above which resistant HIV will out-compete sensitive HIV is derived, as are expressions describing the critical effective doses for the eradication of sensitive and resistant strains. Numerical simulations of the dynamics of the shift from the pre-treatment, equilibrium to the treatment equilibrium are presented and an analytic expression approximating the time taken until virus growth restarts is derived. RESULTS It is shown that competition between strains of virus is the important factor determining which type of virus will eventually start to grow during the course of zidovudine treatment, but host-parasite interactions are the important determinant of when viral resurgence occurs. CONCLUSIONS Although resistant strains are observed after prolonged treatment with zidovudine, this model suggests that it is the growing supply of uninfected CD4+ cells which causes the eventual upsurge in viral burden.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D006678	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.	AIDS Virus,HTLV-III,Human Immunodeficiency Viruses,Human T-Cell Lymphotropic Virus Type III,Human T-Lymphotropic Virus Type III,LAV-HTLV-III,Lymphadenopathy-Associated Virus,Acquired Immune Deficiency Syndrome Virus,Acquired Immunodeficiency Syndrome Virus,Human Immunodeficiency Virus,Human T Cell Lymphotropic Virus Type III,Human T Lymphotropic Virus Type III,Human T-Cell Leukemia Virus Type III,Immunodeficiency Virus, Human,Immunodeficiency Viruses, Human,Virus, Human Immunodeficiency,Viruses, Human Immunodeficiency,AIDS Viruses,Human T Cell Leukemia Virus Type III,Lymphadenopathy Associated Virus,Lymphadenopathy-Associated Viruses,Virus, AIDS,Virus, Lymphadenopathy-Associated,Viruses, AIDS,Viruses, Lymphadenopathy-Associated
D006790	Host-Parasite Interactions	The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.	Host-Parasite Relations,Parasite-Host Relations,Host-Parasite Relationship,Parasite-Host Interactions,Host Parasite Interactions,Host Parasite Relations,Host Parasite Relationship,Host-Parasite Interaction,Host-Parasite Relation,Host-Parasite Relationships,Interaction, Host-Parasite,Interaction, Parasite-Host,Interactions, Host-Parasite,Interactions, Parasite-Host,Parasite Host Interactions,Parasite Host Relations,Parasite-Host Interaction,Parasite-Host Relation,Relation, Host-Parasite,Relation, Parasite-Host,Relations, Host-Parasite,Relations, Parasite-Host,Relationship, Host-Parasite,Relationships, Host-Parasite
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015215	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.	AZT (Antiviral),Azidothymidine,3'-Azido-2',3'-Dideoxythymidine,3'-Azido-3'-deoxythymidine,AZT Antiviral,AZT, Antiviral,BW A509U,BWA-509U,Retrovir,3' Azido 2',3' Dideoxythymidine,3' Azido 3' deoxythymidine,Antiviral AZT,BWA 509U,BWA509U
D015658	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).	HTLV-III Infections,HTLV-III-LAV Infections,T-Lymphotropic Virus Type III Infections, Human,HIV Coinfection,Coinfection, HIV,Coinfections, HIV,HIV Coinfections,HIV Infection,HTLV III Infections,HTLV III LAV Infections,HTLV-III Infection,HTLV-III-LAV Infection,Infection, HIV,Infection, HTLV-III,Infection, HTLV-III-LAV,Infections, HIV,Infections, HTLV-III,Infections, HTLV-III-LAV,T Lymphotropic Virus Type III Infections, Human
D015704	CD4 Antigens	55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. They 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. T4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.	Antigens, CD4,CD4 Molecule,CD4 Receptor,CD4 Receptors,Receptors, CD4,T4 Antigens, T-Cell,CD4 Antigen,Receptors, Surface CD4,Surface CD4 Receptor,Antigen, CD4,Antigens, T-Cell T4,CD4 Receptor, Surface,CD4 Receptors, Surface,Receptor, CD4,Surface CD4 Receptors,T-Cell T4 Antigens,T4 Antigens, T Cell