scholarly journals Limiting dilution analysis of cytotoxic T lymphocytes to human immunodeficiency virus gag antigens in infected persons: in vitro quantitation of effector cell populations with p17 and p24 specificities.

1991 ◽  
Vol 174 (6) ◽  
pp. 1593-1600 ◽  
Author(s):  
R A Koup ◽  
C A Pikora ◽  
K Luzuriaga ◽  
D B Brettler ◽  
E S Day ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Effector Cell ◽  
Mononuclear Cells ◽  
Limiting Dilution Analysis ◽  
Activated State ◽  
Immunodeficiency Virus ◽  
Limiting Dilution

The presence of cytotoxic T lymphocytes (CTL) to the gag antigens of human immunodeficiency virus (HIV) has been described in infected populations. We found that the majority of this immune response as measured in bulk CTL assays of unstimulated peripheral blood mononuclear cells (PBMC) is directed against the p24 component of the p55 gag precursor protein. Using limiting dilution analysis of this effector cell population we confirm that the majority of activated gag-specific CTL circulating in the PBMC of infected hemophilic patients are directed at p24 determinants and are present at frequencies of 1/36,000 to 1/86,000 lymphocytes. By performing in vitro stimulation after limiting dilution, the precursor population of gag-specific CTL are characterized and quantitated. HIV gag-specific CTL precursors are identified at frequencies of 1/1700 to 1/17,000 lymphocytes and are made up of cells with both p17 and p24 specificities. No HIV gag-specific CTL precursor cells are identified in the PBMC of HIV-uninfected individuals. These studies demonstrate that CTL directed at both p17 and p24 determinants make up the cellular immune repertoire in HIV-infected individuals but that only the p24-specific CTL are routinely found in an activated state in the circulation.

scholarly journals Virus-Specific Cytotoxic T Lymphocytes in Human Immunodeficiency Virus Type 1-Infected Chimpanzees

1999 ◽  
Vol 73 (8) ◽  
pp. 7065-7069 ◽  
Author(s):  
Sampa Santra ◽  
Patricia N. Fultz ◽  
Norman L. Letvin
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Chimpanzees have been important in studies of human immunodeficiency virus type 1 (HIV-1) pathogenesis and in evaluation of HIV-1 candidate vaccines. However, little information is available about HIV-1-specific cytotoxic T lymphocytes (CTL) in these animals. In the present study, in vitro stimulation of peripheral blood mononuclear cells (PBMC) from infected chimpanzees with HIV-1 Gag peptides was shown to be a sensitive, reproducible method of expanding HIV-1-specific CD8+ effector CTL. Of interest, PBMC from two chimpanzees had CTL activity against Gag epitopes also recognized by major histocompatibility complex class I-restricted CTL from HIV-1-infected humans. The use of peptide stimulation will help to clarify the role of CTL in vaccine-mediated protection and HIV-1 disease progression in this important animal model.

scholarly journals Mechanism of Action and In Vitro Activity of 1′,3′-Dioxolanylpurine Nucleoside Analogues against Sensitive and Drug-Resistant Human Immunodeficiency Virus Type 1 Variants

1999 ◽  
Vol 43 (10) ◽  
pp. 2376-2382 ◽  
Author(s):  
Zhengxian Gu ◽  
Mark A. Wainberg ◽  
Nghe Nguyen-Ba ◽  
Lucille L’Heureux ◽  
Jean-Marc de Muys ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Nucleoside Analogues ◽  
Drug Resistant ◽  
Immunodeficiency Virus ◽  
Blood Mononuclear Cells ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT (−)-β-d-1′,3′-Dioxolane guanosine (DXG) and 2,6-diaminopurine (DAPD) dioxolanyl nucleoside analogues have been reported to be potent inhibitors of human immunodeficiency virus type 1 (HIV-1). We have recently conducted experiments to more fully characterize their in vitro anti-HIV-1 profiles. Antiviral assays performed in cell culture systems determined that DXG had 50% effective concentrations of 0.046 and 0.085 μM when evaluated against HIV-1IIIB in cord blood mononuclear cells and MT-2 cells, respectively. These values indicate that DXG is approximately equipotent to 2′,3′-dideoxy-3′-thiacytidine (3TC) but 5- to 10-fold less potent than 3′-azido-2′,3′-dideoxythymidine (AZT) in the two cell systems tested. At the same time, DAPD was approximately 5- to 20-fold less active than DXG in the anti-HIV-1 assays. When recombinant or clinical variants of HIV-1 were used to assess the efficacy of the purine nucleoside analogues against drug-resistant HIV-1, it was observed that AZT-resistant virus remained sensitive to DXG and DAPD. Virus harboring a mutation(s) which conferred decreased sensitivity to 3TC, 2′,3′-dideoxyinosine, and 2′,3′-dideoxycytidine, such as a 65R, 74V, or 184V mutation in the viral reverse transcriptase (RT), exhibited a two- to fivefold-decreased susceptibility to DXG or DAPD. When nonnucleoside RT inhibitor-resistant and protease inhibitor-resistant viruses were tested, no change in virus sensitivity to DXG or DAPD was observed. In vitro drug combination assays indicated that DXG had synergistic antiviral effects when used in combination with AZT, 3TC, or nevirapine. In cellular toxicity analyses, DXG and DAPD had 50% cytotoxic concentrations of greater than 500 μM when tested in peripheral blood mononuclear cells and a variety of human tumor and normal cell lines. The triphosphate form of DXG competed with the natural nucleotide substrates and acted as a chain terminator of the nascent DNA. These data suggest that DXG triphosphate may be the active intracellular metabolite, consistent with the mechanism by which other nucleoside analogues inhibit HIV-1 replication. Our results suggest that the use of DXG and DAPD as therapeutic agents for HIV-1 infection should be explored.

scholarly journals MDL 74,968, a new acyclonucleotide analog: activity against human immunodeficiency virus in vitro and in the hu-PBL-SCID.beige mouse model of infection.

1996 ◽  
Vol 40 (5) ◽  
pp. 1072-1077 ◽  
Author(s):  
C G Bridges ◽  
D L Taylor ◽  
P S Ahmed ◽  
T M Brennan ◽  
J M Hornsperger ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Hiv Infection ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Placebo Control ◽  
Intravenous Route ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Orally Bioavailable

The novel acyclonucleotide derivative of guanine, 9-[2-methylidene-3-(phosphonomethoxy)propyl] guanine (MDL 74,968), had antiviral activity comparable to those of 9-(2-phosphonomethoxyethyl) adenine (PMEA) and 2',3'-dideoxyinosine against laboratory strains of both human immunodeficiency virus (HIV) types 1 and 2 cultured in MT-4 cells and several clinical HIV isolates cultured in human peripheral blood mononuclear cells (PBMCs). MDL 74,968 was at least fourfold less toxic than PMEA to MT-4 cells or PBMCs, thereby producing a more favorable in vitro selectivity index for the former compound. Studies of acute toxicity in CD-1 mice showed that MDL 74,968 was not toxic at doses of 1,600 mg/kg of body weight via the intraperitoneal route or at doses of 500 mg/kg via the intravenous route. Furthermore, no adverse effects of MDL 74,968 were apparent when mice were treated at doses of 200 mg/kg twice daily for 5 days. Treatment by continuous subcutaneous infusion of MDL 74,968 or PMEA at the daily dose of 20 mg/kg in the hu-PBL-SCID.beige murine model of HIV infection significantly reduced the severity of infection compared with that in placebo-treated controls. Quantitation of virus recovery by endpoint titration of spleen cells in coculture with mitogen-activated PBMCs demonstrated that MDL 74,968 as well as PMEA significantly reduced the amount of virus (P < 0.02). Moreover, by using DNA extracted from spleens, the mean HIV:HLA PCR product ratio, which takes into account individual variation in immune system reconstitution, were 0.50 and 0.40 for MDL 74,968 and PMEA treatments, respectively, whereas animals receiving the placebo control had significantly higher levels of HIV proviral DNA (mean 0.78; P < 0.02). Taken together, these promising findings suggest that an orally bioavailable prodrug of MDL 74,968 should be developed for the treatment of HIV infection.

scholarly journals Human immunodeficiency virus (HIV) infection in CD4+ T lymphocytes genetically deficient in LFA-1: LFA-1 is required for HIV-mediated cell fusion but not for viral transmission.

1991 ◽  
Vol 173 (2) ◽  
pp. 511-514 ◽  
Author(s):  
G Pantaleo ◽  
L Butini ◽  
C Graziosi ◽  
G Poli ◽  
S M Schnittman ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Hiv Infection ◽  
Cell Fusion ◽  
Leukocyte Adhesion ◽  
Leukocyte Adhesion Deficiency ◽  
Immunodeficiency Virus ◽  
Syncytia Formation ◽  
Hiv 1

In the present study, we demonstrated that expression of the LFA-1 molecule is necessary for cell fusion and syncytia formation in human immunodeficiency virus (HIV)-infected CD4+ T lymphocytes. In contrast, the lack of expression of LFA-1 does not influence significantly cell-to-cell transmission of HIV. In fact, LFA-1- T lymphocytes obtained from a leukocyte adhesion deficiency patient were unable to fuse and form syncytia when infected with HIV-1 or HIV-2, despite the fact that efficiency of HIV infection (i.e., virus entry, HIV spreading, and levels of virus replication) was comparable with that observed in LFA-1+ T lymphocytes. In addition, we provide evidence that LFA-1 by mediating cell fusion contributes to the depletion of HIV-infected CD4+ T lymphocytes in vitro.

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