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F Miedema

Publications and source records attributed to F Miedema.

At least 127 records · Page 7Linked to original sources
PubMed1994

Interference of interleukin-10 with human immunodeficiency virus type 1 replication in primary monocyte-derived macrophages.

Previously we demonstrated an inhibitory effect of interleukin-4 (IL-4) on establishment of human immunodeficiency virus type 1 (HIV-1) infection in primary macrophages. The reported similarities between the biological effects of IL-4 and IL-10 prompted us to study the effect of IL-10 on HIV-1 replication. Treatment of primary macrophages with IL-10 resulted in inhibition of HIV-1 infection. This inhibitory effect was specific for macrophages, since IL-10 did not interfere with HIV-1 replication in primary T cells. Semiquantitative PCR analysis excluded an inhibitory effect of IL-10 on virus entry and reverse transcription. Effects of IL-10 on HIV-1 long terminal repeat-driven chloramphenicol acetyltransferase activity also could not be demonstrated in a transient expression system in primary derived macrophages. In agreement with this, Northern (RNA) blot analysis demonstrated equal amounts of viral RNA species irrespective of IL-10 treatment, also excluding an inhibitory effect on elongation of virus transcription. Monocyte-derived macrophages (MDM) treated with IL-10 after HIV-1 inoculation showed accumulation of apparently mature p24 protein suggestive of an inhibitory effect at the level of virus assembly. IL-10 treatment of MDM prior to HIV-1 inoculation did not result in accumulation of p24 protein. Immunoblot analysis indeed showed the absence of mature p24 and gp120 but accumulation of the Pr53 gag-encoded protein in HIV-1-inoculated, IL-10-pretreated MDM, suggesting an inhibitory effect at the level of protein processing. A combination of IL-4 and IL-10 resulted in a cumulative inhibitory effect on HIV-1 replication in MDM. The recent observation that in the course of HIV-1 infection a shift occurs in the production of IL-2/gamma interferon toward enhanced IL-4 and IL-10 production and the reported shift from preferential macrophage-tropic towards preferential T-cell-tropic HIV-1 variants with progression of disease suggest that cytokines have an important role in the in vivo regulation of HIV-1 tropism.

Base Sequence↗
PubMed1994

Programmed death of T cells in human immunodeficiency virus infection. No correlation with progression to disease.

Programmed death of T cells has been proposed as one of the mechanisms by which HIV affects immune functions in stages of infection where the number of infected cells is low. Indeed, in HIV-infected individuals both CD4+ and CD8+ T cells are primed for programmed cell death, which can be enhanced by polyclonal stimulation. Here, we investigated programmed death of T cells in all stages of HIV infection, including acute infection. In individuals with primary infection the number of T cells dying due to apoptosis was much higher than in the asymptomatic phase of infection and paralleled increased numbers of CD8+ cells. In asymptomatic HIV-infected individuals, cells were dying in increased percentages compared with noninfected controls, although at much lower numbers than during acute infection. Death of T cells was not quantitatively correlated with CD4+ T cell numbers or appearance of more cytopathic, syncytium-inducing HIV variants. Analysis of the phenotype of cells undergoing apoptosis revealed that cell death was not confined to a specific T cell subset nor correlated with expression of certain T cell activation markers. Our results imply that the extent of programmed cell death of T cells in HIV infection does not correlate with progression to disease.

Antigen-Presenting Cells↗
PubMed1994

Quantitative analysis of CD4+ T cell function in the course of human immunodeficiency virus infection. Gradual decline of both naive and memory alloreactive T cells.

Early in human immunodeficiency virus (HIV) infection CD4+ and CD8+ T cells are qualitatively affected. Loss of responses to recall antigen precedes impaired responses to allogeneic MHC and mitogens. The selective quantitative loss of memory T cells in early infection, only partially explains the observed defects. We investigated whether functional loss of T cells is preferentially observed for memory T cells or whether both naive and memory T cell subsets are affected in the course of HIV infection. We studied the proliferative response of CD4+ T cells from HIV-infected individuals to alloantigens, to which normally both naive and memory T cells respond, by limiting dilution analysis. The decreased proliferative response to alloantigens in HIV-infected individuals was associated with a decreased precursor frequency of alloreactive cells. The frequency was decreased in both the CD45RA+ (naive) and the CD45RO+ (memory) subset of CD4+ T cells. Analysis of four individuals in the course of HIV infection revealed similar kinetics of the decline in function in both subsets. Although initially T cell defects may be accounted for by the selective quantitative loss of memory cells, in later stages of HIV infection the function of both CD45RA+ and CD45RO+ cells is affected.

CD3 Complex↗
PubMed1994

Macrophage-tropic variants initiate human immunodeficiency virus type 1 infection after sexual, parenteral, and vertical transmission.

Macrophage-tropic, non-syncytium-inducing, HIV-1 variants predominate in the asymptomatic phase of infection and may be responsible for establishing infection in an individual exposed to the mixture of HIV-1 variants. Here, genotypical and phenotypical characteristics of virus populations, present in sexual, parenteral, or vertical donor-recipient pairs, were studied. Sequence analysis of the V3 domain confirmed the presence of a homogeneous virus population in recently infected individuals. Biological HIV-1 clones were further characterized for syncytium inducing capacity on the MT2 cell line and for macrophage tropism as defined by the appearance of proviral DNA upon inoculation of monocyte-derived macrophages. Both sexual and parenteral transmission cases revealed a selective outgrowth in the recipient of the most macrophage-tropic variant(s) present in the donor. In three out of five vertical transmission cases, more than one highly macrophage-tropic virus variant was present in the child shortly after birth, suggestive of transmission of multiple variants. In three primary infection cases, homogeneous virus populations of macrophage-tropic, non-syncytium-inducing variants were present prior to seroconversion, thus excluding humoral immunity as the selective pressure in favour of macrophage-tropic variants. These observations may have important implications for vaccine development.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Immunological and virological markers determining progression to AIDS.

Infection with the human immunodeficiency virus (HIV-1) results in a severe immunodeficiency characterized by a depletion of CD4+ T-helper cells. Furthermore it is well documented that in asymptomatic persons the number of CD4+ cells is also a good predictor of progression to AIDS. However, persons with similar CD4+ cell counts may differ with regard to clinical progression. For this reason the development of additional markers predictive of disease progression is of major clinical importance. In this review three additional progression markers are discussed: rate of decline of CD4+ cells, T-cell reactivity and HIV biological phenotype. Besides their usefulness as independent progression markers they also provide insight into the immunopathological mechanisms responsible for the final development of AIDS.

Biomarkers↗
PubMed1993

Relation of phenotype evolution of HIV-1 to envelope V2 configuration.

Biological variability of human immunodeficiency virus type-1 (HIV-1) is involved in the pathogenesis of acquired immunodeficiency syndrome (AIDS). Syncytium-inducing (SI) HIV-1 variants emerge in 50 percent of infected individuals during infection, preceding accelerated CD4+ T cell loss and rapid progression to AIDS. The V1 to V2 and V3 region of the viral envelope glycoprotein gp120 contained the major determinants of SI capacity. The configuration of a hypervariable locus in the V2 domain appeared to be predictive for non-SI to SI phenotype conversion. Early prediction of HIV-1 phenotype evolution may be useful for clinical monitoring and treatment of asymptomatic infection.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Prognostic value of HIV-1 syncytium-inducing phenotype for rate of CD4+ cell depletion and progression to AIDS.

OBJECTIVE: To investigate the relation between detection of syncytium-inducing (SI), human immunodeficiency virus type 1 (HIV-1) variants, rate of CD4+ cell decline, and clinical progression. DESIGN: Prospective study during a 2.5-year follow-up period; cohort study with pairwise matched controls. SETTING: The Amsterdam cohort study on the course of HIV-1 infection in homosexual men. PARTICIPANTS: Asymptomatic HIV-1 infected men (n = 225) were tested for the presence of SI variants and were studied prospectively for CD4+ cell decline and clinical progression. In addition, 45 men with a defined moment of appearance of SI variants and 45 matched controls without SI variants were compared for CD4+ cell decline. MEASUREMENTS: Syncytium-inducing variants were detected by cocultivation of peripheral blood mononuclear cells with the MT-2 T-cell line. RESULTS: During a 30-month period, 70.8% of the men with SI variants progressed to AIDS, compared with 15.8% of men without SI variants at entry (P < 0.0001). Multivariable Cox proportional hazard analysis, controlling for CD4+ cell count and HIV-p24 antigenemia, showed a relative hazard for SI variants of 6.7 (95% Cl, 3.5 to 12.7). In the matched control study, before the appearance of SI variants, CD4+ cell counts of 45 men with SI variants and their controls were compared. Syncytium-inducing variants emerged at a mean CD4+ cell count of 0.48 x 10(9)/L(Cl, 0.42 to 0.54), coinciding with the onset of a threefold increased rate of CD4+ cell decline. Men developing AIDS with SI variants had decreased CD4+ cell counts (0.08 x 10(9)/L; 95% Cl, 0.05 to 0.12) at the time of diagnosis compared with persons progressing to AIDS without SI variants (0.25 x 10(9)/L 95% Cl, 0.15 to 0.41) (P = 0.0035]. CONCLUSIONS: The HIV-1 biological phenotype is a practical, binary marker for progression to AIDS, which is independent of decreased CD4+ cell counts and antigenemia. Appearance of SI variants, occurring 2 years before progression to AIDS on the average, is predictive for a significantly increased rate of CD4+ cell decline.

Acquired Immunodeficiency Syndrome↗
PubMed1993

HIV tropism.

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CD4 Antigens↗
PubMed1993

Skewing to the LFA-3 adhesion pathway by influenza infection of antigen-presenting cells.

The effect of influenza (FLU) infection on heterotypic conjugate formation between antigen-presenting cells and T lymphocytes has been studied with FLU-specific T cell clones and FLU-infected B-lymphoblastoid cells (B-LCL). Conjugate formation between FLU-infected B-LCL (FLU+ B-LCL) and T cells was found to be consistently enhanced in comparison with peptide-sensitized or uninfected B-LCL. Treatment of B-LCL with exogenous neuraminidase (NA-NAse) similarly enhanced conjugate formation indicating that increased conjugate formation may be mediated by the viral neuraminidase. Monoclonal antibody blocking experiments revealed that the contribution by CD2/LFA-3 is increased relative to that of LFA-1/ICAM-1 in conjugates between FLU+ B-LCL or NANAse-treated B-LCL and T cell clones. In contrast, both pathways of adhesion contributed equally to conjugate formation between peptide-sensitized B-LCL or control B-LCL and T cell clones. Thus, FLU infection causes increased conjugate formation between antigen-presenting cells and T cells and skews towards CD2/LFA-3-dependent adhesion, independent of T cell receptor signalling.

Antigen-Presenting Cells↗
PubMed1993

T-cell dysfunction in HIV infection: anergy due to defective antigen-presenting cell function?

Before CD4+ T cells are depleted, T cells in asymptomatic HIV-infected individuals are functionally abnormal. These T cells are programmed for death, are non-responsive and fail to produce interleukin-2 after antigenic stimulation. Our view is that these different T-cell abnormalities are explained by the effects of HIV on antigen-presenting cells. Alteration of the functions of the antigen-presenting cell may program T cells for activation-induced death, and may induce anergy in interleukin-2 and interferon-gamma secreting TH1 cells. This results in predominance of TH2 allergic responses instead of cellular immunity dependent on TH1 cells.

Animals↗
PubMed1993

Early replication steps but not cell type-specific signalling of the viral long terminal repeat determine HIV-1 monocytotropism.

The expression of human immunodeficiency virus type 1 (HIV-1) is enhanced after cell activation because of the interaction of cell-encoded nuclear factors that interact with binding sites in the long terminal repeats (LTRs). Here we studied the contribution of cell type-specific activation signals to differences in cytotropism of HIV-1 variants. Four closely related molecular HIV-1 clones with distinct biological phenotypes and different capacities to replicate in primary monocyte-derived macrophages (MDMs) or T cell lines were used. Sequence analysis of these LTRs revealed variation in functionally important regions. Adaptation of virus variants to particular host cells by differences in LTR responsiveness was analyzed. LTR-CAT constructs were transiently transfected in T cells that were stimulated with T cell-specific activation signals such as combinations of anti-CD3 or anti-CD28 MoAB or in primary monocytes that were stimulated with IL-3, IL-4, or GM-CSF. No differences in responsiveness to cell type-specific signals were demonstrated. To further elucidate the level of restriction in cell tropism, transfection of four full-length infectious molecular HIV-1 clones into 5-day cultured MDMs was performed. From all clones, competent virus could be rescued from MDMs by coculture with PHA-stimulated PBLs. However, following cell-free inoculation, proviral DNA could be detected by PCR analysis only in monocytes exposed to HIV-1 clones that previously were shown to establish productive infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1993

Viral phenotype and T cell reactivity in human immunodeficiency virus type 1-infected asymptomatic men treated with zidovudine.

The effect of zidovudine on disease progression in asymptomatic human immunodeficiency virus type 1 (HIV-1)-infected men (n = 52) in relation to CD4 T cell numbers, T cell reactivity, and HIV-1 biologic phenotype was studied in a double-blind randomized trial over 2 years. CD4+ cell numbers and T cell reactivity did not differ significantly between the zidovudine- and placebo-treated groups, except for a transient improvement of both parameters in the zidovudine-treated group during the first 9 months. A marked differential efficacy of zidovudine was observed depending on the HIV-1 phenotype present. Zidovudine did not prevent the emergence of high-replicating syncytium-inducing (SI) variants, and clinical progression was observed in persons with SI variants despite zidovudine treatment. In contrast to nontreated HIV-1-infected asymptomatic persons, zidovudine-treated men who did not develop SI variants did not progress to AIDS. The beneficial effect of zidovudine during the asymptomatic phase may be mainly limited to persons who do not develop SI variants in the course of HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Lack of T cell dysfunction and programmed cell death in human immunodeficiency virus type 1-infected chimpanzees correlates with absence of monocytotropic variants.

In asymptomatic human immunodeficiency virus (HIV) infection in humans, disturbed T cell functions such as anergy and programmed cell death, thought to result from inappropriate signaling by antigen-presenting cells due to HIV infection, precede increase in virus load, decline in CD4+ T cell numbers, and subsequent disease progression. Here, in 3 long-term HIV-1-infected asymptomatic chimpanzees, antigen-presenting cell function was intact and T cells had normal proliferative capacity with no evidence of HIV-1-associated programmed cell death. Polymerase chain reaction analysis demonstrated low frequencies of cells harboring proviral DNA. Primary virus isolation from the infected animals demonstrated the absence of monocytotropic HIV-1 variants, in concordance with complete insusceptibility of chimpanzee monocytes for HIV-1 infection. Possibly, because of the incapacity of HIV-1 to infect monocytes, systemic immune dysfunction will not occur, contributing to controlled viral replication and maintenance of the asymptomatic state in HIV-infected chimpanzees.

Amino Acid Sequence↗
PubMed1993

Predictors of rapid progression to AIDS in HIV-1 seroconverters.

OBJECTIVE: To determine whether at the time of HIV-1 seroconversion rapid progressors to AIDS and a low CD4+ count can be distinguished by the clinical presentation of primary HIV-1 infection and serological and immunological characteristics. DESIGN: Prospective cohort study on HIV-1 infection in homosexual men. SETTING: The Municipal Health Service, Amsterdam, The Netherlands. SUBJECTS: One hundred and eight men who seroconverted for HIV-1 during follow-up. MAIN OUTCOME MEASURES: Progression to AIDS and progression to a CD4+ lymphocyte count < 200 x 10(6)/l. RESULTS: Symptomatic primary HIV infection with fever and skin rash, absence of anti-HIV core and transient HIV p24 antigenemia were independent predictors of progression to AIDS at the time of HIV-1 seroconversion. A low CD4+ count immediately after seroconversion and the calendar year were independent predictors of progression to a low CD4+ count at the time of HIV-1 seroconversion. CONCLUSIONS: Even in the earliest stage of HIV-1 infection a small group of individuals at high risk for rapid progression to AIDS can be recognized by the clinical presentation of primary HIV infection, the presence of HIV p24 antigenaemia and the absence of a serological response to HIV core protein.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Selective in vitro expansion of HLA class I-restricted HIV-1 Gag-specific CD8+ T cells: cytotoxic T-lymphocyte epitopes and precursor frequencies.

OBJECTIVE: To identify HIV-1 Gag cytotoxic T-lymphocyte (CTL) epitopes and HLA restriction of their recognition, and to define precursor frequencies of HIV-1 Gag-specific CTL in the blood of seropositive individuals. METHODS: B-lymphoblastoid cell lines (B-LCL) infected with recombinant vaccinia viruses (rVV) containing a gene coding for HIV-1 Gag (rVV-Gag) were fixed with paraformaldehyde (PFA) and used as antigen-presenting cells (APC) to stimulate peripheral blood mononuclear cells (PBMC) from asymptomatic HIV-seropositive individuals. Specific CTL activity was determined in 51Cr-release assays using B-LCL as targets after infection with rVV-Gag or after pulsing with partially overlapping peptides spanning the Gag sequence. RESULTS: In vitro stimulation resulted in an increased number of CD8+ T cells and CD45R0+ and HLA-DR+ cells. Gag-specific cytotoxicity, mediated predominantly by HLA class I-restricted CD8+ CTL, was observed in all seven individuals studied. Multiple HLA-restricted CTL epitopes were identified with a single culture from one of the individuals. Gag-expressing APC were successfully used as stimulator cells in limiting dilution analysis to determine CTL precursor (CTLp) frequencies. CONCLUSION: PFA-fixed rVV-Gag-infected autologous B-LCL can be used as stimulator cells in bulk PBMC cultures to identify CTL epitopes and to determine CTLp frequencies. This method will facilitate the analysis of HIV-1-specific CTL responses in HIV-infected and vaccinated individuals.

Antigen-Presenting Cells↗
PubMed1993

Progression of HIV infection among injecting drug users: indications for a lower rate of progression among those who have frequently borrowed injecting equipment.

OBJECTIVE: To study markers of progression in a cohort of HIV-infected intravenous drug users (IDU). DESIGN: A prospective epidemiologic study. SETTING AND PATIENTS: We studied progression of HIV infection among 126 IDU attending the Municipal Health Service in Amsterdam. MAIN OUTCOME MEASURES: Progression was defined as a decline of the CD4 cell count to < 200 x 10(6)/l on two consecutive follow-up visits or AIDS. RESULTS: Using Cox modelling, the following baseline variables were predictive of progression. Enhanced progression was associated with: age > 30 years [relative hazard (RH), 7.7 [95% confidence intervals (CI), 1.7-36.0]], core antibody negativity [RH, 5.3 (95% CI, 1.6-17.6)], CD4 cell count [for CD4 cells 350-500 x 10(6)/l, RH, 1.38 (95% CI, 0.37-5.16); for CD4 cells 200-350 x 10(6)/l, RH, 9.20 (95% CI, 2.73-31.05) compared with a CD4 count > 500 x 10(6)/l]. A lower rate of progression was associated with borrowing used injecting equipment. IDU who reported borrowing injecting equipment between 1980 and baseline 10-99 times or > 99 times had a RH of 0.44 (95% CI, 0.22-0.88) and 0.19 (95% CI, 0.03-0.37), respectively, compared with IDU who had borrowed < 10 times. p24 antigen positivity was more predictive than core antibody negativity in a model with time-dependent variables, the relative risk for p24 antigen-positive participants was 3.5 (95% CI, 1.3-9.3). Additional analysis of progression to AIDS in a larger group of IDU showed comparable results with regard to the effect of borrowing on progression. CONCLUSIONS: Our observation that those IDU who reported borrowing injecting equipment most frequently appeared to have the lowest rate of progression, corrected for some sources of potential confounding, requires further epidemiologic confirmation and extended laboratory studies since other sources of bias might have been present. Baseline CD4 count, age and core antibody or p24 antigen were predictive of progression in IDU. We wish to emphasize that our results do not imply that borrowing should be encouraged, but may have implications for our understanding of HIV pathogenesis.

Adult↗
PubMed1992

Maturation- and differentiation-dependent responsiveness of human CD4+ T helper subsets.

The human CD45R0+ (memory) CD4+ T cell population can be subdivided into a large (82%) CD27+ and a small (18%) CD27- subset. Within the CD45R0+CD27- subset, cells accumulate that have been persistently stimulated by Ag in vivo. As an apparent consequence, TLC with a differentiated functional phenotype, producing either high levels of IFN-gamma (Th1-like), high levels of IL-4 (Th2-like) or high amounts of both these cytokines (here referred to as Thx) can primarily be generated from the CD27- memory CD4+ T cell subset. In this study we examined the requirements for induction of proliferation of distinct CD4+CD45R0+ Th subsets. Immobilized CD3 mAb induced proliferation with comparable magnitude and kinetics in all types of TLC. However, interference with intracellular signaling pathways in this activation system, resulted in a strong inhibition of proliferation in TLC derived from CD27+ cells whereas, in contrast, TLC from CD27- cells were relatively resistant to elevation of [cAMP]i, inhibition of protein kinase C activation and the immunosuppressive effects of cyclosporin A. Stimulation with CD3 mAb in soluble form resulted in Il-4 secretion by Th2-like and Thx-type TLC but did not induce IFN-gamma or Il-2 secretion in any Th subset. Interestingly, Th2-like cells but not Thx-type cells were able to use endogenously produced Il-4 for proliferation. These data demonstrate a differential sensitivity of CD45R0+CD4+ Th subsets for immune activation and suppression, which correlated with their maturation stage, as reflected by CD27 membrane expression, as well as with their effector phenotype.

Antibodies, Monoclonal↗