Biomedical subjects

R Esser

Publications and source records attributed to R Esser.

25 records · Page 2Linked to original sources

PubMedDate not supplied

Infection of monocytes/macrophages by HIV in vitro.

Because of the very important role of the mononuclear phagocyte system in the immunopathogenesis of HIV infection, a culture system for in vitro studies of infection of monocytes/macrophages with HIV was developed. A method is described for the infection of human monocytes/macrophages cultured on hydrophobic membranes (Teflon) with different strains of HIV. The HIV isolates can be characterized according to their replication potential on monocytes/macrophages cultures. The biological properties of some HIV1 and HIV2 isolates are compared in lymphocyte and monocyte/macrophage cultures.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

The polysulphated polyxylan Hoe/Bay-946 inhibits HIV replication on human monocytes/macrophages.

Due to the important role of monocytes/macrophages in the pathogenesis of AIDS, potential drugs with anti-HIV activity in lymphocytes must also be effective in monocytes/macrophages. For testing the efficacy of antiviral substances, monocytes/macrophages from peripheral blood were infected, respectively, with highly replicating HIV1 and HIV2 strains, thereby providing an extremely sensitive system of testing. Azidothymidine was found to inhibit both HIV types at 0.04 microgram/ml. The polysulphated polyxylan, Hoe/Bay-946 (MW 6,000 Daltons), which acts through a different mechanism and is being tested in clinical pilot studies in Germany, was also found to be effective against HIV1 and HIV2 in macrophages at concentrations of 10-50 micrograms/ml.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Effect of cytokines and lipopolysaccharides on HIV infection of human macrophages.

Human blood-borne monocytes (MO) differentiating into mature macrophages (MAC) were cultured on hydrophobic Teflon membranes. The cells were infected with two different monocytotropic HIV isolates: HIV1D117III obtained from a perinatally infected child, and HIV2D194 obtained from an AIDS patient who suffered exclusively from neurological symptoms. Virus production monitored by reverse transcriptase activity and HIV-antigen ELISA in cell-free supernatant was of a high level and continued for several weeks. To investigate possible modulatory pathways interfering with HIV infection in MAC we tested various recombinant cytokines as well as bacterial lipopolysaccharides (LPS) in our culture system. Whereas interleukin-1 (IL1) accelerated and increased HIV replication in MO/MAC, the interferons (IFN) alpha, beta and gamma effectively suppressed or delayed infection depending on the concentration used. Suppression was seen at concentrations as low as 0.3 U/ml and was most effective when the IFN were given prior to infection. No effect was observed with IL6 up to 2,000 U/ml. LPS affected virus infection in a complex manner: at 1-100 ng/ml virus replication was inhibited, but it was enhanced at subnanogram concentrations (25-100 pg/ml).

Cytokines↗

PubMedDate not supplied

Expression of macrophage products after in vitro infection of human monocytes/macrophages with HIV.

We studied the response of monocytes/macrophages (MO/MAC) to lipopolysaccharide (LPS) and interferon-gamma (IFN gamma) stimulation with respect to the expression of macrophage-specific products, i.e. macrophage-colony-stimulating factor (M-CSF), c-fms, c-sis, tissue factors, transforming growth factor-beta (TGF beta) and interleukin-8 (IL8) after in vitro infection with HIV. The expression of IL8 was strongly elevated in HIV-infected cells, peaking at 4 h after stimulation with LPS. At that time, the uninfected control showed only weak expression of IL8. Other products, e.g. tissue factor, c-fms, M-CSF and TGF beta were not modulated after stimulation. In contrast to IL8, the expression of c-cis was significantly lower in infected cells after stimulation with IFN gamma compared to uninfected control cells.

Base Sequence↗

PubMedDate not supplied

Cytokine expression of HIV-infected monocytes/macrophages at the single-cell level.

Monocytes of healthy donors were infected with HIV1 in vitro: 14-21 days after infection 50-70% of the cells produced p24 HIV1 antigen as detected with anti-p24 immunostaining; infected cultures showed enhanced secretion of interleukin-6 (IL6), interleukin-8 (IL8) and tumour necrosis factor alpha (TNF-alpha). The expression of cytokines on the single-cell level was further analysed by in situ hybridization using nonradioactive digoxigenin for detection. HIV1 (p24+) -producing cells were compared with non-HIV (p24-) -producing cells. All morphological subtypes of macrophages showed HIV production; no difference in cytokine expression was observed. Immunocytochemistry of HIV-infected and uninfected cultures also showed no difference in the pattern of IL1-beta, IL6, IL8 and TNF-alpha protein expression in the cells.

Cytokines↗

PubMedDate not supplied

Ex vivo expansion of highly purified NK cells for immunotherapy after haploidentical stem cell transplantation in children.

BACKGROUND: Allogeneic natural killer (NK) cells are known to show medium to high cytotoxic activity against HLA-nonidentical leukemia or tumor cells. For a possible benefit of post transplant treatment with NK cells after haploidentical stem cell transplantation (haplo-SCT) we developed a clinical scale procedure for NK cell processing observing Good Manufacturing Practice (GMP). METHODS: Allogeneic donor NK cells were selected from 15 unstimulated leukaphereses using two rounds of immunomagnetic T cell depletion, followed by an NK cell enrichment step. CD56 (+)CD3 (-) NK cells were stimulated and expanded in vitro according to GMP. Quality control of NK cell purity, residual T cells and cytotoxic activity was done by multi-coloured flow cytometric analyses. RESULTS: Purification led to an absolute number of 234-1 237 x 10 (6) CD56 (+)CD3 (-) NK cells from leukapheresis harvests with a median purity of 95 % and a 4 to 6(1/2) log depletion of T cells. After two weeks stimulation with IL-2 a five-fold expansion of NK cells with a T cell contamination below 0.1 % was reached. Median cell viability was 95 % after purification and 99 % after expansion. The IL-2 stimulated NK cells showed a highly increased lytic activity against the MHC-I deficient K562 cells compared to freshly isolated NK cells and a medium cytotoxicity against patients' leukemic cells. CONCLUSIONS: Clinical scale enrichment and activation of allogeneic donor NK cells is feasible. High dose NK cell application may be a new treatment option for pediatric patients with leukemia or solid tumors in case of minimal residual disease or unbalanced chimerism post haplo-SCT as we could show for the first three patients .

Antigens, CD19↗

PubMedDate not supplied

In vivo rheologic effects of lipid apheresis techniques: comparison of dextran sulfate LDL adsorption and heparin induced LDL precipitation.

The effects of two different LDL apheresis techniques, heparin-induced LDL precipitation (HELP) and dextran sulfate LDL adsorption (DSA), were compared in six patients with familial hypercholesterolemia. Total and LDL cholesterol were effectively lowered with both techniques. The reduction of serum triglycerides was more pronounced with DSA, whereas the reduction of HDL cholesterol was more pronounced with HELP. Single sessions using both techniques immediately reduced whole blood and plasma viscosity, as well as erythrocyte aggregation. Serum fibrinogen decreased by 62% (HELP) and 11% (DSA). Maintenance lipid apheresis administered 1 time per week resulted in a sustained reduction of total and LDL cholesterol and was associated with a sustained improvement in blood flow properties. Data suggest that besides serum fibrinogen, serum lipoproteins may adversely effect the rheologic characteristics of blood.

Adsorption↗