József Csongor

Age-dependent alterations of human recombinant GM-CSF effects on human granulocytes

The granulocyte-macrophage colony stimulating factor (GM-CSF) is an important in vivo regulator of granulopoiesis and neutrophil functions. It is well-known that the immune response and the transmembrane signalling in immune cells change with aging. We wished to elucidate the effects of GM-CSF in itself and in priming the activities of other inflammatory agents on neutrophils of elderly persons. Neutrophils of 20 healthy elderly (aged 60-90 years) and 20 healthy young (aged 20-25 years) subjects were studied for superoxide anion production, intracellular free calcium mobilization, antibody dependent cellular cytotoxicity (ADCC) and intracellular killing activities. It was found that GM-CSF is unable to prime neutrophils of elderly subjects to the action of FMLP, metenkephalin or opsonized zymosan. By the use of Pertussis toxin and H7 it was demonstrated that a different signal transduction pathway in neutrophils of elderly subjects is activated by GM-CSF or FMLP if compared to that of young subjects. These results suggest that the lack of priming could contribute to the greater susceptibility of the elderly to infections and that the change of the signal transduction mechanism in neutrophils of elderly subjects might partly explain this phenomenon.

Altered phosphatidylinositol breakdown after K-elastin stimulation in PMNLs of elderly.

The degradation of elastic fibres during atherosclerotic plaque formation in arterial wall is a well known process. The liberated elastin peptides such as K-elastin possess various biological activities: They are chemotactic for monocytes and fibroblasts, stimulate the oxidative burst and the intracellular free Ca2+ mobilisation through the phosphatidylinositol (PIP2) breakdown in PMNLs. It was found that the PIP2 breakdown induced by K-elastin is a pertussis toxin sensitive process in PMNLs of young subjects. In the case of the elderly, the K-elastin-induced oxidative burst, intracellular free Ca2+ elevation was less than in young, and could not be inhibited by pertussis toxin. Studying the K-elastin-induced inositol phosphate (IP) formation in PMNLs of elderly a disturbed PIP2 breakdown was found. K-elastin stimulated the IP formation at a very low level in PMNLs of elderly. This alteration of the second messenger formation (e.g. IP3 and Ca2+) after KE stimulation, might be the consequence of their originally elevated levels in resting PMNLs of elderly.

Effect of lentinan on the chemiluminescence produced by human neutrophils and the murine macrophage cell line C4Mφ

Lentinan, an immunopotentiating polysaccharide, stimulates the production of chemiluminescence (CL) by human neutrophils and the murine macrophage cell line C4M phi. The CL enhancing effect of lentinan opsonized in human serum is greater than that of lentinan itself. Lentinans stimulation of neutrophil CL was increased by 1/2 when opsonized in human serum inactivated at 56 degrees C to remove complement, while the CL was increased two fold by lentinan opsonized in whole serum. This indicates that C3b and immunoglobulin contribute separate signals in the activation process mediated by opsonized lentinan. The distinct roles of the C3b and Fc receptors was further illuminated by the finding that an Fc receptor-negative cell line was unresponsive to lentinan opsonized in heat inactivated serum (56 degrees C), whereas it exhibited a five fold increase in CL in response to lentinan opsonized in serum containing complement. Lentinan in an opsonized form can stimulate the production of CL via C3b and Fc receptors. This mechanism may be considered as one mode of action of lentinan and other similar immunopotentiating and antitumour glucan-type polysaccharides.

Altered Phosphatidylinositol Breakdown in Polymorphonuclear Leukocytes with Aging

It is well known that elderly subjects are susceptible to infections, cancer, and autoimmune disorders (Gladstone and Recco, 1976; Dollet al., 1970; Blumenthal and Berns, 1964). The immune functions were studied extensively in aged humans and animals; the results suggest that the B- and T-lymphocyte functions were altered, particularly the T-cell-mediated immune response (Weksler, 1983; Makinodan and Kay, 1980; Antonaci et al., 1987). It is thought that this decline contributes in large part to the increased incidence of the above-mentioned diseases. Most of the effector functions that occur during the immune response necessitate the stimulation of specific receptors. Among these functions, the most important are proliferation, differentiation, secretion, and phagocytosis (Michell, 1987; Snyderman and Pike, 1984; Fulop et al., 1985). A few studies have been concerned with receptors (Roth, 1986; De Weck et al., 1984) and postreceptor signal-transduction mechanisms (Ito et al., 1982; Fulop et al., 1987b) in the cells of elderly. The aim of this chapter is to elucidate some aspects of the signal-transduction mechanism in the polymorphonuclear leukocytes (PMNL) of elderly subjects.

Serum Complement Activation of SLE Patients During Plasmapheresis

The erythrocyte complement receptor 1 (ECR1)-immune complex binding assay is a sensitive method for the determination of complement fragments which can be activated by bovine serum albumin (BSA)-anti-BSA in vitro. When the C3b/C4b containing bovine serum albumin (BSA)-anti-BSA was formed in the presence of the serum of patients with systemic lupus erythematosus (SLE) its binding to ECR1 was found to be lower than that formed in sera of normal volunteers. The plasmapheresis of SLE patients homozygous for the CR1/E high density allele displays a beneficial effect on the formation of C3b/C4b containing BSA-anti-BSA and its binding to ECR1. There was no significant correlation between the serum C3/C4 level and the percentage of C3b/C4b containing BSA-anti-BSA binding to the ECR1 of SLE patients during plasmapheresis. At the same time, there was an inverse correlation between the serum immune complex level and the ECR1 binding, which was significant in 3 of 5 cases. These data suggest that, besides the determination of different components of complement activation, the functional assay of complement activation might be useful in monitoring the effect of plasmapheresis in SLE.

Inhibition of arachidonic acid release from human peripheral mononuclear cells by heat shock treatment and geldanamycin

The objective of this study was to investigate the effects of heat shock (HS) treatment and geldanamycin (GA) on the release of arachidonic acid (AA) from human peripheral blood mononuclear cells (PBMC), monocytes and lymphocytes. Mononuclear cells prepared from blood of healthy subjects were preincubated with (3)H-AA. The release of (3)H-AA incorporated into the membrane was studied after pretreatment of cells by HS (43 degrees C, 1 h) and GA. The activation of AA producing enzymes was achieved by the addition of phorbol 12-myristate 13-acetate (PMA) or by the combination of PMA+calcium ionophore A-23187. Treatment of cells by HS inhibited the release of AA. Furthermore, the release of AA by PBMC was dose dependently inhibited by GA. The combination of treatments by HS and GA augmented the inhibition of AA release. The HS response involves a diminished release of AA from PBMC. The inhibitory effect of GA on the AA release is a new element in the antiinflammatory pharmacological ability of this drug.

Effect of the ganglionic blocking agent: 1:2:2:6:6-pentamethylpiperidine on different types of allergic skin reactions

We examined the effect of ganglionic blocking agent 1:2:2:6:6-pentamethylpiperidine (Synapleg®, EGyT) on the allergic skin inflammations of immediate (passive cutaneous anaphylaxis, inverse passive Arthus) and delayed (dinitrochlorobenzene, Jones-Mote) hypersensitivity. It was found that the ganglionic blocking agent inhibits the inflammations of immediate hypersensitivity to a greater extent than the delayed ones.