Dendritic cells and interleukin-2: cytochemical and ultrastructural study.

The aim of the present study was to verify the effect of IL-2 on dendritic cell (DC) differentiation. Various cytokines have been indicated as factors inducing DC differentiation, but no data about the interleukin-2 (IL-2) effect on DC differentiation have been reported. Monocytes isolated from peripheral blood were treated in vitro with the following factors: IL-2, IL-4, GM-CSF and G-CSF alone or in combination. Morphological (also ultrastructural) and cytochemical observations were carried out starting from 3 to 21 days of treatment. The results indicate that the differentiation of cells showing dendritic pattern is related to the presence of IL-2. Moreover a synergic effect of IL-2 and GM-CSF was observed. The enzymatic features changed with the culture time: before the differentiation into DC, the stimulated cells expressed the typical pattern of monocytes. On the contrary, at advanced stage of differentiation, some enzyme activities changed and in terminally differentiated dendritic cells the reactions for peroxidase and serine esterase were negative. Considering the morphological features, the ability to interact with lymphocytes and the enzymatic pattern observed, we suppose that IL-2 may act as a maturative factor rather than as a growth factor in the DC differentiation.

Interleukin-2 induces the growth of human glioblastoma cells in culture.

The ability of the T cell growth factor interleukin-2 (IL-2) to support the proliferation of human glioblastoma cells in short-term cultures was evaluated. A morphological, cytochemical and immunocytochemical analysis was carried out at different times of treatment. In the presence of IL-2 growth of tumor cells was observed. On the contrary, in the absence of IL-2 only few colonies derived from tumor fragments were obtained and these were so after a long time. The immunocytochemical study revealed that IL-2 induces the expression of the IL-2 receptor on human glioblastoma cells. In the presence of IL-2 proliferation of infiltrating lymphoid cells inside the tumor fragments was also observed. Morphological and cytochemical analysis of these cells revealed positivity for acid phosphatase (AP), dihydrofolate reductase (DHFR), dipeptydilaminopeptidase (DAP IV) and negativity for serine esterase. These data are in agreement with our previous study on activated lymphoid subsets. On the other hand, an absence of infiltrating lymphocytes was observed in cultures without IL-2. These results indicate that local treatment of human glioblastoma using IL-2 might produce tumor cell proliferation.

Interleukin-2 at different concentrations induces the growth of selective lymphoid cells.

The effects of low and high doses of recombinant interleukin-2 (rIL-2) on cultured peripheral blood mononucleated cells are reported with the aim to show the effects of this immunomodulator in different conditions. The proliferation of various cell types at different IL-2 concentrations was investigated and ultrastructural and enzymatic studies were performed. The data obtained indicate that grade and type of cell stimulation induced by IL-2 is correlated to the dose employed.

Effects of interleukin-2 for the treatment of malignant mesothelioma.

The hematological profile, and clinical parameters in mesothelioma affected patients undergoing a clinical trial to evaluate the efficacy of IL-2 treatment were investigated. Six patients were monitored for 6 weeks following therapy. Blood cell count, morphological and immunophenotypical analysis were performed, as well as clinical evaluations of the patients before and after therapy. Activation of the immune system (increase in lymphocytes, monocytes, eosinophils and HMS lymphocytes) induced by IL-2 was observed. The treatment was well tolerated: our patients had only mild adverse reactions controlled by symptomatic therapy. Eosinophilia represented the most evident negative effect. A slight decrease in CD4-positive subset of lymphocytes was observed after rIL-2 treatment. The therapy did not induce significant changes in the progression of the disease. In one patient necrosis at the tumoral site was observed after loco-regional rIL-2 administration.

Cytochemical demonstration of nitric oxide synthase and 5' nucleotidase in human glioblastoma.

Both nitric oxide (NO), formed from L-arginine by the enzyme nitric oxide synthase (NOS), and adenosine, which is produced by 5' nucleotidase (5' N) acting on adenosine 5' monophosphate (5' AMP) are implicated in several neurophysiological processes. In addition, 5' N is a linker protein involved in cell motility. Alterations of both enzyme activities seem to be responsible for some pathological states of the central nervous system (CNS). In the present report, we have studied the cytochemical demonstration of NOS and 5' N activities in human glioblastoma cells. Enzyme activity of both was observed in tumor cells; moreover, the coincidence of enzyme histochemistry and immunohistochemistry for NOS was noted in most cases. The findings were interpreted on the basis of the cytotoxic effects due to NO production by tumor cells, and on the non-catalytic role of membrane 5' N which acting as an adhesive molecule can favour tumor invasiveness.

Activated lymphoid cells in human gliomas: morphofunctional and cytochemical evidence.

To study defensive infiltrating cells, smear preparation from 20 fresh gliomas and autologous normal peritumoural brain tissue, used as control, were analysed. May-Grünwald Giemsa staining and cytochemical reaction markers of cellular functions [acid phosphatase (AP), dihydrofolate reductase (DHFR), dipeptidilpeptidase (DAP IV) and serine esterase BLT-dependent (SE)], were employed to characterize the cells. The extent of the leukocytic infiltration and the percentage of activated lymphocytes ("hand mirror" shape lymphocytes: HMS; lymphocytes binding tumor: LBT) were also studied. In addition serum levels of T cell growth factor interleukin-2 (IL-2) and of the soluble IL-2 receptor (sIL-2R) were determined in the affected patients. In tumoural imprints, mostly in astrocytomas, we observed an increased percentage of DHFR and DAP IV positive lymphocytes, of HMS lymphocytes and of lymphocytes binding tumoral cells. Serum levels of IL-2 were significantly increased in all patients whilst sIL-2R levels, were high only in glioblastoma. These findings indicate that in malignant gliomas there is stimulation of the immune system as witnessed by the presence of activated cells inside tumor tissue and soluble activating factors in serum.

[Production of gamma-interferon in lymphocytes of subjects with myeloma]. / Produzione di interferon-gamma in linfociti di soggetti affetti da mieloma.

Gamma-IFN production in cultures of 5 myeloma patients' PBL induced with Galactose-oxidase was tested. We observed a marked decrease of IFN production by lymphocytes of IgG and IgD patients, while the response of the cells of an IgA myeloma patient was normal.