In vitro treatment with killed Helicobacter pylori downregulates the production of RANTES by peripheral blood mononuclear cells.

The mechanisms by which Helicobacter pylori colonizes and persists within the gastric mucosa are poorly understood. The gastric immune response observed in vivo during H. pylori infection, is characterized by a polarization of Th1 cell type that seems to be responsible for gastric pathology. The purpose of this study was to test the direct effect of H. pylori cagA(+)/vacA(+ )(live and/or gentamicin-killed) on human peripheral blood mononuclear cells (PBMCs) in order to evaluate the production of regulated activation normal T cell expressed and secreted (RANTES) in vitro. We also evaluated the possible relationship between RANTES release and the presence of IL-12 and IFN-gamma in supernatants of the same cells. In the present study, we show for the first time that the low amount of RANTES in supernatants of PBMC incubated with killed H. pylori is linked, at least in part, to the inhibition of IL-12 and IFN-gamma release.

Differential induction of TNFalpha and IL-18 in human peripheral blood mononuclear cells infected with Leishmania major or Leishmania donovani.

Several cytokines are involved in the host response to Leishmania. However, the role played by cytokines during infection with different species of Leishmania is not univocal. In this work, the production of tumor necrosis factor alpha (TNFalpha) and interleukin 18 (IL-18) during interaction of human phagocytes with Leishmania major or L. donovani was comparatively investigated. Peripheral blood mononuclear cells (PBMC) and monocytes from healthy donors were used. The release of TNFalpha and IL-18 during infection of cells with different species of Leishmania "in vitro" was evaluated. L. donovani induced in both PBMC and monocytes significantly more TNFalpha and IL-18 with respect to L. major. The amounts of TNFalpha released by PBMC were always significantly higher than those released by monocytes of the same donors.

Role of interleukin-18 in peripheral blood mononuclear cells infected with human herpes virus type 6.

OBJECTIVE: Interleukin 18 (IL-18) production represents a critical step in the polarization of the Th1 immune response. Human herpes virus type 6 (HHV-6) possesses a peculiar tropism for immunocompetent cells. To understand the relationships among immunocompetent cells, HHV-6 and cytokines, the role of IL-18 during infection of peripheral blood mononuclear cells (PBMC) with HHV-6 was evaluated. METHODS: PBMC were obtained from healthy HHV-6-seronegative donors, after centrifugation of heparinized venous blood over a Ficoll-Hypaque gradient. Supernatants from PBMC were analyzed for the presence of cytokines. To study the effects of exogenous recombinant human (rh) IL-18 on HHV-6 replication, the number of cells expressing viral antigens and the amount of extracellular virus were analysed. RESULTS: No basal production of IL-18 was found in supernatants of unstimulated PBMC. Appreciable amounts of the cytokine were produced by lipopolysaccharide (LPS)-stimulated PBMC. HHV-6 infection of LPS-treated PBMC downregulated IL-18 production. It was found that the addition of rhIL-18 to HHV-6-infected PBMC downregulated the percentage of antigen-positive cells and the release of extracellular virus. CONCLUSION: Impairment of IL-18 release, which is involved in the induction of antiviral cytokines, such as interferon-gamma, could represent a strategy of the virus to evade the immune response of the host.

Effects of lithium carbonate on cytokine production in patients affected by breast cancer.

It has been reported that lithium salt compounds influence hematopoiesis, which is known to be regulated by a number of cytokines, including tumor necrosis factor (TNF), interleukin-1 (IL-1) and interleukin-6 (IL-6). Since lithium can induce TNF production in human monocytes, we wished to determine if lithium carbonate treatment of neutropenic patients affected by breast cancer results in increased cytokine production. Serum levels of TNF alpha, IL-1 and IL-6 were measured before and at 7 and 180 days after treatment with lithium carbonate. Results indicate that this therapy produced TNF alpha and IL-6, but not IL-1 alpha, elevations in patients affected by unmetastasized breast cancer. Conversely, TNF alpha, but not IL-6, elevations were detected in metastatic patients. Studies are under way to investigate the mechanisms by which lithium salts affect cytokine production in monocytes from cancer patients.

A dot-ELISA for the detection of IgG antibodies to mumps and varicella viruses.

An enzyme-linked immunosorbent assay using nitrocellulose strips (dot-ELISA) for the routine laboratory detection of IgG antibodies to mumps and varicella viruses is described. The virus antigens are dotted onto nitrocellulose strips, and the dotted strips are incubated with the sera to be tested. The bound antibodies are revealed using enzyme-labeled antihuman IgG antibodies. Reliable results are obtained when the assay is carried out at 37 degrees C. The reported data indicate that the dot-ELISA can reliably be used for the detection of IgG antibodies to mumps and varicella viruses in human sera.

Rapid assessment of the antitetanus immune status of a subject using Dot-ELISA.

We describe a Dot-ELISA system for the rapid, specific and reliable assessment of a subject's antitetanus immune status. The conditions for Dot-ELISA were selected to give positive reactions only for sera with antitetanus antibody titers equal to or higher than 0.06 I.U./ml, considered to represent protection when using "in vitro" methods. This Dot-ELISA method could advantageously be applied to the monitoring of vaccination campaigns, as well as for assessing the antitetanus immune status of the wounded.

Dot-enzyme immunoassay for visual detection of Brucella melitensis antibodies.

An indirect enzyme-linked immunosorbent assay, using antigen coupled to paper, has been adapted for the detection of Brucella melitensis antibodies. Optimum conditions were achieved by incubation of 1 ml of diluted serum with a single piece of paper coated with purified Brucella antigens for a period of one hour, and by addition of a goat anti-human enzyme conjugate antibody for one hour again. Under these conditions 80 human sera were examined and the results obtained were compared with Wright agglutination test.

Rapid dot-immunobinding for detecting antibodies to Toxoplasma gondii in human serum.

A modified dot-immunobinding assay is described for the rapid, specific and reliable screening of human sera for Toxoplasma gondii immunity status. This simple, rapid and sensitive assay proved to be a practical diagnostic technique since it can be performed in 3 hours employing a small amount of antigen (0.3 micrograms/microliters).

Evaluation of anti-Listeria monocytogenes antibodies by ELISA.

A new ELISA test using the purified Listeria monocytogenes-derived antigen LM 84 Ag is described together with its application in the diagnosis of listeriosis. Fifty-seven human sera were titrated by the ELISA and the complement fixation method and compared for specificity and sensitivity. The problem of possible cross-reactions with other antigens is discussed.

[Evaluation of anti-HAV IgG on 2 samples of closed populations]. / Valutazione di IgG anti-HAV su due campioni di popolazione "chiusa".

The authors have carried out an epidemiologic research about the diffusion of antibody to hepatitis A antigen in the inhabitants of Ginostra, fraction of Stromboli, and Alicudi Islands (Eolie's arcipelago). We have examined by ELISA 86 human sera. We have detected a percentage of positivity about 82 and 70.6% for two populations. A critic examination of the results with parameters auxiliary (sex, age), showed significant differences of positivity about two different sexs and ages.

"In vitro" study on human mononuclear phagocytic cells behaviour versus DNA and RNA viruses.

It is generally accepted that mononuclear phagocytic cells are of crucial importance in defence against viral infections. Using a method of "in vitro" differentiation from human blood monocytes to macrophages, the interactions between human monocyte-macrophage with herpes simplex virus type 1 and 2, adenovirus type 17, coxsackie virus B type 4, poliovirus type 1 and ECHO virus type 2, are reported. In all viruses tested on monocytes, the infection of the cells was very poor according to the data of specific immunofluorescence and of the residual infectivity. In the macrophage stage all viruses tested were able to infect the cells.

Enzyme-linked immunosorbent assay (ELISA) for streptokinase antibodies.

A micro plate Enzyme-linked immunosorbent assay (ELISA), developed for detection of antibodies to Streptokinase, was used to analyze 80 human sera. The aim was to provide a simple method for antibody screening that required neither sophisticated equipment nor a high degree of technological skill. Preliminary results show that ELISA is specific, reproducible and sensitive. Comparative evaluation of the ELISA and the coagulum lysis test for antibodies against streptokinase show excellent correlation. We also evaluated the anti-Streptolysin O titer either by conventional method or ELISA. The sensitivity of ELISA for detecting anti-Streptolysin O antibodies was 3-4-fold higher than that of the hemolytic test. The sensitivity of ELISA for detecting anti-streptokinase antibodies was 10-20-fold higher than that of the coagulum lysis. The Enzyme-linked immunosorbent assay seems to offer some advantages over the more commonly used coagulum lysis test as far as sensitivity is concerned and potentially it is suggested that this method could be usefully employed clinically in human streptococcal infections.

Comparison of indirect immunofluorescence and enzyme-linked immunosorbent assay for detection of toxoplasma antibody.

Eighty samples of human serum were tested for antibody to Toxoplasma gondii by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF). Development of ELISA suggested that accurate results could only be obtained with serial serum dilutions. ELISA and IIF tests showed a significant degree of correlation, but ELISA was found to be more sensitive: 17% of 24 sera showing negative IIF values showed slightly positive ELISA titres.