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Biomedical subjects

A Cassone

Publications and source records attributed to A Cassone.

At least 199 records · Page 11Linked to original sources

[Molecular diagnosis of Chlamydia pneumoniae diseases].

Chlamydia pneumoniae (C. p.) is an intracellular parasite directly involved in respiratory disease and more recently in chronic degenerative pathologies as atherosclerosis and asthma. Its peculiar life cycle makes cultural isolation difficult, thus, troublesome the diagnosis of the disease. Serology is so far the most common method of diagnosis of the, although the indirect based evidence of the serology may give clinically misleading results. Nucleic acid amplification methods offer indeed rapid, reliable and low cost assessment pathogen bacteria isolation, with relevant benefits for the patient's management. These molecular methods are nowadays essential in presence of bacteria of difficult cultivation or method inconsistent with temporal clinical needs, for they allow to rapidly detect even nucleic acid traces of the infectious agent, providing direct evidence of its presence in the biological samples and hence the relevant therapy. Nucleic acid methods are extensively applied in laboratory diagnosis of Chlamydia trachomatis bringing about the development of sensitive and reliable commercial kits. This review analyses the literature of the genic amplification methods in the search of C. p. in clinical samples highlighting methodological and diagnostic aspects. Although genic amplification methods have been implemented presently by the clinical research labs only, it is anticipated that through their standardisation they could be used by most clinical microbiology laboratories.

Chlamydophila Infections↗

Soluble CD30 and lymphocyte activation gene-3 (CD223), as potential serological markers of T helper-type cytokine response induced by acellular pertussis vaccine.

T cell responses are involved in vaccine-induced immunity to pertussis but no easy-to-monitor, serological markers are available to assess these responses. The lymphocyte activation gene-3 (CD223) molecule is present on, and released by, activated T helper (Th) 1 cells, whereas CD30 molecules have been associated with Th2 immune responses. Starting from the recent knowledge of the cytokine profile induced by pertussis vaccination, we examined the levels of soluble (s)CD223 and sCD30 proteins in child recipients of acellular pertussis (aP) and diphtheria-tetanus (DT) vaccines and in children receiving DT vaccine only, as control. The correlation of the two proteins with specific antibody and T cell responses was assessed. The main findings are: i) sCD223 and sCD30 levels are inversely related, suggesting that the two markers are the expression of different and counter-regulated T-cell responses; ii) sCD30 level correlated with induction of T cell proliferation to pertussis vaccine antigens and antibody response to pertussis toxin. Overall, sCD30 and sCD223 levels seem to be promising candidate markers to assess the induction of Th-type responses in vaccine recipients.

Antibodies, Bacterial↗

60-kDa heat shock protein of Chlamydia pneumoniae is a target of T-cell immune response.

Inflammatory processes contribute to the pathogenesis and complications of atherosclerosis and coronary heart disease (CHD). Several findings indicate that chlamydial heat shock proteins (HSP) may represent a particularly strong antigenic stimulus, able to induce specific humoral (Ab) and T-cell-mediated immune responses (CMI) linking infection by Chlamydia pneumoniae (CP) to immuno-pathological sequelae such as atherosclerosis and CHD. We have here evaluated the ability of chlamydial recombinant (r) HSP60 and rHSP10 to induce specific immune responses in human peripheral blood lymphocytes and in murine models. rHSP60, but not rHSP10, was shown to induce proliferation and Interferon-gamma secretion in lymphocytes of randomly selected blood donors, as well as to generate and detect delayed-type hypersensitivity response in HSP60-vaccinated mice. Overall, the present study provides new hints to evaluate a previous exposition to CP using rHSP60 in humans. Thus the evaluation of specific HSP60 CMI response in healthy subject could be useful to monitor the reactivity to Chlamydia pneumoniae possibly providing a link to CHD pathologies.

Animals↗

A mannoprotein constituent of Candida albicans cooperates with antigen in the induction of a specific primary antibody response in cultures of human lymphocytes.

The effects of Candida albicans mannoproteins on the induction of a primary antibody response to a T-dependent antigen, sheep erythrocytes (SRBC), in cultures of human blood lymphocytes, were investigated. Two experimental systems (bulk and limiting dilution cultures) allowing the detection of both enhancing and inhibitory effects, were used. In bulk cultures, antigen alone elicited a small number of specific antibody forming cells, unless IL-2 was supplied. Addition of the fungal mannoprotein extract or of a purified constituent of it increased 5 to more than 10 times the specific response. When limiting dilution analysis was performed, we observed that: a) a similar number of specific precursor cells was induced by antigen and either IL-2 or mannoprotein; b) the plot of the number of seeded cells versus the log of the fraction of negative cultures was linear in antigen and IL-2 triggered cultures but constantly deviated from linearity when the candidal stimulant was added. Thus, more than one type of precursor cell was limiting in these cultures, and the immunoenhancing effect of mannoprotein may involve multiple cellular interactions.

Adjuvants, Immunologic↗

Generation and characterization of cytotoxic activity against tumor cell lines in human peripheral blood mononuclear cells stimulated "in vitro" by a glucomannan-protein preparation of Candida albicans.

Human peripheral blood mononuclear cells (PBMC) proliferated and generated non-specific cell-mediated cytotoxicity (CMC) after stimulation with a cell-wall glucomannan-protein (GMP) fraction of Candida albicans or chemically-inactivated intact microrganism. No effects were observed using other fungal cell wall components such as glucan or alkali-acid treated glucomannan. The highest CMC level was detected after 7-10 days of PBMC incubation in the presence of 50 micrograms/ml of whole Candida cells and the cytotoxic immunoeffectors elicited by these antigenic stimulations equally affected NK-susceptible (K562) and NK-resistant (Raji, Daudi and Jurkat) tumor cell lines. Both Interleukin-2 (IL-2) and gamma interferon (IFN-gamma) were produced by GMP-stimulated PBMC, the IL-2 peak production constantly preceding that of IFN production. GMP-induced generation of natural CMC was potentiated by the addition of IFN-gamma and a monospecific anti IFN-gamma serum totally abrogated both IFN activity and CMC generation. The cytolytic effectors were shown to be OKT3-, OKT8- and HLA-DR-. They did not possess typical NK markers (e.g. Leu-7 and AB8.28) but were partially recognized by A10, a IgG2a monoclonal antibody reacting to PBMC-NK lymphocytes and activated T cells. These results suggest that the antitumor cytolytic effectors generated in PBMC cultures exposed to Candida material belong either to a discrete subset of natural effectors lacking classical NK markers or to other lymphokine-activated cells. This study also suggests that the human indigenous microrganisms C.albicans may play a role in raising nonspecific antitumor effects in normal host.

Adjuvants, Immunologic↗

Mannoproteins from Candida albicans elicit a Th-type-1 cytokine profile in human Candida specific long-term T cell cultures.

Since T lymphocytes are active producers of regulatory cytokines, long-term T cell cultures (LTTC) specific for a major mannoproteic antigen (MP) of Candida albicans from peripheral blood mononuclear cells (PBMC) of healthy donors were generated and their cytokine profile studied. LTTC consisted of an expanded CD3CD4 T-helper (Th) populations, with a high proportion of CD45R0 T memory cells. Stimulation of LTTC by MP induced a Th-1 type cytokine profile, as indicated by the presence of IFN-gamma and the absence of IL-5 (both as mRNA and protein) in cell cultures and supernatants. These results suggest a predominant Th1 response elicited by C. albicans mannoprotein antigen in human PBMC.

Antigens, Fungal↗