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V Colizzi

Publications and source records attributed to V Colizzi.

157 records · Page 9Linked to original sources
PubMed1978

Depression of contact sensitivity by enhancement of suppressor cell activity in Pseudomonas aeruginosa-injected mice.

Heat-killed Pseudomonas aeruginosa depresses contact sensitivity to oxazolone in C56BL/6 mice. The draining lymph nodes and spleens of mice exhibiting an impaired reactivity to oxazolone contain a cell population capable of depressing the response to oxazolone of recipients sensitized immediately before cell transfer. The suppressive activity of these cells appears to be antigen specific, since they do not affect the response to picryl chloride and because they do not arise in P. aeruginosa-injected but not oxazolone-sensitized mice. These suppressor cells occur in the draining lymph nodes and spleen at 3 and 4 days after sensitization, respectively, and have precursors sensitive to cyclophosphamide. It is concluded that P. aeruginosa depresses contact sensitivity to oxazolone by enhancing the suppressor cell activity of the regulatory cells which arise during conventional sensitization.

Animals↗
PubMedDate not supplied

Genetic restriction in the induction of contact sensitivity by footpad cell transfer.

Cells taken from draining lymph nodes one day after application of oxazolone and picryl chloride induced contact sensitivity in syngeneic but not in allogeneic recipients. In contrast, the immunizing activity of cells taken four days after sensitization was not genetically restricted. The findings that '1-day' cells incubated with anti-hapten antibodies break down the genetic restriction, and that '4-day' cells lose their ability to induce contact sensitivity after complement treatment, suggest that two different mechanisms are involved in the induction of contact sensitivity.

Animals↗
PubMedDate not supplied

Immunology of tuberculosis: new directions in research.

Tuberculosis is still one of the major health problems in almost all over the world. Thus, new directions in basic and applied research on tuberculosis are under investigation. In this review we have provided recent data obtained in our laboratories on three main aspects of the immunology of tuberculosis, namely: i. the role of B lymphocytes in the processing and presentation of Mycobacterium tuberculosis antigens to T cells; ii. the activation and characterization of mycobacterial-specific T cell clones; iii. the T cell regulation of the immune response to M. tuberculosis. The analysis of the antigenic determinants of M. tuberculosis relevant in the antimycobacterial immunity is the major goal of the WHO programme on the immunology of tuberculosis. In fact, the attempt to develop a second generation vaccine against this microorganism is now possible by analyzing recombinant genomic DNA libraries of M. tuberculosis with monoclonal antibodies and T cell clones. In the near future, the identification of epitopes recognized by mycobacterial-specific T cells with helper, cytotoxic and suppressor functions will allow the preparation of recombinant and synthetic vaccines effective in the control of this disease.

Antibodies, Bacterial↗
PubMedDate not supplied

General considerations in the interpretation of I-J genetic restrictions: evidence that the antigen-binding chain of antigen-specific T-suppressor factor has two recognition sites for members of the I-J hierarchy.

(CBA X B10)F1 [(H-2k X H-2b)] mice produce two types of antigen-specific T-suppressor factor (TsF), which can be separated by affinity chromatography on anti-I-J monoclonal antibody. After reduction and alkylation, both chains of F1 TsF are required for biological activity. However, the antigen-binding chain (AgBC) of F1 TgFk (AgBCk) is only complemented by I-Jk and likewise for F1 TsFb. In other words, interchain complementation shows the same genetic restriction in interchain complementation in parental and F1 mice. F1 TsF bearing, for example, I-Jk (TsFk), interacts with haptenized 'antigen-presenting cells' ('APC') and parental I-Jk chains interacts with haptenized 'APC' of both parental haplotypes (dual reactivity). In contrast, the combination of parental AgBCb and F1 I-Jb shows single reactivity and only interacts with haptenized 'APCb'. It was inferred that the antigen-binding chain is responsible for the dual reactivity and, hence, for the interaction with a member of the I-J hierarchy on the 'APC'. It was concluded that the antigen-binding chain of TsF has two recognition sites for members of the I-J hierarchy--one for interchain complementation and the other for interaction with the haptenized 'antigen-presenting cell'. The term member of the I-J hierarchy is used instead of I-J because it is not clear whether the AgBC interacts with I-J or a receptor for I-J, or indeed a receptor for that receptor.

Animals↗
PubMedDate not supplied

Different cytokine production and effector/memory dynamics of alpha beta+ or gamma delta+ T-cell subsets in the peripheral blood of patients with active pulmonary tuberculosis.

Immunity to M.tuberculosis (MTB) infection consists of interactions between various T-cell subsets that control the infection and prevent further reactivation. We analysed the effector/memory T-cell dynamics and cytokines production in the peripheral blood of patients with pulmonary tuberculosis (TB). We observed that the frequency of CD4+ T-cell effectors was significantly increased during active TB, confirming a major role of this T-cell subset in TB immunity. Pre-terminally differentiated CD8+ T-lymphocytes were increased in the peripheral blood as well. In contrast, we observed a reduced number of effector mycobacteria-reactive gammadelta+ T-lymphocytes with a specific defects in reacting to mycobacterial nonpeptidic antigens, suggesting that this innate response is rapidly lost during TB infection. Nevertheless, the frequency of gammadelta+ T-cells effectors in TB patients was higher than the alphabeta+ T-cell response to peptide from MTB-ESAT-6 protein and quantitatively similar to PPD reactivity. Thus, alphabeta+ and gammadelta+ T-cell differentiation and function are differently triggered by active TB infection.

Adult↗
PubMedDate not supplied

Cell surface localization of the 78 kD glucose regulated protein (GRP 78) induced by thapsigargin.

In the present study it was found that the synthesis of the 78 kD glucose-regulated protein (GRP 78 or BIP) is vigorously induced in human rabdomiosarcoma cells (TE 671/RD) following both short-term (1 h) and prolonged (18 h) exposure to 100 nM thapsigargin (Tg). Flow cytometric analysis with a specific anti-GRP 78 polyclonal antibody showed that Tg-treated cells express the GRP 78 on the plasma membrane. Cell surface localization of the Tg-induced GRP 78 was confirmed by biotinylation of membrane-exposed proteins and subsequent isolation of the biotin-labelled proteins by streptavidin/agarose affinity chromatography. It was found that a fraction of the Tg-induced GRP 78 is present among the biotin-labelled, surface-exposed, proteins. Conversely, the GRP 78 immunoprecipitated from unfractionated lysates of Tg-treated and biotin-reacted cells was found to be biotinylated. This is the first report demonstrating surface expression of GRP 78 in cells exposed to a specific GRP 78-inducing stimulus.

Biotin↗
PubMedDate not supplied

Different expression of CD44, ICAM-1, and HSP60 on primary tumor and metastases of a human pancreatic carcinoma growing in scid mice.

Surface adhesion molecules play an important, but still not completely clarified, role in tumor metastasization. In this research, FACS analysis was employed to analyze surface expression of CD44H, CD44v5, CD44v6, ICAM-1 and HSP60 in human pancreatic adenocarcinoma cells growing in vitro or collected ex vivo from primary tumors and lung metastases of tumor-engrafted SCID mice. It was found that, in metastatic cells, the standard form of CD44 (CD44H) is down,-regulated, while a large fraction of cells express on membrane the splice variants v5/v6 and, in addition, ICAM-1 and HSP60. It was also apparent that two cell populations are present in lung metastases: a CD44neg population, including cells expressing CD44v5/v6, ICAM-1 and HSP60 and a population of CD44pos, CD44v5/v6neg, ICAM-1neg and HSP60neg cells. These results demonstrate that, in pancreatic adenocarcinomas, metastasization is correlated with expression of the CD44 variants v5 and v6. Moreover, this is the first report demonstrating HSP60 surface expression on metastatic cells.

Adenocarcinoma↗
PubMedDate not supplied

Antiviral activity and anergy of gammadeltaT lymphocytes in cord blood and immuno-compromised host.

Gammadelta T lymphocytes recognize nonpeptidic microbial antigens without MHC restriction and display both lytic and proliferative responses to human immunodeficiency virus (HIV)-infected cells. This innate recognition involves both T Cell Receptor (TCR) and NK-receptor mediated signalling through non-peptidic metabolites and HLA class I down-regulation. We observed that HLA-masking and nonpeptidic phosphoantigens induce the expression of CD25 and CD69 activation markers on the surface of gammadelta T cells. Interestingly, CD94+ cell depletion by magnetic beads showed that the expression of this antigen is essential for Vdelta2 T cell activation by HLA-masking. Moreover, both phosphoantigen-stimulation and in vitro HIV infection resulted in marked Vgamma9Vdelta2 T cell expansion, whereas HLA-masking was unable to induce proliferative responses. Finally, we observed a relevant hyporesponsiveness to non-peptidic antigens in HIV-infected persons and in cord blood cells from healthy donors when compared to adult PBMC from uninfected donors. Altogether, the reduced ability to naturally recognize the infected cells may contribute to HIV-disease progression and may facilitate maternal transmission of HIV infections.

Adult↗
PubMedDate not supplied

Effective anti-tumor immunity induced in mice by a two-step vaccination protocol.

BACKGROUND: TS/A cells (a Balb/c-derived tumor cell line), when injected into syngenic mice, give rise to rapidly growing tumors. In this study, a vaccination protocol was established which was able to elicit an immune response effective in controlling tumor growth. MATERIALS AND METHODS: T19.2.1, a TS/A clone enginereed to stably express the mycobacterial cell wall-associated 19-kDa lipoprotein, was used as cell vaccine to immunize Mycobacterium Bovis-BCG pre-immunized Balb/c mice. RESULTS: Mice receiving the two-step vaccination protocol were able to develop a strong anti-TS/A DTH reaction. Moreover, following a challenge with wild-type TS/A cells, some vaccinated animals rejected the tumor and the remaining animals showed a significantly increased survival in respect to controls. CONCLUSION: The expression on TS/A cells of the mycobacterial 19-kDa antigen, recognised in the context of a pre-existing memory immune response, promotes the immunological recognition of the otherwise non-immunogenic wild-type TS/A cells.

Adenocarcinoma↗
PubMedDate not supplied

A mechanism for the depression of contact sensitivity with B-cell mitogens.

LPS or DxS impair contact sensitivity to oxazolone in mice, evaluated as ear thickness and DNA synthesis of regional lymph node cells in vitro. Lymphoid cells from LPS- or DxS-injected and sensitized mice were able to transfer specifically the suppression when injected into animals sensitized immediately before cell transfer. This cell suppressor activity was eliminated by nylon wool filtration. These results suggest that B-cell mitogens may enhance suppressor cell activity of regulatory cells which arise during conventional immunization.

Animals↗
PubMedDate not supplied

[Clinical-experimental models for the identification of immunologic parameters to be integrated in traditional staging systems of colorectal neoplasms].

The Authors evaluate new possible models for the staging of colorectal cancer based on clinico-morphological, histo-pathological and bio-immunological parameters. Particularly, they evaluate the possibility of studying host's immunological response against tumor spread by the examination of the "in situ" cellular responses. This study was performed by cytotoxic test and immunohistochemical evaluation of the lymphocytes. The latter seems to give better results compared to the first in the evaluation of the host's immunological response.

Colorectal Neoplasms↗
PubMedDate not supplied

In vitro and in vivo efficacy of heat shock protein specific immunotoxins on human tumor cells.

The presence of heat shock proteins (HSPs) on the surface of tumor cells suggested the possibility of using stress proteins as immunological target for specific immunotoxins (ITs). Flow cytometry analysis showed that U937 cells constitutively express both 28 and 60 kDa HSP in vitro, while the HPC-4 cells only express surface HSPs when grown in vivo, i.e. explanted from SCID mice. Incubation of U937 cells with monoclonal antibodies against 28 or 60 kDa HSP, and then with an immunotoxin consisting of a goat anti-mouse antibody linked to the ribosome inactivating protein Saporin-6 specifically inhibits cell proliferation in vitro. Moreover, an anti-HSP60 immunotoxin prepared by direct linking of the specific monoclonal antibody (MoAb) ML30 to saporin was able to inhibit the proliferation of the U937 line in vitro, and tumor growth in SCID mice bearing the human pancreatic carcinoma line HPC-4 in vivo. Finally, low expression of HSPs on the membrane of peripheral blood mononuclear cells, and their resistance to the toxic effect exerted by anti-HSP immunotoxins, suggest further evaluation of the possible applications of anti-HSP immunotoxins for HSP+tumors.

Animals↗