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A Tagliabue

Publications and source records attributed to A Tagliabue.

At least 73 records · Page 4Linked to original sources
PubMed1989

A monoclonal antibody to the IL-1 beta peptide 163-171 blocks adjuvanticity but not pyrogenicity of IL-1 beta in vivo.

The synthetic fragment VQGEESNDK, corresponding to the amino acid sequence in position 163-171 of human IL-1 beta, possesses the immunostimulatory but not the pyrogenic activity of the mature IL-1 beta polypeptide in vivo. To assess the relevance of this domain of IL-1 beta for its biologic activities, a mAb was raised against the synthetic peptide 163-171. The mAb Vhp20 could effectively recognize human rIL-1 beta in RIA and immunoblotting. In vivo, the mAb Vhp20 was able to selectively inhibit the immunostimulatory activity of IL-1 beta, but it could not affect the fever-inducing capacity of IL-1 beta. It is proposed that functional domains could be identified in the human IL-1 beta protein and that the fragment in position 163-171 is of major importance for the adjuvant capacity of the entire molecule, but irrelevant to its pyrogenic activity.

Adjuvants, Immunologic↗
PubMed1989

Human T cell clones define S1 subunit as the most immunogenic moiety of pertussis toxin and determine its epitope map.

Human T lymphocyte clones specific for pertussis toxin (PT) were used to analyze the fine specificity of the response to PT, the basic component of new acellular vaccines against whooping cough. The majority (83%) of the clones specific for PT recognized S1, the subunit that in animal models has been shown to be highly immunogenic. To map T cell epitopes on S1, 18 S1-specific clones were tested for recognition of recombinant fragments representing NH2-terminal and COOH-terminal deletions of S1 and two recombinant S1 subunits containing amino acid substitutions. This approach led to the identification of three regions of the protein as the sequences containing T cell antigenic sites: 1-42, 181-211, and 212-235. Synthetic peptides were eventually used for a finer localization of the T cell epitopes. Two peptides, one of 13 residues (27-39) at the NH2 terminus and one of 24 residues (171-194) at the COOH terminus, stimulated proliferation of three and four clones, respectively. Both peptides are recognized in association with HLA DR1 molecules. These results stress the role of S1 in the immune response to PT and provide data useful for the development of a recombinant or synthetic antipertussis vaccine containing T cell epitopes from S1.

Amino Acid Sequence↗
PubMed1989

Natural antibacterial activity against Salmonella typhi in human cord blood.

Cord blood mononuclear cells from normal human newborns possess natural antibacterial (NA) activity against Salmonella typhi, as assessed by an in vitro test. NA activity was significantly higher than that observed in PBMC from normal adult donors. Using fractionation on nylon wool and Percoll gradient or C-dependent killing with mAb, it was found that cells of the monocyte-macrophage series and CD4+ T lymphocytes were capable of exerting NA activity in newborns, in contrast with results obtained in adults, where the effector cell was a CD4+ T lymphocyte. The capability of expressing NA activity by CD4+ T lymphocytes from cord blood was also confirmed by flow cytometry sorting. Pretreatment of cord blood mononuclear cells with F(ab')2 fragments against human IgG, but not against human IgA, abrogate the NA activity. Furthermore, human IgA anti-S. typhi cannot arm CD4+ lymphocytes in cord blood. Thus it can be suggested that in newborns, the immune system still being immature, NA activity might be the expression of a mechanism of defence against infections, acting as antibody-dependent cellular cytotoxicity expressed by monocytes and CD4+ T lymphocytes armed with preexisting maternal IgG antibodies. This differs from NA activity of adults which is only mediated by CD4+ T lymphocytes armed by IgA.

Adult↗
PubMed1989

Differential binding of IL-1 alpha and IL-1 beta to receptors on B and T cells.

The interleukin 1 receptors (IL-1R) on the human B lymphoma RAJI and on the murine thymoma EL4-6.1 have been characterized. Equilibrium binding analysis using both 125I-labeled IL-1 alpha and IL-1 beta showed that RAJI cells have a higher number of binding sites/cell for IL-1 beta (2400, Kd 2.2 nM) than for IL-1 alpha (316, Kd 0.13 nM). On the other hand, EL4-6.1 cells have more receptors/cell for IL-1 alpha (22 656, Kd 1 nM) than for IL-1 beta (2988, Kd 0.36 nM). Dexamethasone (DXM) induced on RAJI cells a time-dependent increase in binding sites for both IL-1 beta and IL-1 alpha without affecting their binding affinities. However, while receptor-bound 125I-IL-1 alpha was displaced with equal efficiency by both IL-1 forms, only unlabeled IL-1 beta could effectively displace 125I-IL-1 beta. Cross-linking experiments indicated that RAJI cells have a predominant IL-1R of about 68 kDa, while EL4-6.1 cells have an IL-1-binding polypeptide of 80 kDa. These results suggest that B and T cells possess structurally different IL-1R with distinct binding properties for IL-1 alpha and IL-1 beta.

Animals↗
PubMed1989

Lymphokine-activated tumor inhibition in mice. Ability of a nonapeptide of the human IL-1 beta to recruit anti-tumor reactivity in recipient mice.

The ability of the VQGEESNDK synthetic peptide corresponding to fragment 163-171 of human IL-1 beta to trigger lymphokine-activated tumor inhibition (LATI) of a poorly immunogenic fibrosarcoma (CE-2) of BALB/c mice was compared to that of the whole IL-1 beta. Neither molecule inhibits in vitro proliferation of CE-2 cells. Administration at the tumor challenge site for 10 days of daily injections of 50 micrograms of peptide 163-171 induce a consistent, although limited, inhibition of tumor growth, whereas similar injections of 1 pg of IL-1 beta induced a more marked LATI. However, strong LATI was elicited when these injections were performed in mice challenged with tumor cells admixed at 1/10 cell ratio with nonreactive lymphocytes from CE-2-bearing mice. The L3T4+ lymphocyte subset is mainly responsible for this enhancement. This reaction is abolished when recipient mice are sub-lethally irradiated, treated with cyclosporin A, or when the reactivity of L3T4+ and asialo GM1+ cells is suppressed. A similarly efficient LATI is found on combining the daily peptide injections with that of 10 U of IL-2. LATI stemming from this association, too, is abolished when mice are irradiated or treated with anti-L3T4 antibody, whereas it is not affected by cyclosporin A or anti-asialo GM1 antibody. Finally, a tumor-specific immune memory is acquired by about 50% of mice after LATI induced by IL-1 beta or 163-171 peptide alone and by about 80% of mice after LATI induced by peptide and lymphocytes from tumor-bearing mice or peptide and IL-2. These findings could lead to the building of a molecularly defined system to induce efficient immune recognition of tumor cells by using a peptide that does not cause any of the several inflammation-associated changes induced by the whole IL-1 beta.

Animals↗
PubMed1989

Interleukin 1 and its synthetic peptides as adjuvants for poorly immunogenic vaccines.

The adjuvant activity of the peptide corresponding to the fragment 163-171 of human interleukin 1 beta (VQGEESNDK) has been evaluated on the immune response to both T-dependent and T-independent antigens. The hydrochloride derivative of the peptide showed an effect quantitatively comparable in molar terms to that of the entire protein. At variance with the entire IL 1 protein the peptide appeared devoid of inflammatory effects and therefore it may find clinical applications as adjuvant for poorly immunogenic vaccines or as immunorestorative agent. The activity of other fragments in proximity of the sequence 163-171 was also evaluated. The shorter fragment 165-171 appeared as active as the 163-171 peptide.

Adjuvants, Immunologic↗
PubMed1989

Structure-function relationship of interleukin-1 giving new insights for its therapeutic potential.

The pleiotropic activities of IL-1 have fostered a series of studies on the structure-function relationship in these proteins. In fact, the attempt to dissociate different biological functions of IL-1 should simplify its therapeutic use. About human IL-1 beta, which has been more extensively studied in this respect, enzymatic cleavage of the precursor protein to generate the mature polypeptide appears necessary for its full biological activity. The almost complete integrity of the mature IL-1 beta protein is also required for its ability to bind to the receptor and trigger cellular functions. However, by the use of monoclonal antibodies and recombinant or synthetic peptides, it has been possible to map some IL-1 beta regions important for different activities. Both N-terminal and C-terminal fragments are important for receptor binding. A domain around amino acids 187-204 is apparently involved in the hyperalgesic effects of IL-1 beta. Finally, the fragment in position 163-171 appears to be responsible for a restricted series of the IL-1 beta activities, mainly directed to the immune system, although irrelevant for inflammation-related effects and unable of binding to the IL-1R. It is thus possible, within the sequence of a cytokine, to isolate selectively active domains. This will give us new tools for new therapeutic approaches. Thus, IL-1 might be the prototype of a new generation of cytokines developed with the goal of stimulating specific biological activities without activating the cascade effects which are typical for many cytokines.

Animals↗
PubMed1989

Immunoreactivity for IL-1 beta and TNF alpha in human lymphoid and nonlymphoid tissues.

Monoclonal antibodies (MAbs) against two non-cross-reacting antigens of human IL-1 beta (Vhp20 and BRhC3) and human TNF alpha (B154.2 and B154.7) were applied to identify cytokine-containing cells in tissue sections and in cell suspensions. IL-1 beta- or TNF alpha-positive cells were not present in immunostained cytocentrifuge smears prepared from freshly isolated peripheral blood leukocytes, spleen, and lymph node cells. After 18 hours of culture with bacterial endotoxin (LPS), 80% to 90% of blood monocytes, 30% of spleen macrophages, and 2% to 28% of lymph node macrophages were strongly positive for IL-1 beta with either of the MAbs. Furthermore, 25% to 35% of blood monocytes and 6% to 60% of lymph node macrophages were stained for TNF alpha. Cells positive for IL-1 beta or TNF alpha were extremely rare in sections of normal thymus, spleen, and lymph nodes. Immunoreactivity for IL-1 beta or TNF alpha was frequently observed in sections of granulomatous lymphadenitis (N = 11). IL-1 beta or TNF alpha staining was confined to the epithelioid macrophages forming the granuloma, and the intensity of TNF alpha reactivity was generally stronger. The high frequency of cytokine-containing cells in this pathologic condition was confirmed in a cell suspension study showing that 20% of epithelioid macrophages were weakly positive for IL-1 beta and 80% were strongly positive for TNF alpha. The presence of cytokine-containing cells was investigated in cryostat sections of several nonlymphoid organs with normal histologic appearance. IL-1 beta reactivity was not observed in any of the tissues. TNF alpha reactivity was frequently demonstrated in isolated macrophages embedded in the interstitial connective tissue.

Humans↗
PubMed1989

[Application of bioelectric impedance measurement in the evaluation of body fat].

We compared the data referring to the percentage of body fat in 40 healthy adults (20 males and 20 females) of different weight, aged between 18 and 33 years, measured by biological impedance analysis and skinfold thickness measurement. Of these, 26 were shown to be of normal weight, 9 overweight and 5 underweight according to the body mass index (Weight/Height). All subjects were analysed for bioelectrical impedance with a BIA-103 (Ryl-Detroit) appliance and the skinfolds were measured with a Harpenden Caliper. The correlation between the values obtained with the two methods was shown to be linear and highly significant for both sexes (males: r = 0.71; females: r = 0.77). The study also showed that the content of body fat was higher than the mean values indicated in the literature for the age range considered in 23% of the males and 31% of the females of normal weight.

Adipose Tissue↗
PubMed1989

A short synthetic peptide fragment of human interleukin-1 beta increases both human and murine natural killer activity.

The effect of a short synthetic fragment of human interleukin-1 beta (hu IL-1 beta) on natural killer (NK) activity was examined. Peripheral-blood mononuclear cells (PBMC) from normal donors showed a significant increase in NK activity against K562 leukemia cells after preincubation for 18 h with the IL-1 peptide. A similar augmentation was not observed after culturing the cells in the presence of hu IL-1 beta. The increase in tumor cell lysis could not be ascribed to a cytolytic activity of the synthetic fragment on target cells, since the peptide caused no direct lysis of various tumor cell lines. Although the peptide enhanced NK cytotoxicity of PBMC, highly purified large granular lymphocytes were not susceptible to its stimulatory effect. The addition to the cultures of antibodies to human interleukin-2 (hu IL-2) completely blocked the peptide-induced boost of NK cytotoxicity, suggesting that IL-2 is mainly involved in the activation process. The ability of the IL-1 peptide to increase NK activity was further confirmed in vivo in the mouse. Cytotoxicity against YAC-1 lymphoma cells, which was very low in the spleen of untreated BALB/c mice, was in fact significantly increased after a single inoculation of the peptide. These data thus indicate that a short synthetic peptide fragment of hu IL-1 beta is able to increase both human and murine NK activity.

Animals↗
PubMed1989

Interleukin 1 stimulates production of LTC4 and other eicosanoids by macrophages.

Human recombinant IL-1 alpha stimulates in a dose-dependent fashion the production of 5-lipoxygenase-derived LTC4 and, to a lesser extent, of cyclooxygenase-derived eicosanoids (PGE2, 6-keto PGF1 alpha, TXB2) by murine resident peritoneal macrophages. Enhancement of eicosanoid production was evident on unstimulated macrophages, but only marginal on macrophages phagocytosing zymosan. The effect of IL-1 was similarly achieved at physiological (37 degrees C) as well as at higher (39 degrees C) temperatures. Human recombinant IL-1 beta, human natural IL-1, and partially purified murine IL-1-rich supernatant also stimulated eicosanoid production by macrophages, although IL-1 alpha appeared to be the most effective.

Animals↗
PubMed1989

Defining agonist peptides of human interleukin-1 beta.

The structure-function relationship in the human IL-1 beta protein has been analyzed by means of computer prediction, synthesis of peptides and use of monoclonal antibodies of predetermined specificity. A nine amino acid-long fragment (VQGEESNDK), corresponding to the human IL-1 beta sequence in position 163-171, was shown to possess only some of the IL-1 activities, i.e. those directed to the immune system, while being devoid of IL-1-like inflammatory effects. It is thus proposed that discrete domains within the IL-1 beta protein might be responsible for the different biological activities of the molecule and that the 163-171 fragment may represent one of the immunostimulatory sites of IL-1 beta.

Adjuvants, Immunologic↗
PubMed1988

In vivo restoration of T cell functions by human IL-1 beta or its 163-171 nonapeptide in immunodepressed mice.

The immunorestorative capacities of human (hu) IL-1 beta or its synthetic fragment 163-171 (VQGEESNDK) were assessed in vivo in mice immunodepressed by aging, sublethal irradiation, or both. Subcutaneous administration of hu rIL-1 beta into immunodepressed animals immediately after carrier (horse red blood cells, HRBC) priming could restore to normal levels Th cell activity. This was measured as the ability of spleen cells from HRBC-primed mice to induce a hapten-specific antibody response in spleen cells from nonimmune mice in vitro stimulated with the hapten-carrier conjugate TNP-HRBC. In parallel, the ability of spleen cells from hu rIL-1 beta-treated immunodepressed animals to produce T cell growth factor activity upon in vitro mitogen stimulation was also increased significantly as compared to that of untreated mice and approached that of immunocompetent controls. The immunorestorative activity of hu rIL-1 beta on Th cell activity and T cell growth factor production could be mimicked by the synthetic nonapeptide 163-171 which, at the doses used, produced in most instances even greater effects than the whole protein. Although the optimal immunorestorative doses of the 163-171 peptide were several orders of magnitude higher than those of hu rIL-1 beta, the complete lack of IL-1-like inflammatory and toxic effects suggests that the synthetic hu IL-1 beta fragment may be successfully used as immunomodulating agent in the therapy of T cell immunodeficiencies.

Adjuvants, Immunologic↗
PubMed1988

Impairment of in vitro natural antibacterial activity in HIV-infected patients.

Circulating PBMC of healthy subjects possess an in vitro natural antibacterial (NA) against enteropathogenic bacteria, including Salmonella species. The effector cell of NA activity is a CD: 4+, 8-, Leu-8/TQ-1+ T lymphocyte acting against bacteria via cytophylic IgA in a mechanism similar to antibody-dependent cellular activity. Because AIDS is a profound immunodeficiency caused by HIV involving primarily CD4 lymphocytes and in particular the Leu-8/TQ-1 subset, it was of interest to assess NA activity of HIV+ subjects at various stages of the disease. Results indicate that NA activity against Salmonella typhi and Salmonella paratyphi C is significantly decreased in AIDS as well as in lymphadenopathy syndrome patients. Furthermore, sera containing IgA against salmonellae were not able to arm PBMC from HIV+ patients. The humoral response against S. typhi-LPS was also greatly decreased after HIV infection, in contrast to the known hypergammaglobulinemia seen in these subjects. Defective NA activity might contribute to the increased incidence of salmonellosis observed in AIDS.

AIDS-Related Complex↗
PubMed1988

Dissecting human T cell responses against Bordetella species.

To identify the minimal structures that may be important for the creation of a synthetic and/or recombinant vaccine against whooping cough, human T cell clones were obtained against Bordetella antigens. Cloned peripheral blood T lymphocytes from an immune donor were grown in IL-2 and tested for proliferation in response to inactivated Bordetella species (B. pertussis, B. parapertussis, and B. bronchiseptica) and mutants deficient for the expression of virulence-associated antigens. All the T cell clones obtained were CD4+8- and recognized specifically the Bordetella antigens when presented by autologous B cells. On the basis of the responsiveness to the whole inactivated bacteria, it was possible to cluster the 12 clones obtained into four groups with the following specificity: (1) filamentous hemagglutinin (FHA); (2) B. pertussis-specific antigens; (3) virulence-associated Bordetella-specific antigens; and (4) nonvirulence-associated Bordetella-specific antigens. Using two new B. pertussis deletion mutants, clone 6 (representative of cluster 1) was found to recognize the COOH terminus of FHA. Furthermore, three out of four clones of cluster 3 were specifically stimulated by the soluble 69-kD protein from the outer membrane of B. pertussis. Surprisingly, none of the twelve clones obtained by stimulation in vitro with whole inactivated bacteria recognized pertussis toxin (PT), which is believed to be the most important protein to be included in an acellular vaccine. However, when a new generation of clones was obtained using soluble PT as the in vitro stimulus, it was observed that 11 clones of this group recognized this antigen. Thus, PT does not seem to be the most representative antigen on the whole inactivated bacteria, although T cell memory against PT exists in a donor who had the disease several years ago.

Adult↗
PubMed1988

Comparative analysis of immunological responses to oral (Ty21a) and parenteral (TAB) typhoid vaccines.

The clinical and immunological responses to typhoid vaccination with parenteral (TAB) and oral (Ty21a) vaccines in two groups of 30 adult male subjects were studied. Parameters monitored included specific anti-Salmonella typhi cell-mediated immunity and total and specific antilipopolysaccharide fecal immunoglobulin A (IgA) titers in Ty21a-vaccinated subjects. Peripheral blood lymphocytes antibacterial activity was significantly increased only in Ty21a-vaccinated subjects. Serum arming activity and results of human F(ab')2 anti-IgG and -IgA inhibition tests suggest antibody-dependent cellular cytotoxicity mediated by IgA in those vaccinated with Ty21a. Interestingly enough, the cells of TAB-vaccinated subjects were able to mediate IgG-dependent cellular cytotoxicity, as was observable from the results of blocking experiments. Moreover, total and specific antilipopolysaccharide fecal IgA levels were observed to be significantly increased with Ty21a, up to 8 months post-vaccination schedule. An early-onset, transitory increase in serum IgM rheumatoid factor was also found, exclusively in subjects treated with TAB, and was no longer detectable on day 240. Ty21a was well tolerated and free of side effects, whereas 65% of subjects administered TAB reported fever, headache, malaise, and local tenderness at the injection site. Our data show that the two typhoid vaccines induce different cell-mediated specific immune responses. The role of these responses in protection against Salmonella infection, however, requires further investigation.

Administration, Oral↗
PubMed1988

IgA-driven antibacterial activity against Streptococcus pneumoniae by mouse lung lymphocytes.

To investigate the role of lung lymphocytes (LL) in the local defense mechanisms, we studied the natural antibacterial (NA) activity of mouse LL with an in vitro assay using S. pneumoniae type 3 as target. In parallel, natural killer (NK) activity against YAC-1 tumor cells was investigated. Lung cells obtained by enzymatic digestion were found to exert detectable NA and NK activities, which were further increased after purification of LL (greater than 90% lymphocytes) by carbonyl iron and magnet treatment. Depletion experiments with antibodies and complement indicated that the effector cell of NA activity was a Thy 1.2+, L3T4+, aGM1+ lymphocyte, whereas the effector of NK activity was found to have a Thy 1.2-, aGM1+ phenotype. Preincubation of LL with anti-IgA antibodies, but not with anti-IgG, completely inhibited NA activity, suggesting that it was mediated by preexisting IgA bound to the LL surface. Furthermore, purified IgA from S107 plasmacytoma with specificity for phosphorylcholine, a component of the outer wall of S. pneumoniae, was able to enhance the antibacterial activity of LL and to restore their activity after treatment with anti-IgA. In addition, S107 antibodies were found to specifically induce antibacterial activity against S. pneumoniae in resident alveolar macrophages (AM) and peritoneal exudate cells, which did not express NA activity. We conclude that mouse LL include a subset of IgA-bearing lymphocytes with the phenotype of helper-T cells, which are able to exert NA activity against pneumococcus through an IgA-driven mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗