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C Bona

Publications and source records attributed to C Bona.

At least 19 recordsLinked to original sources
PubMed2000

Kinetics of anti-fibrillin-1 autoantibodies in MCTD and CREST syndrome.

Using a highly sensitive Radioimmunoassay (RIA), the kinetics of synthesis of anti-fibrillin (Fbn-1) autoantibodies were studied in 17 patients with mixed connective tissue disease (MCTD) and two with CREST syndrome calcinosis, Raynaud's oesophageal dismotility, sclerodectyly and teleangiectasis who were found to be positive for this autoimmune response. IgG autoantibodies specific for recombinant Fbn-1 (rFbn-1) (aa 369-425) were found in all patients excepting one with MCTD, multiple sclerosis, and dermatomyositis. IgM were found in fewer cases. Several kinetics patterns of anti-Fbn-1 autoantibodies were observed: a) long lasting persistence of IgG and IgM autoantibodies up to 14 years; b) fluctuation of antibodies during various periods up to 16 years; c) disappearance of antibody response after several years, and d) patients producing IgG but not IgM autoantibodies. No differences in the synthesis of autoantibodies were observed between MCTD patients with a stable disease, and those developing during the course features of systemic sclerosis (SSc), Sjogren's syndrome, or rheumatoid-like arthritis. In one patient displaying a lupus-like syndrome for 3 years, the appearance of anti-Fbn-1 autoantibodies coincided with the occurrence of MCTD and scleroderma. While the detection of anti-Fbn-1 autoantibodies may be clinically useful in differential diagnosis or eventual prognosis of patients with connective tissue diseases, their role in the pathogenesis of scleroderma syndromes requires further investigation.

Autoantibodies↗
PubMed2000

Dendritic cells at a DNA vaccination site express the encoded influenza nucleoprotein and prime MHC class I-restricted cytolytic lymphocytes upon adoptive transfer.

Intradermal inoculation of plasmids expressing antigens that contain MHC class I-restricted epitopes leads to the induction of specific CD8(+) cytotoxic T lymphocytes (CTL). The role of in situ transfected antigen-presenting cells (APC) in the priming of specific CTL subsequent to intradermal DNA immunization was investigated using a plasmid (NPV1) expressing the nucleoprotein (NP) of influenza virus that contains a nuclear targeting signal and a dominant class I/K(d)-restricted epitope. Inoculation of NPV1 leads to in situ transfection of MHC class II(+) and class II(-) cells, as revealed by the nuclear localization of NP. Between 2 and 3% of MHC class II(+) and class II(-) cells with the ability to migrate out of the epidermis expressed NP. Upon adoptive transfer into naive recipients, class II(+) migratory cells recovered from the area inoculated with NP-expressing plasmid were significantly superior regarding the ability to prime virus-specific CTL as compared to MHC class II(-) cells. Together, these results are consistent with the role of local dendritic cells loaded with antigen in the priming of CTL by intradermal DNA immunization.

Adoptive Transfer↗
PubMed1999

Autoantibodies to the extracellular matrix microfibrillar protein, fibrillin 1, in patients with localized scleroderma.

OBJECTIVE: Serum autoantibodies to fibrillin 1, the major component of microfibrils in the extracellular matrix, recently have been reported to occur in the tight skin mouse and in patients with systemic sclerosis, but not in patients with other connective tissue diseases. This study was undertaken to determine whether antifibrillin 1 antibodies could be detected in patients with localized forms of scleroderma. METHODS: Sera from 50 patients with localized scleroderma (27 with linear scleroderma and 23 with morphea) and 51 normal controls were tested for IgG and IgM antifibrillin 1 autoantibodies, using a radioimmunoassay (RIA) and a human recombinant fibrillin 1 protein (rFbn-1). RESULTS: Both in patients with linear scleroderma and in those with morphea, mean levels of IgM and IgG binding to rFbn-1 were significantly higher than in controls. Eight patients with linear scleroderma (30%) and 6 patients with morphea (26%) had IgG autoantibodies to fibrillin 1 (rFbn-1) by RIA, compared with 3 controls (6%) (P = 0.006 and P = 0.022, respectively). No correlations between antifibrillin 1 antibodies and active skin disease or antinuclear antibody positivity were found. CONCLUSION: Autoantibodies to fibrillin 1 occur in patients with both forms of localized scleroderma (linear scleroderma and morphea). The clinical and pathogenetic significance of this autoimmune response remains to be determined.

Autoantibodies↗
PubMed1999

Plasmid expressing the influenza HA gene protects old mice from lethal challenge with influenza virus.

Virus-based influenza vaccines induce less protection in old compared to young subjects due, in part, to age-associated alterations in the immune response. This study shows that old mice produce a less diverse HI antibody response after immunization than adult mice. However, immunization of old and young mice with plasmids expressing the HA gene induced comparable clearance of influenza virus from the lungs and the same level of protection from a lethal challenge with live WSN influenza virus. Thus, genetic immunization may offer advantages for the elderly over virus-base vaccines.

Aging↗
PubMed1999

Induction of antibody response by DNA immunization of newborn baboons against influenza virus.

Previous studies showed that DNA immunization of newborn mice with plasmids expressing influenza virus antigens induced protective immunity. We have now extended the study of neonatal responsiveness to DNA vaccines to nonhuman primates. Baboons immunized as neonates with plasmids expressing type A influenza virus hemagglutinin (HA) and nucleoprotein (NP) in doses ranging from 40 microg to 1 mg per plasmid per dose developed virus-specific humoral responses. The titer and kinetics of appearance of virus-specific IgG antibodies were dose dependent. Specific antibodies were detected by enzyme-linked immunosorbent assay (ELISA) as early as 1 month after birth in baboons immunized with the highest and intermediate doses of vaccine. Virus-neutralizing antibodies were detected in the group of baboons immunized with the highest dose. The specificity of virus-neutralizing antibodies was found to be directed against homologous determinants of HA; however, the IgG antibodies also cross-reacted with HA of a drift variant. Thus, DNA vaccination of newborn baboons with a prototype vaccine against influenza virus resulted in induction of specific humoral immunity.

Animals↗
PubMed1999

Autoantibodies to FK506 binding protein 12 (FKBP12) in autoimmune diseases.

Plasma from 126 patients with various autoimmune diseases and 118 healthy subjects were examined to determine the presence of autoantibodies to FKBP12, one of immunophilins. The frequency of IgG and/or IgM anti-FKBP12 autoantibodies detected by ELISA was as follows; SLE (15/39), SSc (11/27), CREST (4/7), RA (2/8), MCTD (0/5), Graves' disease (4/12), IDDM (2/6), PM/DM (0/3), MG (1/4), AIH (2/6), PBC (4/9), and healthy subjects (5/118). The specificity of the autoantibodies was demonstrated by absorption of the plasma samples with r-FKBP12 and other recombinant proteins. In immunoblotting, IgM anti-FKBP12 autoantibodies reacted with two bands of 12 and 24 kD, the latter representing the dimer. Anti-FKBP12 autoantibodies in some patients reacted more strongly with the dimer than the monomer, suggesting that FKBP12 may also exist as the dimer in vivo. The majority of anti-FKBP12 autoantibodies bound to two synthetic peptides corresponding to amino acid residues of FKBP12, Pro16 approximate to Tyr26 and Thr27 approximate to Phe46. These epitopes are phylogenetically well conserved and responsible for the binding to calcineurin and FK506. The autoantibodies inhibited pentamerization of FKBP12 with FK506, calcineurin, calmodulin, and Ca2+ in vitro. These data define the frequent occurrence of a novel set of autoantibodies to a cytosolic protein involved in the regulation of the immune response.

Amino Acid Sequence↗
PubMed1998

Cellular mechanisms involved in protection against influenza virus infection in transgenic mice expressing a TCR receptor specific for class II hemagglutinin peptide in CD4+ and CD8+ T cells.

Mice transgenic for a TCR that recognizes peptide110-120 of hemagglutinin of PR8 influenza virus in the context of MHC class II I-Ed molecules express the transgenes in both CD4+ and CD8+ T cells. We have found that these TCR-hemagglutinin (TCR-HA) transgenic mice display a significantly increased resistance to the primary infection with PR8 virus compared with the wild-type mice. The TCR-HA transgenic mice mounted significant MHC type II and enhanced MHC type I-restricted cytotoxicity as well as increased cytokine responses in both spleen and lungs after infection with PR8 virus. In contrast, the primary humoral response against PR8 virus was not significantly different from that of the wild-type mice. In vivo depletion and adoptive cell transfer experiments demonstrated that both CD4+ and CD8+ TCR-HA+ T cell subsets were required for the complete clearance of pulmonary virus following infection with a dose that is 100% lethal in wild-type mice. Whereas CD4+ TCR-HA+ T cells were necessary for effective activation and local recruitment of CD8+ T cells, CD8+ TCR-HA+ T cells showed a Th1-biased pattern and MHC type II-restricted cytotoxicity. However, in the absence of in vivo expression of MHC type I molecules on the infected cells, the protection conferred by the TCR-HA+ T cells was impaired, indicating that the enhanced MHC class I-restricted cytotoxicity due to TCR-HA+ CD4+ Th cells was a critical element for clearance of the pulmonary virus by the transgenic mice.

Animals↗
PubMed1998

Enhanced protection against influenza virus of mice immunized as newborns with a mixture of plasmids expressing hemagglutinin and nucleoprotein.

Effective immunization of neonates is an important goal for vaccinology. We show that inoculation of newborn mice with a mixture of plasmids expressing influenza hemagglutinin (HA) and nucleoprotein (NP) genes leads to an enhanced protection subsequent to the lethal challenge with two distinct strains. In sharp contrast, neonatal injection with UV-inactivated influenza virus strain WSN, failed to induce protection against the homologous challenge. Our results show that while plasmid immunization of neonates elicits a protective immunity, the immunization with inactivated virus does not.

Animals↗
PubMed1998

The primary antibody repertoire of kappa-deficient mice is characterized by non-stochastic Vlamda1 + V(H) gene family pairings and a higher degree of self-reactivity.

We have investigated the primary antibody repertoire of genetically manipulated 129/Sv kappa-deficient (JCkappaD) mice, in order to understand the contributions of the lambda-light chain, in the absence of an otherwise predominant kappa-light chain, to the development of humoral immunity. The expression of Vlambda1 gene (lambda1 and lambda3 subtypes) and the Vlambda1 + V(H) (J558, 36-60, V(H)11 and S107) gene family associations were studied in 7.43 x 10(3) mitogen-activated splenic B-lymphocyte clones of JCkappaD origin. Furthermore, the functional significance of the exclusive expression of the lambda-light chain, in the peripheral B-cell repertoire of JCkappaD mice, was analysed by determining natural autoantibody specificities in the circulating serum immunoglobulin and the frequency of autoreactive B-lymphocyte clones in the peripheral B-lymphocyte repertoire. These experiments revealed that: first, of the three available Vlambda genes at the lambda locus, the Vlambda1 gene is the one that is expressed most frequently (59.9%); second, non-random Vlambda1 + V(H) (J558, 36-60) gene family pairings occur in kappa-deficient mice; and third, a higher degree of self-reactivity is generated as a result of exclusive use of the lambda-light chain, as evidenced by higher levels of serum natural autoantibodies as well as a high frequency of autoreactive B-lymphocyte clones in kappa-deficient (129/Sv JCkappaD) mice. These observations suggest that the high murine kappa/lambda ratio in mice may, apart from high sequence diversity at the kappa-locus, be a result of endogenous selection against the lambda-light chain to restrict self-reactivity within the homeostatic threshold.

Animals↗
PubMed1998

The reactivity pattern of hemagglutinin-specific clonotypes from mice immunized as neonates or adults with naked DNA.

In contrast to adult mice immunized with influenza A virus strain WSN and plasmid expressing WSN hemagglutinin (HA) gene which developed primary and secondary anti-HA antibody responses, mice immunized as neonates with virus failed to produce anti-HA antibodies while those immunized with plasmid developed weak primary but strong secondary responses. Analysis of the frequency of HA-specific B clonotypes as well as their reactivity pattern (RP) showed that viral or genetic immunization of adults increased the frequency of clonotypes which exhibit broad RP. The most striking observation of our study is that immunization of neonates with plasmid leads to increased synthesis of anti-HA antibodies as well as to an increased frequency of clonotypes exhibiting an adult-like RP. In contrast, neonatal immunization with virus caused a long-lasting unresponsiveness and the few clonotypes stimulated in vitro exhibited only a monoreactive pattern. Isotype patterns of mAb are also diversified in the case of mice immunized with plasmid as neonates. Rapid replacement of neonatal with adult clonotypes may explain the significant survival of the mice immunized with plasmid and challenged 1 or 3 months later with lethal doses of virus.

Animals↗
PubMed1998

Protective cellular immunity against influenza virus induced by plasmid inoculation of newborn mice.

Neonate organisms display an intrinsic disability to mount effective immune responses to infectious agents or conventional vaccines. Whereas low doses of antigens trigger a suboptimal response, higher doses are frequently associated with tolerance induction. We investigated the ability of a plasmid-expressing nucleoprotein of influenza virus to prime a specific cellular immune response when administered to newborn mice. We found that persistent exposure to antigen following plasmid inoculation of neonates leads to a vigorous priming of specific CTLs rather than tolerance induction. The CTLs were cross-reactive against multiple strains of type A influenza viruses and produced IFNgamma but no IL-4. The immunity triggered by plasmid inoculation of neonates was protective in terms of pulmonary virus clearance as well as survival rate following lethal challenge with influenza virus. Whereas the persistence of the plasmid at the site of injection was readily demonstrable in adult mice at 3 months after inoculation, mice immunized as newborns displayed no plasmid at 3 months and very little at 1 month after injection. Thus, DNA-based immunization of neonates may prove an effective and safe vaccination strategy for induction of cellular immunity against microbes that cause serious infectious diseases in the early period of life.

Animals↗
PubMed1997

Immune response of neonates elicited by somatic transgene vaccination with naked DNA.

Neonates display lower immune responsiveness and higher susceptibility for high-dose tolerance. Quantitative as well as functional differences between the neonatal and adult lymphocytes or antigen presenting cells (APC) respectively, explain the particular immune responsiveness during the early stages of the postnatal development. Reduced numbers of lymphocytes and APCs as well as a modified responsiveness of T cells in neonates, are the main factors that account for the low threshold of tolerance in newborns. Taking into account these particularities, the design of effective vaccines for neonates poses significant difficulties. We hypothesized that a continuous exposure to low doses of antigens may avoid high-zone tolerance and may lead instead, to effective expansion of effector and memory cells. Indeed, inoculation of newborn mice with plasmids encoding nucleoprotein (NP) or hemagglutinin (HA) of influenza virus, led to the priming of specific cytotoxic (CTL), helper (Th) and B cells, rather than induction of unresponsiveness. Mice immunized as neonates with naked DNA and challenged later with lethal doses of influenza virus, displayed significant protection. Thus, DNA immunization may be a promising strategy for vaccination against serious infectious diseases of infants and children.

Adult↗
PubMed1997

Conditions that induce tolerance in mature CD4+ T cells.

Establishment of antigen-specific tolerance among mature T cells has been a long debated, yet poorly understood issue. In this study we have used transgenic mice bearing a class II--restricted TCR specific for the hemmagglutinin of the influenza virus in order to test the behavior of CD4+ T cells upon exposure to antigen in different forms and doses. We first studied the fate of T cells expressing the transgenic TCR (6.5) in double transgenic mice where HA was expressed as a self antigen by hemapoietic cells. In these mice, we found some mature T cells in periphery that had escaped thymic deletion and that showed signs of activation but which were anergic. Mature CD4+6.5+ cells that were transferred into antigen-containing recipients went through an initial phase of expansion after which most cells were deleted and those remaining became unresponsive, as previously described for CD8+ cells. Inducing tolerance in CD4+6.5+ cells in situ in single transgenic mice proved a difficult task: classical protocols using single doses of soluble or deaggregated antigen as well as feeding antigen all failed to induce antigen-specific unresponsiveness. It was only after decreasing cell numbers by CD4 antibody treatment and by repeatedly reintroducing antigen thereafter that unresponsiveness of 6.5+ cells was achieved and maintained. In no case could we observe the appearance of antigen-specific T cells with a Th2 cytokine profile among the remaining cells and therefore conclude that deletion and anergy represent the major mechanisms of tolerance in our studies.

Adoptive Transfer↗
PubMed1997

Induction of humoral and cellular immunity against influenza virus by immunization of newborn mice with a plasmid bearing a hemagglutinin gene.

Neonates and infants display an intrinsic disability to mount protective immune responses to influenza viruses or conventional influenza vaccines. We investigated the ability of naked DNA to prime protective immune responses by inoculating newborn and adult mice with a plasmid (pHA) expressing hemagglutinin (HA) from the neurovirulent strain A/WSN/33 of influenza virus. Continuous exposure to small doses of antigen subsequent to neonatal DNA immunization led to effective priming of specific B and Th cells, rather than tolerance induction. The pHA immunization of adult mice primed a strongly biased Th1 response, whereas in neonates it induced a mixed Th1/Th2 response. In contrast to the effect of live-virus immunization, DNA immunization of neonates was followed by enhanced cytotoxic T lymphocyte responses subsequent to challenge with A/WSN/33 influenza virus. Mice immunized as neonates or adults with pHA plasmid exhibited significant increases in survival and decreases in virus lung titers following lethal challenge with the A/WSN/33 virus or the A/PR8/34 drift variant. Our results demonstrate that DNA vaccination is an efficient and safe means to generate broad humoral and cellular immune responses to influenza viruses, during the earliest stages of postnatal life.

Aging↗
PubMed1996

Kinetics of generation and persistence on membrane class II molecules of a viral peptide expressed on foreign and self proteins.

We had previously shown that a genetically engineered Ig expressing an immunodominant CD4+ T epitope corresponding to the 110-120 amino acids of influenza virus hemagglutinin (HA), activated T cells more efficiently than the synthetic peptide. Taking advantage of a T cell hybridoma specific for HA 110-120 and transfected with a reporter gene under the IL-2 promoter, we studied the kinetics of generation and persistence on surface MHC-II of the HA 110-120 peptide derived from various carriers. Our results show that the generation rate of immunogenic MHC II-peptide complex is dependent on the nature of the carrier. Abs specific for HA 110-120 peptide or for other epitopes on HA affect through various mechanisms the presentation of HA 110-120 peptide to T cells. The persistence of immunogenic MHC II-peptide complex on the surface of APC is not dependent on the nature of the carrier and correlates with the half-life of class II molecules, suggesting an irreversible binding of peptides to MHC-II molecules in 2PK3 murine B lymphoma cells.

Animals↗