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Biomedical subjects

C Bona

Publications and source records attributed to C Bona.

At least 19 recordsLinked to original sources
PubMed2001

Induction of immunological memory in baboons primed with DNA vaccine as neonates.

DNA immunization is a potential vaccination strategy for neonates and infants. We tested the ability of a prototype DNA vaccine against influenza virus to prime lasting immunity when administered to newborn non-human primates. Neonatal DNA vaccination triggered virus-specific and neutralizing antibodies of titers and persistence depending on the vaccine dose. Subsequent exposure to influenza virus, revealed significantly increased recall responses in the baboons vaccinated with DNA during the neonatal stage. The humoral and cellular responses were enhanced in the baboons primed with DNA vaccine as neonates. Thus, neonatal DNA vaccination of non-human primates triggered immune memory that persisted beyond infancy.

Age Factors↗
PubMed2001

Effect of maternal antibodies on influenza virus-specific immune response elicited by inactivated virus and naked DNA.

While vaccines are effective in adults, they are less successful in newborns and infants. Neonatal unresponsiveness to vaccines could be owing to immaturity of lymphocytes and/or to inhibition by maternal antibodies. Unresponsiveness of newborn to vaccines can be overcame by genetic immunization. In the present study we investigated the effect of maternal antibodies on the anti-influenza virus protective response in progeny born to dams immunized with plasmid containing the hemagglutinin gene or UV-inactivated virus. The effect of maternal antibodies was studied in plasmid immunized F1 mice born to BALB/c dams, previously immunized with virus or plasmid and crossed with C57BL/6 males, as well as in offspring born to BALB/c dams immunized with plasmid and then immunized with UV-inactivated WSN virus. We have found that the inhibition period of the anti-HA antibody response in offspring born to dams immunized with DNA is shorter than that of offspring born to dams immunized with virus. Furthermore, there is a persistent inhibitory effect on B cells from offspring born to dams immunized with virus or injected with antiviral monoclonal antibodies (MoAb), after the decline of maternal antibody titers. The analysis of the haemagglutinin-specific clonotype reactivity pattern of offspring born to dams immunized with inactivated influenza virus or with a plasmid showed that clonotypes producing antibodies specific for the immunizing virus strain were predominant in offspring born to dams immunized with DNA compared to those born to dams immunized with virus. Maternal antibodies do not affect cell-mediated immunity. These findings might be used to design efficient vaccination schedules for newborns and infants.

Animals↗
PubMed2001

Lack of skin fibrosis in tight skin (TSK) mice with targeted mutation in the interleukin-4R alpha and transforming growth factor-beta genes.

Scleroderma is a disorder characterized by fibrosis of the skin and internal organs and autoimmunity. Whereas the cause is unknown, interleukin-4 and transforming growth factor-beta have been postulated to play a major part in the fibrosis. To investigate the part played by these cytokines, we prepared TSK/+ mice with a targeted mutation in the interleukin-4R alpha or transforming growth factor-beta genes. The breeding failed to produce TSK/+ transforming growth factor-beta -/- mice so analysis of the role of transforming growth factor-beta was limited to TSK/+ transforming growth factor-beta +/- mice. We observed that TSK/+ interleukin-4R alpha -/- did not develop dermal thickening, and deletion of one allele of the transforming growth factor-beta gene resulted in diminished dermal thickness compared with TSK/+ mice; however, the deletion of interleukin-4R alpha or transforming growth factor-beta had no effect on lung emphysema, which is another characteristic of TSK syndrome. Electron microscopic analysis of skin showed that the collagen fibrils in TSK/+ interleukin-4R alpha -/- mice exhibit normal periodicity but have a smaller diameter than the fibers found in C57BL/6 mice. Analysis of skin and serum samples showed that the deletion of interleukin-4R alpha or one allele of transforming growth factor-beta prevented the increase of skin thickness paralleled with a decrease in the dermal hydroxyproline content and development of autoantibodies associated with TSK syndrome. These results demonstrate the importance of interleukin-4 and transforming growth factor-beta for the development of cutaneous fibrosis in vivo and suggest an important part for these cytokines in wound healing and connective tissue maintenance in general.

Animals↗
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↗
PubMed2000

Induction of skin fibrosis in mice expressing a mutated fibrillin-1 gene.

BACKGROUND: Tight skin mice (TSK) bear a mutated Fibrillin-1 (Fbn-1) gene. Genetic studies show that the TSK mutation is closely associated with the Fbn-1 locus (0-0.7 cM). A previous study showed two recombinants between the Fbn-1 locus and the TSK mutation. TSK mutation and mutated Fbn-1 gene cosegregate in F1 mice. MATERIALS AND METHODS: To elucidate the role of the mutated Fbn-1 gene in occurrence of TSK syndrome, we generated transgenic (Tg) mice expressing mutated Fbn-1 gene. In another set of experiments, we injected normal mice after birth with a plasmid bearing mutated Fbn-1 gene (pdFbn-1). RESULTS: Our results demonstrate that the pdFbn-1 Tg mice developed permanent cutaneous hyperplasia that was permanent. In mice injected as newborns with a plasmid bearing the sense pdFbn-1 gene, cutaneous hyperplasia was transient. In contrast to TSK mice, neither Tg nor mice injected with plasmid developed lung emphysema. The pdFbn-1 Tg and TSK mice spontaneously produced anti-topoisomerase I and anti-Fbn- antibodies, as do humans afflicted by scleroderma; whereas, those injected with a plasmid containing the pdFbn-1 gene produced only anti-Fbn-1 autoantibodies. CONCLUSIONS: The results suggest that, although cutaneous hyperplasia is due to mutated Fbn-1 gene, the TSK syndrome may be multifactorial.

Animals↗
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

Genetic and immunologic features associated with scleroderma-like syndrome of TSK mice.

Tight-skin (TSK) mouse, the experimental model for scleroderma, develops cutaneous hyperplasia and autoantibodies to scleroderma specific autoantigens. TSK syndrome is caused by a mutation on chromosome 2. Induction of cutaneous hyperplasia is due to intragenic duplication of exons 17 to 40 of fibrillin-1 gene, mapping close to TSK locus. The mutant mouse expresses a 14kb Fbn transcript in addition to 11kb wild-type transcript. Immunoprecipation analysis confirms that the mutant transcript is functional and codes for a 420kD fibrillin. The occurrence of TSK syndrome is independent of the presence of mature lymphocytes although splenic/bone marrow cells appear to be capable of transferring the disease in normal animals. Transgenic mice expressing mutant transgene develop mild skin thickness with associate biochemical changes but do not develop anti-topo I antibodies. Among the other factors that may contribute to the develop- ment of hyperplasia, collagen V seems to play an important role.

Animals↗
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↗