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Biomedical subjects

A Bonura

Publications and source records attributed to A Bonura.

10 recordsLinked to original sources
PubMed2006

A hybrid expressing genetically engineered major allergens of the Parietaria pollen as a tool for specific allergy vaccination.

BACKGROUND: Allergy is an immunological disorder affecting about 25% of the population living in the industrialized countries. Specific immunotherapy is the only treatment with a long-lasting relief of allergic symptoms and able to reduce the risk of developing new allergic sensitizations and inhibiting the development of clinical asthma in children treated for allergic rhinitis. METHODS: By means of DNA recombinant technology, we were able to design a head to tail dimer expressing disulphide bond variants of the major allergen of the Parietaria pollen. IgE binding activity was studied by Western blot, ELISA inhibition assays and the skin prick test. T cell recognition was studied by peripheral blood mononuclear cell proliferation. The immunogenicity of the hybrid was studied in a mouse model of sensitization. RESULTS: In vitro and in vivo analysis showed that the disruption of specific cysteine residues in both allergens caused a strong reduction in IgE binding activity of the PjEDcys hybrid. In addition,we were able to show that a reduction in the IgE epitope content profoundly reduced the anaphylactic activity of the hybrid (from 100 to 1,000 times less than wild-type allergens) without interfering with the T cell recognition. Sera from BALB/c mice immunized with the hybrid were able to bind the natural Parietaria allergens and to inhibit the binding of human IgE to wild-type Par j 1 and Par j 2 allergens up to 90%. CONCLUSION: Our results demonstrate that hybrid-expressing disulphide bond variants of the major allergens of the Parietaria pollen displayed reduced allergenicity and maintained T cell reactivity for induction of protective antibodies.

Allergens↗
PubMed2006

Leiomyosarcoma of the inferior vena cava.

Leiomyosarcoma of the inferior vena cava is a rare primary tumour. We present a case report of a 67-year-old man with a long history of abdominal pain and gastroesophageal reflux, who was found to have a large retroperitoneal mass confirmed to be a leiomyosarcoma. The clinical and imaging features are outlined, and in addition the treatment and prognosis.

Aged↗
PubMed2004

The recombinant major allergen of Parietaria judaica and its hypoallergenic variant: in vivo evaluation in a murine model of allergic sensitization.

BACKGROUND: Par j 1 represents the major allergenic component of Parietaria judaica pollen. Its three-dimensional structure is stabilized by four disulphide bridges. A family of three-dimensional mutants of the recombinant Par j 1 (rPar j 1) allergen, showing reduced allergenicity and retained T cell recognition has been recently developed by site-directed mutagenesis. OBJECTIVE: To develop and characterize a murine model of IgE sensitization to rPar j 1. To evaluate similarities between the murine model and the human IgE response. To investigate in this model the recognition of a hypoallergenic mutant of Par j 1, and to study the immune responses elicited in mice by the mutant itself. METHODS: BALB/c mice were sensitized by two intraperitoneal immunizations with rPar j 1 in alum on days 0 and 21. Allergen-specific serum IgE and IgG responses were studied by direct ELISA and immunoblotting, ELISA inhibition and competitive ELISA. Cell proliferation was evaluated in splenocyte cultures. RESULTS: Sensitization with rPar j 1 induced high levels of IgE and IgG1 vs. low levels of IgG2a. Mouse antibodies specific to rPar j 1 were able to compete with human IgE for recognition of rPar j 1. IgE from mice immunized with rPar j 1 showed a significantly reduced binding activity towards the hypoallergenic variant rPjC, which lacks three disulphide bridges. On the contrary, rPjC was recognized by IgG1 and IgG2a antibodies as well as rPar j 1. The proliferative response to rPjC by splenocytes from mice immunized with rPar j 1 was comparable to that stimulated by rPar j 1. Immunization with rPjC induced low levels of IgE antibodies to the rPjC itself, while IgG and proliferative responses were similar to those induced by rPar j 1. CONCLUSION: Conformational variants of allergens, displaying reduced allergenicity accompanied by retained IgG and T cell recognition, offer a safe, specific and flexible approach to immunotherapy of type I allergy. Our mouse model of IgE sensitization to a recombinant allergen, mimicking the human response to its native counterpart, could provide valuable information for pre-clinical testing of such hypoallergenic molecules.

Allergens↗
PubMed2001

Hypoallergenic variants of the Parietaria judaica major allergen Par j 1: a member of the non-specific lipid transfer protein plant family.

BACKGROUND: Par j 1 represents a major allergenic component of Parietaria judaica (Pj) pollen, since it is able to induce an immunoglobulin E (IgE) response in 95% of Pj-allergic patients. It belongs to the non-specific lipid transfer protein family, sharing with them a common three-dimensional structure. METHODS: Disulphide bond variants of the recombinant Par j 1 (rPar j 1) allergen were generated by site-directed mutagenesis, and the immunological activity of rPar j 1 and its conformational mutants was compared with the use of the skin prick test (SPT). The ability to bind IgE antibodies was evaluated by Western blot, ELISA and ELISA inhibition. T cell reactivity was measured by peripheral blood mononuclear cell proliferation assay. RESULTS: The disruption of Cys14-Cys29 and Cys30-Cys75 bridging (PjA mutant) caused the loss of the majority of specific IgE-binding activity. Additional disruption of the Cys4-Cys52 bridge (PjC mutant) and the latter Cys50-Cys91 bridge (PjD mutant) led to the abolition of IgE-binding activity. On the SPT, PjB (lacking the Cys4-Cys52 and Cys50-Cys91 bridges) was still capable of triggering a type I hypersensitive reaction in 9 out of 10 patients, and PjA in 3 out of 10 patients, while PjC and PjD did not show any SPT reactivity. All the mutants preserved their T cell reactivity. CONCLUSION: Recombinant hypoallergenic variants of the rPar j 1 allergen described herein may represent a useful tool for improved immunotherapy.

Allergens↗
PubMed2000

Localization and association to cytoskeleton of COLL1alpha mRNA in Paracentrotus lividus egg requires cis- and trans-acting factors.

COLL1alpha mRNA is asymmetrically distributed in the Paracentrotus lividus egg. Here we examine the involvement of the cytoskeleton in the localization process of collagen mRNA. The use of drugs such as colchicine and cytochalasin B reveals a perturbation of localization collagen mRNA. Moreover, the presence of specific cis-and trans-acting factors involved in cytoskeleton binding and the localization process was investigated. By Northwestern experiment we found that the 3'UTR of COLL1alpha mRNA is also able to bind two proteins of 54 and 40 kDa in a cellular fraction containing the cytoskeleton. Finally, we found that the protein of 54 kDa is LP54, a protein that binds the 3'UTRs of P. lividus maternal bep messengers and is necessary for their localization.

3' Untranslated Regions↗
PubMed1998

Folding and binding activity of the 3'UTRs of Paracentrotus lividus bep messengers.

Bep mRNAs are localized at the animal pole of P. lividus eggs. In the present communication the secondary structures of the 3'UTRs of the bep1, bep3 and bep4 mRNAs are reported. The minimal lengths of these regions required to bind the 54-kDa protein, previously shown to be involved in localization and anchoring of these RNAs, is estimated. Microinjection of the bep3 3'UTR into egg shows that this RNA fragment is also able to become localized to one of the egg poles, as happens for the entire bep3 RNA.

Amino Acid Sequence↗
PubMed1997

A 54-kDa protein specifically associates the 3' untranslated region of three maternal mRNAs with the cytoskeleton of the animal part of the Paracertrotus lividus egg.

Bep mRNAs, i.e., maternal messengers coding for cell surface proteins, are localized in the animal part of Paracertrotus lividus egg and embryos. Here we have examined the involvement of the cytoskeleton in asymmetric distribution of bep3 mRNA. Moreover, in order to understand whether and how cis- and trans-acting factors are necessary for bep3 mRNA localization, we have looked for in vitro-specific interactions between egg proteins and bep3 mRNA. By northwestern assay we have identified a 54-kDa protein that binds to the 3'UTR of bep3 mRNA. This 54-kDa protein also permits association of 3'UTR of bep3 with cytoskeleton elements, indicating its involvement in the localization process. Binding of 54-kDa protein to 3'UTR of bep1 and bep4 has also been demonstrated, suggesting that a binding motif is shared with these other two mRNAs of the same gene family. Northwestern analyses carried out utilizing proteins extracted from different developmental stages indicate that the 54-kDa protein is the only protein able to bind to the 3'UTR of bep3.

Animals↗
PubMed1992

Characterization of bep1 and bep4 antigens involved in cell interactions during Paracentrotus lividus development.

We have identified and partially characterised two antigens, extracted with 3% butanol, from Paracentrotus lividus embryos dissociated at the blastula stage, and encoded by the cDNA clones previously described as bep1 and bep4 (bep-butanol extracted proteins). The cDNA fragments containing the specific central portions of bep1 and bep4 were expressed as MS2 polymerase fusion proteins in Escherichia coli. These two fusion proteins, called 1C1 (bep1) and 4A1 (bep4), were injected subcutaneously into rabbits and the corresponding polyclonal antibodies generated. Western blot analysis of proteins, extracted with 3% butanol, from sea urchin embryos at the blastula stage (b.e.p.), established that both antibodies recognize two 33 KDa proteins. Reducing and non-reducing electrophoretic conditions show that both antibodies against bep1 and bep4 related proteins react also with a protein band of a molecular weight 66 KDa, indicating that these two antigens probably exist as dimers. Immunolocalization with anti 1C1 and 4A1 antibodies shows the presence of the related antigens also on the cell surface. Fab fragments of the polyclonal antibodies against 1C1 and 4A1 inhibited reaggregation of sea urchin embryonic cells, dissociated from blastula stage embryos. This prevention of reaggregation indicates that these proteins probably play a role in cell interaction during sea urchin embryonic development.

Animals↗
PubMed1990

Analysis of the sequence and expression during sea urchin development of two members of a multigenic family, coding for butanol-extractable proteins.

Two cDNA clones related to Paracentrotus lividus butanol-extracted proteins, presumably belonging to cell surface proteins, were isolated by a lambda gt11 expression library of ovary poly A+ RNA. These clones, called bep1 and bep4, of 1,110 and 1,071 bp, respectively, belong to a multigene family. By sequencing analysis, a special structural organization in the coding region is detected. A single copy region is inserted between two regions different from each other but similar in the two clones, which constitute two perfectly preserved domains in the genome and are not always present together in the various members of this gene family. The bep1 and bep4 clones derive from two single genes that are polymorphic in the sea urchin genome. Expression of these clones was studied by Northern blot analysis. Both bep1 and bep4 are transcribed during oogenesis into mRNAs of 1.4 kb, which are stored in eggs and utilized during early embryogenesis. None of these RNAs is, in fact, detectable after the gastrula stage. Moreover, the transcripts of three other members of the family are present in eggs and at the 32 cell stage, but they are also synthesized in the early developmental stages.

Amino Acid Sequence↗