Person: Pastor Vargas, Carlos
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First Name
Carlos
Last Name
Pastor Vargas
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Bioquímica y Biología Molecular
Area
Bioquímica y Biología Molecular
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
Item An Odorant-Binding Protein as a New Allergen from Siberian Hamster (Phodopus sungorus)(Int Arch Allergy Immunol, 2011) Torres, J.A.; Pastor Vargas, Carlos; de las Heras, M.; Vivanco Martínez, Fernando; Cuesta, Javier; Sastre, J.A case of anaphylaxis following a bite from a Siberian hamster (SH; Phodopus sungorus) is described. Skin prick tests with hair, urine and salivary gland extracts from SH were positive, while the tests were negative for hair extracts from other rodents. IgE immunoblotting with the patient serum revealed 3 IgE-binding bands of about 18, 21 and 23 kDa. When the patient's serum was preincubated with rabbit, mouse and gerbil hair extracts, no inhibition of the 3 SH IgE-binding bands was demonstrated. Proteins extracted from the 3 bands were analyzed by N-terminal sequencing and matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry, and peptides were sequenced. IgE-binding bands were identified as being an odorant-binding protein belonging to the lipocalin family. Analysis of the 3 IgE-binding bands found in the hair, urine and salivary glands of SH showed a new allergenic protein lacking cross-reactivity with allergens from other rodents. The 3 bands likely correspond to isoforms of a single allergen.Item Anaphylaxis due to orange soft drinks(J Investig Allergol Clin Immunol, 2012) Navarro,, L A; Pastor Vargas, Carlos; Liñana, J J; Martinez, I; Sanz Maroto, Aroa; Vivanco Martínez, Fernando; Bartolome, BorjaItem Arginine Kinase from the Cellar Spider (Holocnemus pluchei): A New Asthma-Causing Allergen(Int Arch Allergy Immunol, 2010) Bobolea, Irina; Barranco, Pilar; Pastor Vargas, Carlos; Iraola, Victor; Vivanco Martínez, Fernando; Quirce, SantiagoBackground: We report a 31-year-old farmer whose work consists in handling cereal and vegetables, who consulted our clinic because of asthma symptoms after inhalation of dust during manipulation of the deposited material, usually inside the warehouse. Methods and results: Skin prick tests and specific immunoglobulin E (IgE) determinations were negative with common aeroallergens. The patient noted the presence of many spiders in the warehouse, which were identified as the cellar spider Holocnemus pluchei and the common house spider, Tegenaria domestica. Extracts of spider bodies brought in by the patient were obtained and used to perform in vivo and in vitro studies. Molecular characterization of IgE-binding bands was performed by mass spectrometry. We obtained positive prick tests to the extracts of the bodies of both spiders. Immunoblotting displayed different bands in both spider extracts, in a range of 20-70 kDa. All were hemocyanins, except for a 17-kDa protein of Holocnemus identified as an arginine kinase (AK). Bronchial challenge was positive with the extract of the cellar spider and with the AK, but was negative with the domestic house spider. Conclusion: We present the first case of respiratory allergy due to sensitization to AK from a common spider, confirmed by bronchial provocation tests.Item Identification of sole parvalbumin as a major allergen: study of cross‐reactivity between parvalbumins in a Spanish fish‐allergic population(Clin Exp Allergy, 2011) Perez‐Gordo, M.; Cuesta‐Herranz, J.; Maroto, A. S.; Cases, B.; Ibáñez, M. D.; Vivanco Martínez, Fernando; Pastor Vargas, CarlosBackground: Fish allergy is becoming an important health problem in Spain, a country with the third highest level of fish consumption after Japan and Portugal. The most common fish allergens are parvalbumins. In our area, the most widely consumed fish species are lean, such as whiff (Lepidorhombus whiffiagonis) and sole (Solea solea). Adverse reactions to fish are usually related to these species, a fact that is largely unknown to allergists in other countries. Objective: The aim of this study was to identify and purify the major allergen implicated in allergic response to sole and evaluate the IgE cross-reactivity of purified parvalbumins from whiff and sole, which are phylogenetically close, and more distant species (i.e. cod and salmon). Methods: Eighteen Spanish fish-allergic patients with a positive history of type I allergy to fish were recruited from the clinic. Total protein extracts and purified parvalbumins from whiff and sole were tested for their IgE-binding properties by combining two-dimensional Western blotting and mass spectrometry. The extent of cross-reactivity between these parvalbumins along with cod and salmon parvalbumins was investigated by IgE ELISA inhibition assay. Results: An IgE-binding spot of approximately 14 kDa was identified as parvalbumin and confirmed as a major allergen in sole extract, which is recognized by almost 70% of the patients. Whiff parvalbumin was recognized by 83.4% of the patients. High cross-reactivity was determined for all purified parvalbumins by IgE inhibition assay. Conclusions and clinical relevance: Sole and whiff parvalbumin were confirmed as major allergens. The parvalbumins of sole, whiff, cod and salmon were highly cross-reactive, thus suggesting a high amino acid sequence identity between them.Item The C(H)1 domain of IgG is not essential for C3 covalent binding: importance of the other constant domains as targets for C3.(International Immunology, 1998) Munoz, Esther; Vidarte, Luis; Casado, Maria Teresa; Pastor Vargas, Carlos; Vivanco Martínez, FernandoThe covalent binding of C3 to antigen-antibody complexes [immune complexes (IC)] plays a pivotal role in the elimination of antigens. C3 prevents the formation of large IC lattices promoting their solubilization. Subsequently, bound C3 fragments determine the efficacy of antigen presentation, and the generation of antibody responses and immunological memory. C3 binding to IgG-IC generates IgG-C3b-C3b complexes which are detected by SDS-PAGE as two major bands: C3alpha65-heavy chain and C3alpha65-C3alpha43 covalent complexes. Using human heat-aggregated IgG1 as a model of IC, a C3b binding site was localized only in the Cgamma1 domain. However, with true IC of ovalbumin and rabbit IgG anti-ovalbumin, C3b binds to both the Fab and Fc regions of IgG. To study the binding of C3b to the different domains of IgG and particularly to evaluate the involvement of the Cgamma1 domain, we have constructed recombinant single-chain antibodies without Cgamma1, which have the structure: V(H)-linker-V(L)-hinge-Cgamma2-Cgamma3 (scAb). The variable domains were from a mouse mAb anti-HSA and the constant region (hinge-C(H)2-C(H)3) from human IgG1 or rabbit IgG. C3 binds very efficiently to IC formed with human (h-scAb) or rabbit (r-scAb) recombinant antibodies (scAb-HSA) and generates also two bands on SDS-PAGE (C3alpha65-scAb and C3alpha65-C3alpha43), which are the counterparts of those of the complete antibody. In addition, IC formed with scAb activate the alternative pathway to a similar extent as IC of the entire IgG. These data indicate that the Cgamma1 domain is a dispensable region for C3b binding and that the remaining constant domains are as efficient as Cgamma1 in C3b binding. Overall these results support the view that C3 does not specifically recognize a unique site in the Cgamma1 domain. Rather it seems to be able to attach along the antibody molecule. Probably this implies an advantage for effective processing of C3b-IC and elimination of antigens in vivo.Item A small domain (6.5 kDa) of bacterial protein G inhibits C3 covalent binding to the Fc region of IgG immune complexes.(European Journal of Immunology, 1998) Muñoz, Esther; Vidarte, Luis; Pastor Vargas, Carlos; Casado, Maria Teresa; Vivanco Martínez, FernandoAttachment of the complement component C3 to antigen-antibody (Ag-Ab) complexes (immune complexes, IC) is the key molecular event responsible for the elimination of many Ag in the form of Ag-Ab-C3b. The CH1 domain and the Fc region of the Ab, which have previously been involved in the binding of C3b, are also the targets of several bacterial IgG-binding proteins, particularly proteins G and A. Here we describe the ability of a small recombinant protein G domain (B2; 6.5 kDa) to inhibit the covalent binding of C3b to the Fc portion of IgG without affecting the binding to the Fab part. Protein G (B2 domain) produced a remarkable inhibition of covalent binding of C3b to IC formed with rabbit IgG, but none with the F(ab')2 fragment, indicating that B2 interferes with the C3b binding to the Fc region. A weak inhibition was observed with IC formed with mouse IgG2b which preferentially binds B2 domain on the CH1 domain of the Fab. To confirm these data, recombinant single-chain Ab devoid of CH1 domains (scAb), and including the rabbit or human Fc portion (hinge-CH2-CH3), were produced and used to form IC. Protein G-B2 domain inhibited C3b binding to IC formed with scAb of either human or rabbit constant regions, supporting the view of a specific blockade of C3b binding to the Fc region. A similar inhibition of C3b binding was observed using protein A instead of protein G B2 domain and the same set of IC. On the CH1 domain, C3b and B2 bind on opposite faces, and therefore do not interfere with each other in their binding. However, B2 domain bound to the inter-CH2-CH3 region impedes the C3b binding to the Fc. This inhibition clarifies the specificity of C3b for the different regions of IgG and explains how bacterial IgG-binding proteins provide the bacteria with a mechanism of evasion from the opsonizing action of complement and contribute to the virulence. This could be a general mechanism of escape because protein G binds the majority of mammalian Ig.