Biomedical subjects

V del Pozo

Publications and source records attributed to V del Pozo.

23 records · Page 2Linked to original sources

PubMed1994

Ole e I: epitope mapping, cross-reactivity with other Oleaceae pollens and ultrastructural localization.

Ole e I is the major allergen derived from olive tree pollen (Olea europaea) and it is composed of two polypeptides with molecular weights (MWs) of 18 and 20 kD. A panel of six monoclonal antibodies (mAbs) has been prepared and used to map antigenic determinants on this molecule. Four epitope determinants have been identified on Ole e I. Using the purified mAbs produced against Ole e I, we have analyzed the common epitope determinants in olive (O. europaea) and different Oleaceae pollens: ash (Fraxinus excelsior); privet (Ligustrum vulgare); lilac (Syringa vulgaris), and forsythia (Forsythia suspensa). ELISA showed three reactivity groups depending on the recognition of monoclonal antibodies: (1) olive and ash; (2) olive, ash, privet and lilac; and (3) olive, ash, privet, lilac and forsythia. Immunoblotting studies on Oleaceae pollen extracts with these mAbs showed a very similar cross-reactivity pattern. The 18- and 20-kD MW proteins were present in each pollen, except in the case of forsythia. In this case the reactivity pattern was associated with 50- to 55-kD protein bands. This band was recognized by a pool of sera from olive-allergic patients. Finally, ultrastructural localization of Ole e I antigen was performed on the mature olive pollen grain. Ole e I was located in association with dilated endoplasmic reticulum cisternae. Pollen grain walls, nuclei and cytoplasmic organelles were totally devoid of the allergen.

Allergens↗

PubMed1994

Modulation of the Fc gamma RII and Fc gamma RIII induced by GM-CSF, IFN-gamma and IL-4 on murine eosinophils.

Murine eosinophils express the low-affinity Fc gamma receptors recognized by the monoclonal antibody (mAb) 2.4G2, which are involved in the activation of these cells. We have studied the membrane and RNA expression of the low-affinity Fc gamma receptors on murine eosinophils stimulated by granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), and interleukin-4 (IL-4). Flow cytometric analysis (FACS) of eosinophils incubated with GM-CSF and IFN-gamma showed an up-regulation on the expression of these receptors with a maximal effect at 24 hr. IL-4 failed to induce any positive or negative effect in these cells. To assess the pattern of expression of the low-affinity Fc gamma receptors on eosinophils, Northern blot analyses were carried out using specific cDNA probes encoding for the Fc gamma RII and Fc gamma RIII. Murine eosinophils constitutively express transcripts for Fc gamma RII and RIII. Incubation with GM-CSF from 3 to 12 hr produced a potent induction of the two transcripts studied (Fc gamma RII and RIII). IFN-gamma did not induce any important up-regulation of the two transcripts from 3 to 12 hr of incubation. By contrast, IL-4 produced a marked inhibition of both transcripts at 24 hr of incubation. Expression of the gamma-chain transcript which is associated with Fc gamma RIII has been detected on freshly isolated eosinophils. This study demonstrates a different regulation pattern of these receptors depending on the cytokine or growth factor used to stimulate murine eosinophils.

Animals↗

PubMed1993

DR7 and DQ2 are positively associated with immunoglobulin-E response to the main antigen of olive pollen (Ole e I) in allergic patients.

We have studied the relationship between HLA class II haplotypes and alleles, and the IgE antibody response to a highly purified allergen, Ole e I, in allergic patients. Ole e I, is the major antigen from the pollen of olive tree that grows mainly in the Mediterranean. Genomic DNA typing was performed in 40 unrelated patients with seasonal allergic pollenosis who had specific IgE antibodies against Ole e I, detected by double-antibody radioimmunoassay. HLA-DRB and -DQB loci were analyzed by PCR-SSO and RFLP. Phenotypic frequencies were compared with those of 179 healthy unrelated individuals. Significant increases in the phenotypic frequencies of DR7 (pf = 67.5% vs 31.3% in the control population, pc = 0.0023) and DQ2 (pf = 90.0% vs 48.0%, pc = 0.0003) were found, indicating an association between DRB1*0701/2, DQB1*0201 alleles and the IgE antibody response to Ole e I. This is the first time that the HLA-DQ gene has been associated with a positive allergic response.

Allergens↗

PubMed1990

Members of the alpha-amylase inhibitors family from wheat endosperm are major allergens associated with baker's asthma.

We have identified the major antigens or IgE binding components from wheat flour. Thirty-five sera from patients with baker's asthma were used to analyze the reaction with wheat salt-soluble proteins. We found a 15 kDa SDS-PAGE band which reacted with all sera tested. Purified members of the alpha-amylase inhibitor family, which are the main components of the 15 kDa band, were recognized by specific IgE when tested with a pool of reactive sera. Immunodetection after two-dimensional electrophoretic fractionation of crude inhibitor preparations from wheat endosperms also detected several inhibitor subunits as major low-molecular-weight allergens.

Allergens↗

PubMed1990

Release of O2- and LTC4 by murine eosinophils: role of intra- and extracellular calcium.

Using an experimental model of mouse peritoneal eosinophilia, we investigated the role of Ca2+ in the in vitro activation of these cells challenged with specific Mesocestoides corti antigen. We have detected LTC4, a metabolite derived from arachidonic acid by way of 5'lipo-oxygenase and superoxide anion from the oxidative burst, as inflammatory mediators produced by activated eosinophils. Preincubation with hyperimmune mice serum increases the amount of LTC4 and superoxide anion in response to the antigenic extract. Release of O2- is inhibited by Verapamil (a voltage-gated calcium channel) and Quin 2 (an intracellular trapped chelator of calcium). Also, LTC4 produced by preincubated eosinophils challenged with M. corti is dramatically inhibited by Quin 2. Our results suggest an intact mechanism for calcium control for the release of these inflammatory mediators by eosinophils, after specific antigenic stimulation.

Animals↗