Isabel Cortegano

A population of c-Kitlow(CD45/TER119)– hepatic cell progenitors of 11-day postcoitus mouse embryo liver reconstitutes cell-depleted liver organoids

Embryo liver morphogenesis takes place after gastrulation and starts with a ventral foregut evagination that reacts to factor signaling from both cardiac mesoderm and septum transversum mesenchyme. Current knowledge of the progenitor stem cell populations involved in this early embryo liver development is scarce. We describe here a population of 11-day postcoitus c-Kit(low)(CD45/TER119)- liver progenitors that selectively expressed hepatospecific genes and proteins in vivo, was self-maintained in vitro by long-term proliferation, and simultaneously differentiated into functional hepatocytes and bile duct cells. Purified c-Kit(low)(CD45/TER119)- liver cells cocultured with cell-depleted fetal liver fragments engrafted and repopulated the hepatic cell compartments of the latter organoids, suggesting that they may include the embryonic stem cells responsible for liver development.

Immunopathogenesis of human gastrointestinal infection by Anisakis simplex

BACKGROUND Anisakis simplex is a parasite of fish, and in the case of human infestation, it should be considered as a possible cause of gastrointestinal disease, especially in countries where raw or undercooked fish is a frequent food. Clinical features of anisakiasis may simulate acute abdominal pain, such as that found in patients with gastric ulcers, appendicitis, and Crohns disease. Furthermore, many cases of anisakiasis are diagnosed as eosinophilic gastroenteritis, which is a broad term for a specific disease. OBJECTIVE The purpose of this study was to investigate the immunopathogenesis of human gastrointestinal infestation by A simplex. METHODS Thirteen intestinal biopsy specimens from patients with anisakiasis were analyzed for the presence of messenger (m)RNA for different cytokines and inflammatory mediators by RT-PCR. Specific IgE, eosinophil cationic protein, eosinophil protein X, and tryptase levels were measured in each patients serum. Also, cell cultures were set up with lymphocytes from some patients and stimulated in vitro with Anisakis and Ascaris antigens. RESULTS We performed immunologic phenotyping in 13 patients. All patients underwent biopsy after emergency surgery caused by episodes of acute abdominal pain. In all cases inflammatory infiltrate composed of eosinophils and lymphocytes was found in the intestinal wall. We demonstrated that after infestation, a T(H2)-type immune response occurred. Also, major basic protein, nitric oxide, and eotaxin were found in the tissue, and eosinophil cationic protein and eosinophil protein X levels were elevated in sera. CONCLUSION These data and in vitro lymphocyte cultures indicate that a T(H2) mechanism plays an important role in the inflammatory infiltrate produced by the anchorage of parasites in the gastrointestinal wall.

Molecular cloning and characterization of an IgE-reactive protein from Anisakis simplex: Ani s 1.

Ingestion of the parasitic nematode Anisakis simplex in undercooked fish can cause severe allergic reactions in some individuals. Using pooled human sera from sensitized patients we have probed an expression library for A. simplex antigens. One positive clone was found to encode a full length 21 kDa protein with strong homology to nematode troponins. The recombinant protein was expressed as a GST-fusion protein and found by immunoblot analysis to react with sera from 20% of allergic patients. The presence of functional EF-hand Ca(2+) binding motifs was demonstrated by gel-shift analysis.

A Role for DNA Polymerase μ in the Emerging DJH Rearrangements of the Postgastrulation Mouse Embryo

ABSTRACT The molecular complexes involved in the nonhomologous end-joining process that resolves recombination-activating gene (RAG)-induced double-strand breaks and results in V(D)J gene rearrangements vary during mammalian ontogeny. In the mouse, the first immunoglobulin gene rearrangements emerge during midgestation periods, but their repertoires have not been analyzed in detail. We decided to study the postgastrulation DJH joints and compare them with those present in later life. The embryo DJH joints differed from those observed in perinatal life by the presence of short stretches of nontemplated (N) nucleotides. Whereas most adult N nucleotides are introduced by terminal deoxynucleotidyl transferase (TdT), the embryo N nucleotides were due to the activity of the homologous DNA polymerase μ (Polμ), which was widely expressed in the early ontogeny, as shown by analysis of Polμ−/− embryos. Based on its DNA-dependent polymerization ability, which TdT lacks, Polμ also filled in small sequence gaps at the coding ends and contributed to the ligation of highly processed ends, frequently found in the embryo, by pairing to internal microhomology sites. These findings show that Polμ participates in the repair of early-embryo, RAG-induced double-strand breaks and subsequently may contribute to preserve the genomic stability and cellular homeostasis of lymphohematopoietic precursors during development.

Genetic restrictions in olive pollen allergy

BACKGROUND The major antigen of olive tree pollen, Ole e 1, produces an IgE response restricted by DQ2. OBJECTIVE Our purpose was to further analyze the genetic restrictions associated with IgE and IgG antibodies against Ole e 1 and IgE against the recently described antigen Ole e 3. METHODS Twenty-two nuclear olive pollen-allergic families (n = 88) were selected. DRB1 and DQB1, TCR-Valpha 8.1, the high-affinity receptor of IgE (FcepsilonRI-beta) Rsa I exon 7 and intron 2 and TNF-beta (LTalpha-Nco I) polymorphisms were determined by PCR and analyzed for association with allergic traits by the multiallelic transmission disequilibrium test. RESULTS Significant associations were found among HLA-DQB1*0201 (n = 29) and high levels of IgG (P =.023) and IgE (P =.0136) antibodies to Ole e 1 and with IgE specific to Ole e 3 (P =.0368). DRB1*0701 was associated with high levels of total serum IgE (P =.04) and IgG against Ole e 1 (P =.025). The FcepsilonRI-beta Rsa I exon 7, allele 1 (n = 39), was associated with high levels of total serum IgE (P =. 01), IgE antibodies against Olea europaea extract (P =.004), and specific antibodies to Ole e 1, IgG (P =.04), and IgE (P =.006). The FcepsilonRI-beta Rsa I intron 2, allele 2 (n = 33), was associated with IgE antibodies to O europaea extract (P =.003) and specific antibodies to Ole e 1, IgG (P =.025), and IgE (P =.05). CONCLUSIONS We found a new association between IgE antibody response to Ole e 3 and DQB1*0201 and verified the previously reported association between Ole e 1-specific response and DQB1*0201. Also, the association between FcepsilonRI-beta and IgE antibodies against Ole e 1 was demonstrated.

Allergy to dermatophagoides in a group of Spanish gypsies: genetic restrictions.

Background: Spanish gypsies have traditionally lived as nomads, a reason why few epidemiological studies were done in this ethnic group. However, the high prevalence of asthmatic diseases demonstrated in a population residing in the North of Spain induces us to analyse whether it was due to the influence of genetic loci previously implicated in other population studies as causing the disorders. Methods: DRB1* and DQB1* HLA class II, TCR-Vα8.1, FcΕRI-β Rsa I exon 7 and intron 2, TNF-β (LTα-Nco I) and CD14, were tested for association with asthma and atopy by multiple regression analysis, in 5 families comprising 87 individuals. Results: Significant associations were found with DQB1*02 (p = 0.02) and DQB1*0301 (p = 0.008) and elevated levels of total serum IgE. A negative association (p = 0.02) was found between total serum IgE and DRB1*14. FcΕRI-β Rsa I-In2 allele 1 was associated with high levels of total serum IgE (p = 0.04). Levels of Der p 1 IgE antibodies were negatively associated with DRB1*11-DQB1*0301 (p = 0.007), and positively with TCR Vα-8 allele 1 (p = 0.04) and with FcΕRI-β Rsa I-In2 allele 1 (p = 0.009). Conclusions: Our results do not show any association between asthma and the genetic loci studied although they do suggest the existence of multiple genetic influences on the allergic response in these families.

A Population of CD19highCD45R−/lowCD21low B Lymphocytes Poised for Spontaneous Secretion of IgG and IgA Antibodies

Ab responses to selected Ags are produced by discrete B cell populations whose presence and functional relevance vary along the ontogeny. The earliest B lineage-restricted precursors in gestational day 11 mouse embryos display the CD19+CD45R/B220− phenotype. Phenotypically identical cells persist throughout gestation and in postnatal life, in parallel to the later-arising, CD19+CD45R+ B cells. Very early after birth, the CD19+CD45R− B cell subset included high frequencies of spontaneously Ig-secreting cells. In the adult spleen, a small subset of CD19highCD45R−/lowIgM+/−IgD−CD21/Cr2−/low cells, which was detected in perifollicular areas, displayed genetic and phenotypical traits of highly differentiated B cells, and was enriched in IgG- and IgA-secreting plasma cells. In vitro differentiation and in vivo adoptive transfer experiments of multipotent hemopoietic progenitors revealed that these CD19highCD45R−/low B cells were preferentially regenerated by embryo-, but not by adult bone marrow-, derived progenitors, except when the latter were inoculated into newborn mice. Both the early ontogenical emergence and the natural production of serum Igs, are shared features of this CD19highCD45R−/low B cell population with innate-like B lymphocytes such as B1 and marginal zone B cells, and suggest that the new population might be related to that category.

Study of apoptosis in human lymphocytes by toxic substances implicated in toxic oil syndrome.

Toxic Oil Syndrome is a multisystemic disease that occurred in epidemic proportions in Spain in 1981 caused by the ingestion of rapeseed oil denatured with aniline. Several data implicate T cells in the pathogenesis of the disease. We evaluated the mechanisms of cytotoxicity in human lymphocytes of TOS-related products: aniline, 3-(N-phenylamino)-1,2-propanediol and its mono- and di-oleyl esters and eosinophilia myalgia-related product such as 3-(phenylamino)-L-alanine, which is chemically similar to 3-(N-phenylamino)-1,2-propanediol, and has been found in manufactured L-tryptophan. Our results show that only di-oleyl ester of 3-(N-phenylamino)-1,2-propanediol induces apoptosis in human lymphocytes, in a concentration and time-dependent way, confirmed by morphology, expression of phosphatidylserine in membrane and analysis of DNA degradation.

Immunological Aspects of the Toxic Oil Syndrome

The Toxic Oil Syndrome (TOS), which occurred in Spain in 1981, was caused by the ingestion of rapeseed oil denatured with 2% aniline, sold illegally as edible oil. The number of unaffected individuals exposed to the toxic oil is unknown, but more than 20,000 people suffered from the disease.

Altered marginal zone and innate-like B cells in aged senescence-accelerated SAMP8 mice with defective IgG1 responses

Aging has a strong impact on the activity of the immune system, enhancing susceptibility to pathogens and provoking a predominant pre-inflammatory status, whereas dampening responses to vaccines in humans and mice. Here, we demonstrate a loss of marginal zone B lymphocytes (MZ, CD19+CD45R+CD21++CD23lo) and a decrease of naive B cells (CD19+IgD+), whereas there is an enhancement of a CD19+CD45Rlo innate-like B cell population (B1REL) and the so-called aged B cell compartment (ABC, CD45R+CD21loCD23loCD5−CD11b−) in aged senescence-accelerated (SAMP8) mice but not in aged senescence-resistant (SAMR1) mice. These changes in aged SAMP8 mice were associated with lower IgG isotype levels, displaying low variable gene usage repertoires of the immunoglobulin heavy chain (VH) diversity, with a diminution on IgG1-memory B cells (CD11b−Gr1−CD138−IgM−IgD−CD19+CD38+IgG1+), an increase in T follicular helper (TFH, CD4+CXCR5+PD1+) cell numbers, and an altered MOMA-1 (metallophilic macrophages) band in primary follicles. LPS-mediated IgG1 responses were impaired in the B1REL and ABC cell compartments, both in vitro and in vivo. These data demonstrate the prominent changes to different B cell populations and in structural follicle organization that occur upon aging in SAMP8 mice. These novel results raise new questions regarding the importance of the cellular distribution in the B cell layers, and their effector functions needed to mount a coordinated and effective humoral response.