Pablo Hernán Sotelo

University of Santiago, Chile, CiudadSantiago, Santiago Metropolitan, Chile

Are you Pablo Hernán Sotelo?

Claim your profile

Publications (5)16.78 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Gastric cancer (GC) is the third most common cause of cancer death worldwide. Natural killer cells play an important role in the immune defense against transformed cells. They express the activating receptor NKG2D, whose ligands belong to the MIC and ULBP/RAET family. Although it is well established that these ligands are generally expressed in tumors, the association between their expression in the tumor and gastric mucosa and clinical parameters and prognosis of GC remains to be addressed. In the present study, MICA and MICB expression was analyzed, by flow cytometry, in 23 and 20 pairs of gastric tumor and adjacent non-neoplasic gastric mucosa, respectively. Additionally, ligands expression in 13 tumors and 7 gastric mucosa samples from GC patients were evaluated by immunohistochemistry. The mRNA levels of MICA in 9 pairs of tumor and mucosa were determined by quantitative PCR. Data were associated with the clinicopathological characteristics and the patient outcome. MICA expression was observed in 57% of tumors (13/23) and 44% of mucosal samples (10/23), while MICB was detected in 50% of tumors (10/20) and 45% of mucosal tissues (9/20). At the protein level, ligand expression was significantly higher in the tumor than in the gastric mucosa. MICA mRNA levels were also increased in the tumor as compared to the mucosa. However, clinicopathological analysis indicated that, in patients with tumors >5 cm, the expression of MICA and MICB in the tumor did not differ from that of the mucosa, and tumors >5 cm showed significantly higher MICA and MICB expression than tumors ≤5 cm. Patients presenting tumors >5 cm that expressed MICA and MICB had substantially shorter survival than those with large tumors that did not express these ligands. Our results suggest that locally sustained expression of MICA and MICB in the tumor may contribute to the malignant progression of GC and that expression of these ligands predicts an unfavorable prognosis in GC patients presenting large tumors.
    No preview · Article · Dec 2015 · Oncology Reports
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new paradigm has emerged relating the pathogenesis of rheumatoid arthritis (RA), focused on the balance between T helper type 17 cells and regulatory T cells (T(regs) ). In humans, both subpopulations depend on transforming growth factor (TGF)-β for their induction, but in the presence of inflammatory cytokines, such as interleukin (IL)-6, the generation of Th17 is favoured. Tocilizumab is a therapeutic antibody targeting the IL-6 receptor (IL-6R), which has demonstrated encouraging results in RA. The aim of this study was to evaluate the effect of tocilizumab on Th1 cells, Th17 cells, IL-17 and interferon (IFN)-γ double secretors Th17/Th1 cells, and T(regs) in RA patients. Eight RA patients received tocilizumab monthly for 24 weeks and blood samples were obtained every 8 weeks to study T cell populations by flow cytometry. The frequency of Th17 cells, Th1 cells and Th17/Th1 cells was evaluated in peripheral blood mononuclear cells (PBMCs) activated in vitro with a polyclonal stimulus. T(regs) were identified by their expression of forkhead box protein 3 (FoxP3) and CD25 by direct staining of PBMCs. Although no changes were detected in the frequency of Th1 or Th17 cells, the percentages of peripheral T(regs) increased after therapy. In addition, the infrequent Th17/Th1 subpopulation showed a significant increment in tocilizumab-treated patients. In conclusion, tocilizumab was able to skew the balance between Th17 cells and T(regs) towards a more protective status, which may contribute to the clinical improvement observed in RA patients.
    Full-text · Article · Mar 2013 · Clinical & Experimental Immunology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Phage display library technology is a common method to produce human antibodies. In this technique, the immunoglobulin variable regions are displayed in a bacteriophage in a way that each filamentous virus displays the product of a single antibody gene on its surface. From the collection of different phages, it is possible to isolate the virus that recognizes specific targets. The most common form in which to display antibody variable regions in the phage is the single chain variable fragment format (scFv), which requires assembly of the heavy and light immunoglobulin variable regions in a single gene. In this work, we describe a simple and efficient method for the assembly of immunoglobulin heavy and light chain variable regions in a scFv format. This procedure involves a two-step reaction: (1) DNA amplification to produce the single strand form of the heavy or light chain gene required for the fusion; and (2) mixture of both single strand products followed by an assembly reaction to construct a complete scFv gene. Using this method, we produced 6-fold more scFv encoding DNA than the commonly used splicing by overlap extension PCR (SOE-PCR) approach. The scFv gene produced by this method also proved to be efficient in generating a diverse scFv phage display library. From this scFv library, we obtained phages that bound several non-related antigens, including recombinant proteins and rotavirus particles.
    Full-text · Article · Jul 2012 · mAbs

  • No preview · Article · Jan 2012 · mAbs
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Genomic replication and partial assembly of Rotavirus takes place in cytoplasmic viral structures called viroplasms. NSP5 is a viral phosphoprotein localized in viroplasms and its expression is imperative for viral cycle progress. During infection three isoforms of NSP5 can be observed by SDS-PAGE (26, 28 and 33-35kDa) and previous reports suggested that they differ in their phosphorylation patterns. In this study we obtained NSP5 from infected cells and by mass spectrometry we were able to identify nine phosphorylation sites. We detected that in all the isoforms the same residues can be found either phosphorylated or unmodified. Quantitative analysis showed that the 28kDa isoform has a higher phosphorylation level than the 26kDa isoform suggesting that migration properties depend on the total number of phosphorylated residues. Moreover, we identified two not previously described modifications for this protein: an N-acetylation in Serine-2 and an intramolecular disulfide bond in a highly conserved motif, CXXC which is located between two charged alpha-helix motifs.
    Full-text · Article · Apr 2010 · Virus Research