Molecular and functional characterization of porcine Siglec-3/CD33 and analysis of its expression in blood and tissues

Dev Comp Immunol. 2015 Aug;51(2):238-50. doi: 10.1016/j.dci.2015.04.002. Epub 2015 Apr 16.

Abstract

A cDNA clone encoding a 380 a-a type 1 transmembrane protein with homology to human Siglec-3/CD33 was obtained from a swine small intestine library. An analysis of protein sequence identified two immunoglobulin-like domains, a transmembrane region, and a carboxi-terminal tail with two tyrosine-based signalling motifs. Binding assays of Siglec-3 transfected CHO cells to polyacrylamide glycoconjugates showed a preference for α2-6-linked sialic acids. Using mAbs raised against a fragment containing the two Ig-like domains, porcine Siglec-3 was found to be expressed on monocytes and granulocytes, and their bone marrow precursors. It was also detected in lymph node, splenic and alveolar macrophages. MAbs immunoprecipitated, from granulocyte lysates, a protein of 51-60 kDa under both non-reducing and reducing conditions. MAbs were also used to analyse functional activity of Siglec-3 on bone marrow and blood cells. Engagement of Siglec-3 by mAb had no apparent effect on cell proliferation or cytokine production.

Keywords: CD33; Monoclonal antibody; Monocyte; Myeloid cells; Siglec-3; Swine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / metabolism
  • Blood Cells / immunology*
  • CHO Cells
  • Cricetulus
  • Gene Expression Profiling
  • Humans
  • Intestine, Small / physiology*
  • Myeloid Cells / immunology*
  • N-Acetylneuraminic Acid / metabolism
  • Protein Binding
  • Sequence Homology, Amino Acid
  • Sialic Acid Binding Ig-like Lectin 3 / genetics
  • Sialic Acid Binding Ig-like Lectin 3 / immunology
  • Sialic Acid Binding Ig-like Lectin 3 / metabolism*
  • Swine / immunology*
  • Transgenes / genetics

Substances

  • Antibodies, Monoclonal
  • Sialic Acid Binding Ig-like Lectin 3
  • N-Acetylneuraminic Acid