title: Effect of one year of cryopreservation on the activity of lysosomal hydrolases from EBV-transformed lymphocytes.
abstract: BACKGROUND
  The Epstein-Barr virus (EBV) was used as an agent of B lymphocyte proliferation for subsequent diagnosis of lysosomal storage disease. Due to the constant handling of long-preserved samples in our cell bank, we decided to observe the behavior and then compare cultured and frozen samples for at least one year's cryopreservation.
  
  
  METHODS
  Twenty-five samples from healthy individuals were used to assess the possible changes in activity of enzymes β-galactosidase, β-glucosidase, α-iduronidase, α-galactosidase, and α-glucosidase. Transmission electron microscopy was used to confirm cell transformation of B lymphocytes into EBV-infected cells, generating lymphoblastoid cell lines.
  
  
  RESULTS
  Transmission electron microscopy findings confirmed previous reports in the literature that is, significant and evident morphological changes in the nucleus occur after day 12 and the consequent cell transformation into EBV-infected cells. After thawing and subsequent treatment with the five enzymes utilized, we observed no significant changes in samples cryopreserved for more than one year, as compared to samples cultured for 12 days.
authors.affiliation: Postgraduate Program in Biological Sciences and Biochemistry, Department of Biochemistry, Federal University of Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil. melloas@gmail.com
authors.forename: A S
authors.initials: AS
authors.lastname: de Mello
authors.forename: F B
authors.initials: FB
authors.lastname: Mendes
authors.forename: K
authors.initials: K
authors.lastname: Michelin-Tireli
authors.forename: M V
authors.initials: MV
authors.lastname: Camelier
authors.forename: J C
authors.initials: JC
authors.lastname: Coelho
mesh_terms: D001402:B-Lymphocytes / Q000201:enzymology* / Q000378:metabolism / Q000821:virology*; D002460:Cell Line; D002472:Cell Transformation, Viral; D015925:Cryopreservation; D004854:Herpesvirus 4, Human / Q000378:metabolism; D006801:Humans; D006867:Hydrolases / Q000378:metabolism*; D007068:Iduronidase / Q000378:metabolism; D008213:Lymphocyte Activation; D008247:Lysosomes / Q000201:enzymology*; D000519:alpha-Galactosidase / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D006867:Hydrolases; D000520:alpha-Glucosidases; D001617:beta-Glucosidase; D000519:alpha-Galactosidase; D001616:beta-Galactosidase; D007068:Iduronidase