title: Modulation of antifreeze activity and the effect upon post-thaw HepG2 cell viability after cryopreservation.
abstract: Most antifreeze proteins (AFPs) exhibit two types of "antifreeze activity" - thermal hysteresis (TH) and ice recrystallization inhibition (IRI) activity. The mechanism of TH activity has been studied in depth and is the result of an adsorption of AFPs to the surface of ice with an ice-binding face (IBF). In contrast, the mechanism of ice recrystallization and its inhibition is considerably less understood. In this paper, we examine several different antifreeze proteins, glycoproteins and mutants of the Lolium perenne AFP (LpAFP) to understand how IRI activity is modulated independently of TH activity. This study also examines the ability of the various AF(G)Ps to protect HepG2 cells from cryoinjury. Post-thaw cell viabilities are correlated to TH, IRI activity as well as dynamic ice shaping ability and single ice crystal growth progressions. While these results demonstrate that AF(G)Ps are ineffective as cryoprotectants, they emphasize how ice crystal habit and most importantly, ice growth progression affect HepG2 cell survival during cryopreservation.
authors.affiliation: Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Chantelle J
authors.initials: CJ
authors.lastname: Capicciotti
authors.affiliation: Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Poisson
authors.affiliation: Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Boddy
authors.affiliation: Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. Electronic address: rben@uottawa.ca.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Ben
mesh_terms: D000327:Adsorption; D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry*; D002470:Cell Survival / Q000502:physiology*; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000737:chemistry*; D003460:Crystallization; D029941:Fish Proteins / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D007053:Ice; D008129:Lolium / Q000737:chemistry; D011485:Protein Binding
chemical_list: D021301:Antifreeze Proteins; D003451:Cryoprotective Agents; D029941:Fish Proteins; D006023:Glycoproteins; D007053:Ice
keywords: Antifreeze protein; Biological antifreezes; Cryopreservation; Ice recrystallization inhibition; Thermal hysteresis