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Elving, Josefine, 2006. Immunostimulatory DNA : studies on the importance of secondary structure formation and CpG-motifs for IFN-alpha induction/inhibition using ODNs related to the genome of porcine circovirus type 2. SLU, Dept. of Molecular Biosciences, Uppsala. Uppsala: SLU, Dept. of Molecular Biosciences

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Abstract

Nucleotide sequences containing CpG-motifs are recognized as immunomodulators in pigs among other species. Phosphodiester oligodeoxynucleotides (ODNs), such as ODN H, have been demonstrated to be potent inducers of interferon-alpha (INF-alpha) in porcine blood mononuclear cells (poPBMC) provided they are pre-treated with Lipofectin®. In the present study the IFN-alpha inducing activity of ODN H was demonstrated to be altered after addition of poly-G sequences at the 5' and/or 3' end and by increasing the number of nucleotides (nt) in the base-pairing sequence of the ODN. Alterations that facilitated the formation of secondary structures reduced the need for pre-treatment with Lipofectin®. Furthermore, deliberate destruction of secondary structures by heat-treatment of ODN 2216 reduced the IFN-alpha inducing capacity of that ODN. Thus, results suggest that the stimulatory activity of the ODNs is dependent on secondary structure formation. Other ODNs are recognized as potent inhibitors of the INF-alpha production in poPBMC. The ODN PCV2/1 corresponding to a 20 nt long sequence from the genome of PCV2, has been identified as such an inhibitory ODN. Further, it was demonstrated that the inhibitory capacity of ODN PCV2/1 not depend on the presence of a central CpG-motif. Further, results from the in vitro studies show a significant difference between ODN PCV2/1 found in the genome of PCV2 from healthy pigs in Sweden and ODN PCV2/1S1, which predominates in pigs from farms with PMWS in Sweden. However, the biological significance of these findings remain to be elucidated.

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Nukleotidsekvenser i mikrobiellt DNA som innehåller CpG-motiv kan
fungera som immumodulatorer hos bl.a. gris. För att efterlikna detta in
vitro kan man använda sig av oligodeoxynukleotider (ODN). Vissa
fosfodiester ODN, såsom ODN H, har visat sig kunna aktivera vita
blodkroppar så att de producerar interferon-alfa (IFN-a) förutsatt att
oligodeoxynukleotiderna förbehandlats med Lipofektin®. Denna studie
visar att den IFN-a inducerande förmågan hos ODN H kan förändras
genom tillsats av poly-G sekvenser till 5’ och/eller 3’ änden samt
genom en ökning av antalet nukleotider i den basparande sträckan. För
att undersöka hur den stimulatoriska aktiviteten påverkas av
denaturering utfördes studier på ODN 2216, som har förmågan att
baspara med sig själv. Resultaten visade på en minskning av den IFN-a
inducerande aktiviteten efter denaturering vilket tyder på att den
stimulatoriska aktiviteten hos en ODN är beroende av formation av
sekundärstrukturer. Andra ODN har visat sig kunna inhiberar IFN-a
produktionen från vita blodkroppar, till dessa hör ODN PCV2/1 som
motsvarar en 20 nt lång sekvens som återfinns i genomet hos porcint
circovirus typ 2 (PCV2) hos friska grisar i Sverige. In vitro studien
visar att det centrala CpG-motivet inte är nödvändigt för den
inhiberande förmågan hos ODN PCV2/1. Studien visar dock på en
signifikant skillnad mellan den IFN-a inhiberande kapaciten hos ODN
PCV2/1 och ODN PCV2/1S1, som dominerar bland grisar från svenska
besättningar med PMWS och saknar det centrala CpG-motivet. Det
kvarstår dock att klarlägga den bilogiska relevansen av dessa fynd.

Main title:Immunostimulatory DNA
Subtitle:studies on the importance of secondary structure formation and CpG-motifs for IFN-alpha induction/inhibition using ODNs related to the genome of porcine circovirus type 2
Authors:Elving, Josefine
Supervisor:Fossum, Caroline
Examiner:UNSPECIFIED
Series:UNSPECIFIED
Volume/Sequential designation:-
Year of Publication:2006
Level and depth descriptor:Other
Student's programme affiliation:BTEMP Biotechnology Programme 240 HEC
Department:(VH) > Dept. of Molecular Biosciences
Keywords:interferon, porcine circovirus, PCV-2, CpG, secondary structure, inhibitory, PCR, ODN
URN:NBN:urn:nbn:se:slu:epsilon-s-7320
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-7320
Subjects:SLU > (VH) > Dept. of Molecular Biosciences
Language:English
Deposited On:02 Oct 2017 07:27
Metadata Last Modified:02 Oct 2017 07:27

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