gms | German Medical Science

55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Intratumoural application of immunostimulatory oligonucleotides does not inhibit tumour growth

Intratumorale Applikation von immunstimulatorischen Oligonukleotiden führt zu keiner Inhibition des Tumorwachstums

Meeting Abstract

  • corresponding author Wolfgang Hamel - Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • C. Ginzkey - Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • J. Krause - Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • S. Brecht - Institut für Pharmakologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • J. Steinmann - Institut für Immunologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel
  • H. M. Mehdorn - Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocMO.12.08

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2004/04dgnc0123.shtml

Veröffentlicht: 23. April 2004

© 2004 Hamel et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

On the search for better adjuvants for immunotherapy of brain tumours we considered intratumoural application of oligodeoxynucleotides (ODN) containing immunostimulatory sequences (ISS) characterized by the CpG motif. We became aware of studies showing that mere intratumoural application of CpG-ODN resulted in prolonged survival of rats implanted with brain tumours. However, when used as an adjuvant in DNA vaccination studies these CpG-ODNs did not augment anti-tumour effects. Thus, the efficacy of intratumoural CpG-ODN administration was reassessed using the syngeneic 9L gliosarcoma model.

Methods

9L cells were implanted into the striatum of Fisher 344 rats. CpG- or mCpG-ODN (mutated in both CpG motifs), or saline were either admixed with tumour cells on the day of implantation or administered intratumourally on day 3 after tumour cell implantation. This day was chosen according to preliminary experiments and previous reports. Minocycline that is also known to inhibit tumour neovascularization was given i.p. to prevent microglia/macrophage activation in respective animals. After three weeks brains were removed and frozen in liquid nitrogen following splenectomy. Tumour size was determined and immunohistochemical studies were performed.

Results

Intratumoural injection of mCpG-ODN on day 3 resulted in tumours (1392 mm3 ±624,15; mean ±standard deviation) similar in size to saline treated animals (1255 mm3 ±423,05). CpG-ODN admixed with tumour cells on the day of implantation or injected intratumourally on day 3 resulted in larger tumours (2790 mm3 ±1122,72 and 2300 mm3 ±1575,32). This occurred despite the fact that CpG-ODN but not mCpG-ODN exerted some growth inhibitory effect on 9L cells in vitro which had not been observed by other investigators. In saline treated animals minocycline led to the formation of larger tumours (1936 mm3 ±427,86), and minocycline did not have an effect on tumour size in CpG-treated animals (2248 mm3 ±180,69). Cytotoxic T cells generated from restimulated spleen preparations (CTL assay) revealed strong cytotoxic effects in all groups with specific lysis of up 90% of target cells (9L) whereas another syngeneic cell line (MADB 106) was not lysed. Whereas IFN-g production as determined by the ELISPOT assay was increased in some but not all animals treated with CpG- or mCpG-ODN, IFN-g was suppressed in CpG-ODN and saline-treated animals having also received minocycline. Integrity of CpG- and mCpG-ODN was proven by bilateral intracerebral injection without tumour. After 5 and 8 days strong upregulation of ED-1 and MHC II on microglial and macrophage cells was observed in CpG- but not in mCpG-treated animals, although no T-cell infiltrates were found (TCR-, CD4-, CD8-, CD25-). In all tumour-bearing animals strong T-cell and microglial/macrophage infiltrates were observed irrespective of the adjuvant treatment.

Conclusions

In the syngeneic model tested immunostimulatory ODN did not elicit anti-tumour effects but resulted in larger tumours. This is inconsistent with other studies and may be related to the animal model under investigation. Such differences may hint towards relevant mechanisms involved in immunological tumour rejection.