Adjuvanticity and toxicity of cobalt oxide nanoparticles as an alternative vaccine adjuvant.
OBJECTIVE
There are very few adjuvants licensed for use in human vaccination, and alum-based adjuvants are the most widely used. Alum adjuvants predominantly boost Th2 immune responses and there is a need for new adjuvants that also stimulate Th1 immunity. We recently reported that cobalt oxide nanoparticles (Co(3)O(4)NPs) stimulate Th1-type immune responses in vivo. Here, we exploited this property to examine whether Co(3)O(4)NP could act as an adjuvant using the model antigen ovalbumin.


METHODS
Female C57BL/6 mice were immunized subcutaneously twice with ovalbumin plus adjuvant (Co(3)O(4)NPs or Imject® Alum) followed by intraperitoneal stimulation with soluble ovalbumin.


RESULTS
Co(3)O(4)NPs induced a more balanced Th1- and Th2-type response, triggering higher specific Th1-dependent IgG2c production in addition to Th2-dependent IgG1 and less 'allergic' IgE production, and induced less inflammation at both the subcutaneous and intraperitoneal injection sites.


CONCLUSIONS
Co(3)O(4)NPs could be a very useful adjuvant where both Th1 and Th2 responses are needed to clear pathogens.
ELEGI/Colt Laboratory, Center for Inflammation Research, University of Edinburgh, Edinburgh, UK.
Wan-Seob
WS
Cho
Kenneth
K
Dart
Dominika J
DJ
Nowakowska
Xiaozhong
X
Zheng
Ken
K
Donaldson
Sarah E M
SE
Howie
D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000633:toxicity; D000818:Animals; D002460:Cell Line; D003035:Cobalt / Q000633:toxicity*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D053768:Metal Nanoparticles / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D010087:Oxides / Q000633:toxicity*
D000276:Adjuvants, Immunologic; D010087:Oxides; D003035:Cobalt; C060728:cobalt oxide