UBC Theses and Dissertations
The role of cholera toxin and tape stripping in epicutaneous immunization Kahlon, Roopjeet
In this study I have characterized the role of cholera toxin (CT) and tape stripping (TS) in eliciting and enhancing cellular immune responses generated by the epicutaneous application of peptide. In addition, the role of TLR4 signaling in the induction of skin elicited cellular and humoral immune responses was investigated. The CD4 T cell response to antigen was studied using a TCR transgenic mouse that has rearranged TCRα and TCRβ genes allowing it to express a T cell receptor specific for Ova323-339 in complex with I-A[sup d] MHC class II molecules. To characterize the CD8 T cell response, naive C57BL/6 mice were immunized with an MHC class I restricted epitope of ovalbumin, namely SIINFEKL (Ova254-267), and the resultant peptide specific CTLs were enumerated using multimeric Class I MHC-peptide complexes. The function of the CTLs was characterized using cytotoxicity assays. The effect of CT and TS on DC migration was also determined. When used together, TS and CT enhanced peptide specific CD4 T cell proliferation above levels achieved with either treatment alone. Similarly, CD8 T cell proliferation was optimal in mice treated with both modalities. The generation of functional CTL through the skin did not require IL-12p40, a key Th1 promoting molecule, suggesting a role for other Th1 promoting factors. Both CT and TS enhanced the immigration of DCs to the draining lymph nodes in Balb/c mice revealing a potential mechanism for their adjuvant effects. Finally, TLR4 signaling was not required for the generation of epicutaneous T cell or antibody mediated immune responses in these model systems. Epicutaneous immunization is a promising approach for the generation of epitope-specific T cell responses. As such, it may provide a practical, cost effective alternative to conventional needle immunization.