Vaccination of class I major histocompatibility complex (MHC)-restricted murine CD8+ cytotoxic T lymphocytes towards soluble antigens: immunostimulating-ovalbumin complexes enter the class I MHC-restricted antigen pathway and allow sensitization against the immunodominant peptide.

In vivo induction of anti-ovalbumin (OVA) cytotoxic T cell responses was brought about in an MHC class I-restricted fashion by immunizing H-2b mice with OVA in immunostimulating complexes (ISCOM). ISCOM formation with the hydrophilic soluble protein OVA was achieved upon unmasking hydrophobic protein domains by treatment at low pH values. The effector cells induced were MHC restricted, specific for the immunodominant peptide of OVA (258-276), and expressed the CD8+ CD4- phenotype. These results suggest that ISCOM-based vaccines may be useful to direct hydrophilic soluble antigens into the MHC class I presentation pathway in order to vaccinate CD8+ T lymphocytes.