As expected, the MHC-class II-restricted CD4+ T cell proliferation was compromised in the Cat-S KO BM-DCs (data not shown), illustrating the involvement of Cathepsin-S in cleaving the invariant chain of the MHC-class II molecule (Nakagawa et al., 1999). Open in a separate window Figure 5. LeX-modified antigen is cross-presented in a TAP- and Cathepsin-S-independent fashion.To examine whether cross-presentation of OVA-LeX involves TAP or Cathepsin-S (A) TAP1 KO and (B) Cat-S KO BM-DCs and WT BM-DCs were pulsed with OVA-LeX or native OVA and co-cultured with OT-I T cells for 3 days. nature and strength of immune responses and should be considered for optimizing current vaccination strategies. DOI: http://dx.doi.org/10.7554/eLife.11765.001 with either OVA-LeX or native OVA mixed with anti-CD40 using a prime-boost protocol. Spleens were analyzed by flow cytometry to determine the frequency of (C) H2-Kb/SIINFEKL-tetramer-binding CD8+ T cells and IFN- or TNF production by activated CD8+ T cells was determined by intracellular staining after OVA-specific re-stimulation ex vivo. Dots represent individual mice (n=4C5 mice/group; **p