The same well-characterized T cell epitope SIINFEKL expressed in the context of a cytoplasmic or secreted protein in BCG induces different CD8+ T cell responses.

Abstract Mycobacterium bovis BCG is still the most widely used vaccine against tuberculosis and CD8 + T cells play important roles in fighting infection. We investigated how well antigen is processed and presented to CD8 + T cells using the same well-characterized CD8 + T cell epitope SIINFEKL expressed in either a cytoplasmic (GFP-OVA) or secreted (85B-OVA) context from BCG. We report that secreted SIINFEKL from 85B-OVA BCG is presented better than cytoplasmic SIINFEKL expressed by GFP-OVA BCG.