Isolation and characterisation of exosomes from human cancer cell lines and patient material.

Exosomes are of great interests today because of their ability to elicit anti-tumour immunity. In this study, we isolated and characterised cancer cell lines derived exosomes (CEX) and plasma derived exosomes (PEX) that might have the potential to be used as cell free vaccines of higher efficacy in cancer treatment. After successful isolations of exosomes using ultracentrifugations, they were first quantified using Bradford assay and subsequently characterised using western blot and flow cytometry analysis. Comparisons between exosomes isolated from RPMI-8226, SGH-MM5 and K562 cells with and without heat shocked (HS) treatment indicated that HS CEX contained higher amounts of proteins as well as increased amounts of antigen presenting, and tetraspanin molecules like major histocompatibility complex (MHC) class I and cluster of differentiation (CD) 81. Exosomes isolated from plasma of cancer patients also contained more exosomal proteins and showed elevated amounts of MHC class I, MHC class II, CD86, CD9 and CD81 when compared to healthy donors. Taken together, these results demonstrate that HS CEX and cancer PEX may have better immunostimulating abilities, thus highlighting their possible applications in cancer treatment by cross presenting exosomes carrying tumour peptide antigens to CD8+ cytotoxic T lymphocytes (CTLs).Bachelor of Science in Biomedical Science