Cathepsins are crucial in antigen processing in the major histocompatibility complex class II (MHC II) pathway. Within the proteolytic machinery three classes of proteases, cystein-, aspartic-, and serine proteases, are present in the endocytic compartments. The combined action of these proteases generates antigenic peptides from antigens, which are loaded to MHC II molecules for CD4+ T cell presentation. We generated a novel high sensitive phosphonate-based serine protease activity-based probe to visualize cathepsin G (CatG) activity in low amounts of cell lysate. Application of this activity-based probe for CatG detection showed no differences in CatG activity in primary human antigen presenting cells (APC), when exposed with Epstein-Barr virus (EBV). However, CatG activity was increased in monocytes and macrophages after exposure with the human immunodeficiency virus (HIV), indicating a defense mechanism of these APC after viral infection. Here we demonstrate that our serine protease activity-based probe can be used to detect CatG activity in low numbers of primary cells from human peripheral blood.
|Title of host publication||21st Polish Peptide Symposium, Suprasl, Bialystok, Poland. Oral presentation|
|Publication status||Published - 2011|