TNF and abscess: Once B. fragilis (ATCC 25285) leaks into the abdominal cavity, it leads to inflammation due to the increased production of pro-inflammatory cytokines TNF-α and IL-1β and abscess formation, then PSA is internalised by antigen-presenting cells after antigen presentation loading on the MHC II compartment to generate IL-10 producing T cells for controlling excessive inflammation6, 26, 27.