Checkpoint Inhibitors: Conquering Cancer with a Little (T)-Help from Our Microbial Friends

Excerpt

Checkpoint inhibitors (CPIs) are a new class of drugs designed to block either the cytotoxic T-lymphocyte antigen 4 (CTLA-4) or the programmed cell death protein-1 (PD-1), which are used by cancer cells to evade host immune system. Blocking these proteins increases recognition of cancer cells by the immune system with consequent eradication by activated effector T cells [1]. CTLA4 and PD(L)1-directed monoclonal antibodies (mAb) are approved for the therapy of several types of cancers regardless of the patient’s age, based on the results of clinical trials. In addition to their effectiveness, these therapies are associated with serious adverse events that differ from those associated with conventional chemotherapy, since CPIs activate the immune system against the self [2]. …