In this webinar, learn how escaping immune system surveillance is a major obstacle for immunotherapies against cancer. Tumor cells secrete soluble factors allowing them to escape immune surveillance. Exosomes, or small vesicular structures excreted by normal cells, have a plethora of biological significance as these exosomes play a significant role in intracellular communication and help in the activation of immune response. However, in the case of cancer, exosomes secreted by tumor cells can induce apoptosis of activated T cells or impair the differentiation of monocytes to myeloid derived suppressor cells. We found out that tumor derived exosomes inhibit antigen specific proliferation and induce B cell hyperactivation, but are functionally suppressed. We also investigated whether TLR4 mediated signaling has a major role in this immune suppression.