Effect Of Tumor On Its Draining Lymph Nodes In IL-7 Expression

Cancer is a common disease worldwide and causes thousands of deaths annually.The immune system of the organism has an immunological surveillance fuction to clear the cancer cells in vivo.One important reason for tumor progression lies in that tumors can suppress the normal immunological surveillance function of the immune system of the organism to avoid detection.In one hand,the theory of cancer immunoediting attributes to the escape of cancer cells from immune attack.In the other hand,the immune system of advanced cancer patients is usually in an inhibitory state,leading to a high morbidity and lethallty rate of infection.Lymph nodes(LNs)draining of pathological sites provide suitable microenvironment where adaptive immune responses mainly take place.Na?ve lymphcytes receive the activation signal from antigen presenting cells(APC)to be activated and proliferate,followed by migrating to the pathological sites and fighting against the pathogen.LNs consist of lymphcytes and stromal cells.The stromal cells provide lymphcytes with appropriate microenviroments for their survival.Unfortunately,the microenvironment in the tumor draining lymph nodes(TDLNs)of cancer patients seems to be in favor of tolerance.The effects of tumor cells on TDLNs have not been elaborated clearly.We mainly focus on the structure and function of TDLN.In mice tumor model,we performed flowcytometry,immunohistochemistry and immunofluorescence to check our hypothesis.Our results have indicated that tumor cells may directly affect the TDLNs by decreasing the fibroblastic reticular cells(FRCs)population that led to less IL-7 secretion.As a result,the amount of T cells in TDLNs declined with less survival signals.Less T cells in the TDLNs means weakening ability of immune surveillance.Clinically,these results have also been confirmed in LNs biopsies from colon cancer patients at different clinical stages with immunohistochemistry.Taken together,we have showed that tumor cells could inhibit the immunological function of the TDLNs directly,which may partly explain the weak immunological surveillance function of TDLNs.