摘要
Splenomegaly is a well-known phenomenon typically associated with inflammation.However,the underlying cause of this phenotype has not been well characterized.Furthermore,the splenomegaly phenotype seen in lymphotoxin(LT)signaling-deficient mice is characterized by increased numbers of splenocytes and splenic neutrophils.Splenomegaly,as well as the related phenotype of increased lymphocyte counts in non-lymphoid tissues,is thought to result from the absence of secondary lymphoid tissues in LT-deficient mice.We now present evidence that mice deficient in LTα1β2 or LTβR develop splenomegaly and increased numbers of lymphocytes in non-lymphoid tissues in a microbiota-dependent manner.Antibiotic administration to LTα1β2-or LTβR-deficient mice reduces splenomegaly.Furthermore,re-derived germ-free Ltbr−/−mice do not exhibit splenomegaly or increased inflammation in non-lymphoid tissues compared to specific pathogen-free Ltbr−/−mice.By using various LTβ-and LTβR-conditional knockout mice,we demonstrate that retinoic acid-related orphan receptorγT-positive type 3 innate lymphoid cells provide the required active LT signaling to prevent the development of splenomegaly.Thus,this study demonstrates the importance of LT-mediated immune responses for the prevention of splenomegaly and systemic inflammation induced by microbiota.
