The complement system is an important component of the human immune system. Once considered a hepatic-derived and serum-active innate immune system, the complement system is now recognized as a complex network that includes fluid-phase, cell surface, and intracellular proteins, and is a core component of innate and adaptive immunity at both systemic and local tissue levels. Recent research has revealed a new concept of the intracellular active complement system, that is "Complosome", which is gradually changing the established research paradigm in this field. The Complosome has been shown to play an important role in regulating T cell proliferation, activation and response, macrophage polarization, and other life activities, demonstrating its huge research potential and indicating that further exploration of its functions is needed. This article summarizes the recent advances in research on the Complosome based on the literature reports, and discusses potential directions for future research in this field.

Complement; T cells; Monocytes; Tumor cells