Refined egoist: The toxin-antitoxin immune system of T6SS.

The Type VI secretory system (T6SS) is a key regulatory network in the bacterial system, which plays an important role in host-pathogen interactions and maintains cell homeostasis by regulating the release of effector proteins in specific competition. T6SS causes cell lysis or competitive inhibition by delivering effector molecules, such as toxic proteins and nucleic acids, directly from donor bacterial cells to eukaryotic or prokaryotic targets. Additionally, it orchestrates synthesis of immune effectors that counteract toxins thus preventing self-intoxication or antagonistic actions by competing microbes. Even so, the mechanism of toxin-antitoxin regulation in bacteria remains unclear. In response, this review discusses the bacterial T6SS's structure and function and the mechanism behind toxin-antitoxin secretion and the T6SS's expression in order to guide the further exploration of the pathogenic mechanism of the T6SS and the development of novel preparations for reducing and replacing toxins and antitoxins.