Project description:Biofilm formation is generally recognized as a bacterial defense mechanism against environmental threats, including antibiotics, bacteriophages, and leukocytes of the human immune system. Here, we show that for the human pathogen Vibrio cholerae, biofilm formation is not only a protective trait, but also an aggressive trait to collectively predate different types of immune cells. We find that V. cholerae forms biofilms on the eukaryotic cell surface using an extracellular matrix comprising primarily mannose-sensitive hemagglutinin pili, toxin-coregulated pili, and the secreted colonization factor TcpF, which is distinct from the matrix composition of biofilms on abiotic surfaces. These biofilms encase immune cells and establish a high local concentration of a secreted hemolysin to kill the immune cells, before the biofilms disperse in a c-di-GMP-dependent manner. Together, these results uncover a mechanism for how bacteria employ biofilm formation as a multicellular strategy to invert the typical relationship between the human immune system as the hunter and bacteria as the hunted.
Project description:Biofilm formation is generally recognized as a bacterial defense mechanism against environmental threats, including antibiotics, bacteriophages, and leukocytes of the human immune system. Here, we show that for the human pathogen Vibrio cholerae, biofilm formation is not only a protective trait, but also an aggressive trait to collectively predate different types of immune cells. We find that V. cholerae forms biofilms on the eukaryotic cell surface using an extracellular matrix comprising primarily mannose-sensitive hemagglutinin pili, toxin-coregulated pili, and the secreted colonization factor TcpF, which is distinct from the matrix composition of biofilms on abiotic surfaces. These biofilms encase immune cells and establish a high local concentration of a secreted hemolysin to kill the immune cells, before the biofilms disperse in a c-di-GMP-dependent manner. Together, these results uncover a mechanism for how bacteria employ biofilm formation as a multicellular strategy to invert the typical relationship between the human immune system as the hunter and bacteria as the hunted.
