The endotoxin of which of the following gram-negative bacteria DOES NOT play any pa in the pathogenesis of the natural disease?

Vibrio cholerae possess the lipopolysaccharide O antigen(LPS, endotoxin). It does not play any role in the pathogenesis of cholera but is responsible for the immunity induced by the killed vaccines. The watery diarrhea of cholera results from the action of a cholera toxin which is a potent protein enterotoxin produced by the organism in the small intestine. It has 2 subunits A and B, Ganglioside GM1 serves as receptor for subunit B which in turn promotes the entry of subunit A into the cell. Activation of subunit A1 cause increase in level of cAMP and results in prolonged hypersecretion of water and electrolytes. Ref: Textbook of Microbiology By Ananthanarayan And Paniker page 311. Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e chapter 17.