Liposome fluidity alters interactions between the ganglioside GM1 and cholera toxin B subunit.

Cholera toxin is a complex protein with a biologically active protein (A subunit) and a cell targeting portion (B subunit). The B subunit is responsible for specific cell binding and entry of the A subunit. One way to limit potential toxicity of the toxin after exposure is to introduce cellular decoys to bind the toxin before it can enter cells. In this study the ganglioside GM1, a natural ligand for cholera toxin, was incorporated into liposomes and the interaction between fluorescent B subunit and the liposome determined. Liposome membrane fluidity was determined to play a major role in the binding between liposomes and the cholera toxin B subunit. Liposomes with lower fluidity demonstrated greater binding with the B subunit. The findings from this study could have important implications on formulation strategies for liposome decoys of toxins.