Isotherm and nonlinear least-squares fit of data from isothermal titration microcalorimetry experiment with acetylated MnC PS and MAb MNC46-1, specific for deacetylated MnC PS. The average stoichiometry of binding (N), from three experiments with MAb 46-1 and two experiments with MAb MNC207-1, specific for acetylated MnC PS (data not shown), is 10.7 ± 1.5. K, thermodynamic binding constant; ΔH, enthalpy of binding; ΔS, entropy of binding.