Investigation on the Thermokinetics Process of Hemoagglutination by Isothermal Titration Calorimetry

Microcalorimetry was adopted to detect the reaction of phytohemagglutinin (PHA) with 20% rabbit red blood cell (RBC), thermokinetics curves and parameters were obtained, so as to evaluate agglutinate activity of PHA objectively from reaction process and thermokinetics character aspect. The results showed that thermokinetics parameters of PHA titrated with 20% rabbit RBC were: K (3.24X10(5) L.mol(-1)) Delta(r)G(m)(circle minus) (-32.722 kJ.mol(-1)), Delta(r)H(m)(circle minus) (-238.548 kJ.mol(-1)), Delta(r)S(m)(circle minus) (-0.664 kJ.mol(-1).K(-1)). The hemoagglutination is exothermic reaction for Heat>0, and it could progress spontaneously for Gibbs free energy was negative (Delta G<0), and the reaction was entropy decreasing and driven by enthalpy (Delta H<0, Delta S<0, vertical bar Delta H vertical bar>vertical bar T Delta S vertical bar), the driving force may be chemical bonding force, Van der Waals force and hydrogen bond interaction, the reaction system kept in stable and ordered condition after agglutination. In conclusion, the admix ampoule microcalorimetry established in this study could be adopted as an effective technique for sensitive, precise, quantitative and consecutive detection of hemoagglutination and other antigen-antibody reactions.