Evaluation of the optimal incubation temperature for detecting certain IgG antibodies with potential clinical significance.

It is commonly believed that IgG antibodies react optimally at 37 degrees C, but there are few published data supporting this. In this study, 140 antibodies from the Rh, Kell, Duffy, Kidd, and SsU blood groups were studied by a low-ionic-strength solution indirect antiglobulin technique at four different temperatures of incubation: 10, 22, 30, and 37 degrees C. Only titration score differences of greater than 10 were considered significant. None of the 140 antibodies sensitized red cells (RBC) significantly better at 10, 22, or 30 than at 37 degrees C. All antibodies, except one example of anti-c, sensitized RBCs as well at 30 as at 37 degrees C. At 22 degrees C, 100 percent of Kidd and SsU, 94 percent of Kell, and 82 percent of Duffy, but only 49 percent of Rh antibodies sensitized RBCs as well as they did at 37 degrees C. It is possible that these differences reflect the influence of antigenic structures and/or topography on the thermal dynamics of the antigen-antibody bond.