Immunohistochemical studies on specificity and affinity of the BB5-antibody against human parathyroid tissue

Localisation of parathyroid tissue in hyperparathyroidism may be difficult with standard methods. Immunoscintigraphy, using radiolabeled antibodies against epitopes of human parathyroid cells, could be a promising alternative. Therefore, we studied the necessary preconditions, whether the so-called BB5-antibody, directed against parathyroid cell membranes possesses sufficient specificity and affinity to be employed in immunoscintigraphy. Specificity was tested immunohistochemically with APAAP-staining of 39 different human tissues. Additionally, an immunoscore-based quantitative comparison was performed to test the affinity of BB5-antibody for normal and pathologic parathyroid tissue. Specificity was proven by the fact that of all 39 tested tissue-types only the parathyroid tissue was BB5-positive. Normal parathyroid tissue showed a significantly higher affinity to the BB5-antibody than pathologic parathyroid tissue (p < 0.03). However, all tissue samples from primary or secondary hyperparathyroidism exhibited sufficient staining. We conclude that the BB5-antibody fulfills the necessary conditions to be tried for immunoscintigraphical localisation of the parathyroid glands.