Characterization of immunocompetent cells in the diseased canine periodontium

The beagle dog with naturally occurring periodontal disease is one of the m ost widely used animal models in periodontal research for histological stud ies on disease pathogenesis and on the effect of potential therapeutic regi mens. However, previous studies were restricted to morphological assessment of immunocompetent cells because of the lack of available cell-specific ma rkers. In this study we systematically characterized the specificity and im munoreactivity of a panel of anti-human antibodies for identification (ABC method) of immunocompetent cells in formalin-fixed, EDTA-decalcified, paraf fin-embedded inflamed periodontal tissues obtained from six beagle dogs. Ca nine lymph nodes and a panel of different human tissues served as positive controls. Polyclonal anti-CD3 immunolabeled canine T-lymphocytes specifical ly. Anti-CD79 alpha (clone HM57) reacted with B-lymphocytes and plasma cell s, and CD79 alpha (clone JCP117) showed no staining in canine tissues. Neut rophils, monocytes, small macrophages, and keratinocytes reacted with an an ti-myeloid/ histiocyte antibody (clone MAC387). Anti-CD68 (clones PG-M1 and EBM11) immunolabeled large macrophages and plasma cells. Clone EBM11 also stained osteoclasts and cementoclasts. With the exception of JCB117, all an tibodies revealed similarly favorable immunolabeling of canine and human im munocompetent cells. Long-term EDTA decalcification appeared to weaken immu nostaining of plasma cells with HM57. MAC387 and CD68 can be used to distin guish macrophages in different differentiation stages in canine periodontal tissues.