Immunocytochemical Labeling of Anaplasma Marginale Theiler in Dermacentor Andersoni Stiles with Peroxidase- Antiperoxidase Technique

Colonies of Anaplasma marginale in midgut epithelial cells of adult ticks that had been infected as nymphs were specifically labeled, using the unlabeled antibody peroxidase-antiperoxidase method of immunocytochemistry. Visual comparison of infected and control tissue sections with the electron microscope demonstrated deposition of ring-like peroxidase-antiperoxidase complexes over organisms within the colonies. The intensity of labeling differed among organisms within a single colony, possibly as a result of varying antigenicity. The labeling observed on organisms in the colonies was similar to that seen on anaplasmal initial bodies in inclusions of infected bovine erythrocytes examined concurrently.