Cell-mediated immune response in anaplasmosis in cattle.

The cell-mediated immune response (CMIR) was demonstrated during experimental Anaplasma marginale infection in cattle, in vivo by the intradermic skin test and in vitro by the leucocyte migration inhibition test (LMIT). The skin test showed a delayed hypersensitivity reaction which reached its maximum after 48-72 hours. Histopathological examination of the skin biopsies revealed excessive infiltration by mononuclear cells and accumulation of oedematous fluid in the deeper dermal layers. For LMIT, the particulate antigen was used and the inhibition of leucocyte migration was significant in vaccinated and carrier animals as compared to controls.