|Detection of Reaginic Homocytotropic Antibodies
in Sera of Buffalos Infected with Fasciola Gigantica.
|Hassan M. El-Said
|Department of Medicine, Infectious Diseases and Fish diseases, Faculty
of Veterinary Medicine, Cairo University, Egypt.
The development of specific reaginic IgE-like antibodies in response
to natural Fasciola gigantica infection in buffalos was investigated. An
immediate (type I) hypersensitivity response was elicited in the skin of
infected buffalos in response to intra-dermal injection of antigen prepared
from F. gigantica flukes. The specificity of the elicited reaction was
indicated by the lack of response to heterologous antigens. Sera of fasciola-infected
buffalos passively sensitized skin mast cells of non-infected buffalo recipients,
as indicated by the specific elici-tation of homologous passive cutaneous
anaphylaxis (PCA) in response to fluke antigen. The homocytotropic nature
of antibod-ies was demonstrated by the inability of reaginic sera to provoke
heterologous PCA in the skin of cattle, donkeys and guinea pigs. Reaginic
antibodies were heat-labile and required a latent period of 72 hours for
fixation to skin mast cells. The properties of buffalo reaginic antibodies
are consistent with properties of IgE of humans and other ruminant species.
The immunoprotective role of reaginic IgE against fasciola infection is