Canine distemper virus-associated encephalitis: modification by passive antibody administration

Area of Science:

• Veterinary Neurology
• Immunopathology
• Virology

Background:

• Canine distemper virus (CDV) is a significant pathogen affecting dogs, with potential for neurological complications.
• The pathogenesis of CDV-induced central nervous system (CNS) lesions and the role of specific antibodies in modulating these lesions require further elucidation.

Purpose of the Study:

• To investigate the impact of CDV-specific antibody treatment on the development and severity of CNS lesions in gnotobiotic puppies experimentally infected with CDV.
• To compare the neuropathological findings in antibody-treated dogs with those receiving normal serum and with previously reported CDV infection cases.

Main Methods:

• Gnotobiotic puppies were infected intraperitoneally with a virulent strain of CDV (R252).
• Puppies were treated with either normal serum (NS) or CDV-specific antibody.
• Central nervous system (CNS) lesions were evaluated using light and immunofluorescence microscopy.

Main Results:

• Dogs treated with normal serum exhibited minimal CNS lesions, primarily affecting the grey matter of the frontal lobe.
• Dogs receiving CDV-specific antibody developed extensive and severe CNS lesions, including laminar cortical necrosis, gliosis, astrocytic activation in the frontal lobe, cerebellar degeneration, and spinal cord lesions.
• Eosinophilic intracytoplasmic and intranuclear viral inclusion bodies were observed in neurons of antibody-treated dogs.

Conclusions:

• Treatment with CDV-specific antibodies in the context of experimental CDV infection can paradoxically exacerbate CNS pathology, leading to more severe neuropathological changes.
• The findings highlight a complex immunopathological response in CDV infection and suggest that antibody-mediated enhancement or altered immune responses may contribute to severe neurological disease.