A pathologist examines autopsy tissue from a patient who died of rabies encephalitis. Cytoplasmic eosinophilic inclusions are noted in hippocampal neurons. These inclusions represent accumulation of which material?

• A Aggregated ubiquitinated proteins and viral nucleocapsids ✓
• B Excess glycogen due to lysosomal enzyme deficiency
• C Lipofuscin from oxidative membrane peroxidation
• D Calcium deposits from mitochondrial injury

Explanation

Negri bodies — the pathognomonic cytoplasmic inclusions of rabies virus infection in neurons — consist of aggregates of viral nucleocapsid proteins (primarily N protein) associated with ubiquitinated host proteins, forming inclusion bodies visible by H&E as eosinophilic, round-to-oval structures. Their presence in hippocampal and cerebellar Purkinje cells is used for post-mortem diagnosis. Lipofuscin is a wear-and-tear pigment, and glycogen accumulations appear in lysosomal storage diseases.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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