1) A generic term for any circumscribed mass of foreign (e.g., lead or viruses) or metabolically inactive materials (e.g., ceroid or Mallory bodies), within the cytoplasm or nucleus of a cell. Inclusion bodies are in cells infected with certain filtrable viruses, observed especially in nerve, epithelial, or endothelial cells.

2) generic term for any circumscribed mass of foreign (for example, lead or viruses) or metabolically inactive materials (for example, ceroid or Mallory bodies), within the cytoplasm or nucleus of a cell; inclusion bodies are in cells infected with certain filtrable viruses, observed especially in nerve, epithelial, or endothelial cells.