The presence of Mott cells in the lymph nodes of rats with experimental autoimmune encephalomyelitis

Mott cells are plasma cells that have multiple spherical Russell bodies packed in their cytoplasm. Russell bodies are dilated endoplasmic reticulum cisternae filled with aggregates of immunoglobulins that are neither secreted nor degraded. Mott cells were observed in our study by light and electron microscope in the lymph nodes of rats with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Mott cells were detected on hematoxylin and eosin (HE)-stained lymph node sections as vacuolated cells with eccentrically positioned nuclei and large number of faint blue spherical inclusions in the cytoplasm. Electron microscopic investigation revealed the presence of Russell bodies of the medusa form inside Mott cells in lymph node ultra-thin sections of EAE animals. Mott cells expressed the plasma cell marker CD138 and either kappa or lambda immunoglobulin light chains, indicating their origin from polyclonally activated B cells. Finally, Mott cells were associated with active EAE, as they were not found in the lymph nodes of EAE-resistant Albino Oxford rats. The presence of Russell bodies implies an excessive production of immunoglobulins in EAE, thus further emphasizing the role of B cells, and among them Mott cells, in the pathogenesis of this animal model of multiple sclerosis.

Automated summary

In our study, we observed Mott cells, which are plasma cells with multiple spherical Russell bodies in their cytoplasm, in the lymph nodes of rats with experimental autoimmune encephalomyelitis (EAE). These Russell bodies are filled with aggregates of immunoglobulins that are not secreted or degraded. Mott cells were found to express the plasma cell marker CD138 and originated from polyclonally activated B cells. The presence of Russell bodies suggests excessive production of immunoglobulins in EAE, highlighting the importance of B cells, including Mott cells, in the pathogenesis of this animal model of multiple sclerosis.