Mott cells are plasma cells defective in immunoglobulin secretion

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Mott cells are plasma cells with intracellular immunoglobulin inclusions (Russell bodies).
• These cells are abundant in lymphoid organs of autoimmune mice.
• The exact biochemical mechanisms underlying Mott cell formation are not fully understood.

Purpose of the Study:

• To generate and characterize hybridoma cell lines representing Mott cells.
• To investigate the biochemical basis of immunoglobulin accumulation within Mott cells.
• To elucidate the cellular defects responsible for the Mott cell phenotype.

Main Methods:

• Hybridoma technique was employed to fuse spleen cells from NZB autoimmune mice with a non-immunoglobulin-producing hybridoma cell line (Sp2/0-Ag14).
• Ultrastructural analysis was performed to examine the morphology of intracellular inclusions.
• Biosynthetic labeling studies were conducted to assess immunoglobulin production and secretion.

Main Results:

• Hybridoma cell lines exhibiting the Mott cell phenotype were successfully produced.
• Ultrastructural examination revealed that inclusions represent distended cisternae of the rough endoplasmic reticulum.
• Biosynthetic labeling confirmed a complete or partial block in immunoglobulin secretion in these cell lines.
• The secretory defect may be linked to an abnormal immunoglobulin light chain.

Conclusions:

• The generated hybridoma cell lines provide a valuable model for studying Mott cells at the biochemical level.
• Mott cell inclusions are indicative of a significant disruption in the immunoglobulin secretory pathway.
• Abnormalities in immunoglobulin light chain structure are a potential cause for the observed secretory block in Mott cells.