Appearance of a variant of MOPC 104E which does not react with dextran B-1355s

Area of Science:

• Immunology
• Cancer Biology
• Biochemistry

Background:

• MOPC 104E is a well-characterized mouse plasmacytoma model.
• It produces immunoglobulin M (IgM) lambda myeloma protein with specific binding to dextran B-135s.
• Myeloma proteins are monoclonal antibodies produced by plasma cells.

Purpose of the Study:

• To report the spontaneous emergence and characterization of a MOPC 104E variant.
• To investigate the properties of the myeloma protein secreted by this variant.
• To establish a new research model for studying immunoglobulin diversity.

Main Methods:

• In vivo tumor passage in Balb/C mice.
• Immunochemical analysis of secreted myeloma proteins.
• Assessment of dextran binding specificity.

Main Results:

• A stable variant of MOPC 104E tumors was identified.
• The variant secretes an IgM (lambda) myeloma protein.
• This variant protein does not react with dextran B-135s, unlike the parent MOPC 104E protein.

Conclusions:

• Spontaneous genetic or epigenetic changes can alter myeloma protein specificity.
• The variant MOPC 104E provides a novel tool for investigating structure-function relationships of IgM antibodies.
• This discovery has implications for understanding antibody repertoire and potential therapeutic targets.