Studies of Thirty Different Bence Jones Protein-Producing Plasma Cell Neoplasms in an Inbred Strain of Mouse

Abstract

Thirty different Bence Jones protein-producing plasma cell tumors of BALB/c mice were studied with reference to their protein products and to the renal damage resulting from the Bence Jones proteinuria. From their molecular structure the Bence Jones proteins were easily classified into three groups: 22 tumors produced the L-chain-type proteins; 5 the β_2A-type proteins; and 3 the RPC-20-type proteins. No histological or cytological criteria could be found to distinguish the tumors of the 3 protein groups. The proteins differed greatly within each group, especially the L-chain and β_2A types; these differences included electrophoretic mobility, peptide composition, rate of excretion, and the resulting degree of renal damage. The term “Bence Jones protein” is not specific for a single type of protein molecule; it covers several types of molecules produced by plasma cell neoplasms. The myeloma kidney, in all the tumors, contained proteinaceous tubular casts that began in the distal tubule and subsequently involved the entire nephron. Pronounced differences in the rate and degree of cast formation from one tumor to another were found and these were independent of the concentration of urinary Bence Jones protein. It was concluded that the “myeloma kidney” is a specific lesion depending upon certain characteristics of the proteins that induce it.