Tumors of Immunoglobulin-Producing Cells and Thymus-Derived Lymphocytes

Abstract

The immunoglobulin-producing cells differentiate so that one specialized cell and its progeny by mitosis are limited to produce immunoglobulin molecules with a single binding specificity. The binding specificity of an immunoglobulin molecule is determined by the interaction of the VL and VH regions of the light (L) and heavy (H) chains. There is now compelling evidence to support the concept of Dreyer and Bennett (1965), that single L or H chains are each controlled by two separate genes VL or VH and CL or CH genes, and the differentiation of the immunoglobulin-forming clones begins with the process that activates a single VL and VH gene in a cell. This type of differentiation might have very little special significance, were it not for the fact that a single mammalian (vertebrate?) haplotype can probably generate 103 to 104 different immunoglobulin producing clones. The population size of each specialized clone in the organism is usually relatively small, e.g. 103 to 104 cells, making it difficult to isolate in quantity individual clones and their products. Further the immunoglobulin producing clone does not develop in a single step but develops sequentially in time and space in the organism.