ISSN:
0192-253X
Keywords:
B cell development
;
immunoglobulin M
;
B cell tumor
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Tumors of B lymphocyte origin have been used as models for normal B cells “frozen” at particular stages of their development. Surface properties, amount, and intracellular location of immunoglobulin and the synthesis of J chain have all been used as indicators of developmental stages. Each requires special techniques or yields data that are difficult to compare from one experiment to the next. For these reasons, we have developed a metric for B cell development that is simple to perform and allows quick quantitative comparisons of cell lines.It has recently been established that the membrane (μm) and secreted (μs) forms of the IgM heavy chain differ at their extreme carboxy termini. The two proteins differ slightly in size and are easily distinguished when they are compared without their carbohydrate on sodium dodecyl sulfate (SDS) polyacrylamide gels. We have examined four mouse tumors derived from the B lymphocyte lineage whose phenotypes resemble late pre-B cells (internal μ only; uninduced 70Z/3), small B lymphocytes (high levels of surface IgM; LPS-induced 70Z/3, WEHI 231), lymphoblasts (both membrane and secreted IgM; WEHI 279.1), and plasma cells (copious IgM secretion; MOPC 104E). Despite the fact the 70Z/3 and WEHI 231 secrete no detectable IgM, all of the tumors synthesize at least intracellular forms of both μm and μs. The proportion of μm is stable and is characteristic of each tumor. The 70Z/3 cells and WEHI 231 cells synthesize about 75% of their total μ as μm; WEHI 279.1 cells synthesize about 30% and MOPC 104E cells about 5% of their total μ as μm. The population of LPS-stimulated B lymphocytes shows a similar progression during its differentiation. The proportion of μm correlates with other developmentally regulated parameters (Fc receptor, Ia and plasma cell antigen levels, and J chain) and can be used as a simple metric for comparison with developing B lymphocytes and determination of the developmental stage of a B cell tumor.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020030106
Permalink
