Hematopoietic Tumors: Normal or Abnormal Models of Leukocyte Differentiation?

One of the major problems in cellular immunobiology has been the issue of resolving the cellular bases of the many different specific functional properties mediated by the immune system. This is in essence a dual problem, as it involves both a detailed phenotypic characterization of all the differentiation lineages in the hematopoietic system, and the correlation of each cellular subset with specific functional properties. This problem is particularly compounded both by the wide heterogeneity in the differentiation stages of cells within hematopoietic tissues, and by the requirements for collaboration and interaction amongst different cell types in the mediation of specific immunological functions (Katz and Benacerraf, 1977). Analysis of the cell types involved in any given immune response is further complicated by the wide heterogeneity in cell populations when cell suspensions are obtained from in vivo tissue and blood sources.