We analyzed the heterogeneity of Drosophila hemocytes on the basis of the expression
of cell-type specific antigens. The antigens characterize distinct subsets which partially
overlap with those defined by morphological criteria. Oil the basis of the expression
or the lack of expression of blood cell antigens the following hemocyte populations
have been defined: crystal cells, plasmalocytes, lamellocytes and precursor cells.
The expression of the antigens and thus the different cell types are developmentally
regulated. The hemocytes are arranged ill four main compartments: the circulating
blood cells, the sessile tissue, the lymph glands and the posterior hematopoietic
tissue. Each hemocyte compartment has a specific and characteristic composition of
the various cell types. The described markers represent the first successful attempt
to define hemocyte lineages by immunological markers in Drosophila and help to define
morphologically, functionally, spatially and developmentally distinct subsets of hemocyles.
