MURINE MAST-CELLS AND MONOCYTES EXPRESS DISTINCTIVE SETS OF CD45 ISOFORMS

CD45 isoform expression patterns were examined in various mast and mon ocyte cell populations. The reverse transcription-polymerase chain rea ction (RT/PCR) and Southern analysis showed these myeloid cells expres s characteristic sets of CD45 isoforms. Mast cells produce mRNA for tw o splice variants, one containing exons 5, 7 and 8 of the alternativel y expressed exons (therefore lacking exons 4 and 6) and another contai ning variable exons 7 and 8. Monocytes express three prominent CD45 mR NA species, one which includes exons 5, 7 and 8, another with exons 7 and 8 and the third containing only exon 8 of the variable exons. Thes e results show that there are clear differences within the myeloid lin eage sub-populations with respect to CD45 exon usage which appear to d elineate mast cell and monocyte specific patterns. (C) 1997 Elsevier S cience Ltd. All rights reserved.