Profile of human macrophage transcripts: insights into macrophage biology and identification of novel chemokines

High throughput partial sequencing of randomly selected cDNA clones has proven to be a powerful tool for examining the relative abundance of mRNAs and for the identification of novel gene products. Because of the important role played by macrophages in immune and inflammatory re- sponses, we sequenced over 3000 randomly se- lected cDNA clones from a human macrophage library. These sequences represent a molecular inventory of mRNAs from macrophages and pro- vide a catalog of highly expressed transcripts. Two of the most abundant clones encode recently identi- fied CC chemokines. Macrophage-derived chemo- kine (MDC) plays a complex role in immunoregula- tion and is a potent chemoattractant for dendritic cells, T cells, and natural killer cells. The chemo- kine receptor CCR4 binds MDC with high affinity and also responds by calcium flux and chemotaxis. CCR4 has been shown to be expressed by Th2 type T cells. Recent studies also implicate MDC as a major component of the host defense against hu- man immunodeficiency virus. J. Leukoc. Biol. 64: 49-54; 1998.