RIBONUCLEASES AND HOST-DEFENSE - IDENTIFICATION, LOCALIZATION AND GENE-EXPRESSION IN ADHERENT MONOCYTES IN-VITRO

Several ribonucleases of the RNase A family function as antibacterial, anti-parasitic, and anti-viral agents. In this work, we have shown th at mRNAs encoding five of the six known human ribonucleases of the RNa se A family are expressed in cultured human monocytes, and that ribonu cleases are released by adherent monocytes in culture. Using a polyclo nal antiserum prepared against recombinant protein, we have detected o ne of these ribonucleases, RNase 4, in lysates of normal human periphe ral blood monocytes, but not granulocytes or lymphocytes, by Western b lotting. Subcellular localization by immunoelectron microscopy demonst rated the presence of RNase 4 in the cytoplasmic granules of isolated monocytes. Interestingly, mRNA encoding RNase 4 could not be detected in freshly isolated monocytes, emerging only after 16 h in culture, su ggesting the possibility of de novo protein synthesis in association w ith monocyte differentiation. (C) 1997 Elsevier Science B.V.