TY - JOUR
T1 - Effects of parenteral recombinant human macrophage colony-stimulating factor on monocyte number, phenotype, and antitumor cytotoxicity in nonhuman primates
AU - Munn, David H.
AU - Garnick, Marc B.
AU - Cheung, Nai Kong V.
PY - 1990/5/15
Y1 - 1990/5/15
N2 - Recombinant human macrophage colony-stimulating factor (rhM-CSF) was given to cynomolgus monkeys by continuous intravenous infusion or subcutaneous injection, at a dose of 50 to 100 μg/kg/d in repetitive 14-day cycles. Starting within 24 to 48 hours of initiation of rhM-CSF, there was a progressive increase in the number of circulating monocytes, from a baseline of 811 ± 253 cells/μL to a peak of 3,495 ± 712 cells/μL. on day 5 to 7. Many of these cells were large, granular, and extensively vacuolated. The expanded cell population expressed HLA-DR, LFA3, CD11b (904), and CD14 (MY4), and was 77% CD16 (FcRIII) positive by two-color cytofluorometry. In functional assays, fresh monocytes showed little cytotoxicity against cultured human melanoma cells (SKMel-1), with or without prior rhM-CSF treatment. However, after 3 days of in vitro culture in rhM-CSF, monocytes from treated animals mediated efficient antibody-dependent cytotoxicity (ADCC) against SKMel-1 using the murine monoclonal antibody 3F8 (IgG3, anti-ganglioside GD2). Under the same conditions, monocytes from control animals showed little ADCC (17% versus 82%, P < .05). Antitumor cytotoxicity in the absence of antibody was less efficient and was not significantly different between the two groups. There was a mild decrease in platelet count during rhM-CSF treatment, without clinical symptoms. No abnormalities of serum biochemical parameters were seen. We conclude that parenteral rhM-CSF increases the number of circulating monocytes in nonhuman primates, and that these monocytes mediate increased antitumor ADCC after a brief period of in vitro differentiation. This study has implications for the design of possible future clinical trials combining antitumor monoclonal antibodies and rhM-CSF.
AB - Recombinant human macrophage colony-stimulating factor (rhM-CSF) was given to cynomolgus monkeys by continuous intravenous infusion or subcutaneous injection, at a dose of 50 to 100 μg/kg/d in repetitive 14-day cycles. Starting within 24 to 48 hours of initiation of rhM-CSF, there was a progressive increase in the number of circulating monocytes, from a baseline of 811 ± 253 cells/μL to a peak of 3,495 ± 712 cells/μL. on day 5 to 7. Many of these cells were large, granular, and extensively vacuolated. The expanded cell population expressed HLA-DR, LFA3, CD11b (904), and CD14 (MY4), and was 77% CD16 (FcRIII) positive by two-color cytofluorometry. In functional assays, fresh monocytes showed little cytotoxicity against cultured human melanoma cells (SKMel-1), with or without prior rhM-CSF treatment. However, after 3 days of in vitro culture in rhM-CSF, monocytes from treated animals mediated efficient antibody-dependent cytotoxicity (ADCC) against SKMel-1 using the murine monoclonal antibody 3F8 (IgG3, anti-ganglioside GD2). Under the same conditions, monocytes from control animals showed little ADCC (17% versus 82%, P < .05). Antitumor cytotoxicity in the absence of antibody was less efficient and was not significantly different between the two groups. There was a mild decrease in platelet count during rhM-CSF treatment, without clinical symptoms. No abnormalities of serum biochemical parameters were seen. We conclude that parenteral rhM-CSF increases the number of circulating monocytes in nonhuman primates, and that these monocytes mediate increased antitumor ADCC after a brief period of in vitro differentiation. This study has implications for the design of possible future clinical trials combining antitumor monoclonal antibodies and rhM-CSF.
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M3 - Article
C2 - 2186820
AN - SCOPUS:0025331307
SN - 0006-4971
VL - 75
SP - 2042
EP - 2048
JO - Blood
JF - Blood
IS - 10
ER -