Immature macrophages derived from mouse bone marrow produce large amounts of IL-12p40 after LPS stimulation.
Production of IL-12 is an important indicator of the macrophage's ability to regulate immune responses. In this study, we investigated the IL-12 production by macrophages in different developmental stages. To this end, macrophages were generated in vitro from precursors stimulated with M-CSF, GM-CSF or IL-3. Density separation yielded populations enriched in different maturation stages. Invariably, only cells banding at the 40-50% Percoll interface produced large amounts of IL-12p40 when stimulated with LPS, whereas only low levels of IL-12p70 were produced. These cells represented immature macrophages, as indicated by the absence of precursor markers CD31/ER-MP12, Ly-6C/ER-MP20 and ER-MP58, and by the low level of expression of mature-cell markers like ER-HR3, scavenger receptor and CD11b/Mac-1. Upon further maturation, the macrophages' ability to produce IL-12p40 decreased, coinciding with increased nitric oxide production upon LPS stimulation. These results show that immature macrophages produce high levels of IL-12p40 and thus may either contribute to IL-12p70 production or regulate it.
Departmento de Immunologia, Universidade de São Paulo, SP, Brasil.
M A P
MA
Oliveira
G M A C
GM
Lima
M T
MT
Shio
P J M
PJ
Leenen
I A
IA
Abrahamsohn
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002454:Cell Differentiation / Q000187:drug effects; D002469:Cell Separation / Q000379:methods; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D018664:Interleukin-12 / Q000096:biosynthesis*; D053762:Interleukin-12 Subunit p40; D007377:Interleukin-3 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D009569:Nitric Oxide / Q000502:physiology; D021122:Protein Subunits / Q000096:biosynthesis*
D053762:Interleukin-12 Subunit p40; D007377:Interleukin-3; D008070:Lipopolysaccharides; D021122:Protein Subunits; D018664:Interleukin-12; D009569:Nitric Oxide; D016173:Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor