Human resident peritoneal macrophages: phenotype and biology

Abstract

Macrophages represent the primary line of host defences in the peritoneal cavity. In order to study the metabolic activity and maturation stage of human resident peritoneal macrophages (PM phi). peritoneal fluid (PF) was taken by Douglas puncture from healthy hyperstimulated infertile women undergoing oocyte retrieval for in vitro fertilization. Peritoneal fluid and macrophage culture fluids were studied for different inflammatory mediators such as interleukin-1 (IL-1), tumour necrosis factor (TNF) and interleukin-6 (IL-6). The level of macrophage colony-stimulating factor (M-CSF), which represents a macrophage proliferation and differentiation factor, was determined in the PF and in the serum. Furthermore, the macrophage phenotypic profile was analysed, in particular the expression of sex steroid hormone receptors. IL-1. IL-6 and TNF were detectable in the PF and in the culture supernatants of PM phi whether stimulated or not by IFN-gamma and LPS. The mean level of M-CSF in the PF was 6.37 +/- 2.02 ng/ml as measured by RIA; this level did not correlate with the concentration of PM phi. The mean PF-M-CSF level was 1.4-fold higher than in the sera as measured by a EIA. Oestrogen and progesterone receptors could not be demonstrated on the PM phi analysed, so that a direct relationship between the ovarian steroid concentration in these women and the function of PM phi was unlikely. As compared to peripheral blood monocytes (Mo). PM phi showed a phenotypic profile, with some more mature features, e.g. increased expression of CD14, CD68, FcRII, FcRIII, CR3, CR4 and MHC class II determinants. These results indicate that resident PM phi have acquired in vivo a certain differentiation and/or activation state under micro-environmental factors where cytokines secreted by the M phi themselves or by other cells such as the mesothelium may play important roles.

Human peritoneal macrophages show functional characteristics of M‐CSF‐driven anti‐inflammatory type 2 macrophages

“…2B, right panel). IL-6 production by pMU has been documented before [14] and this was dramatically elevated in pMU from peritonitis patients [15]. These data suggest that pMU may perhaps not be as polarized as in vitro generated MU2, but, nevertheless, they do have the high IL-10-producing capacity typical of MU2, suggesting a potential anti-inflammatory activity.…”

Catalase Plays a Critical Role in the CSF-independent Survival of Human Macrophages via Regulation of the Expression of BCL-2 Family

“…In a previous study, we reported that human A-M⌽ and GM-CSF-induced monocyte-derived macrophages (GM-M⌽) are resistant to hydrogen peroxide (H 2 O 2 ) via their high basal and inducible levels of catalase activity and that M-CSF-induced monocyte-derived macrophages (M-M⌽) are sensitive to low levels of H 2 O 2 with low levels of catalase activity (2). GM-M⌽ is phenotypically identical to A-M⌽, whereas M-M⌽ closely resembles peritoneal M⌽ in respect to morphology, cell surface antigen expression, and several biological functions (2)(3)(4)(5)(6)(7). In vivo A-M⌽ express BCL-2 family proteins such as BCL-2 and BCL-X L that prevent H 2 O 2 -induced apoptosis via inhibition of caspase-3 or -9 activation and cytochrome c release from mitochondria (8 -11).…”

Intraperitoneal macrophages and tumor immunity: A review

“…Table II lists several resident Ms and their tissue specificity. Macrophages comprise the vast majority (>90%) of the white blood cells in the peritoneal cavity, and are considered the first line of defense for the immune system in the abdomen [22][23][24][25][26][27].…”