Distribution of macrophages during fish development: an immunohistochemical study in carp ( Cyprinus carpio , L.)

Abstract

A monoclonal antibody against carp macrophages (WCL15) has been utilised in flow cytometry, immuno-histochemistry and immuno-electron microscopy to assess the distribution of monocytes/macrophages in developing carp lymphoid tissues. In suspensions of living cells WCL15 reacted strongly with cytoplasm and plasmic membrane of macrophages. It also cross-reacted with a subpopulation of thrombocytes, but this reaction could be neglected by double immunostaining in combination with a thrombocyte-specific marker. In Bouin-fixed tissues the antibody distinctly recognised macrophages. Macrophages were found from day 2 post-fertilisation in head kidney and in the dorsal portion of the yolk sac epithelium. From 1 week onwards macrophages were found scattered in thymus and gut and during the second week in spleen. Macrophages increased in number in all lymphoid tissues until the 6-8th week post-fertilisation, but they decreased except in thymus, where they became localised mainly in the cortical-medullary boundary, and in white pulp areas of head kidney. The role of macrophages in allowing an early non-specific defence in young fish and in co-operating during the differentiation processes of T-cells and B-cells is discussed.

The ontogeny of mucosal immune cells in common carp (Cyprinus carpio L.)

“…The intermediate cell mass transforms into the 'dorsal aorta' in zebrafish (Willett et al 1999), which is the equivalent of the aortagonad-mesonephros region, the first site of definitive haematopoiesis in tetrapods. WCL15 + cells (monocytes/macrophages) first appeared in the lamina propria of the intestine at 7 dpf, which is about the same age as in other studies (Romano et al 1998), while intraepithelial macrophages (IEM) appear considerably later around 4 wpf (Joosten et al 1995). These intraepithelial macrophages have been shown to ingest antigens, and are proposed to have a role in antigen presentation (Rombout et al 1989a, b;Joosten et al 1995).…”

“…The principles of laboratory animal care . WCL15 (mouse IgM) reacts (on tissues) with the cytoplasm of macrophages and monocytes (Weyts et al 1997;Romano et al 1998). …”

“…Cells (Romano et al 1998) and humoral factors (Huttenhuis et al 2005a) of the innate immune system are already present at 2 dpf, while the thymus (the first organ of the adaptive immune system) starts developing from 3 to 4 dpf (Romano et al 1999;Huttenhuis et al 2005). Systemic antibody responses appear considerably later at 1-2 months, while juvenile tolerance is evoked before this age (Mughal and Manning 1985;Van Muiswinkel et al 1985;Mughal et al 1986).…”

“…Peyers Patches) like in mammals. The carp intestine contains many immunoglobulin positive (Ig + ) lymphoid cells [recognized with the mAb WCI12 (Koumans- Van Diepen et al 1995)] and granulocytes in the lamina propria, but also (Ig + ) macrophages [recognized with the mAb WCL15 (Weyts et al 1997;Romano et al 1998)] and even more Ig -lymphoid cells in the epithelium (Rombout et al 1993a, b). Macrophages (Joosten et al 1995) have been implicated in the uptake of macromolecules in the second segment of the intestine (Rombout et al 1985).…”

The mitochondrial import gene tomm22 is specifically required for hepatocyte survival and provides a liver regeneration model

“…S1A,B). In addition, using the monoclonal antibody WCL15 (Romano et al, 1998;van der Sar et al, 2004), we detected several macrophages engulfing dying hepatocytes in oli s469 mutants (Fig. 2H), whereas in WT livers macrophages can only very occasionally be observed in the periphery of the liver (Fig.…”