Characterization of mouse macrophage differentiation antigens by monoclonal antibodies

The murine beta-chemokine TARC is expressed by subsets of dendritic cells and attracts primed CD4+ T cells

To investigate specific properties of dendritic cells (DC) which are not shared by other antigen-presenting cells, we compared gene expression patterns of mouse DC and macrophages by differential mRNA display. One of the cDNA identified coded for a murine homolog of the human beta-chemokine, thymus and activation-regulated chemokine (TARC). The gene is expressed in a subset of bone marrow-derived DC and is up-regulated after lipopolysaccharide (LPS) stimulation. In vivo, murine TARC (mTARC) is constitutively expressed by thymic DC, lymphnode DC and CD11c+ cells in the lung. No expression was detected in bone marrow-derived macrophages and LPS-activated B cells. Recombinant mTARC has no chemoattractant activity on naive peripheral CD4+ T cells. In contrast, mTARC induced migration of primed ovalbumin-specific CD4+ T cells with a preference for Th2 cells during the early phase of the T cell response. These observations suggest that mTARC directs migration of antigen-experienced T helper cells to DC in lymphoid as well as in non-lymphoid organs.

Neutrophils secreting tumor necrosis factor alpha infiltrate the central nervous system of BALB/c mice with experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) can be induced in resistant BALB/c mice by ultrasound-formed adjuvant emulsion. In contrast to susceptible mouse strains large numbers of neutrophils secreting TNF-alpha occupied the central nervous system (CNS) of BALB/c mice with severe EAE, whereas only small numbers of macrophages and CD4+ T-cells could be detected. CNS infiltration was preceded with activation of microglial cells. Ultrasound formed adjuvant induced early IFN-gamma expression in popliteal lymph nodes of BALB/c mice, whereas conventional adjuvant induced delayed IFN-gamma production. Although the clinical outcome of EAE was similar to that seen in susceptible mice, the pathogenesis was distinct having possible implications on the different forms seen in multiple sclerosis.

Antigen localisation regulates immune responses in a dose- and time-dependent fashion: a geographical view of immune reactivity

This review summarises experimental evidence to illustrate that induction of immune reactivity depends upon antigen reaching and being available in lymphoid organs in a dose- and time-dependent manner. If antigen reaches lymph organs in a localised staggered manner and with a concentration gradient, a response is induced in the draining lymph node. Antigen-presenting cells are of critical importance to transport antigen from the periphery to local organised lymphoid tissue. If antigen is all over the lymphoid system, then it deletes all specific cells in the thymus or induces them within a few days; because of their limited life-span they then die off, leaving the repertoire depleted of this specificity. If antigen does not reach lymphoid organs it is ignored by immune cells. Once a response is induced, activated but not resting T cells will reach antigen outside lymphoid organs, whereas activated B cells differentiate into plasma cells in an inducing environment, mostly in lymphoid tissue including bone marrow, but also in chronic lymphoid-like infiltrations in peripheral organs. In immunopathology (when the infectious agent is known) or in autoimmunity (when the triggering infectious agent is not known or not recognised) lymphoid tissue may become organised close to the antigen (e.g. in organ-specific autoimmune diseases) and may thereby maintain an autoantigen-driven disease-causing immune response for a long time. The notion that native T cells get induced or silenced in the periphery may be questioned because induction can only occur in lymphoid organs providing anatomical structures where critical cell-cell interactions are properly guided and where, therefore, cells are likely to meet sufficiently frequently and in a critical milieu. Since overall immune reactivity critically depends upon the localisation of antigens in a dose- and time-dependent manner, it seems more likely-but this remains to be shown-that activated T cells may get exhausted in non-lymphoid peripheral tissues, whereas they are usually maintained in lymphoid organs. The critical role of antigen in regulating immune responses also has relevance for our understanding of immunological defence against epithelial and mesenchymal tumours, against many infectious diseases and for understanding autoimmunity and immunological memory. Collectively the data indicate that antigen, dependent upon localisation, dose and time, seems to be the simplest regulator of immune responses.

Immunophenotyping of murine peritoneal macrophages and lymphocytes by flow cytometry

Peritoneal cells include mainly macrophages and both T and B lymphocytes. We describe a simple procedure to analyze by flow cytometry the antigens expressed on macrophage and/or lymphocyte membranes. F4/80 and CR3 macrophage antigens were detected with anti-F4/80 and anti-Mac-1 monoclonal antibodies (mAb) respectively, CD4 and THY1.2 T lymphocyte antigens with GK1.5 and J1j mAbs respectively, B CD5 lymphocytes were identified with LY1.2 mAb and Fc gamma RII/Fc gamma RIII were detected with 2.4G2 mAb.

Markers of mouse macrophage development detected by monoclonal antibodies

In this review, we present and discuss a selected panel of antibody-defined markers expressed during different stages of mouse macrophage development. We distinguish four categories of markers, which are characteristic of: (1) macrophage precursors and immature macrophages (ER-MP12, ER-MP20, ER-MP54, ER-MP58); (2) mature macrophages in general (F4/80, BM8, Mac-1, Mac-2, ER-BMDM1); (3) macrophage subsets (ER-HR3, ER-MP23, ER-TR9, Forssman antigen, MOMA-1, MOMA-2, Monts-4, SER-4), and (4) IFN-gamma-stimulated macrophages (H-2Ia, LFA-1, ICAM-1, 158.2, MBR-2, TM-2, TM-4, and TM-5). It should be noted that many of the markers in this last category are inducible by other stimuli as well. The rigid classification of markers into four separate groups should be regarded as a digitalization of a continuum, thus inevitably implicating a simplification of the complex phenotypic changes that occur during mononuclear phagocyte development. Nevertheless, the current selection of antibodies against markers for different developmental stages of macrophages constitutes an important tool for characterization of mouse macrophages which participate in various biological processes.

Tumor growth changes the contribution of granulocyte-macrophage colony-stimulating factor during macrophage-mediated suppression of allorecognition

Tumor-bearing host (TBH) macrophages (M phi) suppress T cell alloresponses, and this study suggests granulocyte-macrophage colony-stimulating factor (GM-CSF), a molecule associated with suppressive M phi activity during tumor growth, signals more immunosuppression. In the absence of M phi, GM-CSF increased T cell proliferation in response to alloantigen. However, TBH M phi-mediated suppression of allorecogntion was further induced by GM-CSF. Allogeneic mixed lymphocyte reaction (MLR) cultures, containing normal host (NH) M phi, were either unaffected or enhanced. Prostaglandin E2 (PGE2), a highly suppressive monokine that decreases alloreactivity, did not seem to be involved in the suppression caused by the TBH M phi/GM-CSF interaction. M phi-CSF (M-CSF) addition to cultures did not reverse the suppression caused by TBH M phi and GM-CSF, and inhibition of PGE2 synthesis did not change the response to M-CSF. TBH Ia- M phi, a suppressor population that predominates among splenic M phi during tumor growth, demonstrated significantly lower reactivity in the presence of GM-CSF. In contrast, alloresponses suppressed by NH Ia- M phi demonstrated higher reactivity in the presence of GM-CSF. The data collectively suggest that TBH M phi respond differently to GM-CSF, and that tumor-induced changes in GM-CSF responsiveness affect M phi accessory ability.

Phenotypic characterization of three long-term-cultured murine resident macrophage lines

The antigenic phenotypes of three long-term cultured murine resident macrophage lines selected in vitro from cell suspensions of different tissues--namely MAY 1 (from the peritoneal cavity), MASP (from the spleen) and MALU (from lung tissue)--were determined using a panel of monoclonal antibodies. The results indicate that all three cell lines belong to the mononuclear phagocyte system and express characteristics indicating a rather high differentiation state. However, there was a significant difference in antigen expression between the two macrophage lines obtained from solid tissues (MASP from spleen and MALU from lung), which were very similar in their antigenic pattern, and the MAY 1 line obtained from the peritoneal cavity, which seemed to be less well differentiated. The antigenic profile of the "mesothelial" cell population associated with the MASP line indicates that this cell population is difficult to characterize and to include in a particular lineage.

Establishment of murine macrophage-like mutant and hybrid cell lines: comparative analysis of the differentiation induced by 1 alpha,25-dihydroxyvitamin D3 and recombinant murine interferon-gamma

The purpose of this study is to establish the monocyte/macrophage-like cell lines which are sensitive to potent systemic and local factors, 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2 VD3) and interferon-gamma (IFN-gamma). We established two variant mouse macrophage-like cell lines, whose responses to 1 alpha,25(OH)2 VD3 and IFN-gamma differed from one another. The AH-sensitive mutant cell line (G3) was induced by allowing P388D1 tolerant to 8-azaguanine. G3 mutant cells were then fused with the 1 alpha,25(OH)2 VD3-stimulated bone marrow cells isolated from DBA/2 mice. After AH selection the hybrid cell line (XC) was established. The G3 mutant cell line and the XC hybrid cell line had macrophage-like characteristics, such as surface antigens, Fc receptor, C3 receptor, and lysosomal enzymes. The treatment of G3 mutant cells with 1 alpha,25(OH)2 VD3 inhibited cell proliferation with morphological changes, and increased acid phosphatase activity, phagocytic activity, and F4/80 antigen expression on the cell surface. In contrast, IFN-gamma inhibited cell proliferation without effect on acid phosphatase activity and phagocytic activity but increased F4/80 antigen expression. In XC hybrid cells, on the other hand, IFN-gamma, but not 1 alpha,25(OH)2 VD3, inhibited cell proliferation with morphological changes but increased phagocytic activity and F4/80 antigen expression. In addition, IFN-gamma, but not 1 alpha,25(OH)2 VD3, dose-dependently increased multinucleated cell formation of both cells. These findings suggest that the G3 mutant cell line with macrophage-like characteristics is 1 alpha,25(OH)2 VD3- and IFN-gamma-sensitive, and that the XC hybrid cell line is, despite its macrophage-like characteristics, only IFN-gamma-sensitive. Therefore, these newly established cell lines will provide useful systems in studying the differentiation of monocyte/macrophage lineage.