Sources/Clones
Dako (MAC 387).
Fixation/Preparation
Applicable to formalin-fixed paraffin sections, acetone-fixed cryostat sections or fixed-cell smears. Requires enzymatic pretreatment for optimum immunostaining but immunoreactivity is not enhanced by HIER.
Background
MAC 387 (IgG1, K) was raised against purified peripheral blood monocytes (Flavell et al, 1987). The antibody recognizes the leukocyte antigen L1 or calprotectin (Steinbakk et al, 1990). The L1 antigen consists of three non-covalently bound polypeptide chains with a total molecular mass of 365 kD. L1 was discovered more than 15 years ago as a major cytosol protein fraction (50-60%) of neutrophilic granulocytes (Fagerhol et al, 1990). This antigen is expressed in neutrophil granulocytes, monocytes, certain reactive tissue macrophages, squamous epithelia and reactive epidermis (Brandtzaeg et al, 1988). It is also reputed to be expressed in early inflammation and is present only in cells of the mononuclear-phagocyte system and not the dendritic system. In vitro experiments have shown the purified composite molecule to exhibit striking antimicrobial properties (Steinbakk et al, 1990).
Applications
MAC 387 antibody produces a cytoplasmic labeling pattern in many myelomonocytic cells. Apart from identifying reactive macrophages, MAC 387 also highlights macrophages in several histiocytoses including hemophagocytic syndrome, Rosai-Dorfman disease and Langerhans' cell histiocytoses (Malone, 1991; Brandtzaeg et al, 1992). True histiocytic lymphomas should be MAC 387+, whilst a small number of large cell anaplastic lymphomas may show immunopositivity (Norton & Isaacson, 1989). Squamous cell carcinomas of the skin, bronchus, bladder and oral cavity may show immunoreactivity (Brandtzaeg et al, 1992), helping us to distinguish them from other types of carcinoma.
Comments
Although both MAC 387 and KP1 are good broad-spectrum macrophage markers, MAC 387 is less specific for cells of the mononuclear-phagocyte system than KP1. Tissues rich in macrophages are suitable as positive controls.
References
•Brandtzaeg P, Jones DB, Flavell DJ, Fagerhol MK 1988. Mac 387 antibody and detection of formalin resistant myelomonocytic L1 antigen. Journal of Clinical Pathology 41: 963-970.
•Brandtzaeg P, Dale I, Gabrielsen T-1992. The leucocyte protein L1 (calprotectin): usefulness as an immunohistochemical marker antigen and putative biological function. Histopathology 21: 191-196.
•Fagerhol MK, Andersson KB, Naess-Andresen C-F, Brandtzaeg P, Dale I 1990. Calprotectin (The L1 leukocyte protein). In: Smith NL, Dedman TR (eds) Stimulus Response Coupling: The Role of Intracellular Calcium-Binding Proteins. Boca Raton: CRC Press, pp 187-210.
•Flavell DJ, Jones DB, Wright DH 1987. Identification of tissue histiocytes on paraffin sections by a new monoclonal antibody.
•Journal of Histochemistry and Cytochemistry 35:1217-1226. Malone M 1991. The histiocytoses of childhood. Histopathology 19: 105-119. Norton AJ, Isaacson PG 1989. Lymphoma phenotyping in formalin-fixed and paraffin wax embedded tissues: II. Profiles of reactivity in the various tumour types. Histopathology 14: 557-579.
•Steinbakk M, Naess-Andresen CF, Linghaas E et al 1990. Antimicrobial actions of calcium binding leucocyte L1 protein, calprotectin. Lancet 336: 763-765.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
Dako (MAC 387).
Fixation/Preparation
Applicable to formalin-fixed paraffin sections, acetone-fixed cryostat sections or fixed-cell smears. Requires enzymatic pretreatment for optimum immunostaining but immunoreactivity is not enhanced by HIER.
Background
MAC 387 (IgG1, K) was raised against purified peripheral blood monocytes (Flavell et al, 1987). The antibody recognizes the leukocyte antigen L1 or calprotectin (Steinbakk et al, 1990). The L1 antigen consists of three non-covalently bound polypeptide chains with a total molecular mass of 365 kD. L1 was discovered more than 15 years ago as a major cytosol protein fraction (50-60%) of neutrophilic granulocytes (Fagerhol et al, 1990). This antigen is expressed in neutrophil granulocytes, monocytes, certain reactive tissue macrophages, squamous epithelia and reactive epidermis (Brandtzaeg et al, 1988). It is also reputed to be expressed in early inflammation and is present only in cells of the mononuclear-phagocyte system and not the dendritic system. In vitro experiments have shown the purified composite molecule to exhibit striking antimicrobial properties (Steinbakk et al, 1990).
Applications
MAC 387 antibody produces a cytoplasmic labeling pattern in many myelomonocytic cells. Apart from identifying reactive macrophages, MAC 387 also highlights macrophages in several histiocytoses including hemophagocytic syndrome, Rosai-Dorfman disease and Langerhans' cell histiocytoses (Malone, 1991; Brandtzaeg et al, 1992). True histiocytic lymphomas should be MAC 387+, whilst a small number of large cell anaplastic lymphomas may show immunopositivity (Norton & Isaacson, 1989). Squamous cell carcinomas of the skin, bronchus, bladder and oral cavity may show immunoreactivity (Brandtzaeg et al, 1992), helping us to distinguish them from other types of carcinoma.
Comments
Although both MAC 387 and KP1 are good broad-spectrum macrophage markers, MAC 387 is less specific for cells of the mononuclear-phagocyte system than KP1. Tissues rich in macrophages are suitable as positive controls.
References
•Brandtzaeg P, Jones DB, Flavell DJ, Fagerhol MK 1988. Mac 387 antibody and detection of formalin resistant myelomonocytic L1 antigen. Journal of Clinical Pathology 41: 963-970.
•Brandtzaeg P, Dale I, Gabrielsen T-1992. The leucocyte protein L1 (calprotectin): usefulness as an immunohistochemical marker antigen and putative biological function. Histopathology 21: 191-196.
•Fagerhol MK, Andersson KB, Naess-Andresen C-F, Brandtzaeg P, Dale I 1990. Calprotectin (The L1 leukocyte protein). In: Smith NL, Dedman TR (eds) Stimulus Response Coupling: The Role of Intracellular Calcium-Binding Proteins. Boca Raton: CRC Press, pp 187-210.
•Flavell DJ, Jones DB, Wright DH 1987. Identification of tissue histiocytes on paraffin sections by a new monoclonal antibody.
•Journal of Histochemistry and Cytochemistry 35:1217-1226. Malone M 1991. The histiocytoses of childhood. Histopathology 19: 105-119. Norton AJ, Isaacson PG 1989. Lymphoma phenotyping in formalin-fixed and paraffin wax embedded tissues: II. Profiles of reactivity in the various tumour types. Histopathology 14: 557-579.
•Steinbakk M, Naess-Andresen CF, Linghaas E et al 1990. Antimicrobial actions of calcium binding leucocyte L1 protein, calprotectin. Lancet 336: 763-765.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
