Fc alpha-receptor expression on the myelomonocytic cell line THP-1: comparison with human alveolar macrophages.
Immunoglobulin A (IgA) and alveolar macrophages are two important components of the immune system in the respiratory tract. Fc alpha-receptors (Fc alpha R) are present on neutrophils, eosinophils and a series of human mononuclear phagocytes, including monocytes, alveolar macrophages and leukaemia cell lines (U-937). In the present study, using idiotypes and anti-idiotypic antibodies, we report that THP-1 cells, a myelomonocytic cell line, constitutively express Fc alpha R and that all IgA preparations used bind the receptor. Of the stimuli used (phorbol myristate acetate, retinoic acid, calcitriol), only calcitriol can induce differentiation of THP-1 cells, as assessed by CD14 expression. The expression of Fc alpha R appears to be independent of cell differentiation, since calcitriol pretreatment has no effect on IgA-binding. Finally, My43, a monoclonal antibody recognizing the Fc alpha R on U-937 cells, does not bind to THP-1 cells or to human alveolar macrophages. In addition, preincubation of THP-1 cells or human alveolar macrophages with My43 does not diminish IgA-binding to these cells. Ribonucleic acid (RNA) encoding the Fc alpha R isolated from U-937 is expressed, although possibly at a lower level, in alveolar macrophages and THP-1 cells. In conclusion, Fc alpha R are constitutively expressed on THP-1 cells and share some characteristics with the Fc alpha R described in human alveolar macrophages. THP-1 cells, therefore, may represent a reasonable model for further investigation of the interaction of immunoglobulin A and tissue macrophages.
Sibille
Y
Y
Experimental Medicine Unit, Catholic University of Louvain, Brussels, Belgium.
Depelchin
S
S
Staquet
P
P
Chatelain
B
B
Coulie
P
P
Shen
L
L
Vander Maelen
C
C
Vaerman
J P
JP
D001483:Base Sequence; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D016676:Macrophages, Alveolar / Q000276:immunology*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011961:Receptors, Fc / Q000096:biosynthesis*
C045281:IgA receptor; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011961:Receptors, Fc