Lack of SC/pIgR-mediated epithelial transport of a human polymeric IgA devoid of J chain: in vitro and in vivo studies.
Three human polymeric IgA (pIgA) myeloma proteins of tetrameric size were compared for their J-chain content, their in vitro secretory component (SC)-binding ability, and their capacity to be transcytosed by polymeric immunoglobulin receptor (pIgR)-expressing epithelial cells in vitro and rat hepatocytes in vivo. One of the three pIgA preparations, pIgA-L, was shown to lack J chain and was unable to combine with purified free human and rat SC, whereas pIgA-G and pIgA-C contained J chain and combined readily with SC. Furthermore, pIgA-L was not transferred into rat bile after intravenous injection, and was hardly transported apically by polarized Madin-Darbey canine kidney cell monolayers expressing the human pIgR, whereas pIgA-G and pIgA-C were efficiently transported in both test systems. Together with our recent demonstration that antibodies to human J chain block the SC/pIgR-mediated epithelial transport of pIgA, these data unanimously confirm the proposed key role of J chain in the epithelial transport of polymeric immunoglobulins into exocrine secretions.
Catholic University of Louvain, Christian de Duve's Institute of Cell Pathology, Unit of Experimental Medicine, Brussels, Belgium.
J P
JP
Vaerman
A
A
Langendries
D
D
Giffroy
P
P
Brandtzaeg
K
K
Kobayashi
D000818:Animals; D001646:Bile / Q000276:immunology / Q000378:metabolism; D001692:Biological Transport; D002478:Cells, Cultured; D004285:Dogs; D004586:Electrophoresis; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D007122:Immunoelectrophoresis; D007070:Immunoglobulin A; D007144:Immunoglobulin J-Chains; D007231:Infant, Newborn; D009101:Multiple Myeloma / Q000276:immunology* / Q000378:metabolism; D009194:Myeloma Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011971:Receptors, Immunologic / Q000378:metabolism; D019056:Receptors, Polymeric Immunoglobulin / Q000378:metabolism*; D012635:Secretory Component / Q000378:metabolism*; D014461:Ultracentrifugation
D007070:Immunoglobulin A; D007144:Immunoglobulin J-Chains; D009194:Myeloma Proteins; D011971:Receptors, Immunologic; D019056:Receptors, Polymeric Immunoglobulin; D012635:Secretory Component