title: Incomplete assembly of IgA2m(2) in Chinese hamster ovary cells.
abstract: Myeloma and Chinese hamster ovary (CHO) cells are frequently used for the production of recombinant antibodies. With increasing interest in producing recombinant IgA for protection against infectious agents, it is essential to characterize the IgA produced in these cells. Here we show that while myeloma cells secrete IgA2m(2) predominantly as H(2)L(2), CHO cells secrete H(2)L and H(2) in addition to fully assembled H(2)L(2). When the CHO cells also synthesize J chain and secretory component (SC), polymeric IgA and secretory IgA in which SC is disulfide bonded to the polymeric IgA are produced. Blocking cysteines on purified IgA2m(2) protein by alkylating with iodoacetamide stabilizes the disulfide bonds between the H and L chains suggesting that the disulfide bonds between H and L chains are unstable. Taken together our results suggest that the covalent assembly of IgA2m(2) is different in myeloma and CHO cells.
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics and the Molecular Biology Institute, University of California Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095, USA. kotec@lifesci.ucla.edu
authors.forename: Koteswara R
authors.initials: KR
authors.lastname: Chintalacharuvu
authors.forename: Brian
authors.initials: B
authors.lastname: Gurbaxani
authors.forename: Sherie L
authors.initials: SL
authors.lastname: Morrison
mesh_terms: D000818:Animals; D016466:CHO Cells; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D007070:Immunoglobulin A / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D007126:Immunoglobulin Allotypes / Q000235:genetics / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000378:metabolism; D009101:Multiple Myeloma / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D007070:Immunoglobulin A; D007126:Immunoglobulin Allotypes; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D011994:Recombinant Proteins