Human monoclonal antibody derived from an autoimmune thrombocytopenic purpura patient, recognizing an intermediate filament's determinant common to vimentin and desmin.
Human monoclonal antibody (mAb) technology has been helpful in identifying autoantibodies that are involved in various autoimmune disorders. We report here the results of such an attempt to immortalize antibody-forming cells from spleen of an autoimmune thrombocytopenic purpura (ATP) patient and characterize the resulting mAb. The human mAb we derived, denoted (4G9), binds to the cytoskeletal network. Using immunofluorescence analyses of permeabilized and fixed cell lines and tissues, the 4G9 mAb was shown to be anti-vimentin specific by virtue of its intracellular staining pattern, decoration of cell lines of mesenchymal (but not epithelial) origin, and by the fact that polyclonal anti-vimentin (and not anti-actin, prekeratin, tubulin or vinculin) antibodies inhibited its binding to intermediate filaments of a fibroblastoid cell line. The presence of vimentin in platelets was also confirmed in the present study by immunoblotting of platelet extract using murine anti-vimentin mAb. Interestingly, in addition to vimentin the 4G9 mAb decorated intermediate filaments in desmin-expressing muscular cells, suggesting that the 4G9 epitope is most likely located within the homologous sequences that are known to be shared between vimentin and desmin.
Hematology Unit, Kaplan Hospital, Rehovot, Israel.
D
D
Varon
S
S
Linder
E
E
Gembom
L
L
Guedg
H
H
Langbeheim
A
A
Berrebi
Z
Z
Eshhar
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015551:Autoimmunity; D003893:Desmin / Q000276:immunology*; D000939:Epitopes; D006801:Humans; D011696:Purpura, Thrombocytopenic / Q000276:immunology*; D014746:Vimentin / Q000276:immunology*
D000911:Antibodies, Monoclonal; D003893:Desmin; D000939:Epitopes; D014746:Vimentin