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Anti‐Beta‐2 Glycoprotein I Antibodies Affect Bcl‐2 and Bax Trophoblast Expression without Evidence of Apoptosis
Author(s) -
DI SIMONE NICOLETTA,
CASTELLANI ROBERTA,
RASCHI ELENA,
ORIETTA BORGHI M.,
MERONI PIER LUIGI,
CARUSO ALESSANDRO
Publication year - 2006
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1351.034
Subject(s) - apoptosis , glycoprotein , affect (linguistics) , trophoblast , antibody , chemistry , microbiology and biotechnology , beta (programming language) , biology , immunology , pregnancy , placenta , biochemistry , genetics , psychology , communication , fetus , computer science , programming language
Antiphospholipid antibodies (aPLs) reacting with beta‐2 glycoprotein I (β2GPI) have been associated with recurrent fetal loss and pregnancy complications. The aim of the study was to investigate whether aPLs with anti‐β2GPI specificity induce apoptosis of human trophoblasts in vitro . To this end, human anti‐β2GPI monoclonal IgM derived from a patient with antiphospholipid syndrome and a human irrelevant monoclonal IgM were incubated with human trophoblast cell cultures for 24, 48, and 72 h. In all the cultures we evaluated: (i) Bcl‐2 and Bax mRNA and protein expression by Western blot and reverse transcription polymerase chain reaction (RT‐PCR), respectively; (ii) DNA fragmentation by a commercial ELISA kit and by agarose gel electrophoresis; and (iii) the percentage of cells reactive with the monoclonal antibody (MAb) M30 by indirect immunofluorescence. The results were: Bcl‐2/Bax ratio increased in untreated trophoblast cells during the time of culture, showing the highest values detectable after 72 h (2.68 and 2.28 at protein and mRNA levels, respectively). Cell incubation with anti‐β2GPI MAbs induced a significant Bcl‐2/Bax ratio reduction in comparison with untreated cells (1.22 and 1.28 at protein and mRNA levels, respectively, after 72 h incubation). No significant difference was detected after cell exposure to irrelevant MAbs. However, neither DNA fragmentation nor increase in cells positive for the caspase‐cleaved epitope of cytokeratin 18 cytoskeletal protein (M30) was found. In Conclusion, anti‐β2GPI antibodies react with trophoblast cells and reduce the Bcl‐2/Bax ratio, but without any clear apoptotic effect.