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DNA –histone complexes as ligands amplify cell penetration and nuclear targeting of anti‐ DNA antibodies via energy‐independent mechanisms
Author(s) -
Zannikou Markella,
Bellou Sofia,
Eliades Petros,
Hatzioannou Aikaterini,
Mantzaris Michael D.,
Carayanniotis George,
Avrameas Stratis,
Lymberi Peggy
Publication year - 2016
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/imm.12542
Subject(s) - histone , dna , antibody , chemistry , microbiology and biotechnology , nuclear dna , biology , biochemistry , genetics , gene , mitochondrial dna
Summary We have generated three monoclonal cell‐penetrating antibodies ( CPA bs) from a non‐immunized lupus‐prone ( NZB × NZW )F 1 mouse that exhibited high anti‐ DNA serum titres. These CPA bs are polyreactive because they bind to DNA and other cellular components, and localize mainly in the nucleus of HeLa cells, albeit with a distinct nuclear labelling profile. Herein, we have examined whether DNA –histone complexes ( DHC ) binding to CPA bs, before cell entry, could modify the cell penetration of CPA bs or their nuclear staining properties. By applying confocal microscopy and image analysis, we found that extracellular binding of purified CPA bs to DHC significantly enhanced their subsequent cell‐entry, both in terms of percentages of positively labelled cells and fluorescence intensity (internalized CPA b amount), whereas there was a variable effect on their nuclear staining profile. Internalization of CPA bs, either alone or bound to DHC , remained unaltered after the addition of endocytosis‐specific inhibitors at 37° or assay performance at 4°, suggesting the involvement of energy‐independent mechanisms in the internalization process. These findings assign to CPA bs a more complex pathogenetic role in systemic lupus erythematosus where both CPA bs and nuclear components are abundant.