Human autoantibodies that react with both cell nuclei and plasma membranes display specificity for the octamer of histones H2A, H2B, H3, and H4 in high salt.

Abstract

Sera of some patients with systemic lupus erythematosus and related diseases contain a polyclonal antibody population (cross-reactive antinuclear antibodies [X-ANA]) that react specifically with both core mononucleosomes and plasma membranes of viable nucleated cells. Native mononucleosomes and nucleosome cores assembled from long DNA and the inner histones were indistinguishable in terms of inhibition of binding of X-ANA to nuclei of tissue sections and to polynucleosomes on the walls of plastic tubes. In contrast, mononucleosomes selectively depleted of histones H2A and H2B did not inhibit these reactions. A method was developed for isolation of X-ANA from serum that took advantage of the dual specificity of these antibodies. Immunosedimentation in sucrose density gradients revealed that 125I-labeled Fab' fragments of highly pure X-ANA formed complexes with the inner histones H2A, H2B, H3, and H4 in 2 M NaCL, but not in 0.15 M salt. These results indicate that X-ANA recognize an epitope of the inner histone in 2 M salt, and that in 0.15 M NaCL this epitope is not formed unless the histones interact with DNA to generate a nucleosome structure. Furthermore, in light of the previous demonstration that the epitope is destroyed by trypsin, it may be localized in the N-terminal region of histone H2A or H2B.

Human peripheral blood monocytes display surface antigens recognized by monoclonal antinuclear antibodies.

“…Rekvig and Hannestad (18)(19)(20)(21) characterized antibodies obtained from the sera ofpatients with systemic lupus erythematosus that reacted with both plasma membranes and nuclei. The "cross-reactive anti-nuclear antibodies" displayed specificity for the octomer of histones present in core mononucleosomes but not for free histone or free DNA.…”

“…Other investigators have described the presence of DNA and histone on the surface of human peripheral blood mononuclear cells (PBL) obtained from normal individuals (14)(15)(16)(17)(18)(19)(20)(21). These studies employed techniques that did not use antibodies (14)(15)(16)(17), or used sera from SLE patients that may have contained a multitude of specificities for both nuclear and nonnuclear antigens (18)(19)(20)(21).…”

“…These studies employed techniques that did not use antibodies (14)(15)(16)(17), or used sera from SLE patients that may have contained a multitude of specificities for both nuclear and nonnuclear antigens (18)(19)(20)(21). We recently produced and characterized several monoclonal anti-histone and anti-DNA autoantibodies derived from murine models of lupus (22).…”

Antibodies specific for left-handed Z-DNA.

“…With antigenic structures that depend on high salt concentration, such as core histone octamers, antibody reactivity can be maintained in the presence of concentrated salt (14). Additional confirmation of the presence of Z-specific antibodies was obtained by carrying out radioimmunoassays in 4 M NaCl.…”

Extracellularly occurring histone H1 mediates the binding of thyroglobulin to the cell surface of mouse macrophages.

“…Similarly, nuclear transcription factors with homeodomains become secreted before being taken up by neighboring cells where they affect gene transcription in a paracrine fashion (48). Besides these examples, it became obvious in the past that the core histones H2A, H2B, H3, and H4 are frequently detected at the cell surface of leukocytes or endothelial cells (49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). The question on how histones reach the plasma membrane and how they are anchored at the cell surface remains a matter of debate.…”