Naturally occurring masked antibodies in murine sera recognize a component of the mitotic spindle apparatus.
Antibody activities previously masked in autoimmune MRL and normal Balb/c mice were expressed by briefly subjecting their sera to acidic (pH 2.0) or alkaline (pH 12.0) environments. An enzyme-linked immunosorbent assay (ELISA) revealed that these pH-expressable immunoglobulins reacted with specific nucleotide-BSA antigens (primarily 5'-AMP, -GMP, -TMP) but not with single (ss)- or double (ds)-stranded DNAs or with unconjugated BSA. ELISA analysis of pH-expressed antibodies purified via GMP-BSA/Sepharose indicated that they bound not only to the homologous hapten (GMP) but to AMP and TMP as well, i.e., anti-pAGT antibodies. Further, indirect immunofluorescent assays (IIF) with fixed HEp-2 cells demonstrated that purified anti-pAGT antibodies recognized an epitope within the mitotic spindle apparatus. These results document the existence of a previously undefined masked antibody population in murine sera with specificities directed toward certain nucleotides and a component of the mitotic spindle apparatus. Last, these anti-pAGT (or anti-mitotic spindle) antibodies are not restricted to murine systems inasmuch as they have been detected in every human serum (greater than 100 samples) examined thus far.
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000974:Antibodies, Antinuclear / Q000032:analysis; D001327:Autoimmune Diseases / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008807:Mice, Inbred BALB C; D008941:Spindle Apparatus / Q000276:immunology*
D000906:Antibodies; D000974:Antibodies, Antinuclear