Anti-DNA-, anti-DWEYS-, anti-NMDAR-specific Abs in human SLE serum. (A) Serum with anti-NMDAR reactivity displays strong binding to dsDNA, DWEYS, and NR2A, whereas control serum without specific reactivity does not bind. The graphs represent titrations of reactive serum (●; two samples assayed in triplicate) and control serum (○; two samples assayed in triplicate) in serial dilutions, starting at 1:125 (dilution 1) and decreasing 2-fold each. (B) The graph shows that dsDNA binding by serum cross-reactive with DWEYS is inhibited by the soluble DWEYSNVWLSN peptide (black bars), assayed from 200 M to 0.02 M excess to Ab, but not by the control DYENLREHRR peptide (red bar) at 200 M excess. (C) Mice injected with anti-NMDAR serum (●; n = 4) show levels of human IgG in their circulation similar to mice injected with control serum lacking anti-NMDA Ab (○; n = 4). IgG concentration was measured 48 h after LPS injection, before brain perfusion, with an ELISA. Serial dilutions of mouse serum were assayed, starting from 1:1,000 (dilution 1) and decreasing 2-fold each. All values represent the mean ± SD.