APS-derived monoclonal antibodies P1-117 and P2-6 were cloned as full-length human IgG1 and purified. Full-length mature rhβ2GPI, a mutant version containing alanines in positions R39-R43 (rhβ2GPIΔ39-43),
R. int DNA methyltransferase (
R. int DNMT, WP_118597735.1), and a mutant version containing alanines in positions R122-R126 (
R. int DNMTΔ122-126) were expressed and purified. (A) Representative ELISA titration curve showing P1-117 binds to R39-R43 within domain I (DI) of β2GPI. (B) Representative
R. int ELISA showing P1-117, P2-6 negative control (binding domain I outside R39-R43),
R. int-immunized, and sham-immunized mouse sera, respectively. X-axis shows serum dilutions (1:100 serum = 10 μg/mL antibody) in 2-fold dilutions. (C) Representative ELISA titration curve of P1-117 and P2-6 binding to
R. int DNMT or
R. int DNMTΔ122-126, respectively. (D) Human trophoblast cells were treated with media, P1-117 (50 μg/mL) or IgG isotype control (50 μg/mL). After 48 h, cell migration was measured (n = 4, *p
Figure 4.. APS Patients Have Significantly Elevated…
Figure 4.. APS Patients Have Significantly Elevated Levels of Anti- R. int DNMT IgG that…
Figure 4.. APS Patients Have Significantly Elevated Levels of Anti-R. int DNMT IgG that Positively Correlate with Anti-β2GPI IgG Autoantibodies ELISAs of R. int DNMT and R. int DNMTΔ122-126 plasma diluted 1:1000 and probed for IgG. (A) Averages from 2-3 time points are shown as individual points. APS patients have significantly higher anti-R. int DNMT IgG (n = 15, p = 0.0112) compared to NHD (n = 20). APS patient plasma contains significantly less anti-R. int DNMTΔ122-126 IgG compared to wild-type DNMT (n = 15, p = 0.0103). APS plasma anti-R. int DNMTΔ122-126 IgG values were not significantly different from NHD plasma anti-R. int DNMT IgG or anti-R. int DNMTΔ122-126 IgG, respectively (n = 20 each). (B) Average APS anti-R. int DNMT IgG levels (x axis) significantly correlate with increasing anti-β2GPI IgG (y axis). Pearson r = 0.569, R2 = 0.323, p = 0.0271 two-tailed. (C) Average NHD R. int DNMT IgG levels (x axis) do not correlate with average anti-β2GPI IgG (y axis). Pearson r = 0.216, R2 = 0.047, p = 0.361 two-tailed. Two-tailed Mann-Whitney U test performed for inter-group comparison and two-tailed Wilcoxon signed-rank test performed for intra-group comparison. APS, antiphospholipid syndrome; NHD, normal healthy donor. Error bars represent ± SEM. *p < 0.05, ns = not significant.
Figure 5.. Immunization of BALB/c Mice with…
Figure 5.. Immunization of BALB/c Mice with R. int Induces Human β 2 GPI Cross-Reactivity
Figure 5.. Immunization of BALB/c Mice with R. int Induces Human β2GPI Cross-Reactivity (A) Clustal Omega alignment of RGGMR DI epitope in β2GPI, Roseburia intestinalis L1-82 (R. int) and Bacteroides thetaiotaomicron VPI-5482 (B. theta). B. theta lacks T cell mimotope homology but contains a partial B cell mimotope (GGMR) homology. (B and C) Proliferative response to immunization was determined using ATP luminescence in triplicates. Fold increase was determined by averaging triplicates from stimulated populations and dividing by the average of the unstimulated (“no antigen”) cells in RLU. Splenocytes (B) and peripheral lymphocytes isolated from inguinal and axillary lymph nodes (C) were restimulated ex vivo with rhβ2GPI. (B) Splenocytes from R. int-immunized mice (n = 7) respond significantly more to rhβ2GPI than sham-immunized mice (n = 7, p = 0.0017) and B. Theta-immunized mice (n = 6, p = 0.0047). (C) Peripheral lymphocytes from R. int-immunized mice (n = 7) respond significantly more to rhβ2GPI than sham-immunized mice (n = 7, p = 0.0006) and B. theta-immunized mice (n = 6, p = 0.0012). (D and E) Mice were immunized s.c. with lysates from R. int, B. theta, or no lysates (sham) in IFA followed by three s.c. IFA boosts. Representative ELISA using 1:100 diluted serum. Values represent the average OD450 of individual mice in triplicates. (D) R. int-immunized mice have significantly more serum anti-β2GPI IgG (n = 8) compared to B. theta-immunized mice (n = 7, p = 0.0003) and sham-immunized mice (n = 7, p = 0.0003). R. int-immunized and B. theta-immunized sera lose significantly binding to rhβ2GPI39-43 compared to rhβ2GPI. (E) R. int-immunized mice have significantly more serum anti-R. int DNMT IgG (n = 8) compared to B. theta-immunized mice (n = 7, p = 0.0205) and sham-immunized mice (n = 7, p = 0.0003). R. int-immunized and B. theta-immunized sera lose significantly binding to R. int DNMTΔ122-126 compared to R. int DNMT. Two-tailed Mann-Whitney U test performed for inter-group comparison and two-tailed Wilcoxon signed-rank test performed for intra-group comparison. Error bars represent ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ns = not significant.
Figure 6.. Gavage of (NZW × BXSB)F…
Figure 6.. Gavage of (NZW × BXSB)F 1 Male Mice with R. intestinalis Induces Anti-Human…
Figure 6.. Gavage of (NZW × BXSB)F1 Male Mice with R. intestinalis Induces Anti-Human β2GPI IgG Autoantibodies and Thromboses (NZW × BXSB)F1 mice were gavaged weekly with R. intestinalis L1-82 (R. int) or media after two weeks of vancomycin treatment. (A and B) Sera from 16-week-old mice were tested for anti-human β2GPI IgG or anti-R. int DNMT IgG by ELISA at 1:100 dilution. (A) R. int gavage of male mice (n = 17) induces significantly elevated anti-human β2GPI IgG compared to males gavaged with media (n = 16, p = 0.006) and females gavaged with R. int (n = 6, p = 0.0002). R. int gavage of male mice induces significantly elevated anti-R. int DNMT IgG compared to males gavaged with media (p < 0.0001) and females gavaged with R. int (p < 0.0001). (B) Anti-human β2GPI IgG positively correlates with anti-R. int DNMT in male R. int-gavaged mice at 16 weeks of age. Pearson r = 0.626, R2 = 0.392, p = 0.007 two-tailed. (C) Shown are representative micrographs of H&E-stained myocardium from two R. int-gavaged males that died spontaneously because of autoimmunity at 17 weeks (upper panel) and 16 weeks (lower panel) of age, respectively. R. int-gavaged males show widespread myocardial and subendocardial lymphocytic infiltrates. (D) Shown are representative micrographs of H&E-stained myocardium from two male mice gavaged with media that survived beyond 34 weeks at which point they were euthanized (representative images of two separate mice, upper and lower). Surviving mice show unremarkable myocardium without any evidence of inflammation or myocardial infarction. Scale bar, 500 μm. Two-tailed Mann-Whitney U test performed for inter-group comparison and two-tailed Wilcoxon signed-rank test performed for intra-group comparison. Error bars represent ± SEM. **p