GL-2045 drives self-limited complement activation. GL-2045 exposure to NHS results in increased cleavage of both C4 and C3, but does not enhance cleavage of C5. NHS was incubated with various concentrations of GL-2045, IVIG, and HAGG for 90 minutes at 37°C. Levels of C4a, C3a, and C5a were evaluated using the CBA human anaphylatoxin kit. The results are shown as the least squares mean ± SE estimated by ANCOVA. Natural log variance stabilizing transformation and Tukey procedure for multiple comparisons adjustment were used to test the differences. *P < .05, **P < .01, ***P < .001 compared with no-treatment control.