Table 4.

Potency of LHR domain combination variants in complement pathway-specific Wieslab and red blood cell hemolytic assays

Human CR1 truncation	Wieslab IC50 (nM) ± SD			Hemolytic IC50 (nM) ± SD
Domain	Classical	Lectin	Alternative	Classical	Alternative
LHR-AAA	30.9 ± 3.8∗∗∗	23.9 ± 1.9∗∗∗	No activity	11.3 ± 4.4∗	No activity
LHR-AAB	2.2 ± 0.3∗∗	1.5 ± 0.9	Weak activitya	1.1 ± 0.3∗	Weak activitya
LHR-AAAB	2.8 ± 0.6∗∗	2.0 ± 1.3	Weak activitya	0.8 ± 0.4	Weak activitya
LHR-ABC/CSL040	0.8 ± 0.3	0.4 ± 0.04	0.4 ± 0.1	0.2 ± 0.1	6.0 ± 2.7
LHR-BBC	5.3 ± 0.9∗∗	2.1 ± 0.4∗∗	0.4 ± 0.1	1.7 ± 0.5∗	10.8 ± 3.6

See Figure 4 for graphical data. CSL040 containing LHR-ABC was used as a control/comparator. The IC₅₀ values listed are the mean ± SD of three independent experiments, shown graphically in Figure 5. Statistically significant differences for individual HuCR1 fragment IC₅₀ values compared to CSL040 for each pathway assay were calculated by an unpaired t test; ∗ p < 0.05; ∗∗ p < 0.005; and ∗∗∗ p < 0.0005.

CR1, complement receptor 1; LHR, long homologous repeat.

^aIC₅₀ values could not be determined.