Figure 2.

Dose-dependent activity of human soluble CR1 truncation variants containing tandem multiplications of the LHR-A domain in vitro. The indicated CR1 LHR-A domain variants (Fig. 1) were tested in the following complement assays: the Wieslab classical (A), lectin (B), and alternative (D) pathways assays; and the red blood cell hemolytic assays specific for the classical (C) and alternative (E) pathways (CH50 and ApH50, respectively). LHR-A(GS30)A refers to an LHR-AA construct containing a 30-amino acid Gly-Ser linker between each LHR-A domain. CSL040 containing LHR-ABC was used as a control/comparator. Data points show the mean (±SD) activity (%) for each CR1 variant concentration (nM) tested. IC₅₀ values calculated from these data are shown in Table 1. CR1, complement receptor 1; LHR, long homologous repeat.