A Novel Antibody against Human Properdin Inhibits the Alternative Complement System and Specifically Detects Properdin from Blood Samples
Figure 2
Monoclonal antibodies specifically detect properdin in human serum.
(A) Purified human properdin, human serum, recombinant mouse properdin, human embryonic kidney (HEK) cell supernatant and fetal calf serum were immobilized on an ELISA plate. In house mAb 1340 (1 µg/mL) and commercial mAb A235 (1 µg/mL) detected only purified human properdin or human serum, respectively. MAb A233 (1 µg/mL) detected all antigens tested. Shown are the respective means (± s.e.m.) for two independent experiments. After background subtraction data were normalized to mAb 1340 reactivity against properdin (set to 100%). (B) Human properdin was isolated from human serum by immunoprecipitation (IP) using mAb 1340 (left lane). The precipitated proteins and purified control properdin (right lane) were separated by non-reducing, denatured SDS-PAGE. Western blot detection was performed with mAb 1340 and a peroxidase conjugated anti-mouse IgG antibody. The generated mAb precipitated and detected properdin monomer (∼55 kDa), dimer (∼110 kDa) and trimer (∼165 kDa), respectively.