• Complement Factor H (CFH), a complement regulatory protein, is a soluble glycoprotein circulating in human plasma. It is mainly secreted by Kupfer cells, liver cells, vascular endothelial cells and platelets, and is one of the most abundant complement components in blood. CFH provides critical negative regulation of the alternative pathway of the complement cascade by isolating the complement component C3b, accelerating the decay of C3 and C5 converting enzymes, preventing local complement activation, and also acting as a cofactor of C3b inactivation factor I (FI). Homozygous mutation of this gene results in markedly reduced serum C3, abnormal renal histology, spontaneous membranoproliferative glomerulonephritis (MPGN), hematuria, proteinuria, and increased mortality at 8 months of age. When the regulatory function of CFH is impaired, complement-mediated tissue damage and inflammation can occur, such as hemolytic uremic syndrome (HUS) and chronic hypo-complement nephropathy.
• Protein expression analysis: Human CFH was detectable in serum of homozygous B-hCFH mice but not in wild-type mice.
• mRNA expression analysis: Mouse Cfh mRNA was only detectable in liver of wild-type C57BL/6JNifdc mice. Human CFH mRNA was only detectable in liver of homozygous B-hCFH mice.

Gene targeting strategy for B-hCFH mice.
The exons 1-22 of mouse Cfh gene that encode signal peptide, functional domain and 3’UTR are replaced by human counterparts in B-hTSLP mice. The promoter and 5’UTR region of the mouse gene are retained. The human CFH expression is driven by endogenous mouse Cfh promoter, while mouse Cfh gene transcription and translation will be disrupted.

Strain specific CFH expression analysis in wild-type C57BL/6JNifdc mice and homozygous humanized B-hCFH mice by ELISA. Serum was collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCFH mice (H/H) (male, n=3, 8-week-old). Protein expression level of CFH was analyzed by ELISA (Abcam, ab137975). Human CFH was exclusively detectable in homozygous B-hCFH mice

Strain specific analysis of CFH mRNA expression in wild-type C57BL/6JNifdc mice and B-hCFH mice by RT-PCR. Liver mRNA were isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCFH mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse Cfh mRNA and human CFH primers. Mouse Cfh mRNA was detectable only in wild-type mice. Human CFH mRNA was detectable only in homozygous B-hCFH mice but not in wild-type mice.