B6-hCFB Mice

Catalog Number: C001710

Strain Name: C57BL/6JCya-Cfbtm1(hCFB)/Cya

Genetic Background: C57BL/6JCya

Reproduction: Homozygote x Homozygote

 

Strain Description

Complement factor B (CFB) is a circulating serine protease that plays a central role in the alternative pathway of the complement system, a critical component of innate immunity. Encoded by the CFB gene, this protein is primarily synthesized by hepatocytes, adipocytes, and monocytes, reflecting its systemic and local involvement in immune surveillance and inflammation [1]. Upon activation by factor D, CFB forms the active enzyme factor Bb, which, in complex with complement component C3b, constitutes the alternative pathway C3 convertase (C3bBb). This convertase catalyzes the cleavage of C3 into the anaphylatoxin C3a and the opsonin C3b, leading to the amplification of the complement cascade and the subsequent elimination of pathogens and damaged cells [2]. Dysregulation of CFB activity, often stemming from genetic polymorphisms within the CFB locus, has been implicated in the pathogenesis of several human diseases, including age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and systemic lupus erythematosus (SLE), underscoring the delicate balance required for proper complement regulation and immune homeostasis [3-4]. These associations highlight CFB as a key mediator of both protective and pathological immune responses.

The B6-hCFB mouse is a humanized model constructed by replacing the sequence of the mouse Cfb gene in situ with the corresponding sequence from the human CFB gene. The homozygous B6-hCFB mice are viable and fertile and can be used for studies on age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and systemic lupus erythematosus (SLE), and pathogenesis of immune-related diseases, as well as for CFB-targeted drug development.

 

Strain Strategy


Figure 1. Gene editing strategy of B6-hCFB Mice. The sequences from ATG start codon to TAA stop codon of the endogenous mouse Cfb gene were replaced with the sequences from ATG start codon to TAA stop codon of the human CFB gene.

 

Application

  • CFB-targeted drug screening, development, and evaluation;
  • Research on the pathological mechanisms and therapeutic approaches of age-related macular degeneration (AMD);
  • Research on the pathological mechanisms and therapeutic approaches of atypical hemolytic uremic syndrome (aHUS);
  • Research on the pathological mechanisms and therapeutic approaches of systemic lupus erythematosus (SLE) and other immune-related diseases.

 

Validation Data

1. RT-qPCR


Figure 2. Gene expression in the liver, and gall bladder of homozygous B6-hCFB mice and wild-type (WT) mice. The results of RT-qPCR showed that there was significant expression of the human CFB gene in the liver, and gall bladder of B6-hCFB mice, while the mouse Cfb gene was not expressed. In contrast, only the expression of the mouse Cfb gene was detected in WT mice, and the expression of the human CFB gene was not detected (NA: Not Applicable).

 

2. ELISA


Figure 3. Detection of the expression of human CFB protein in the serum and plasma of B6-hCFB mice and wild-type (WT) mice. The results of ELISA show that the expression of hFactor B in the serum and plasma of homozygous B6-hCFB mice is significantly higher than that in WT mice (NA: Not Applicable).

 

References
[1]Kavanagh D, Barratt J, Schubart A, Webb NJA, Meier M, Fakhouri F. Factor B as a therapeutic target for the treatment of complement-mediated diseases. Front Immunol. 2025 Feb 14;16:1537974.
[2]Ricklin D, Reis ES, Mastellos DC, Gros P, Lambris JD. Complement component C3 - The "Swiss Army Knife" of innate immunity and host defense. Immunol Rev. 2016 Nov;274(1):33-58.
[3]Takahashi K, Banda NK, Holers VM, Van Cott EM. Complement component factor B has thrombin-like activity. Biochem Biophys Res Commun. 2021 May 7;552:17-22.
[4]Thakkinstian A, McEvoy M, Chakravarthy U, Chakrabarti S, McKay GJ, Ryu E, Silvestri G, Kaur I, Francis P, Iwata T, Akahori M, Arning A, Edwards AO, Seddon JM, Attia J. The association between complement component 2/complement factor B polymorphisms and age-related macular degeneration: a HuGE review and meta-analysis. Am J Epidemiol. 2012 Sep 1;176(5):361-72.