CFB drives the AP amplification loop through the following steps:
C3 Convertase Formation: Binds C3b to form the pro-convertase C3bB .
Factor D Activation: Cleavage by Factor D generates C3bBb, the active AP C3/C5 convertase .
Complement Cascade: C3bBb cleaves C3 into C3a/C3b and C5 into C5a/C5b, amplifying inflammation and membrane attack complex (MAC) formation .
Biomarker: Low CFB expression in LUAD correlates with advanced tumor stage and smoking history .
Therapeutic Target: Inhibition of CFB/C3bBb is under investigation for autoimmune disorders .
CFB Human, Native is isolated from human serum using chromatographic techniques :
| Parameter | Specification |
|---|---|
| Purity | >95% (SDS-PAGE) |
| Storage Buffer | 10 mM sodium phosphate, 145 mM NaCl, pH 7.2 |
| Concentration | 1.0 mg/mL (varies by batch) |
| Pathogen Testing | Negative for HIV-1/2, HCV, and HBsAg |
GWAS Findings: Variants near CFB (e.g., rs4151657) associate with cardiometabolic traits .
Knockout Models: Cfb−/− rats exhibit reduced inflammation in metabolic syndrome studies .
Gene Expression: Regulated by cytokines (e.g., IFN-γ) and oxidative stress .
Complement Factor B, also referred to as CFB, is a protein encoded by the CFB gene. This protein is a key element of the complement system's alternative pathway. CFB, circulating in the bloodstream as a single polypeptide chain, undergoes cleavage upon activation of the alternative pathway. This cleavage, facilitated by complement factor D, produces two fragments: Ba, a non-catalytic chain, and Bb, a catalytic subunit. The active Bb subunit, a serine protease, interacts with C3b to form the alternative pathway C3 convertase, a crucial enzyme in the complement cascade. Furthermore, Bb plays a role in the proliferation of preactivated B lymphocytes, while Ba, conversely, inhibits their proliferation.
Human Complement Factor B, derived from human plasma, is a glycosylated polypeptide chain with a molecular weight of 93 kDa.
A sterile solution that has been filtered.
The CFB protein solution is buffered with 10mM Sodium phosphate and 145mM NaCl, at a pH of 7.2.
For optimal stability, CFB Human should be stored at 4°C and used within 2-4 weeks of opening the vial. For extended storage, freezing below -20°C is recommended. The addition of a carrier protein (0.1% HSA or BSA) is advised for long-term storage. Repeated freezing and thawing should be avoided.
Purity exceeds 95.0% as assessed by SDS-PAGE analysis.
Each plasma donation has undergone rigorous testing and is confirmed negative for antibodies against HIV-1, HIV-2, HCV, and the surface antigen of the Hepatitis B virus (HBsAg).
CFB, C3/C5 convertase, Glycine-rich beta glycoprotein, GBG, PBF2, Properdin factor B, BF, BFD, AHUS4, ARMD14, CFAB, CFBD, FB, FBI12, GBG, H2-Bf.
Human Plasma.
Ethical research with AI/AN populations must acknowledge historical research abuses such as the Barrow Alcohol Study and Havasupai tribe biospecimen misuse case . Researchers should recognize tribal nations as sovereign entities with government-to-government relationships with federal institutions, as affirmed through Presidential executive orders beginning with President Reagan . Many tribal IRBs consider their entire population as "vulnerable" and may require full board review for all research, as exemplified by the Navajo Nation which does not allow expedited or exempt research .
Research frameworks should:
Incorporate indigenous perspectives in planning, reviewing, and conducting research
Prioritize research questions that benefit the communities involved
Develop partnerships characterized by mutual respect and long-term commitment
Address tribe-specific cultural considerations in methodology
Tribal research oversight varies significantly from standard academic IRBs in structure and focus:
| Academic/Federal IRBs | Tribal Research Oversight |
|---|---|
| Focus on individual protection | Focus on community protection |
| Standardized review processes | Customized review based on tribal needs |
| Emphasis on scientific validity | Equal emphasis on cultural appropriateness |
| Universal ethical principles | Tribe-specific ethical considerations |
According to the search results, "there are over 50 known research oversight entities used by tribes" with considerable variety in how review is handled:
Self-administered tribal IRBs (e.g., Cherokee Nation, Chickasaw Nation)
Tribal College or University IRBs (e.g., Lummi Nation works with Northwest Indian College IRB)
Regional tribal organization IRBs (e.g., Southwest Tribal IRB, California Rural Indian Health Board IRB)
Research review through Tribal Councils or Health Departments
Effective cross-cultural research requires understanding fundamental differences in organizational approaches. Research shows distinct characteristics between academic/federal and tribal organizations:
Methodological recommendations include:
Being both "task- and relationship-oriented" while changing style throughout the project
Maintaining "a sense of urgency, but also take the time to build a solid foundation"
Identifying "champions at every level of the organization (for example, within tribal government, health care organizations, and community agencies)"
Demonstrating that stakeholder "input matters and will influence what happens"
Genetic research presents unique challenges given historical misuse of biospecimens. Methodological approaches should include:
Separate, detailed informational materials about genetic components
Explicit protocols for handling, storing, and potentially sharing genetic data
Clear consent processes for each potential use of biological specimens
Inclusion of tribal representatives in decisions about future uses
Adherence to tribal protocols for biological materials
When these methodological considerations are properly addressed, participation rates can be high. One study achieved 98.8% consent for DNA research and 97.8% consent for placental tissue research after thoughtfully addressing cultural concerns .
Data sovereignty is fundamental to ethical research with AI/AN communities. Methodological frameworks should establish:
Tribal ownership and control of all community data
Prohibition of secondary data use without explicit tribal approval
Clear protocols for data storage, access, and potential sharing
Tribal review rights for publications in draft form
Co-authorship consideration for tribal partners
Cultural context inclusion to prevent misinterpretation
The search results emphasize that "tribes need meaningful ownership and control over data collected from their members" and "data collected for a given study must not be used for another study without prior tribal approval" .
Experimental design must account for:
Informed Consent Design: Tribes are "becoming increasingly involved in the informed consent process" with specific concerns about contact information and reading level appropriateness.
Subject Selection Methodology: Some tribal IRBs consider their entire population as "vulnerable" requiring specialized approaches to sampling and recruitment.
Incentive Structure: Ensure participants are not coerced through "potential loss of services or huge incentives" .
Tribal Capacity Assessment: The tribe itself must not be coerced into participation and should clearly understand resource expectations (funding, staffing, facilities) .
Longitudinal Engagement: Relationships should be established before funding opportunities arise, as "good ideas will find their funding avenue" .
Successful integration requires:
Bidirectional Knowledge Exchange: Researchers must listen and learn while also contributing expertise. As one expert notes: "Listen well, but also offer your expertise, giving useful information in an understandable way. There is a reason you are at the table" .
Methodological Flexibility: Researchers should be willing to adjust standard scientific approaches to accommodate indigenous perspectives. This requires "learning to be humble" and understanding that "it's okay if you get your hand slapped. Learn from it. That's growth" .
Recognition of Knowledge Validity: Indigenous knowledge systems should be respected as valid epistemological frameworks, not merely as cultural context.
Collaborative Analysis Frameworks: Involving tribal members in data interpretation to ensure cultural accuracy.
Appropriate Attribution: Crediting tribal knowledge contributions while respecting restrictions on sharing certain cultural information.
Addressing historical trauma requires methodological approaches that:
Acknowledge specific historical research abuses such as the Barrow Alcohol Study that stigmatized AN study participants as a "generation of despair" leading to municipal bond rating drops .
Recognize ongoing impacts of past research harms, including the Havasupai case where biospecimens collected for diabetes research were used without permission for unauthorized purposes .
Implement transparent processes that demonstrate accountability.
Establish clear benefits to the community that outweigh potential risks.
Develop "patience" and willingness to "settle down and go with the flow" rather than imposing rigid research timelines.
Urban AI/AN research presents unique challenges regarding individual consent versus tribal authority:
Methodological approaches should:
Distinguish between identifying individuals as AI/AN versus by specific tribal affiliation
Develop clear protocols for when tribal consultation is required
Engage with urban Indian organizations for guidance
Consider implications for both individuals and tribal communities
Address the heterogeneity of urban AI/AN populations
Research involving AI/AN communities can benefit from motivation frameworks such as Learned Needs Theory (LNT), which explains how motivation applies to human behavior through:
Achievement Needs: The "pursuit of excellence and perfectionism toward goal attainment" influences how participants engage with research tasks and outcomes.
Affiliation Needs: The desire for "establishing, maintaining, and developing personal relationships" affects recruitment, retention, and community engagement strategies.
Power Needs: How individuals "attempt to influence accountability and funnel the accumulation of resources to enhance status" impacts community-researcher power dynamics.
Effective research design should incorporate these motivational factors to develop "research-based approaches and best practices that consider the varying needs" of AI/AN communities and participants.
Successful research partnerships should be evaluated beyond traditional academic metrics to include:
Relationship Quality Indicators: Depth and durability of research relationships
Community Benefit Metrics: Tangible improvements to community wellbeing
Knowledge Transfer Assessment: Skills and capacity developed within the community
Process Satisfaction Measures: Community evaluations of research processes
Sustainability Indicators: Ongoing collaboration potential and community-driven research capacity
As one expert noted, successful collaboration requires "communication" and "having champions at every level of the organization" while ensuring that everyone knows "they are part of a team" and receives "regular feedback" .
When data interpretations differ between academic researchers and tribal perspectives:
Create structured processes for discussing interpretive differences
Consider multiple analytical frameworks including indigenous epistemologies
Document divergent interpretations rather than forcing consensus
Develop collaborative writing approaches that accommodate multiple perspectives
Recognize the validity of indigenous interpretive frameworks alongside academic perspectives
The CFB gene is located on chromosome 6 in humans . The gene encodes a single-chain polypeptide that circulates in the blood. Upon activation, Complement Factor B is cleaved by Complement Factor D into two fragments: Ba and Bb . The Bb fragment is a serine protease that combines with Complement Factor 3b (C3b) to form the C3/C5 convertase, which is essential for the activation of the complement system .
Complement Factor B is integral to the alternative pathway of complement activation. This pathway is part of the body’s first line of defense against pathogens. When the alternative pathway is activated, Factor B is cleaved, and the Bb fragment associates with C3b to form the C3 convertase (C3bBb). This complex amplifies the response by cleaving more C3 molecules, leading to the opsonization of pathogens and the formation of the membrane attack complex (MAC), which can lyse invading cells .
The Bb fragment has several important functions:
Mutations or deficiencies in Complement Factor B can lead to various immune disorders. For instance, Complement Factor B deficiency (CFBD) is characterized by an increased susceptibility to bacterial infections, particularly those caused by Neisseria species . Additionally, certain variants of the CFB gene have been associated with age-related macular degeneration (ARMD14), highlighting its role in ocular health .
The crystal structure of human Complement Factor B has been resolved at a 2.3-angstrom resolution, providing insights into how the five-domain proenzyme is kept inactive until needed . This structural information is crucial for understanding the precise mechanisms of complement activation and for developing therapeutic interventions.