High-Specificity Monoclonal Antibodies (HbS, HbA, panHb) for Rapid Newborn Screening and POC Diagnostic Development
Sickle Cell Disease (SCD) is a group of inherited haemoglobin disorders caused by a point mutation in the HBB gene (Glu6Val, GAG→GTG in β-globin codon 6), affecting an estimated 300,000–400,000 neonates annually. According to Nature Reviews Disease Primers (Piel et al.), approximately 80% of these births occur in Sub-Saharan Africa, where universal newborn screening remains limited. Without early diagnosis and prophylactic penicillin, childhood mortality can reach 50–90% in untreated regions. The sickle allele frequency is highest in malaria-endemic zones — reaching 20–30% in parts of West and Central Africa — because HbAS carriers have a survival advantage against Plasmodium falciparum malaria. While HPLC and isoelectric focusing (IEF) are gold-standard diagnostic methods, Rapid Diagnostic Tests (RDTs) using monoclonal antibodies offer the only scalable, point-of-care solution for high-burden, low-resource settings.
Specific for Sickle Hemoglobin (HbS). Positively tested on HbSS; negative on HbAA/HbCC. Ideal for identifying SCD and Trait.
Specific for Normal Adult Hemoglobin (HbA). Negative on HbSS/HbCC. Critical for differentiating SCD from Sickle Trait.
Universal Hemoglobin marker. Reacts with HbAA, HbSS, and HbCC. Essential as a validity control in multi-line RDTs.
The sickle gene mutation arose independently in multiple geographic regions as a malaria-protective adaptation, resulting in a distinct geographic distribution that directly defines where SCD RDT solutions are most needed.
| Region | Estimated Annual SCD Births | HbS Carrier Frequency | Highest-Burden Countries |
|---|---|---|---|
| Sub-Saharan Africa | ~240,000–300,000 (≈80% of global) | Up to 20–30% in endemic zones | Nigeria, DR Congo, Ghana, Cameroon, Tanzania |
| India | ~40,000–50,000 | 1–40% (tribal and certain caste communities) | Maharashtra, Gujarat, Chhattisgarh, Madhya Pradesh, Odisha |
| Middle East | ~7,000 | 2–25% | Saudi Arabia, Oman, Bahrain, Kuwait |
| Mediterranean | ~2,000 | 1–10% | Greece, Italy, Turkey, Cyprus |
| Americas | ~10,000 | ~8% (Afro-descendant populations) | Brazil, USA, Jamaica, Cuba |
*Adapted from Piel FB et al., Nature Reviews Disease Primers. The WHO estimates over 5 million people globally carry two copies of pathological haemoglobin genes.
| Product Name | Host / Isotype | Concentration | Validation (LFA) |
|---|---|---|---|
| HbSS Antibody | Mouse / IgG1 | 5.69 mg/mL | HbSS (+), HbAA (-), HbCC (-) |
| HbAA Antibody | Mouse / IgG1 | 1.83 mg/mL | HbAA (+), HbSS (-), HbCC (-) |
| panHb Antibody | Mouse / IgG1 | 4.03 mg/mL | HbAA (+), HbSS (+), HbCC (+) |
*All antibodies purified via Protein A affinity chromatography. Formulated in 10mM PBS, pH 7.4.
SCD is caused by a single nucleotide transversion in HBB codon 6 (GAG→GTG), substituting glutamic acid with valine (Glu6Val) in the β-globin chain. This creates Haemoglobin S (HbS, βS), which polymerizes under deoxygenated conditions — distorting RBCs into the sickle shape that drives all downstream pathophysiology. Understanding the distinct biochemical properties of each haemoglobin variant is essential for designing specific, high-performance antibodies.
| Hb Variant | Subunit Composition | β-Globin Mutation | Key Biochemical Property | RBC Phenotype |
|---|---|---|---|---|
| HbAA (Normal) | α₂β₂ (~64.5 kDa) | None — Glu at codon 6 | Fully soluble in oxy- and deoxy-states. Normal O₂ affinity (p50 ~26 mmHg). No polymerization tendency. | Biconcave disc morphology; normal 120-day lifespan |
| HbSS (Sickle Cell Disease) | α₂βS₂ (~64.5 kDa) | Glu6Val (GAG→GTG); homozygous | Deoxy-HbS polymerizes via hydrophobic Val6 contacts. Polymer nucleation at O₂ sat <85%. Gel concentration ~17 g/dL (deoxy). Irreversibly sickled cells accumulate. | Sickle/crescent morphology; haemolysis (Hb ~6–10 g/dL); 10–20 day lifespan |
| HbCC | α₂βC₂ (~64.5 kDa) | Glu6Lys (GAG→AAG); homozygous | Forms intracellular tetrahedral crystals (not fibers). Does not polymerize or induce sickling. Causes RBC dehydration and membrane rigidity. Less soluble than HbA. | Target cells and folded cells; mild haemolytic anaemia; near-normal lifespan |
| HbAS (Sickle Trait) | α₂β₂ + α₂βS₂ (mixed) | One HBB allele Glu6Val; heterozygous | ~60% HbA / ~40% HbS. Sufficient HbA prevents polymerization under normal physiological pO₂. Polymerization only under extreme hypoxia (<40 mmHg). | Normal RBC morphology; asymptomatic; malaria-protective advantage |
| panHb (all variants) | α₂-chain conserved epitopes | N/A — conserved region | Targets shared structural epitopes in the α-globin chain or conserved β-globin regions unaffected by the Glu6Val or Glu6Lys mutations. Binds HbAA, HbSS, HbSC, and HbCC equally. | Used as RDT sample validity control to confirm adequate haemoglobin loading |
Neonates with HbSS are typically asymptomatic for the first 4–6 months of life because fetal haemoglobin (HbF, α₂γ₂) does not carry the Glu6Val mutation. HbF actively inhibits HbS polymer growth by partitioning into hybrid tetramers (α₂βSγ) that are polymer-incompetent. As γ-globin is progressively replaced by βS-globin during the switch from HbF to adult Hb (typically complete by 6–12 months), HbS polymer formation accelerates. This makes the first year of life the critical window for newborn screening — ideally within 72 hours of birth, before HbF decline exposes the child to full pathophysiology.
The Glu6Val (HbS) and Glu6Lys (HbC) mutations occur at the extreme N-terminus of the β-globin chain. Antibodies targeting epitopes in the α-globin subunit or in β-globin regions distal to codon 6 retain full binding affinity to all haemoglobin variants. Sekbio's SCD-panHb antibody exploits this molecular conservation: it confirms that haemoglobin is present regardless of genotype (HbAA, HbSS, HbSC, or HbCC), acting as an internal positive control that distinguishes a true HbS-negative result from a failed test due to insufficient lysed RBCs.
By utilizing Sekbio’s targeted SCD panel, developers can create 3-line RDTs capable of distinguishing clinical phenotypes:
Our antibodies are specifically engineered to survive the harsh conditions of whole-blood lysis required for rapid hemoglobin testing. With ultra-high purity and validated LFA performance, we help you bring reliable SCD screening to the communities that need it most.
Contact our technical team for protocol optimization and bulk pricing.
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