The CGB3 antibody targets the beta-3 subunit of human chorionic gonadotropin (hCG), a glycoprotein hormone critical in pregnancy. hCG, composed of α and β subunits, is primarily produced by placental syncytiotrophoblasts to maintain progesterone secretion during early gestation. The β subunit, encoded by the CGB gene cluster (CGB1-9), determines hormone specificity. Among these, CGB3. CGB5. and CGB8 encode the β subunit of bioactive hCG, while others may regulate trophoblast invasion or have non-coding roles.
CGB3 antibodies are essential tools in research and diagnostics. They help detect hCG in pregnancy tests and monitor conditions like gestational trophoblastic diseases (e.g., choriocarcinoma, molar pregnancies) where hCG levels rise abnormally. Additionally, hCG is ectopically expressed in some cancers (e.g., bladder, lung), making CGB3 antibodies valuable in oncology for biomarker studies.
Structurally, CGB3 antibodies recognize epitopes unique to the β subunit, distinguishing hCG from similar hormones like luteinizing hormone (LH). This specificity supports studies on hCG’s roles beyond pregnancy, including angiogenesis, immune modulation, and potential oncogenic signaling. However, cross-reactivity with other CGB variants or degraded forms can pose challenges. Ongoing research focuses on refining antibody specificity and exploring therapeutic applications, such as targeting hCG-expressing tumors.