Development of a Heart Failure Detection Kit Based on Antibody Against Amino-Terminal Pro-Brain Natriuretic Peptide (NT-proBNP): Identification and Immunogenicity Exploration of NT-proBNP Protein

Heart failure (HF) remains a major public health problem with high morbidity and mortality worldwide. The use of cardiac biomarkers such as N-terminal pro–B-type natriuretic peptide (NT-proBNP) has been established as a reliable tool for HF diagnosis and prognosis. However, the high cost and technical requirements of conventional immunoassays limit their accessibility in low-resource settings. This study aims to produce and characterize polyclonal antibodies against NT-proBNP as a preliminary step toward developing an affordable, locally produced detection kit suitable for primary healthcare use in Indonesia. Three male Oryctolagus cuniculus rabbits were immunized intramuscularly with recombinant human NT-proBNP antigen emulsified in Freund’s adjuvant. Immunogenicity was assessed using indirect ELISA at 405 nm absorbance. The ELISA results demonstrated a progressive increase in NT-proBNP-specific antibody titers from week 1 to week 4, with peak levels observed after the second booster (week 7). This pattern reflected the establishment of both primary and secondary humoral immune responses. The absorbance values indicated that NT-proBNP antigen is immunogenic and capable of inducing significant polyclonal antibody production in rabbits. The resulting polyclonal antibodies have multi-epitope recognition potential, which is advantageous for developing point-of-care immunoassays such as lateral flow tests. These results represent an essential foundation for subsequent phases, including antibody purification, affinity testing, and prototype development of an NT-proBNP-based heart failure detection kit optimized for Indonesian healthcare settings. Human NT-proBNP is confirmed to be a highly immunogenic protein capable of inducing the production of specific polyclonal antibodies in rabbits