Monoclonal antibodies against human neurotrophin-3

Hybridomas producing monoclonal antibodies (MoAbs) against human neurotrophin-3 (hNT-3) were established using recombinant hNT-3 produced in CHO cells and E. coli as immunogens. Of the five MoAbs obtained, MoAb 3w3 showed the highest antibody titer and also best neutralized NT-3 activity as measured by the survival of chick embryonic day-8 dorsal root ganglia neurons. A sandwich enzyme immunoassay (EIA) for NT-3 was established with solid phase MoAb 3W3 and the Fab' fragment of MoAb 3W3 conjugated to horseradish peroxidase. The detection limit was 2.7 pg/well of NT-3 and no cross-reactivity with nerve growth factor up to 100 ng/well was observed. Using this EIA system we have screened a variety of cell lines for NT-3 production. Among these tested, only human Burkitt's lymphoma Namalwa cells were found to be producing NT-3.