MONOCLONAL-ANTIBODIES AGAINST HST-1 GENE-PRODUCT

Four monoclonal antibodies (MAbs) against the hst-1 gene product (hst- 1 protein) were obtained by a somatic cell hybridization technique. Th e recognition sites of these MAbs designated HS-131, HS-210, HS-233 an d HS-276 on the hst-1 protein were evaluated by competitive binding as say with synthetic polypeptides. HS-131 MAb and HS-276 MAb recognize t he epitope located within the 59-73 and the 197-206 amino acid sequenc es, respectively. The epitopes recognized by HS-210 and HS-233 MAbs co uld not be determined, but these MAbs showed neutralizing activity aga inst hst-1 protein. Using HS-131 and HS-233 MAbs, a sensitive sandwich enzyme immunoassay (sandwich EIA) has been developed. The assay sensi tivity was 1.2-2.5 pg/well of hst-1 protein. Acidic and basic fibrobla st growth factors were not cross-reactive up to a concentration of 1 m ug/ml.