Fifteen hybridoma cell lines producing monoclonal antiboclies （McAb） against recombinant human tu-mor necrosis factor a （rhTNFa） have been established by fusing SP 2/0 cells with spleen cells from aBALB/c mouse immunized with rhTNFa. Following J M Davis’s Works

semi-solid medium was usedfor initial cloning. Five of them were studied further. Their main chromosome- numbers range were 96 to105

all of them were IgG1 subclass. The affinities of these McAbs were estimated to be 1. 25 ×108 mol/L

1. 12×108 mol/L

2. 34×108 mol/L

8. 55 × 107 mol/L

1. 04×108 mol/L

respectively.Two groups of mice challenging with E Coli （107 organisms）

one group treated with 2mg/kg anti-TNF monoclonal antibody

the other did not. There was a higher survival rate in treated group

the serumTNF level was significantly lower too

and the untreated mice had severe pathologic changes in vlscera.