Effect of anti-alpha-fetoprotein serum on growth and plating efficiency of alpha-fetoprotein-producing hepatoma cells in vitro

The effect of a specific rabbit antiserum to rat alpha-fetoprotein (AFP) was examined on the growth and the plating efficiency of AFP-producing rat hepatoma cells (AH70Btc Clone 10-5) in cultures. The addition of anti-AFP serum to the culture medium inhibited cell growth moderately and inhibited plating efficiency markedly, although no inhibitory effect of complexes of AFP and antibody to AFP was observed on cell growth. Anti-AFP globulin in the immune serum was demonstrated on the cell surface by fluorescent antibody technique. Several clones producing low levels of AFP were obtained by long-term treatment of the original Clone 10-5 cells with anti-AFP serum. These treated clones showed characteristics that differed from the untreated original clone 10-5 cells: The relative plating efficiency of the treated clones on agar plates containing 5% anti-AFP serum was higher than the original Clone 10-15 cells and the amount of AFP secreted by the treated clones was lower.