Studies related to the potential antigenicity of the Bowman-Birk inhibitor, an anticarcinogenic protease inhibitor isolated from soybeans.
Soybeans are known to contain certain proteins that are allergenic; therefore the anticarcinogenic Bowman-Birk protease inhibitor (BBI), an 8-kDa protein isolated from soybeans, could be capable of generating an immune response that would contraindicate its use as a cancer chemopreventive agent. In the present investigation, the stimulation of antibody production in response to BBI was measured after the administration of BBI by various routes and treatment regimens. A significant antibody titer to BBI was observed when the animals were treated with BBI by intraperitoneal injection once or three times per week. In these studies, higher antibody titers were observed at earlier time points. When the animals were treated with BBI by oral gavage, little or no antibody production was observed, regardless of the treatment regimen. The doses and treatment regimens used in this study have been previously demonstrated to be effective in preventing tumor formation. The results of this study indicate that antibody production in response to BBI administered orally should not present a complication to BBI treatment.