Reactivity of the sera of vaccinated Swiss mice with MCF-7 cells. MCF-7 cells were grown on tissue culture slides and incubated with sera (at 1:100 dilution) from mice immunized with PBS (a), BTAA alone (b) or BTAA in combination with NLP (c). Anti-BTAA antibody binding was determined by streptavidin-peroxidase method using aminoethylcarbazol as a substrate (Immunoperoxidase, magnification 200x).