Mab-ZAP: A tool for evaluating antibody efficacy for use in an immunotoxin

Immunotoxins, consisting of antibodies coupled to toxins, are extremely use ful tools in the elimination of specific cell populations in vitro and in v ivo for research and therapeutic applications. The antibody is used to targ et the toxin to a specific cell population, which is distinguished by its c ell-surface antigen. Not all antibodies are suitable for creating an immuno toxin, and large numbers of antibodies may need to be screened. This is a t ime-consuming and expensive process if each potential candidate must be con jugated to the toxin and purified. A faster and more economical way to iden tify potential targeting antibodies is to use a second immunotoxin, an anti -Ige antibody that is coupled to the toxin. The second immunotoxin eliminat es the need to couple every candidate antibody to the toxin because it can simply be added to cells in culture with the antibody of interest. Using th is method, many antibodies can be screened quickly and efficiently for thei r ability to internalize.