Cytokine Knockouts

My personal history in the field of cytokines had an initial period of several years during which my student and then colleague, Werner Muller, tried in vain to attract me to them. My interest always vanished when I was confronted with complex data pointing to func­ tional redundancy of cytokines in cell culture systems. When gene targeting in the mouse germline became possible, this frustration came to an end. We and others immediately embarked on analyzing the in vivo function of cytokines and