Targeted Expression of Chemokines In vivo

One of the main reasons for interest in chemokines is the ease with which their expression can be documented in physiological settings involving leukocyte trafficking or in diseases characterized by inflammatory cell infiltration. In the case of most ELR-containing CXC chemokines, their ability to attract neutrophils in vitro is paralleled by a similar activity when injected In vivo (1 –3 ). However, in the case of non-ELR CXC and most CC chemokines, injection In vivo has resulted in disparate and inconsistent reports of activity (4 –6 ). Thus, in order to be able to infer anything about the function of chemokines in normal physiology or disease, it must be demonstrated that their in vitro activities accurately predict their In vivo activities.