CHEMOKINES AND CHEMOKINE RECEPTORS DURING ACTIVATION AND DEACTIVATIONOF MONOCYTES AND DENDRITIC CELLS AND IN AMPLIFICATION OF TH1 VERSUS TH2 RESPONSES

Chemokines are a superfamily of small cytokines which are generally ch emotactic for leukocytes. The general features of chemokines and their receptors are reviewed. Recent evidence indicates that receptor expre ssion dictates the spectrum of action of chemokines, as shown recently for Th1 and Th2 cells. Chemokines represent amplification loops of po larized Th1 and Th2 responses. Receptor expression is tightly regulate d during differentiation, activation, and deactivation of mononuclear phagocytes and dendritic cells. Thus, regulation of receptor expressio n is crucial as a set point of the chemokine system.