A natural CCL5/RANTES variant antagonist for CCR1 and CCR3

The N-terminal domain of the chemokine CCL5/ regulated upon activation normal T cell expressed and secreted (RANTES) has been shown to be critical for its biological activity on leukocytes. Several N-terminus-modified CCL5/RANTES derivatives, such as N-Terminal truncated CCL5/RANTES, Met-RANTES, and amino-oxypentane (AOP)-RANTES exhibited antagonist or partial agonist functions when investigated on the properties of their receptors CCR1, CCR3, and CCR5. Studying 95 Affican samples from Cameroon, we found a naturally occurring variant of CCL5/RANTES containing a missense mutation located in the first amino acid of the secreted form (S24F). S24F binds CCRI, CCR3, and CCR5 and triggers receptor down-modulation comparable to CCL5/RANTES. Moreover, in CCR5 positive cells, S24F elicits cellular calcium mobilization equivalent to that obtained with CCL5/ RANTES. By contrast, S24F does not provoke any response in CCRI and CCR3 positive cells. As CCL5/RANTES is able to attract different subtypes of leukocytes into inflamed tissue and intervenes in a wide range of allergic and autoimmune 'diseases, the discovery of this natural Nterminus-modified CCL5/RANTES analogue exhibiting differential effects on CCL5/RANTES receptors, opens up additional perspectives for therapeutic intervention.