Messenger RNA expression before and after CD40 activation.

CD11b⁺ DCs, but not CD11b⁻ DCs, express the M-CSFR, MIP-1α, and decysin after CD40 activation; CD11b⁻ DCs express TECK. Two-fold dilutions of cDNA were prepared from RNA purified from CD11b⁻ and CD11b⁺ thymic DCs, freshly after sorting or after 24 hours of CD40 activation by means of an agonistic anti-CD40 antibody. (A) CD11b⁻ DCs express high levels of DC-LAMP and TECK freshly after isolation. After 24 hours of CD40 activation, DC-LAMP is still expressed, but only very little decysin is expressed and TECK expression is down-regulated. MIP-1α and M-CSFR mRNA were never detected, before or after CD40 activation. (B) After CD40 activation, CD11b⁺ DCs up-regulate DC-LAMP and express very high amounts of decysin. CD11b⁺ DCs express MIP-1α and the M-CSFR freshly after sorting and retain some M-CSFR expression after CD40 activation. However, CD11b⁺ DCs do not express TECK, either freshly or after CD40 activation. (C) Controls from MoDCs (fresh or CD40-activated), tonsillar CD3⁺ T cells, and CD20⁺ B cells show that DC-LAMP and decysin are expressed only in mature DCs. The analysis is representative of 4 separate experiments using 2 separate thymus samples.