Transcriptional response of human dendritic cells to Borrelia garinii—defective CD38 and CCR7 expression detected

Abstract: Lyme borreliosis is a disease, which can affect several organs and cause a variety of symp-toms. In some patients, the infection may become chronic, even after antibiotic therapy, and cause persisting damage. Dendritic cells (DC) are in-volved in the initiation of innate and adaptive im-mune responses. To study interactions between Borrelia garinii (Bg), one of the causative agents of Lyme borreliosis, and human DC, we used a cDNA microarray to compare the Bg-induced DC tran-scriptional response with the response induced by LPS. The Bg-induced response consisted of a smaller number of genes than the LPS-induced response. The microarray showed that the ectoen-zyme CD38, which has an important role in DC chemotaxis and migration to lymph nodes, was strongly up-regulated by LPS but practically not at all by Bg. This finding was confirmed with quanti-tative RT-PCR and with flow cytometry at the pro-tein level. In addition, RT-PCR showed that CCR7 expression was 11-fold greater in LPS-stimulated than in Bg-stimulated cells. These findings suggest that Bg may affect crucial DC functions by block-ing the up-regulation of important molecules in DC migration to lymph nodes, thus affecting further immune responses in Lyme borreliosis infection. J