Decreased migration of myeloid dendritic cells through increased levels of C-reactive protein

Background: In head and neck squamous cell carcinoma (HNSCC), a variety of immunomodulatory mediators contribute to strongly impaired immune functions. The secretion of C-reactive protein (CRP) by HNSCC cells and its influence on human myeloid dendritic cells (MDC) was investigated. Materials and Methods: The CRP levels were analyzed using photometric methods and real-time PCR. The MDC were isolated from peripheral blood by 'magnetic bead separation' and incubated with different CRP concentrations. The CRP isoforms were analyzed by native PAGE (polyacrylamide gel electrophoresis). The cells were analyzed using migration assays and flow cytometry. Results: HNSCC cell lines were able to autonomously express C-reactive protein. Pentameric CRP triggered the down-regulation of chemokine receptor CCR5 and led to a decreased migration of human MDC. Conclusion: CRP appeared to be a modulator of the migration activity of human MDC. The functional modulation of immune cells represents a crucial immune escape mechanism of human carcinomas.