Effect of azithromycin on Chlamydia pneumoniae –mediated Interleukin-4 responses

Abstract

RATIONALE: Expression of both co-inhibitory and co-stimulatory molecules is a key feature of antigen-presenting cells which allow initiation or suppression of T-cell activation. Excessive expression of coinhibitory molecules may be associated with tolerogenic properties of dendritic cells (DC). Expression of B7-family of co-inhibitory molecules by DC was assessed. METHODS: Blood samples from 14 patients with stage II-III pancreatic cancer were studied. Monocyte-derived dendritic cells were obtained. Expression of CD273 (B7-DC), CD274 (B7-H1), CD275 (B7-H2), CD276 (B7-H3), B7-H4, B7-H5 and B7-H6 molecules was assessed by FCM. CaCo-2 cell line served as a positive expression control. RESULTS: Expression of CD276 molecule was approximately 100% (99.1; range 98.6 to 99.7) with high MFI (53.6; range 42.5 to 92.7). CD274 expression was 60.5 % (range 53.6 to 66.9 %). Only 23.6% (range 20.6 to 38.3 %) of DC expressed CD273 and CD275 + DC varied from 11.8% to 30.0% (median 14.8%). The expression of B7-H4, B7-H5 and B7-H6 was absent in the majority of DC. Only 2 DC samples expressed B7-H4 (2.6% and 3.1%), and 2 other samples of DC had noticeable B7-H5 expression (3.0% and 4.2%). B7-H6 was seen only in one DC sample at 9.6%. CONCLUSIONS: CD274 and CD276 are constitutive for DC while expression of CD273 and CD275 is present in relatively low numbers of DC. Expression of B7-H4, B7-H5 and B7-H6 is also present in some of the DC samples in pancreatic cancer. The expression of these molecules by dendritic cells in pancreatic cancer patients may impact disease course.