Modulation by lipopolysaccharide of inflammatory cytokine production by two T cell lines

Naive mouse macrophages become activated following recognition of L5178Y lymphoma cells via concurrent ligation of CD40, NKG2D, and CD18 molecules

Under different circumstances, tumors can inhibit or activate macrophage (Mphi) effector functions. We studied the mechanisms of tumor-Mphi interactions leading to Mphi activation. The results show that L5178Y mouse T cell lymphoma cells can prime naive mouse Mphi to subsequent LPS stimulation, resulting in increased NO production and antilymphoma effects in vitro. L5178Y cells, but not naive splenocytes, primed Mphi to ligation of TLR4 but not TLR9. L5178Y-primed Mphi incubated with LPS showed down-regulation of CD40 and up-regulation of NKG2D expression. Although L5178Y T cell lymphoma cells primed naive mouse Mphi, several other mouse and human cells lines failed to prime mouse Mphi. Neither L5178Y-conditioned supernatants nor coculture of Mphi and L5178Y cells in Transwells resulted in priming, indicating that direct L5178Y cell-Mphi contact was needed. Several receptor-ligand pairs are reciprocally expressed on Mphi and L5178Y cell membranes and can be potentially involved in Mphi priming. Of these, the CD40-CD154 pair played the most important role, as blocking the interaction of these molecules substantially reduced in vitro Mphi priming. Furthermore, simultaneous blocking of interactions between CD40-CD154, NKG2D-H60, and CD18-ICAM-1/2 led to complete abrogation of Mphi-mediated NO secretion and complete inhibition of Mphi-mediated tumor cell cytostasis. The priming of Mphi to LPS with L5178Y cells was also observed in vivo. These results suggest that contact with certain tumor cells via CD40, NKG2D, and CD18 molecules on the Mphi may facilitate Mphi-mediated antitumor immune surveillance.

A polymorphism in the promoter of the CD14 gene (CD14/-159) is associated with the development of coronary artery lesions in patients with Kawasaki disease

OBJECTIVE

To investigate whether a polymorphism in the CD14 gene is associated with Kawasaki disease (KD).

STUDY DESIGN

We extracted DNA from the whole blood of 69 control children and 67 patients with KD. We determined a polymorphism in the CD14 gene at position -159 upstream from the major transcription site (CD14/-159) by restriction fragment assay. We then investigated the association between CD14/-159 and the onset of KD and development of coronary artery lesion (CAL).

RESULTS

The genomic and allelic frequencies of the polymorphism were not different between normal children and KD patients. The KD patients with TT genotypes at CD14/-159 had more CAL complications than those with CT and CC (OR, 4.05; 95% CI, 1.34-12.22). The frequencies of the T allele was significantly higher than that of the C allele in KD patients with CAL (OR, 2.20; 95% CI, 1.23-3.94). Their data were confirmed in the patients whether the patients were treated with intravenous gamma-globulin. KD patients with TT genotypes had significantly higher levels of C-reactive protein and vascular endothelial growth factor, which had previously been reported as risk factors for CAL, than those with CC genotypes.

CONCLUSION

These results indicate that the T allele and TT genotype at CD14/-159 are risk factors for CAL in KD, and that the development of CAL in KD may be related to the magnitude of CD14 toll-like receptor response.

Sirolimus interferes with the innate response to bacterial products in human whole blood by attenuation of IL-10 production

Current immunosuppressive strategies are aimed at abrogating the allospecific T-cell response against donor tissues or organs. However, little information is yet available on the potential influences of these drugs on innate immune responses. In order to address this, we have employed a whole blood model. Human whole blood was pretreated with sirolimus, cyclosporine A or tacrolimus in therapeutic as well as supra therapeutic doses, and subsequently stimulated with lipopolysaccharide (LPS), peptidoglycan (PepG) or lipoteichoic acid (LTA). Plasma cytokine analyses revealed a potent inhibitory effect of sirolimus on interleukin(IL)-10 production induced by all bacterial products tested. In contrast, cyclosporine A and tacrolimus inhibited the tumour necrosis factor (TNF)-alpha production in response to LPS, but not to PepG and LTA. Using a quantitative mRNA analyses, we also observed that sirolimus significantly decreased the IL-10 mRNA accumulation to sub-basal levels in peripheral blood mononuclear cells (PBMC). This suggests that the sirolimus inhibits IL-10 production by interfering with the IL-10 gene transcription. However, the molecular mechanism of this inhibition remains unclear. Based on the present study and observations by others, we postulate that the clinical use of the sirolimus may be associated with a dysregulated innate immune response to bacterial infection and thus an increased risk of hyperinflammation and sepsis.