BackgroundTo understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with the... Show moreBackgroundTo understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with the presence of tumor-infiltrating lymphocytes (TILs), and their prognostic relevance in UM patients. Materials and methodsExpression of PD-1 and PD-L1 was assessed in 71 UM tissue samples by immunohistochemistry and quantitative real-time PCR (qRT-PCR), and further validated by western blotting. The effect of interferon gamma (IFN-gamma) on PD-1/PD-L1 expression was determined on four UM cell lines. ResultsImmunoreactivity of PD-1 was found in 30/71 cases and of PD-L1 in 44/71 UM samples. Tumor-infiltrating lymphocytes were found in 46% of UM tissues. PD-1 was expressed on TILs while tumor cells expressed PD-L1. UM with and without TILs showed expression of PD-1 in 69% and 18% cases, respectively (p=0.001). Similarly, PD-L1 was found in 75% of UM with TILs and in 50% of cases without TILs, respectively (p=0.03). DFS rate were lower in patients with TILs with expression of PD-1 and PD-L1, but the rate of DFS was higher with expression of PD-L1 in patients without TILs. After treatment of UM cell lines with IFN-gamma, PD-1 expression was induced in all UM cell lines whereas PD-L1 expression was found at a lower level in untreated cells, while expression also increased following treatment with IFN-gamma .ConclusionOur study suggests that increased infiltration with TILs promotes the aggressive behavior and suppresses the immune response of UM cells, thereby inhibiting immunotherapy. Show less
Kritikou, E.; Duijn, J. van; Nahon, J.E.; Heijden, T. van der; Bouwman, M.; Groeneveldt, C.; ... ; Bot, I. 2018
The development of atherosclerosis is tightly regulated by the innate and adaptive immune system. Communication between these two compartments occurs, among others, upon presentation of lipid... Show moreThe development of atherosclerosis is tightly regulated by the innate and adaptive immune system. Communication between these two compartments occurs, among others, upon presentation of lipid antigens to the NKT cell population by CD1d-expressing antigen-presenting cells. Recent evidence states that also mast cells express CD1d and can directly communicate with NKT cells. However, no such relationship has been reported in atherosclerosis. Here, we aimed to elucidate in vivo the CD1d-mediated interaction between mast cells and NKT cells upon atherosclerosis progression.\n mice and subsequently placed the animals on a Western-type diet for 10 weeks.\n circulating T cells.\nThis study is the first to illustrate that disruption of the CD1d communication pathway between mast cells and NKT cells aggravates atherosclerosis, through a shift towards pro-inflammatory T cell responses. This ability of mast cell action during plaque progression sheds new light on their role in atherosclerosis. Show less
The immune system plays an important role in the balance between viral clearance and viral persistence in HPV related (pre)malignant lesions. In this thesis, we analyzed HPV clade A9-specific T... Show moreThe immune system plays an important role in the balance between viral clearance and viral persistence in HPV related (pre)malignant lesions. In this thesis, we analyzed HPV clade A9-specific T-cell responses in relation to virological and clinical outcome to gain further insight into HPV-specific cellular immunity in relation to the natural course of disease. In depth analysis of cellular immune responses against the E6 antigen of HPV16 and the closely related members of clade A9 (HPV31, 33, 35, 52 and 58) showed us that HPV-specific cross-reactive CD4+ T cells are rare and unlikely to mediate cross protection (chapter 2). The clinical course of cervical HPV infection and HPV-specific immune responses in prospective studies are described in chapter 4 and 5. In those chapters, a strong correlation is observed between a persistent HPV infection or progressive disease and the lack or failure of a type-specific immune response (>90% of the cases). No correlation is detected between HPV type-specific cellular immune responses and virological clearance of the infection and HPV type-specific immunity may be associated with clearance of a cervical HPV induced lesion (chapter 4 and 5). Interestingly, a statistically significant trend could be detected between the presence of a type-specific immunity (HPV16E2) and regression of a low-grade lesion (chapter 5). A similar, but - due to small number of patients __ not statistically significant trend was observed in chapter 4. Together, this suggests that the local innate immune system might play a role in the clearance of transient infections, whereas the cellular immune response can play a role in regression of histologically proven HPV induced lesions. Detection of HPV16 type-specific cellular immune responses in vivo, by the use of a DTH skin test, confirmed that cellular immune responses in healthy subjects consist of both HPV-specific CD4+ Th1/Th2 and CD8+ T cells (chapter 3). Show less
