Residual Lymphocytes in GM-CSF and IL-15 Differentiated Monocyte-Derived Dendritic Cells Enables Cytotoxic T Lymphocyte Responses.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4907-4907
Author(s):  
Melinda Y. Hardy ◽  
Andrew J. Kassianos ◽  
Ray Wilkinson ◽  
Annelie Vulink ◽  
Derek N.J. Hart ◽  
...  

Abstract We investigated the capacity of IL-15 to differentiate human dendritic cells (DC) from monocytes in the presence of GM-CSF (IL-15 MoDC) and compared them with MoDC differentiated in IL-4 and GM-CSF (IL-4 MoDC) as used in many immunotherapy protocols. IL-15 MoDC expressed higher levels of CD40 and HLA-DR and importantly, induced MART-1 specific cytotoxic T lymphocyte (CTL) responses with superior lytic capacity, when compared to IL-4 MoDC. In response to activation, IL-15 MoDC secreted high levels of IFN-γbut low or no IL-12, whereas IL-4 MoDC secreted high IL-12 but low or no IFN-γ. Using an IFN-γ blocking antibody, we demonstrated that IFN-γ production by the IL-15 MoDC did not account for the superior CTL responses induced. Despite immunoselecting monocytes to greater than 97% purity prior to DC differentiation, we noticed a small population (1–2%) of CD56+ and CD3+ lymphocytes in the IL-15 MoDC preparations that were less prominent in IL-4 MoDC differentiated from the same monocytes. Removal of the residual lymphocytes from monocytes prior to differentiation into IL-15 MoDC diminished their capacity to induce CTL but did not affect the expression of HLA-DR or CD40. These data suggest that IL-15-dependent cross-talk between the small lymphoid populations present and DC, during DC differentiation from monocytes results in superior CTL priming that is independent of IL-12 and IFN-γ. Based on these results, appropriately manufactured IL-15 MoDC preparations containing defined numbers of lymphoid cells should be considered for immunotherapy.

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
C. R. Nascimento ◽  
R. C. Valente ◽  
J. Echevarria-Lima ◽  
C. F. L. Fontes ◽  
L. de Araujo-Martins ◽  
...  

Although known as a Na,K-ATPase inhibitor, several other cellular and systemic actions have been ascribed to the steroid Ouabain (Oua). Particularly in the immune system, our group showed that Ouabain acts on decreasing lymphocyte proliferation, synergizing with glucocorticoids in spontaneous thymocyte apoptosis, and also lessening CD14 expression and blocking CD16 upregulation on human monocytes. However, Ouabain effects on dendritic cells (DCs) were not explored so far. Considering the peculiar plasticity and the importance of DCs in immune responses, the aim of our study was to investigate DC maturation under Ouabain influence. To generate immature DCs, human monocytes were cultured with IL-4 and GM-CSF (5 days). To investigate Ouabain role on DC activation, DCs were stimulated with TNF-αfor 48 h in the presence or absence of Ouabain. TNF-induced CD83 expression and IL-12 production were abolished in DCs incubated with 100 nM Ouabain, though DC functional capacity concerning lymphocyte activation remained unaltered. Nevertheless, TNF-α-induced antigen capture downregulation, another maturation marker, occurred even in the presence of Ouabain. Besides, Ouabain increased HLA-DR and CD86 expression, whereas CD80 expression was maintained. Collectively, our results suggest that DCs respond to Ouabain maturating into a distinct category, possibly contributing to the balance between immunity and tolerance.


2017 ◽  
Vol 31 ◽  
pp. 039463201774250 ◽  
Author(s):  
Hye-Youn Son ◽  
Vasso Apostolopoulos ◽  
Chul-Woo Kim

Inducing cancer-specific cellular immune responses has become an attractive strategy in cancer treatment. In this study, we investigated the role of several adjuvants in eliciting T/Tn-specific cellular immunity and protection against T/Tn expressing tumor challenge. T/Tn (9:1) antigen was purified from blood type “O” erythrocytes donated from healthy Korean volunteers. Immunization was performed using: T/Tn only, T/Tn mixed with Freund’s adjuvant (T/Tn + FA), keyhole limpet hemocyanin (KLH)-conjugated T/Tn mixed with FA (KLH-T/Tn + FA), and oxidized mannan-conjugated T/Tn mixed with FA (ox-M-T/Tn + FA). Mice immunized with ox-M-T/Tn + FA generated T/Tn-specific CD3, helper T (Th) cells, major histocompatibility complex (MHC) II, and MHC I; T/Tn presentation was significantly high and tolerogenic CD11b+ was the lowest among the tumor models. To verify Th type, we stained intracellular cytokines (interferon gamma (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4, and IL-10) using CD3 co-staining. Th1 (IFN-γ and GM-CSF) cytokines were highly expressed and showed high FasL/Fas ratios, cytotoxic T lymphocyte (CTL) activity, and cytotoxic T lymphocyte precursor (CTLp) activity in mice immunized with ox-M-T/Tn + FA. Lymphocyte infiltration was highest in mice immunized with ox-M-T/Tn + FA. Additionally, we monitored FasL, MHC I, CD301, and T/Tn expression levels using immunohistochemistry (IHC) on macrophage and tumor sites. The expression of all markers was highest in the ox-M-T/Tn + FA group. Furthermore, tumor retardation and survival rate were highest in the ox-M-T/Tn + FA group. These results demonstrate that a vaccine formulation of T/Tn conjugated with ox-M and mixed with FA-induced cellular immunity and sustained a humoral immune response without over-activating the immune system, thus effectively inhibiting tumor growth.


Blood ◽  
2011 ◽  
Vol 118 (20) ◽  
pp. 5498-5505 ◽  
Author(s):  
Nataša Obermajer ◽  
Ravikumar Muthuswamy ◽  
Jamie Lesnock ◽  
Robert P. Edwards ◽  
Pawel Kalinski

Abstract Dendritic cells (DCs) and myeloid-derived suppressor cells (MDSCs) show opposing roles in the immune system. In the present study, we report that the establishment of a positive feedback loop between prostaglandin E2 (PGE2) and cyclooxygenase 2 (COX2), the key regulator of PGE2 synthesis, represents the determining factor in redirecting the development of CD1a+ DCs to CD14+CD33+CD34+ monocytic MDSCs. Exogenous PGE2 and such diverse COX2 activators as lipopolysaccharide, IL-1β, and IFNγ all induce monocyte expression of COX2, blocking their differentiation into CD1a+ DCs and inducing endogenous PGE2, IDO1, IL-4Rα, NOS2, and IL-10, typical MDSC-associated suppressive factors. The addition of PGE2 to GM-CSF/IL-4–supplemented monocyte cultures is sufficient to induce the MDSC phenotype and cytotoxic T lymphocyte (CTL)–suppressive function. In accordance with the key role of PGE2 in the physiologic induction of human MDSCs, the frequencies of CD11b+CD33+ MDSCs in ovarian cancer are closely correlated with local PGE2 production, whereas the cancer-promoted induction of MDSCs is strictly COX2 dependent. The disruption of COX2-PGE2 feedback using COX2 inhibitors or EP2 and EP4 antagonists suppresses the production of MDSC-associated suppressive factors and the CTL-inhibitory function of fully developed MDSCs from cancer patients. The central role of COX2-PGE2 feedback in the induction and persistence of MDSCs highlights the potential for its manipulation to enhance or suppress immune responses in cancer, autoimmunity, or transplantation.


2018 ◽  
Vol 115 (12) ◽  
pp. 3126-3131 ◽  
Author(s):  
Ling Chen ◽  
Takeshi Azuma ◽  
Weiwei Yu ◽  
Xu Zheng ◽  
Liqun Luo ◽  
...  

Induced B7-H1 expression in the tumor microenvironment initiates adaptive resistance, which impairs immune functions and leads to tumor escape from immune destruction. Antibody blockade of the B7-H1/PD-1 interaction overcomes adaptive resistance, leading to regression of advanced human cancers and survival benefits in a significant fraction of patients. In addition to cancer cells, B7-H1 is expressed on dendritic cells (DCs), but its role in DC functions is less understood. DCs can present multiple antigens (Ags) to stimulate dominant or subdominant T cell responses. Here, we show that immunization with multiple tumor Ag-loaded DCs, in the absence of B7-H1, vastly enhances cytotoxic T lymphocyte (CTL) responses to dominant Ag. In sharp contrast, CTL responses to subdominant Ag were paradoxically suppressed, facilitating outgrowth of tumor variants carrying only subdominant Ag. Suppressed CTL responses to subdominant Ag are largely due to the loss of B7-H1–mediated protection of DCs from the lysis of CTL against dominant Ag. Therefore, B7-H1 expression on DCs may help maintain the diversity of CTL responses to multiple tumor Ags. Interestingly, a split immunization approach, which presents dominant and subdominant Ags with different DCs, promoted CTL responses to all Ags and prevented tumor escape in murine tumor models. These findings have implications for the design of future combination cancer immunotherapies.


2009 ◽  
Vol 182 (6) ◽  
pp. 3372-3379 ◽  
Author(s):  
Vincent Lombardi ◽  
Laurence Van Overtvelt ◽  
Stéphane Horiot ◽  
Philippe Moingeon

2000 ◽  
Vol 191 (9) ◽  
pp. 1499-1512 ◽  
Author(s):  
Franziska Lechner ◽  
David K.H. Wong ◽  
P. Rod Dunbar ◽  
Roger Chapman ◽  
Raymond T. Chung ◽  
...  

Although hepatitis C virus (HCV) infection is very common, identification of patients during acute infection is rare. Consequently, little is known about the immune response during this critical stage of the disease. We analyzed the T lymphocyte response during and after acute resolving HCV infection in three persons, using interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) and human histocompatibility leukocyte antigen (HLA) peptide tetramer assays. Acute infection was associated with a broadly directed T helper and cytotoxic T lymphocyte (CTL) response, which persisted after resolution of clinical hepatitis and clearance of viremia. At the earliest time point studied, highly activated CTL populations were observed that temporarily failed to secrete IFN-γ, a “stunned” phenotype, from which they recovered as viremia declined. In long-term HCV-seropositive persons, CTL responses were more common in persons who had cleared viremia compared with those with persistent viremia, although the frequencies of HCV-specific CTLs were lower than those found in persons during and after resolution of acute HCV infection. These studies demonstrate a strong and persistent CTL response in resolving acute HCV infection, and provide rationale to explore immune augmentation as a therapeutic intervention in chronic HCV infection.


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