Combined phospholipids adjuvant augments anti-tumor immune responses through activated tumor-associated dendritic cells.

Dendritic cells (DCs) can initiate both naïve and memory T cell activation, as the most potent antigen-presenting cells. For efficient anti-tumor immunity, it is essential to enhance the anti-tumoral activity of tumor-associated DCs (TADCs) or to potently restrain TADCs so that they remain immuno-stimulating cells. Combined phospholipids (cPLs) adjuvant may act through the activation of DCs. This study demonstrated the potential mechanism of tumor growth inhibition of cPLs adjuvant, and confirmed that cPLs adjuvant could induce the maturation and activation (upregulation of MHC-II, CD80, CD40, IL-1ß, IL-12, IL-6 expression) of BMDCs in vitro. Then we isolated tumor infiltrating lymphocytes (TILs) from solid tumor and analyzed the phenotype and cytokines of TILs. The examination of the TILs revealed that cPLs adjuvant upregulated the expression of co-stimulatory molecules (MHC-II, CD86), phosphatidylserine (PS) receptor (TIM-4) on TADCs and enhanced the cytotoxic effect (CD107a), as well as pro-inflammatory cytokine production (IFN-γ, TNF-α, IL-2) by the tumor-resident T cells. Taken together, cPLs adjuvant may be an immune-potentiating adjuvant for cancer immunotherapy. This reagent may lead to the development of new approaches in DC-targeted cancer immunotherapy.

Direct electron transfer from pseudoazurin to nitrous oxide reductase in catalytic N2O reduction.

Pseudoazurin (PAz), a well-characterized blue copper electron-transfer protein, is shown herein to be capable of mediating electron transfer to the nitrous oxide reductase (N(2)OR) from Achromobacter cycloclastes (Ac). Spectroscopic measurements demonstrate that reduced PAz is efficiently re-oxidized by a catalytic amount of N(2)OR in the presence of N(2)O. Fits of the kinetics resulted in K(M) (N(2)O) and k(cat) values of 19.1±3.8 µM and 89.3±4.2s(-1) respectively. The K(M) (PAz) was 28.8±6.6 µM. The electrochemistry of Ac pseudoazurin (AcPAz) in the presence of Ac nitrous oxide reductase (AcN(2)OR) and N(2)O displayed an enhanced cathodic sigmoidal current-potential curve, in excellent agreement with the re-oxidation of reduced AcPAz during the catalytic reduction of N(2)O by AcN(2)OR. Modeling the structure of the AcPAz-AcN(2)OR electron transfer complex indicates that AcPAz binds near Cu(A) in AcN(2)OR, with parameters consistent with the formation of a transient, weakly-bound complex. Multiple, potentially efficient electron-transfer pathways between the blue-copper center in AcPAz and Cu(A) were also identified. Collectively, the data establish that PAz is capable of donating electrons to N(2)OR in N(2)O reduction and is a strong candidate for the physiological electron donor to N(2)OR in Ac.