The precursor frequency of alloreactive CTLs is proportional to the number of T cell epitope specificities

The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide（s） onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes （PBLs） of HLA-A2 negative individual. Ten HLA-A2 restricted peptides （all were normal cell components ） were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide（s） were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was ＇analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide（ s）. The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.

Clinical Study on Treatment of Advanced Non-small Cell Lung Cancer by Arsenious Acid Combined with Tα-1 Thymus Peptide and Megestrol Acetate

Objective: To observe the therape utic effect of arsenious acid combined with Tα-1 thymus peptide and megestro l acetate on advanced non-small cell lung cancer.Methods: Nintey-two patients were divided randomly into the tr eated group( n =45) and the control group( n =47). The treated group were tr eated with arsenious acid combined with Tα-1 thymus peptide and megestrol ac etate, and the control group were treated with chemotherapy in the NP protocol .Results: (1) Therapeutic effect :In the 36 patients of the treated group, 2 were evaluated as CR, 8 as PR, 9 as MR, 8 as SD and 9 as PD, the CR+PR rate being 27.7% (10/36), while in the 40 patients of the control group, the co rresponding numbers were 3, 10, 11, 9, 7 and 32.5% (13/40). Comparison between t he CR+PR rate between the two groups showed insignificant difference ( P >0.05 ). (2)Clinical benefit rate: The positive rate of Karnofsky scores in the treate d group and the control group was 44.4% and 20.0% respectively; and the positive rate of body weight in the two groups was 33.3% and 12.5% respectively, the dif ference between the two groups was significant ( all P <0.05). (3)Changes of T- cell subsets and NK cell activity: CD4 and CD4/CD8 ratio after treatment i n the treated group increased significantly ( P <0.05), while in the control group, CD3, CD4, CD4/CD8 ratio and NK cell activity all lowered significantly ( P <0.01). Comparison between the two groups after treatment showed significa nt difference in CD4, CD4/CD8 ratio and NK cell activity, with those in the trea ted group all higher than those in the control group ( P <0.01). (4)Adeverse -reaction: No serious adverse reaction was found in both two groups. (5)Media n survival period:The treated group was 30 weeks and that in the control group w as 28.5 weeks, and the difference between the two groups was insignificant ( P >0.05).Conclusion: Arsenious acid combined with Tα-1 thymus peptide and megestrol acetate was a relatively effective scheme with low toxicity in tre ating advanced NSCLC.

Tumor-targeted delivery of siRNA by surface-modified LPC nanoparticles

With increasing knowledge of the molecular mechanisms of endogenous RNA interference,systemic delivery of small interfering RNA（siRNA） via targeted nanoparticles has emerged as a potential strategy for cancer gene therapy.In this study,a novel formulation[liposome-protamine-chondroitin sulfate nanoparticles（LPC-NP）]was developed for siRNA delivery by self-assembling with charge-charge interaction.The LPC-NP was further modified by DSPE-PEG_（2000） and DSPE-PEG_（2000）-T7 by the post-insertion method.T7,a transferrin-like seven-amino acid peptide,is a targeting ligand for transferrin receptor-overexpressed MCF-7 breast cancer cells.The particle size and zeta potential of LPC-NP were approximately 90 nm and ＋35 mV,respectively. It was shown that PEG modification could significantly decrease aggregation of LPC-NP in serum,and T7 peptide modified LPC-NP could significantly increase the cellular uptake and the gene-silencing effect of siRNA.In vitro cytotoxicity assay exhibited that significant cell growth inhibition was achieved in MCF-7 cells after the delivery of anti-EGFR siRNA.Our encouraging results suggested that T7-modified LPC-NP might be a promising carrier for RNAi-based tumor therapy.

Phytomedicines as potential inhibitors of β amyloid aggregation: significance to Alzheimer's disease

Throughout the history of drug development, plants have been an important source for the discovery of novel therapeutically active compounds for many diseases. The ethnopharmacological approach has provided several leads to identify potential new drugs from plant sources, including those for memory disorders. For the treatment of Alzheimer's disease the drug discovery focus shifted from cholinesterase inhibitors, to other targets primarily based on two key neuropathological hallmarks, namely the hyperphosphorylation of the tau protein resulting in the formation of neurofibrillary tangles(NFTs), and the increased formation and aggregation of amyloid-beta peptide(Aβ) derived from amyloid precursor protein(APP). The present article aims to provide a comprehensive literature survey of plants and their constituents that have been tested for Aβ aggregation, thus possibly relieving several features of Alzheimer's disease(AD).