[Factors Affecting the Preservation of Human Peripheral Blood Mononuclear Cells at 4 ℃].

OBJECTIVE: To analyze the preservation effect and related influencing factors of human peripheral blood mononuclear cells under serum-free condition at 4 ℃. METHODS: Human peripheral blood mononuclear cells were isolated by density gradient centrifugation, and stored at 4 ℃ under different cell concentrations, supplemented with human serum albumin, and glucose. The cell viability, total cell number, viable cell number and cell phenotype were detected during preservation of 72 h. RESULTS: With the prolongation of storage time, the number of human peripheral blood mononuclear cells gradually decreased(r=0.982). Compared with the cell concentration of (5-6)×106 cells/ml, the cell number decreased more slowly when the cell storage concentration was (1-2)×106 cells/ml; Adding human serum albumin and glucose can effectively improve the survival rate of human peripheral blood mononuclear cells, among which 2% human serum albumin has a better preservation effect; Compared with the blank control group, the analysis results of cell subsets showed that the downward trends of NK cells and T cells were significantly slowed after adding albumin and glucose. CONCLUSION: The cell density of (1-2)×106/ml and 2% human serum albumin are more suitable for the preservation of PBMC, and 5% glucose can improve the preservation effect of human peripheral blood mononuclear cells at 4 ℃.

Mapping ApoE/Aß binding regions to guide inhibitor discovery.

Blocking the interaction between the E4 isoform of apolipoprotein E (ApoE) and amyloid beta-peptide (Aß) may be an avenue for pharmacological intervention in Alzheimer's disease (AD). The main regions of interaction of the two proteins are, respectively, ApoE244-272 and Aß12-28. These protein segments are too large to facilitate the design of small molecule inhibitors. We mapped the primary components of ApoE/Aß interaction to smaller peptide segments. Within the three motifs that are primarily responsible for ApoE/Aß interaction, we identified four peptides that substantially block ApoE/Aß interaction and further improved their inhibitory activity by rational hydrophobic amino acid substitution. Moreover, the mapping results provide the clue that the Aß residues which interact with ApoE appear to be in the same region where Aß self-interacts. According to this information, we found that Congo Red and X-34 could strongly inhibit ApoE/Aß interaction. Our findings extend our understanding of ApoE/Aß interaction and may guide the discovery of inhibitors that treat AD by antagonizing ApoE/Aß interaction.