Objective To observe polyclonal antibodies immobilized on magnetic submicron particles (MSP) as affinity adsorbents and test the reliability of predicted maximum adsorption activity of an enzyme/mutant from a cell lysate (Vs) in recognizing positive mutants.Methods Escherichia coli alkaline phosphatase (ECAP) and Pseudomonas Aeruginosa arylsulfatase (PAAS) were purified by affinity chromatography to serve as immunogens for the preparation of their antisera, which after fractionation by 33％ ammonium sulfate and DEAE-cellulose chromatography yielded the respective polyclonal antibodies.After activation of COOH on MSP, polyclonal antibodies of each enzyme were immobilized to give MSP-polyAb.Activities of an adsorbed enzyme were measured with a chromogenic substrate of 4-nitrphenol by determining absorbance at 405nm after the termination of reaction by alkali.Based on the response curve of activities of the adsorbed enzyme to protein quantities of a lysate, Vs was predicted for comparison.Results The maximum adsorption quantity of ECAP or PAAS on the respective MSP-polyAb was about 2.0mg/g.Specific activity of ECAP after affinity purification was about 70-fold of that of PAAS.ECAP mutant R168K showing about 50％ activity improvement versus ECAP was recognized by comparison of Vs predicted with only 2.5μg of MSP-polyAb;with PAAS mutant G138S as the starting one, the use of 10.0μg of MSP-polyAb to predict Vs recognized the mutants bearing more than 20％ activity improvement.Conclusion With an optimized quantity of MSP-polyAb to predict Vs, weak positive mutants of an enzyme of low activity can be recognized when activities of the adsorbed enzyme/mutant are reliably measured.

BACKGROUND: Compared with the traditional organic fluorescent dyes, quantum dots present good biomarker characteristics. Especially, quantum dots for cell labeling and targeted bioimaging present unique optical properties.OBJECTIVE: To investigate the biocompatibility of CdSe/ZnS quantum dots with mononuclear macrophages.METHODS: The macrophages RAW264.7 were inoculated into 96-well plates containing 0, 50, 100 mg/L CdSe/ZnS quantum dots for 1 or 2 hours. Then, the fluorescent signal was detected by flow cytometry. After 0-24 hours of culture,the fluorescence signal intensity of the macrophages cultured with 50 mg/L CdSe/ZnS quantum dots was detected by flow cytometry. After 18 hours of culture, quantitative PCR was used to detect the levels of tumor necrosis factor α and interleukin 1β in macrophages, and macrophage proliferation cell apoptosis were detected by MTT and flow cytometry,respectively.RESULTS AND CONCLUSION: The fluorescence signal intensity was positively correlated with the mass concentration of CdSe/ZnS quantum dots, and the intensity of the fluorescent signal was increased with the labeling time. After labeling using 50 mg/L CdSe/ZnS quantum dots, the fluorescence signal of macrophages increased continuously with time, and reached the peak at 18 hours. Compared with 0 mg/L quantum dot group, 50, 100mg/L quantum dot groups could significantly promote the expression of tumor necrosis factor α and interleukin 1β in macrophages (P < 0.01 or P < 0.05).The level of tumor necrosis factor α in the 100 mg/L quantum dot group was higher than that in the 50 mg/L quantum dot group (P < 0.01). The expression of interleukin-1β showed no difference between 50 and 100 mg/L quantum dot groups.The cell proliferation in the 50 and 100 mg/L CdSe/ZnS quantum dot groups was significantly higher than that in the 0 mg/L quantum dot group (P < 0.05), but there was no difference between the former two groups. In addition, 50 and 100 mg/L CdSe/ZnS quantum dots had no significant effect on apoptosis of macrophages. To conclude, CdSe/ZnS quantum dots could activate macrophages and promote their proliferation and secretion of inflammatory factors, but did not affect their apoptosis.

Objective:To investigate the effect of butyrate produced by bacterial metabolism on immune features of murine bone marrow-derived dendritic cells(BMDCs) and its potential mechanisms.Methods: BMDCs were prepared from bone marrow cells of C57BL/6 mice by being cultured with GM-CSF and IL-4.The expression of CD80,CD86,B7-DC and MHCⅡ on BMDCs and its pri-ming ability on the proliferation of OVA257-264 antigen specific CD8+T cell were analyzed by using Flow cytometry.The mRNA levels of IL-6 and IL-12 in BMDCs were detected by real-time fluorescence quantitative PCR(q-PCR).Simultaneously,Griess reaction and Western blot was used for analyzing the levels of NO2-in BMDCs culture supernatant and the ERK phosphortylation in BMDCs respectivly.Results:Butyrate could decrease the levels of CD80,CD86,MHCⅡand B7-DC,and downregulate the capability of BMDCs in priming the proliferation of CD8+T cells.Furthermore,the secretions of IL-6,IL-12,NO2-and the phosphorylation of ERK were sup-pressed.Conclusion:Butyrate down-regulats the immune functions of BMDCs via inhibition of ERK phosphorylation in TLR 4 signaling pathway.

Objective:To explore the value of monocyte subsets and CD64 expression in the diagnosis and prognosis of sepsis.Methods:A prospective case-control study was designed. 30 septic patients and 30 non-septic patients who were admitted to the intensive care unit (ICU) of the PLA Army Characteristic Medical Center from March 2021 to March 2022 were enrolled. After 1, 3, and 5 days of ICU admission, peripheral blood samples were taken from patients. Flow cytometry was used to detect the proportion of monocyte subsets and the expression level of CD64 on the surface, and the difference of expression between patients in two group was analyzed. The risk variables for sepsis were analyzed using single-factor and multi-factor Logistic regression. The diagnostic efficacy of each risk factor for sepsis was determined using the receiver operator characteristic curve (ROC curve).Results:One day after ICU admission, the proportions of monocytes and classic monocytes in white blood cells (WBC) of septic patients were significantly lower than those of non-septic patients [proportion of monocytes to WBC: (4.13±2.03)% vs. (6.53±3.90)%, proportion of classic monocytes to WBC: 1.97 (1.43, 2.83)% vs. 3.37 (1.71, 5.98)%, both P < 0.05]. The proportion of non-classical monocytes in monocytes was significantly higher in septic patients than that in non-septic patients [(11.42±9.19)% vs. (6.57±4.23)%, P < 0.05]. The levels of CD64 expression in monocytes, classic monocytes, intermediate monocytes and non-classic monocytes were significantly higher in sepsis patients than those in non-septic patients [mean fluorescence intensity (MFI): 13.10±6.01 vs. 9.84±2.83 for monocytes, 13.58±5.98 vs. 10.03±2.84 for classic monocytes, 13.48±6.35 vs. 10.22±2.99 for intermediate monocytes, 8.21±5.52 vs. 5.79±2.67 for non-classic monocytes, all P < 0.05]. Multivariate Logistic regression research showed that CD64 in typical monocytes [odds ratio ( OR) = 1.299, 95% confidence interval (95% CI) was 1.027-1.471, P = 0.025] and the proportion of non-typical monocytes in monocytes ( OR = 1.348, 95% CI was 1.034-1.758, P = 0.027) were the independent risk factors for sepsis. ROC curve showed that the area under the ROC curve (AUC) of CD64 expression of classical monocytes, the fraction of non-classical monocytes in monocytes, and procalcitonin (PCT) in the diagnosis of sepsis was 0.871. A correlation analysis revealed a negative relationship between the acute physiology and chronic health status evaluation Ⅱ (APACHE Ⅱ) on the first, third, and fifth days following ICU admission and the expression level of CD64 in patients' classic monocytes ( r values were -0.264, -0.428 and -0.368, respectively, all P < 0.05). Conclusions:Combining the proportion of non-classical monocytes in monocytes, the level of plasma PCT, and the CD64 expression of classic monocytes in peripheral blood has good efficacy in identifying sepsis and assessing its severity.