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Ren H.-M.,National Vaccine and Serum Institute
Chinese Journal of Biologicals

Chitosan binds to antigen molecules and forms nanoparticles by various methods. As an immune adjuvant, chitosan is worthy to be studied because of the stable physiochemical properties and diverse immune routes of the nanoparticles. This paper reviews the physiochemical characters of chitosan, the method for preparation of nanoparticles, application of chitosan as an immune adjuvant, the immune route of chitosan nanoparticles as well as the type of induced immune response. Source

Objective: To compare the purification efficacy of HBsAg expressed in Hansenula polymorpha by hydrophobic interaction chromatography using columns 3146VL, 3147L, 3148H and 3149VH with various butyl densities in WorkBeads 40/10000 Bus low series of Bio-Work and CIM Monoliths C4 of BIA. Methods: HBsAg was dissolved with various loading buffers, then loaded onto the column pre-filled with WorkBeads type 4 and C4 butyl chromatographic column, and eluated with various elution buffers. The flow-through and elution peaks were collected and determined for HBsAg content, based on which the flow-through and elution rates were calculated, and the optimal loading and elution buffers were screened. Results: The optimal column for purification of HBsAg was 3147L, while the optimal loading buffer was 20 mmol/L PB containing 4% ammonium sulfate. Neither 20 mmol/L PB nor 20 mmol/L PB containing 30% isopropanol was the ideal elution buffer. The optimal loading buffer on CIM Monoliths C4 was 50 mmol/L MOPS containing 3% ammonium sulfate and 20 mmol/L PB containing 4% ammonium sulfate, while the optimal elution buffer was 50 mmol/L MOPS containing 0.1% Triton X-100. Conclusion: It is feasible to introduce WorkBeads series which may be used repeatedly and CIM Monoliths C4 which is resistant to high flow rate into the purification of HBsAg expressed in Hansenula polymorpha. Source

Yang X.-Q.,National Vaccine and Serum Institute
Chinese Journal of Biologicals

Objective: To analyze the regularity and characteristics of (suspected) adverse events following immunization (AEFI) of hepatitis B (HB) vaccine reported in documents. Methods: Based on CNKI Chinese database retrieval system, all cases of AEFI associated with the HB vaccine in the past 15 years were collected and analyzed by categorical statistics. Results: The clinical manifestations of (suspected) AEFI of HB vaccine were mainly allergic reactions (41.13%). The maximum percentage (48.39%) of (suspected) AEFI cases were induced by recombinant HB vaccine (Saccharomyces cerevisiae). The percentages of (suspected) AEFI cases appeared 0.5-24 h after immunization, after the second dose and at ages of less than one year were 35.48%, 37.90% and 49.19% respectively. Conclusion: The total case number of (suspected) AEFI of HB vaccine increased as compared with that reported previously in documents. However, it could not be concluded that the percentage of AEFI case increased, which should be further analyzed accurately. Source

Wei J.-B.,National Vaccine and Serum Institute
Chinese Journal of Biologicals

Objective: To develop a method for evaluation of vaccine-induced specific cellular killing activity based on flow cytometry(FCM) and perfect the method for assessment of vaccine and gene therapeutic drugs. Methods: Lymphocytes were labeled with CFSE (carboxyfluorescein diacetate, succinimidyl ester) and treated with TNFα to mimic the cytotoxic effect of cytotoxic killer cells, then determined by FCM after propidium iodide (PI) staining, based on which the concentrations of CFSE and PI and time for treatment were optimized. Mice were immunized with therapeutic hepatitis B vaccine with known high cellular immunity, of which the specific lymphocytes were isolated from spleen and stimulated with specific peptide. The lymphocytes of unimmunized mice were isolated as target cells and sensitized with specific antigenic peptide. A procedure was developed based on the optimization of conditions including the staining of target cells, the stimulation time of effector cells, as well as the action time between target and effector cells. Results: The cells were divided into CFSE+PI-, CFSE+PI+, CFSE -PI+ and CFSE-PI- groups by CFSE/PI staining, meanwhile, and survival and apoptotic cells were well distinguished. The optimal time for labeling of target cells with CFSE was 6 h, while that for stimulation of effector cells was 72 h, and the optimal action time between target and effector cells was 6 h. However, both the effector to target cell ratios of 100:1 and 50:1 might be adopted. Conclusion: A method for evaluation of vaccine-induced specific cellular killing activity based on FCM was successfully developed, which may be used for effective and precise assessment of CTL activity and perfection of method for assessment of vaccines and therapeutic drugs. Source

Li X.,University of Saskatchewan | Li X.,National Vaccine and Serum Institute | Huang H.,University of Saskatchewan | Zhang X.,University of Saskatchewan | And 5 more authors.
American Journal of Respiratory Cell and Molecular Biology

In mouse models of asthma, therapeutic use of allergen-presenting IL-10-differentiated dendritic cells (DCs) can abrogate airway hyper-responsiveness, and reduce other asthma-related responses to near background. Analogous human DCs can suppress human T cell responses in vitro, but the operative mechanisms are poorly defined. We investigated the ability of IL-10-treated human DCs to induce tolerance among autologous T cells of subjects with asthma and the mechanisms by which they do this. CD14+ monocyte-derived DCs were differentiated in the presence of IL-10 (DC10) ex vivo from 11 donors with asthma and 4 control donors, and characterized for relevant markers. They were pulsed with specific or irrelevant allergen, and cultured with autologous peripheral blood CD4+ T cells, either alone or together with autologous immunostimulatory DCs (DC-TNF), and the impact of this treatment on the T-cell responses was assessed for each donor. The DC10 expressed reduced levels of some relevant markers (CD40, CD80, human leukocyte antigen-DR) and stimulatory cytokines (IL-6 and IL-12), but augmented levels of Ig-like transcript-22/CD85j and IL-10 relative to DC-TNF. In cocultures, they dampened DC-TNF-driven T helper (Th) type 2 cell proliferation and cytokine (IL-4, -5, and -13) secretion. They also drove the development from atopic CD4+CD25loFoxp3lo cells of a population of IL-10-secreting CD25+Foxp3+LAG-3+CTLA-4 + regulatory T cells (Tregs). These Tregs suppressed stimulatory DC-induced autologous Th2 cell proliferation and cytokine secretion in a contact-dependent manner. Our data indicate that IL-10-treated human DCs induce Th2 cell allergen tolerance ex vivo by driving the differentiation of Tregs. Source

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