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The COVID-19 epidemic that occurred at the end of 2019 spreads rapidly to all parts of the world, putting the global public health system to a severe test. With the continuation of the epidemic, SARS-CoV-2 variants are constantly emerging. In particular, the mutation of the spike protein can cause changes in the infectivity and antigenicity of the virus, resulting in an increase in the infectivity and a decline in the protective efficacy of existing vaccines, and even the replacement of epidemic strains. This is also one of the reasons why the epidemic has not been effectively controlled so far. Nowadays, the main circulating variants have changed their characteristics to a certain extent, and the neutralization sensitivity of some variants to neutralizing monoclonal antibodies, immune sera and convalescent sera has decreased to a certain extent compared with the original strains. The emergence of variants is not only related to the characteristics of the virus itself, but also to the changes of transmission host and the chronic infection in people with deficient immunity. The emerging variants should be closely monitored, and their functional characteristics should be systematically studied so as to provide data for vaccine research and development and the designation of immunization strategies.
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Objective@#To make a preliminary assessment on the immunogenicity of a quadrivalence recombinant human papillomavirus (HPV) vaccine (6, 11, 16 and 18 types) (Hansenulapolymorpha) in healthy women aged 18-45 years in phaseⅠclinical study.@*Methods@#It was a single-center, double-blind, randomized, placebo-controlled phaseⅠ clinical study. Women aged 18-45 years were randomized (2∶1) to receive HPV vaccine (n=60) or placebo control (n=30) at months 0, 2 and 6. Antibodies against HPV6/11/16/18 were detected by pseudovirus-based neutralisation assay in serum samples collected at 0 d, 180 d and 210 d. Seroconversion rates and geometric mean titres (GMT) of antibodies against the four types of antigens were calculated.@*Results@#Seroconversion rates of the vaccination group at 180 d (before the third dose) and 210 d (one month after the third dose) were generally similar and between 85%-100% for all types of antibodies. The GMT of antibodies at one month after the last dose improved significantly compared with those before immunization.@*Conclusions@#These results showed that the HPV vaccine had good immunogenicity in the population of healthy women aged 18-45 years. Higher antibody titers were elicited by the vaccine compare with the tites before the first dose and in the placebo control group.
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Objective To make a preliminary assessment on the immunogenicity of a quadriva-lence recombinant human papillomavirus (HPV) vaccine (6, 11, 16 and 18 types) (Hansenulapolymor-pha) in healthy women aged 18-45 years in phaseⅠclinical study. Methods It was a single-center, doub-le-blind, randomized, placebo-controlled phaseⅠclinical study. Women aged 18-45 years were randomized (2 : 1) to receive HPV vaccine (n=60) or placebo control (n=30) at months 0, 2 and 6. Antibodies against HPV6/11/16/18 were detected by pseudovirus-based neutralisation assay in serum samples collected at 0 d, 180 d and 210 d. Seroconversion rates and geometric mean titres ( GMT) of antibodies against the four types of antigens were calculated. Results Seroconversion rates of the vaccination group at 180 d ( be-fore the third dose) and 210 d ( one month after the third dose) were generally similar and between 85％-100％ for all types of antibodies. The GMT of antibodies at one month after the last dose improved signifi-cantly compared with those before immunization. Conclusions These results showed that the HPV vaccine had good immunogenicity in the population of healthy women aged 18-45 years. Higher antibody titers were elicited by the vaccine compare with the tites before the first dose and in the placebo control group.
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Human papillomavirus (HPV) infection is the most common sex-transmitted virus infection. Persistent infection of HPV could cause cancers in different parts of the body, such as cervix and anus. Up to now, three prophylactic HPV vaccines have been approved to prevent HPV infection and related diseases. It is well accepted that neutralizing antibodies are the mediator of protection. Analysis of immunogenicity has been playing a key role in HPV vaccine clinical trials, especially in the evaluation of durability of immune responses, immunobridging in young girls and boys, and reduced-dose schedules. There is still no unique method for the evaluation of immunogenicity of HPV vaccines in clinical trials. The data of immunogenicity from different clinical trials cannot be compared directly. It is urgently needed to establish a high throughput and protection-related unique assay as well as standard materials for its standardization. To accelerate the development and evaluation of prophylactic HPV vaccines, a standardized method should be well validated and transferred to different laboratories to make clinical immunogenicity data comparable.
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Cervical cancer is the second most common cancer in women worldwide. It is clear that persistent infection of high-risk human papillomaviruses (HR-HPVs) is the main cause for this disease. Among the several HPV types associated with carcinoma, HPV-16 is the most prevalent type and present in about 50% of tumor specimens. The major capsid protein (L1) of HPV can self-assemble into virus-like particles (VLPs) with immunogenicity similar to infectious virions. Neutralizing epitopes are the structural basis of the current prophylactic HPV vaccines. The efficacy of HPV vaccines is critically dependent upon the integrity of type-specific neutralizing epitopes. Recently, considerable headway has been made in studying the epitopes of HPV16 based on neutralizing antibodies. Notably, more and more HPV16 variants have appeared along with increasing immune pressure. To study the phenotypic variations in HPV16 L1 protein, 1 204 naturally occurring sequences were analyzed and a phylogenetic tree was then constructed including four clades. Moreover, after compared the aforementioned sequences with the 114K reference sequence, eight "hot mutation sites" , six "specialized mutation sites" and 20 "epitope-related mutation sites" were found. Generally, sera raised against VLPs can neutralize the corresponding HPV types, but not other types. However, it is not known whether intragenotypic variants of human papillomavirus type 16 (HPV-16) can be neutralized by sera vaccinated with a single variant VLPs. It is, therefore, imperative to understand the neutralizing epitopes and intragenotypic variants of HPV-16 for the production of prophylactic vaccines with high potency and broad coverage.
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Objective@#To validate a pseudovirus-based neutralization assay for the detection of antibodies against human papillomavirus (HPV) in human serum samples.@*Methods@#The specificity, accuracy, precision, range of linearity, limit of detection and robustness of the neutralization assay were evaluated using HPV-negative serum samples, vaccinated serum samples with quadri-valent vaccine, and international standards for detecting antibodies against HPV16 and HPV18.@*Results@#Based on the data of the HPV-naïve samples, the criteria of positivity was determined as follows: the 50% inhibitory dose (ID50) of the tested sample was not less than 40 and 2-fold not less than that for bovine papillomavirus. The neutralization assay showed good accuracy with a recovery rate of 87%-122% and excellent reproducibility with intra- and inter-assay variation of 5%-27% and 10%-26% respectively. The HPV16 and HPV18 international standards were used to define the limit of quantification, which was 1.28 IU/ml for HPV16 and 0.96 IU/ml for HPV18. Acceptable ranges of variation for the key parameters of this assay were defined, which showed the good robustness of the pseudovirus-based neutralization assay.@*Conclusion@#The pseudovirus-based neutralization assay for the detection of HPV antibodies showed good specificity, accuracy, sensitivity, and robustness, suggesting that it could be used to evaluate the immunogenicity of HPV vaccines.
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Objective Observe the efficacy and safety of glucocorticoid deescalation combined antiviral therapy on severe hepati‐tis B .Methods Forty‐nine patients with early severe hepatitis were selected and divided them into observation group(n=24) and control group (n=25) randomly .Control group were given the conventional synthetic therapy while observation group were given conventional synthetic therapy combined glucocorticoid deescalation therapy .Then compare the differences of TBIL ,ALT ,PTA be‐fore and after treatment ,and the improvement time of syndrome and death rate between two groups .Results The death rate in ob‐servation group and control group were 16 .7% and 32 .0% respectively(P0 .05) .After the treatment ,the TBIL ,ALT ,PT were improved in both two groups(P 0 .05) .Conclusion Glucocorticoid deescalation therapy could decrease the death rate ,shorten the syndrome lasting time in treating severe hepatitis B .It was an effective and safety meth‐od .
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Objective To establish a high throughput phenotypic test for the detection of drug re-sistance in human immunodeficiency virus(HIV)strains. Methods The gene encoding luciferase was in-activated through restriction enzyme digestion and ligation. LacZ gene was used to replace the genes encoding original protease and reverse transcriptase. pol genes were amplified from pSG3△env plasmid and cloned in-to a new backbone plasmid through infusion. The factors that might affect the results of the test were opti-mized. Results The parental backbone plasmid pNL4-3. Lac was constructed,of which the gene encoding luciferase was inactivated and bearing the LacZ gene instead of genes encoding protease and reverse tran-scriptase. Several influential factors including cell numbers(10 000 / well),virus inoculation(200 TCID50 /well)and the concentration of DEAE-dextran(15 μg/ ml)were optimized. The reproducibility of this test was confirmed by testing 12 anti-HIV drugs against 2 pseudovirus strains 8 times,presenting the coefficient of variations(CVs)from 4. 32% to 28. 46% . Six types of pseudovirus were constructed and tested against the 12 anti-HIV drugs,the results of which were compared with those by using the pSG3△env-based pseud-ovirus test. The results of the two tests presented good consistency. Conclusion The high throughput phe-notypic test based on pNL4-3. Lac plasmid,combining the advantages of pSG3△env and pNL4-3 systems, could be used to analyze the drug resistance patterns of HIV-1 infectors and screen new drugs for antiretrovi-ral therapy in a rapid and effective way.
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Objective To study the in vivo expression and biodistribution of Ad5-Fluc (Adenovirus carrying firefly luciferase genes) in mice.Methods The recombinant Ad5-Fluc virus was constructed and infected to BALB/c or nude mice through three different routes.The protein expression level,tissue distribution and the characteristics of infection were analyzed by in vivo bioluminescence imaging technology.Results Compared to other two routes,the BALB/c mice infected through muscular route had the longest expression cycle (over 60 days) and the highest expression level,while the virus was transferred into the liver and spleen after infection.The nude mice had a significantly extended expression cycle than BALB/c mice.Moreover,the characteristic of liver tropism was eliminated after Ad5 F35 infection in mice,while maintained similar expression efficiency.Conclusion Due to the highest expression efficiency,the muscular route would be the optimal route for Ad5 vector based vaccination.In addition,Ad5F35 virus could become an ideal alternative vaccine vector for eliminating the liver tropism.
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Objective To evaluate the quality of four domestic and three imported fourth-generation HIV diagnostic reagents.Methods The specificity and sensitivity of these assays were analyzed when testing HIV negative samples and HIV-1 RNA positive samples.The relative seroconversion sensitivity index was analyzed when testing BBI seroconversion panels.Results The sensitivity of seven 4th-generation assays were 100％ (95％ CI:99.86％-100％ ),and one sample at the window period of HIV-1 infection were detected as positive.Of the seven assays,one imported assay exhibited the relative largeδ + value (1.0892),and the small δ+ value were found on the remaining six assays (0.0836-0.3003 ).For the samples negative for HIV antibody,varying degrees of false positives were observed on the seven assays ( specificity:97.80％ -99.60％,δ- value:-1.3803 to -0.4778).When testing the BBI seroconversion panels,the relative seroconversion sensitivity index of domestic assays were -0.500-0,however,which of imported assays were -0.600 and -0.700.Conclusion The seven reagents exhibited high sensitivity and specificity.The 4th generation HIV assays can be used as blood screening reagents to find the samples at window period of HIV-1 infection,thus indicating the certain meaning in reducing the transmission risk of HIV-1 for fourth-generation HIV diagnostic reagents.However,the better efficiency to detect HIV-1 early infection was observed on the imported assays than on the domestic assays.
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Objective To compare cellular immune responses in mice elicited by Chinese different AIDS candidate vaccines.Methods According to their different immunization procedures,BALB/c mice were immunized with 6 AIDS candidate vaccines,separately.Spleen cells were isolated for the detection of cellular immune response to HIV-specific peptides using enzyme-linked immunosorbent spot(ELISPOT)assay and intracellular cytokine staining(ICS)method.Results AIDS vaccines were evaluated by using potential T-cell epitopes(PTE)Gag,Env and Pol peptides pool and ELISPOT.The positive conversion rates for cellular immune response of 1#-6# vaccines fluctuated from 70% to 100%.The vaccine-induced cellular immune responses to specific peptides pool are different not only in magnitude but also in breadth.The Th1type cytokines,IFN-γand IL-2,were detected with ELISPOT in 1# and 2# vaccines.The productions of IFN-γand IL-2 induced by both of the two vaccines showed a moderate correlation(r1 =0.62,P1 ＜0.01 ;r2=0.79,P2 ＜ 0.01).The positive conversion rate of IFN-γ secreting cells of 1 # vaccine was 66.7%(10/15)mice detected with both ELISPOT and ICS.And the results tested by ELISPOT and ICS showed moderate correlation(r = 0.55,P ＜ 0.05).Conclusion The magnitude and breadth of cellular immune responses induced by different AIDS candidate vaccines are different.Being induced by different AIDS candidate vaccines,the IFN-γand other Th1 type cytokines detected by ELISPOT or ICS could be used to evaluate the cellular immune responses in mice.
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Eleven env mutants were designed and generated by site-directed mutagenesis of the regions around Nab epitopes and deletions of variable regions in env.The immunogenicities of the generated mutants were evaluated using single-cycle infection neutralization assays with two pseudoviruses and IFN-γELISPOT.Overall,five mutants(dWt,M2,M5-2,M5-1 and dM7)induced highed neutralization activities for both pseudoviruses than plasmid Wt,while only two of the mutants(dWt and M5-2)showed significant differences(P<0.05).Two mutants(M2 and dM2)induced more Env-specific T cells than plasmid Wt.Statistically however,significance was only reached for mutant M2.Thus,properly modified HIV-1 Env may have the potential to induce potent cellular and humoral immune responses.
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The ELISPOT assay is increasingly used for assessing cellular immune responses in clinical trials of HIV-1 or cancer vaccines. However, to date, data from clinical trials do not consistently show that immune responses are correlated with clinical endpoints. This is due in part to the lack of assay standardization and validation across laboratories and therefore, a quality control panel is required to establish competency and comparability amongst different laboratories. In this study peripheral blood mononuclear cells (PBMCs) from healthy individuals were screened and frozen in liquid nitrogen. The recovery and viability of the PBMCs and the frequencies of interferon (IFN)-γ-secreting cells after CEF peptide pool stimulation were detected after various intervals in seven different laboratories. The recovery and viability did not differ significantly after different intervals. Although the frequencies of IFN (interferon)-γ-secreting cells among thawed PBMCs (peripheral blood mononuclear cells) fluctuated after CEF peptide pool stimulation at different intervals, they were not significantly decreased compared with those among fresh PBMCs. However, the viabilities, recoveries and frequencies of IFN-γ-secreting cells differed significantly among the seven laboratories. Our results indicate that cryopreserved PBMCs could be used as a quality control panel for ELISPOT. However, the procedures for ELISPOT need to be standardized amongst different laboratories.
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Objective To establish a pseudovirus-based neutralization assay. Methods The functional gp160 genes were amplified from plasmids containing HIV-1 gene. The products were ligased into pcDNA3.1 plasmid and positive clones were screened by digestion with restriction enzymes. The pseudoviruses were harvested by co-transfection of the positive clone and pSG3△env plasmid. The neutralizing activities of monoclonal antibodies and HIV-1 antibody positive plasma were measured by these pseudoviruses. Results The four strains of psedoviruses (CHB01, CHB02, CHBC03 and CHAE04) had been successfully obtained. Monoclonal antibody 4E10 could neutralize all of 4 pseudoviruses while 2G12 could not neutralize any pesudoviruses. Monoclonal antibody 2F5 could neutralize pseudovirus CHB01, CHB02 and CHAE04 but not CHBC03, while IgG1b12 could neutralize pseudovirus CHB01, CHB02 and CHBC03 but not CHAE04. The neutralizing activities of 43 of HIV-1 antibody positive plasma against different subtypes of pseudovirus were significant differences and the cross-neutralization effects for some samples exist. Conclusion The harvested pseudoviruses could be used in the neutralization assay. However, the neutralizing characteristics of different pseudoviruses may be different.
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Objective To study the influence of site-directed deglycosylation of the HIV-1 envelope (Env) on its immunogenicity and assembly of functional pseudovirus. Methods Site-directed deglycosylation were performed using cycling mutagenesis and selection of mutants with DpnⅠ. Single-cycle infection assay was employed to analyze the effect of the mutations on the ability of functional pseudovirus assembly. The influence of deglycosylations on the immunodeficiency of Env was evaluated using pseudovirusbased neutralization assay and ELISPOT assay. Results Mutant N197Q induced higher neutralization activities for both pseudoviruses, but lower Env-specific T-cell response. And N197Q rendered the Env to lose the ability of functional pseudovirus assembly. Mutant G2 induced higher neutralization activities for pseudovirus 74-2 but lower for pseudovirus Wt, and had almost no influence on Env-specific T-cell response and functional pseudovirus forming. Conclusion The site-directed deglycosylation of the HIV-1 Env affects the pseudovirus forming and its immunogenicity.
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Objective To evaluate the differences between the third and the fourth generations of anti-HIV assays,and different kits within the same generation.Methods A total of 989 HIV-negative samples,185 samples positive for HIV-1 RNA.1st-generation international references of HIV antibodies and samples from 9 sets of BBI seroconversion panels were detected by 8 kits of the third generation and 4 kits of the fourth.Results The fourth generation kits can detect HIV infection earlier than the third generation kits.However,the detected days of HIV infection with different kits of the fourth generation were different whilst no significant difierences were found with difierent kits of the third generation.Furthermore,the capacity of detecting samples with different genotypes for different reagents was different,especially the capacity of domestic reagents on detecting HIV-1 O group and HIV-2 samples was relatively weak.Conclusion These data provided information to improve the quality of anti-HIV diagnostic reagents further.
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Objective To establish the mouse model for human papillomavirus types 16, 45 and 58 by the corresponding pseudovirions. Methods The 293FT cells were co-transfected with eodon-modified HPV eapsids genes together with a reporter plasmid containing the luciferase gene. The cells were collected and lysed, then the pseudovirus was collected and the titration was performed. The mouse was subcutaneous-ly injected with Depo-Provera. After 4 d and intravaginally injected with nonoxynol-9, and 6 h later pseud-oviruses were inoculated in intravaginal. After 7 d, the mouse was instilled luciferin substrate intravaginally, and the expression level of the lueiferase gene was detected by the in vivo Imaging System (IVIS). Results Three types (HPV16, HPV45 and HPV58) of pseudoviruses had been produced and the titer was 3.7×108 TU/ml, 1.5×108 TU/ml and 1.2×108 TU/ml, respectively. The luminescent regions could be detected in the mice which were infected with the pseudovirions, the luminescent signal intensity for types 16,45 and 58 was 1.779×106p/s, 5.738×105×p/s and 1.829×106p/s, respectively. Conclusion The mouse models for HPV16, 45 and 58 have been successfully established based on pseudovirions, which will be very useful for the research of HPV infection intervention, the evaluation of HPV vaccines and the screening of the prophylactic agents.