Evaluation of the immunogenicity and efficacy of a Hib polysaccharide-protein conjugate vaccine by using PsaA as carrier protein / 中华微生物学和免疫学杂志

Objective To prepare a conjugate vaccine by linking Haemophilus influenzae type b (Hib)polysaccharide to PsaA protein carrier and evaluate the immunogenicity and efficacy of the conjugate vaccine. Methods A recombinant protein rPsaA,expressed by using the genetic engineering technology, was used as a protein carrier to prepare conjugate vaccine together with Hib polysaccharide. Ten mice at age of 3 weeks were immunized with the conjugate vaccine,while another 10 age-matched mice were immunized with Hib-tetanus toxoid(Hib-TT)vaccine which was produced formerly as a control. The mice treated with equal volume of PBS were set up as the negative control. The IgG antibodies in serum samples against PsaA and Hib polysaccharide were detected in two weeks after the final immunization. A suspension of Pneumococ-cus was injected into the middle ears of mice from experiment and control group. Histopathological analysis was performed to measure the clearance of bacteria in the middle ears and the severity of infection on days 3 and 7 after bacterial challenge. Results The rPsaA protein was prepared by the genetic engineering tech-nology and purified successfully with anion-exchange column. The Hib polysaccharide-PsaA protein conju-gate vaccine was prepared through a series of amide condensation reactions. The detection of IgG antibodies against PsaA protein and Hib polysaccharide in the immunized mice demonstrated that there was no signifi-cant difference with the titer of IgG against Hib polysaccharide between the mice immunized with the Hib-PsaA conjugate vaccine and those immunized with the Hib-TT vaccine. Less Pneumococcus strains were de-tected in the middle ears of mice immunized with the conjugate vaccine than those mice immunized with the Hib-TT vaccine three days after challenge. The mice from control group showed severe inflammation in the middle ears than those from experiment group. The Hib polysaccharide-PsaA protein conjugate vaccine im-proved protection against Pneumococcus infections as compared with the Hib-TT vaccine. Conclusion The rPsaA protein could be produced by genetic engineering technology and purified by anion-exchange column. The Hib polysaccharide was successfully conjugated with the rPsaA protein through amide condensation reac-tion. Both anti-PsaA and anti-Hib immune responses were induced in young mice by the injection of Hib pol-ysaccharide-PsaA protein conjugate vaccine. Apart from providing protection against Hib infection,the con-jugate vaccine might also be used for the prevention of acute otitis media caused by Pneumococcus infection.

Immunogenecity of cytomegalovirus-infected fibroblasts / 细胞与分子免疫学杂志

AIM: To analyze the capability of cytomegaIovirus (CMV)-infected human embryonic lung fibroblasts (HELFs) to induce immune response. METHODS: HELFs were infected with cytomegalovirus and stained with antibody against HLA-A2 molecular, the expression of HLA-A2 was detected by FCM. The infected HELFs were incubated with individual pp65 peptide NLVPMVATV. While the uninfected and unloaded infected HELFs served as control respectively. After PBMC was added to the differently treated HELFs and incubated, the immune response was measured with IFN-γ release as readout. RESULTS: The expression of HLA-A molecular on infected fibroblasts diminished markedly compared with that on the uninfected. The peptides expressed on the infected HELFs together with those pulsed externally induced a stronger response than the infected HELFs alone. CONCLUSION: Although CMV can downregulate the expression of MHC Ⅰ on the infected cells, it can not decrease the capacity of cells to present peptides loaded externally, and therefore still induce immune response to some extent.

The HLA-A2 restriction and immunogenicity of hepatitis C virus-spedfic cytotoxic T lymphocyte epitopes / 中华微生物学和免疫学杂志

Objective To explore the HLA-A2 restriction and immunogenicity of 5 previously identified HCV-speeific CTL epitopes. Methods Based on T2 cell, to explore the HLA-A2 restriction of previously identified HCV-specific CTL epitopes by MHC-peptide complex stabilization assay;To detect pep-tide-specific CTL in HLA-A2~+ PBMC stimulated by HLA-A2-restricted peptides by intracellular cytokine staining(ICS) and ELISPOT; To explore the cytotoxicity of peptide-specific CTL to same peptide-loaded T2 cells (target cells) by CTL cytotoxicity test. Results Among 5 previously identified CTL epitopes NS4b_78 (SMMAFSAAL) and NS5a_367 (TVSSALAEL) have high-affinity for HLA-A2 molecules(FI 1) ;ELISPOT results shown that NS4b_78(SMMAFSAAL) and NSSa_367(TVSSALAEL) induced high levels of IFN-γ-se-creting cells [(60±6) SFC/10~4 PBMC vs (4±1 ) SFC/10~4 PBMC, P < 0.01 ; (10 ± 3 ) SFC/10~4 PBMC vs (2±1 ) SFC/10~4 PBMC, P <0.01, respectively] ;ICS results indicated that there were high percentages of CD8~+ IFN-γ~+ T cells in total CD8~+T cells stimulated by these peptides [(2.33 ±0.22 ) % vs (0.05±0.01)%, P <0.001 ; (0.36±0.06)% vs (0.03±0.01)%, P <0.001, respectively]. Furthermore,peptide-specific CTL could effectively kill same peptide-loadcd T2 cells. Conclusion NS4b_78 (SMMAF-SAAL) and NSSa_367 (TVSSALAEL) were identified as HLA-A2-restricted CTL epitopes which could in-duce immune response in vitro.

The immunogenicity and safety of three-component DTaP vaccine in Korean infants / 소아과

PURPOSE: We conducted the study to evaluate the immunogenicity and safety of three component DTaP vaccine (Infanrix(R)) in a group of Korean healthy infants on a three-dose primary vaccination. And we compared the immunogenicity of this DTaP vaccine with two component DTaP vaccine which has been widely used in Korea. METHODS: We enrolled one hundred fifty one healthy infants aged 8-9 weeks. These infants were vaccinated at age 2, 4 and 6 months of age with three component DTaP vaccine. Solicited adverse events were actively monitored for 72 hours following each vaccination, and all adverse events after each vaccination were observed for three weeks. Anti-diphtheria toxoid Ab., anti-tetanus toxoid Ab., anti-pertussis toxin Ab., anti-filamentous hemagglutinin Ab., and anti-pertactin Ab. were measured using ELISA for assessing immunogenicity of study vaccine in 60 infants. Immunogenicity analysis of two component DTaP vaccine was performed with same methods in 14 infants as control. RESULTS: The seroconversion rates of anti-diphtheria toxoid Ab, anti-tetanus toxoid Ab. anti- filamentous hemagglutinin Ab. were 100% in both group. Seroconversion rate of anti-pertactin Ab in study group was 100%, but the rate in control group was 50%. However, geometric mean concentration of anti-pertussis toxin Ab. was higher in control group. Mild local and systemic reactions were observed within three days after vaccination, and no serious adverse events related study vaccine were happened during study period. CONCLUSIONS: Our study results suggest that three component DTaP vaccine (Infanrix(R)) is a well- tolerable and high immunogenic vaccine, especially anti-Pertactin Ab. of the study vaccine is very immunogenic. It can be available as routine DTaP vaccination in our infants.

Antibody Response and Adverse Reaction Following Immunization with MMR Vaccine Produced on Human Diploid Cells in Korean Children

No abstract available.

Immunogenicity and Safety of Recombinant Hepatitis B Vaccine(Engerix B) / 감염

BACKGROUND: Several studies on the efficacy and safety of the hepatitis B vaccine have shown variable immunogenicity. In this study we reexamined the immunogenicity and safety of recombinant hepatitis B vaccine, Engerix B which have currently been administered to the children in Korea. METHODS: Serum samples were collected from 126 children and 111 adults who were immunized according to the 0, 1, 2-month and 0, 1, 6-month vaccination schedule. Anti-HBs antibody titers were measured by ELISA in sera obtained after each immunization, and compared by immunization schedules. RESULTS: In 62 children with 0, 1, 2-month immunization schedule seroconversion rate was 83.9% after 1st vaccination, 96.8% after 2nd, and 98.4% after 3rd. In 64 children with 0, 1, 6-month immunization schedule seroconversion rates was 78.1% after 1st vaccination, 87.5% after 2nd and 100% after 3rd. In 50 adults immunized with 0, 1, 2-month schedule seroconversionrates was 48.0% after 1st vaccination, 74.0% after 2nd and 90.0% after 3rd. In 61 adults immunized with 0, 1, 6-month schedule seroconversion rate was 44.3% after 1st vaccination, 65.6% after 2nd and 93.4% after 3rd. Seroconversion rate after 0, 1, 2- month vaccination schedule were 98.4% in children and 90.0% in adults. Seroconversion rate after 0, 1, 6-month schedule were 100% in children and 93.4% in adults. There were no significant local and systemic untoward reactions among vaccinees. CONCLUSION: The recombinant Engerix B is excellent in immunogenicity with 93.4% and 100% seroconversion rates in adults and children, respectively. There is no significant difference in seroconversion rate between two vaccination schedule. The vaccine is safe.

The change of anti-HBs titer after hepatitis B vaccination in newborn according to dosage and time

We studied anti-HBs titer, positive and effective rate in relation to dosages(5microgram, 10microgram) and time interval after third vaccination in 23 infants born to HBsAg negative mother. The babies were divided into two groups. In one group(n=12), 5microgram of Hepavax was administered intramusculary at 1 month, 2 months and 6 months of age, in other group (n=11), 10microgram of Hepavax at same time interval. And the anti-HBs was studied at 2 months and 3 year after third vaccination by radioimmunoassay. The results were as follows: 1) The anti-HBs positive rate was 100% in two groups at 2 months and 3 years after vaccination. 2) The geometric mean anti-HBs titer at 2 months after third vacciantion was 9418.3+/-13041.5 IU/L in 5microgram group and 12750.0+/-12750.5 IU/L in 10microgram group, and 3 year after vaccination, 949.4+/-1404.0 IU/L in 5microgram group, 1067.4+/-1067.7 IU/L in 10microgram group. There were no significant difference between two groups, although mean anti-HBs titer decreased significantly after 3 years. 3) The effective rate at 3 years after vaccination was 66.7% in 5 microgram group and 72.8% in 10microgram group. There was no statistical significant difference between two groups.