RESUMO
Objective:To evaluate the effects of a booster immunization with a candidate tetanus toxoid, reduced diphtheria toxoid and acellular pertussis combined vaccine (Tdap) in a rat model after primary vaccination with diphtheria, tetanus, acellular pertussis and Sabin strain inactivated poliovirus combined vaccine (DTacP-sIPV) or diphtheria, tetanus, acellular pertussis, inactivated poliovirus and haemophilus type b combined vaccine (DTacP-IPV/Hib) for further preclinical study.Methods:Wistar rats were randomly divided into three groups and respectively immunized with a self-developed DTacP-sIPV, a marketed DTacP-IPV/Hib and normal saline at 0, 1, and 2 months of age. Serum levels of antibody against each component in each group were detected before immunization and after each dose. A booster dose of the candidate Tdap was given 10 months after primary immunization. Serum levels of antibody against each component in each group were detected before, 1 month and 6 months after the booster immunization.Results:One month after three doses of primary immunization, the geometric mean titers (GMT, Log2) of antibodies against diphtheria toxoid (DT), tetanus toxoid (TT), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) in the DTacP-sIPV group were 17.41, 18.34, 18.11, 19.93 and 13.91, respectively, and the seroconversion rates of these components all reached 100%. Ten months after primary immunization, the GMTs of antibodies against DT, TT, PT, FHA and PRN decreased to 15.17, 14.26, 13.60, 14.51 and 10.39, respectively, and the seroconversion rates remained above 89%. One month after booster immunization, the GMTs of antibodies against DT, TT, PT and FHA in the DTacP-sIPV and DTacP-IPV/Hib groups were 16.49/17.26, 16.80/17.63, 16.70/17.74 and 18.48/19.26, respectively, and the seroconversion rates of these components all reached 100% with no significant difference between the two groups ( P>0.05). The GMTs of anti-PRN antibody in the DTacP-sIPV and DTacP-IPV/Hib groups were 13.07 and 11.00, and the seroconversion rates were 100% and 88%, which were higher in the DTacP-sIPV group than in the DTacP-IPV/Hib group ( P<0.05). Six months after booster immunization, the GMTs of antibodies against DT, TT, PT, FHA and PRN in the DTacP-sIPV and DTacP-IPV/Hib groups decreased to 15.74/14.87, 15.07/15.14, 14.84/15.73, 16.62/16.37 and 11.44/9.96, respectively, and the seroconversion rates remained above 88%. Conclusions:Booster vaccination with the candidate Tdap vaccine induces humoral immune response following primary immunization with DTacP-sIPV or DTacP-IPV/Hib in the Wistar rat model, while the antibody titer decreases with time.
RESUMO
Objective To investigate the effects of different concentrations and adsorption methods of aluminum hydroxide adjuvant produced by different manufacturers on the immunogenicity of the diphtheria-tetanus-acellular pertussis and inactivated poliovirus combined vaccine ( DTaP-sIPV) . Methods Five anti-gens of DTaP were adsorbed onto different concentrations (0. 42 mg/ml, 0. 47 mg/ml and 0. 52 mg/ml) of aluminum hydroxide from different manufacturers through sequential and separate adsorption. Adsorbability, anti-pertussis toxin ( PT)/filamentous hemagglutinin ( FHA)/pertactin ( PRN)/diphtheria toxoid ( DT)/tet-anus toxoid ( TT) antibodies and the potency of vaccines were detected. Results The adsorbability of alu-minum hydroxide adjuvant slightly decreased with the reduction of concentration. No significant difference in potency and antibody level was observed between sequential and separate adsorption. Moreover, no signifi-cant difference in antibody level was observed between vaccines prepared with aluminum hydroxide adjuvant produced by General Chemical Corp and our institute. Conclusion Aluminum hydroxide adjuvant produced by our institute at the concentration of 0. 52 mg/ml and separate adsorption method are suitable for prepara-tion of DTaP-sIPV.
RESUMO
Objective To evaluate the BALB/c murine infective effects in different concentrations and different aerosol challenge times by Bordetella pertussis.Methods Four experiment groups according to different concentrations and different aerosol challenge times were designed.BALB/c murines were challenged by aerosol way.Group 1: 1010cfu/mL Bordetella pertussis challenge 15 min, group 2: 1010cfu/mL challenge 30 min, group 3: 109cfu/mL challenge 30 min, group 4: 1011cfu/mL challenge 30 min, using the normal saline challenge 30 min as control.At 0d,3d,7d,14d and 21d after challenge, the WBCs of all groups were measured and lung tissues were homogenized to calculate the bordetella pertussis clone in lung.Results After 3 days of challenge, WBCs in all groups were slightly increased.The WBCs of group 1, group 2, group 3 and group 4 were significantly increased after 7 days, with the average numbers of 8.52×109 per/L, 1.74×1010per/L, 1.15×1010per/L and 5×1010per/L, respectively.After 14 days, they were 1.77×1010per/L, 1.67×1010per/L, 1.27×1010per/L and 3.84×1010per/L respectively.WBCs in all groups were dramatically declined after 21 days.The WBC of negative control group had no obvious change during the whole process with the stable number of 3.4~7.0×109per/L.Bordetella pertussis were detected in lung of all experimental groups in each sampling point.The CFU in lung wase at peak at 7d or 14d after challenge, which was obviously decreased at 21d.Conclusion This aerosol challenge method can establish a bordetella pertussis infection mouse model successfully.
