RESUMO
@#Objective To optimize the adsorption condition of hepatitis A virus(HAV)antigen by aluminum hydroxide[Al(OH)_3]adjuvant and evaluate the immunogenicity of the adsorbed products. Methods The final molar concentration of buffer(0. 01,0. 02 and 0. 04 mol/L),pH value(5. 5,6. 0,6. 5,7. 0,7. 5 and 8. 0),final molar concentration of sodium chloride(NaCl)(0. 075,0. 13,0. 15,0. 17,0. 45,0. 75 and 1. 0 mol/L),mixing mode(mixing after dilution and mixing directly without dilution)and dropping order[HAV stock solution into Al(OH)_3 solution,and Al(OH)_3 solution into HAV stock solution]were selected for single factor screening. Taking Al(OH)_3 adsorption rate as the evaluation index,the selected factors were optimized by orthogonal test. NIH mice were immunized intraperitoneally with adsorbed products prepared under optimal and suboptimal combination conditions with 0. 5 mL/mouse,10 mice in each group with half male and half female. After 28 d of immunization,the blood samples were collected from eyeball or heart,and the serum was separated. The HAV antibody level was detected by ELISA,and the immunogenicity of adsorbed products was evaluated by the seroconversion rate of mouse serum antibody. Results The results of single factor screening test showed that the final molar concentration of buffer,pH value and final molar concentration of NaCl had significant influence on the adsorption effect(F = 6. 582,14. 007 and 8. 612,respectively,each P < 0. 05),while the mixing mode and dropping order had no effect(t =-0. 696 and 1. 153,respectively,each P > 0. 05). The final molar concentration of buffer was 0. 01 and 0. 02 mol/L,the pH value was 5. 5 ～ 7. 0,and the final molar concentration of NaCl was 0. 13 ～ 0. 17 mol/L. The orthogonal test showed that the order of the influence on adsorption effect was the final molar concentration of buffer > pH value > NaCl final molar concentration. The optimal combination was pH 6. 3 + final molar concentration of buffer 0. 01 mol/L + NaCl molar final concentration 0. 15 mol/L,and the suboptimal combination was pH 5. 8 + final molar concentration of buffer 0. 02 mol/L +NaCl final molar concentration 0. 17 mol/L. The seroconversion rate of serum antibody in mice immunized with the adsorbed products prepared by the optimal and suboptimal combination was both 100%. Conclusion The adsorbed products prepared under the optimized conditions have good immunogenicity,which lays a foundation of the research of inactivated hepatitis A vaccine
RESUMO
Background & objectives: Universal salt iodization (USI) was implemented in all counties of China in 1995. This study was undertaken to assess the status of iodine deficiency disorders control and prevention after 10 years of implementation of USI in a severe iodine deficiency region in China. Methods: Thirty primary school were selected in Gansu province utilizing cluster sampling methodology for the years 1995 and 2005. In each selected school, 40 children aged 8-10 yr were randomly selected for thyroid and IQ examination, and urinary samples were collected from 12. On the spot casual urine samples and salt samples were collected from a subset of children included in the study. In 2005, casual urine samples were also collected from 50 pregnant and lactating women in each cluster. Effect of health education was studied by a combination method of giving questionnaires to and observing students and families. Results: The total goiter rates (TGR) were found to be 13.5 and 38.7 per cent in 2005 and 1995 respectively. The medians urinary iodine excretion levels of children were 191.8 and 119.9 μg/l in 2005 and 1995. The median urinary iodine excretion level of women was 161.9 μg/l. The mean intelligence quotient (IQ) was 96.9 in 2005 significantly more than that in 1997 (P<0.05). The health education pass rate of children and women were 21.1 and 51.1 per cent respectively. Interpretation & conclusion: After ten years of universal salt iodization (USI), iodine nutrition of people improved and the current iodine nutrition status of population was adequate. Decrease in TGR and increase in IQ showed that IDD control and prevention had made great progress through ten years USI, salt iodization played the key role in IDD control and prevention for sustained elimination of IDD, the programme of USI and other measures like health education should be persisted and enforced.