A型口蹄疫合成肽疫苗的免疫效力评价

摘要

[Objective] We developed a synthetic vaccine against foot-and-mouth disease type A.[Methods] We studied two peptide-based vaccines containing residues 131 to 159 of VP1,20 to 35 of VP4,21 to 35 of 3A and 29 to 42 of 3B of the AF/72 strain of foot-and-mouth disease virus (FMDV) coupled with a CpG oligodeoxynucleotide (5'-TCGCGAACGTTCGCCCGATCGTCGGTA-3') in guinea pigs.We assayed the FMDV-specific IgG level,serum neutralizing antibody titer,splenic lymphocytes proliferative capacity and peripheral blood T lymphocyte CD4-CD8 subsets distribution.[Results] The data show that high dose did not ensure a good immunity.In our study,8％ (4/5) of peptide 364-2.5-inoculated guinea pigs (2.5 μg of peptide 364 per animal) were protected against AF/72 strain challenge,while the protection ratio from other peptide-immunized groups was lower except the inactivated vaccineinoculated group which showed a full protection.Our results also indicated that the stimulatory ability of CD4 + T lymphocyte response played a key role in evaluating effective FMDV vaccine.The highest percentage of CD4 + T lymphocyte was 36.6％ appeared in inactivated vaccine-immunized guinea pigs,the second was 33.7％ in peptide 3642.5-vaccinated group,whereas the remaining ranged from 18.1％ to 27.7％.There was no obvious relation between CD8 + T cells and anti-FMDV infection; our data showed that the CD4/CD8 ratio was not always appropriate for assessing the immune system status.[Conclusion] In general,we not only designed an effective vaccine against FMDV type A,but also discovered some useful information of humoral and cellular responses induced by foot-and-mouth disease vaccines.%[目的]研制A型口蹄疫(foot-and-mouth disease,FMD)新型合成肽疫苗,为畜牧业减少经济损失.[方法]应用两种含有口蹄疫病毒(foot-and-mouth disease virus,FMDV) AF/72株VP1[131-159]、VP4 [20-35]、3A [21-35]和3B[29-42]4个抗原表位的合成肽联合CpG寡聚脱氧核苷酸(5'-TCGCGAACGTTCGCCCGATCGTCGGTA-3')在豚鼠上进行了免疫效力评价.[结果]2.5 μg/只的合成肽364能保护4/5的豚鼠免受FMDV AF/72株的攻击,灭活苗组获得完全保护,其他组的保护效力仅为3/5;保护效力最高的两组的外周血CD4+T淋巴细胞含量高达33.7％和36.6％,而其他组不超过27.7％,PBS组仅为18.1％.[结论]本研究筛选出一组免疫效力较好的口蹄疫A型合成肽疫苗,可以作为候选疫苗进行进一步评价.