葡萄球菌肠毒素B突变体的免疫原性研究

目的：研究葡萄球菌肠毒素B(SEB)突变体的免疫原性和作为超抗原疫苗的应用前景。方法：利用小鼠动物模型，分别对SEB23位突变体(SEB-M23)和150位突变体(SEB-M150)作毒力、免疫原性和保护力试验。结果：小鼠致死性试验表明，与野生型SEB(SEB-N)相比，SEBM23的毒力大幅度下降，而SEB-M150的毒力则未见下降。淋巴细胞增殖试验发现，SEB-M150与SEB-N相比，cpm掺入量相似．说明150位突变并不影响SEB超抗原的活性；SEB-M23与SEB-N相比，其cpm掺入量显著下降，表明23位突变可显著降低SEB超抗原活性。ELISA结果显示，以SEB-N、SEB-M23、SEB-M150三种蛋白免疫小鼠，都能诱生一定量的抗体。且产生的抗体水平非常接近，无统计学意义。主动免疫治疗和被动免疫治疗结果证明，SEB-M23蛋白免疫的小鼠能抵抗野生型SEB致死剂量的攻击，同时被动转移免疫小鼠的抗血清能保护接受致死剂量SEB-N的小鼠免于死亡。结论：SEB-M23毒力低、免疫原性强，有可能成为一种很有希望的超抗原候选疫苗，用于某些疾病的预防。

Vaccine potential of staphylococcal enterotoxin B mutants

Aim To study the immunogenicity of staphylococcal enterotoxin B (SEB) mutants and the feasibility of superantigen vaccine.Methods Animal model was used to evaluate the virulence,immunogenicity and protective effect of SEB mutant at the residue 23 (SEB-M23) and SEB mutant at the residue 150(SEB-M150).Results Mouse lethality assay and lymphocyte proliferation test indicated that compared with wild type SEB(SEB-N),the virulence and superantigen toxicity of SEB-M23 mutant decreased sharply while the virulence and superantigen toxicity of SEB-M150 mutant showed no marked difference.Enzyme-linked immunosorbent assay manifested that immunized mice with these three proteins produced very similar anti-SEB titers.The results of active and passive immunization therapy demonstrated that SEB-M23-immunized mice could resist SEB-N lethal challenge and mice were completely protected from SEB lethality by antisera from SEB-M23-immunized mice.Conclusion Since SEB-M23 showed normal antigenicity but low toxicity,it is a promising superantigen vaccine.