炭疽疫苗A16R诱导小鼠的黏膜与系统免疫应答

Mucosal and systemic Immune Responses Induced with Live Attenuated Anthrax Vaccine A16R in Mice

目的 探索炭疽减毒活疫苗A16R诱导黏膜与系统免疫的规律。方法 将6～8周龄的BALB/c小鼠随机分为3组,每组5只,将炭疽疫苗A16R以5×10~7 cfu(相当于人用1/20剂量)和2×10~8 cfu(相当于人用1/5剂量)经皮下接种,每周采集尾血,采用ELISA间接法检测血清中特异性抗PA的IgG抗体;在免疫8周后,活杀小鼠,分离NALT、鼻通道、脾、小肠Peyer结及腹股沟淋巴细胞,采用流式细胞术检测其淋巴细胞表型的变化;并收集肺灌洗液,采用ELISA法检测特异性抗PA的sIgA抗体。结果 1/5剂量组能诱导较高、较快血清IgG的增加,免疫8周后,血清抗体效价仍然持续在高水平,但1/5剂量组肺灌洗液中仅能检测到微弱的sIgA抗体,而1/20剂量组基本检测不到;NALT、NP、PP和腹股沟淋巴结中CD_3^+、CD_4^+、CD_8^+和CD45R^+的细胞差异无显著意义,但是脾细胞中CD_3^+细胞构成比小于对照组,CD45R^+细胞构成比高于对照组,T/B比值低于对照组;1/20剂量与1/5剂量组差异无显著意义。其他部位的淋巴组织的细胞表型无显著变化。结论 炭疽疫苗A16R主要诱导系统免疫应答,而不能诱导有效的呼吸道和消化道黏膜免疫。

Objective To explore the mucosal find systemic immune mechanisms of live attenuated anthrax vaccine A16R in mice.Methods Divide the BALB/c mice aged 6-8 weeks into 3 groups randomly,5 mice per group. Inoculate s.c. the mice in 2 test groups with live attenuated anthrax vaccine A16R at dosages of 5 x 107 cfu(equal to 1/20 human dose) and 2 x 108 cfu(equal to 1/5 human dose) respectively,and those in control group with 100 ;J normal saline. Collect venous blood every week for detecting the specific IgG to PA in sera by indirect ELISA.Kill the mice 8 weeks after inoculation and separate NALT,NP,spleens,PP nodes and groin lymphocytes to detect cell phenotype by FAGS, and collect lung washings for detecting specific slgA to PA by ELISA. Results IgG were induced in the mice inoculated with the vaccine at 1/5 human dose rapidly and maintained at a high level even 8 weeks after inoculation. However, little slgA was detected in the lung washings of them. No slgA was detected in the lung washings of mice inoculated with 1/20 human dose.No significant difference were observed in the CD3+ , CD4+ , CD8+ and CD45R+ cells in NALT, NP, PP and groin lymph node of the 3 groups. However,compared with those in control group, the CD/ cell constituent ratio in spleen cells of mice in the 2 test groups was low,CD45R+ cell constituent ratio was high,and T/B value was low. No significant difference were observed in the ratios in the 2 test groups. The cells phenotypes in lymph tissue at other sites showed no significant change. Conclusion Anthrax vaccine A16R induced systemic immune response but no effective respiratory or mucosal immune response.