Pal Sukumar, Peterson Ellena M, de la Maza Luis M
Department of Pathology, Medical Sciences, Room D440, University of California, Irvine, CA 92697-4800, USA.
Vaccine. 2005 Nov 16;23(46-47):5351-8. doi: 10.1016/j.vaccine.2005.06.026. Epub 2005 Jul 19.
Chlamydia trachomatis infections can occur early in life and may result in long-term sequelae. To assess the feasibility of implementing a vaccine in newborns, groups of 2-day-old BALB/c mice were immunized intranasally (i.n.) with 1x10(4) inclusion forming units (IFU) of C. trachomatis mouse pneumonitis (MoPn). As a control, newborn mice were sham-immunized i.n. with minimal essential medium. In the vaccinated animals, strong Chlamydia-specific humoral and cell-mediated immune responses were observed. Six weeks after immunization, mice were challenged with MoPn i.n. or intravaginally (i.vag.). For the i.n. challenge, mice were inoculated with 10(4) or 10(5)IFU of MoPn per mouse, and in the case of the i.vag. challenge, each animal received 10(6)IFU. By day 10 post-infection (p.i.), the vaccinated mice challenged i.n. with 10(4)IFU, had gained an average of 6.7+/-1% of their body weight. In contrast, the sham-immunized mice had lost 14.9+/-1% of their weight (P<0.05). The mean number of IFU/lungs in the vaccinated animals was 800+/-300, while for the sham-immunized mice was 211+/-49x10(6) (P<0.05). Significant differences between the Chlamydia-vaccinated and the sham-immunized mice were also found in the groups challenged with 10(5)IFU. In the mice challenged i.vag., a significant decrease in the number of mice with positive cultures, and the intensity and duration of vaginal shedding was noted in the vaccinated mice compared to the sham-immunized mice (P<0.05). In conclusion, these results indicate that vaccination of neonatal mice can result in a protective response against a subsequent pulmonary or genital challenge with Chlamydia.
沙眼衣原体感染可在生命早期发生，并可能导致长期后遗症。为评估在新生儿中接种疫苗的可行性，将2日龄的BALB/c小鼠分组，经鼻内（i.n.）接种1×10⁴个沙眼衣原体鼠肺炎（MoPn）包涵体形成单位（IFU）。作为对照，新生小鼠经鼻内假接种最低限度基本培养基。在接种疫苗的动物中，观察到了强烈的沙眼衣原体特异性体液免疫和细胞介导免疫反应。免疫6周后，小鼠经鼻内或阴道内（i.vag.）用MoPn攻击。对于经鼻内攻击，每只小鼠接种10⁴或10⁵个MoPn的IFU，对于阴道内攻击，每只动物接受10⁶个IFU。感染后第10天（p.i.），经鼻内用10⁴个IFU攻击的接种疫苗小鼠，体重平均增加了6.7±1%。相比之下，假接种小鼠体重减轻了14.9±1%（P<0.05）。接种疫苗动物肺中IFU/肺的平均数为800±300，而假接种小鼠为211±49×10⁶（P<0.05）。在用10⁵个IFU攻击的组中，接种沙眼衣原体疫苗的小鼠和假接种小鼠之间也发现了显著差异。在经阴道内攻击的小鼠中，与假接种小鼠相比，接种疫苗小鼠的培养阳性小鼠数量、阴道排菌强度和持续时间均显著降低（P<0.05）。总之，这些结果表明，新生小鼠接种疫苗可产生针对随后沙眼衣原体肺部或生殖器攻击的保护性反应。
