Lyons Joseph M, Morré Servaas A, Airo-Brown Lucy P, Peña A Salvador, Ito James I
Department of Infectious Diseases, City of Hope National Medical Center and Beckman Research Institute, Duarte, California 91010, USA.
BMC Infect Dis. 2005 Nov 17;5:105. doi: 10.1186/1471-2334-5-105.
Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen causing female genital tract infection throughout the world. Reinfection with the same serovar, as well as multiple infections with different serovars, occurs in humans. Using a murine model of female C. trachomatis genital tract infection, we determined if homotypic and/or heterotypic protection against reinfection was induced following infection with human oculogenital strains of C. trachomatis belonging to two serovars (D and H) that have been shown to vary significantly in the course of infection in the murine model.
Groups of outbred CF-1 mice were reinfected intravaginally with a strain of either serovar D or H, two months after initial infection with these strains. Cellular immune and serologic status, both quantitative and qualitative, was assessed following initial infection, and the course of infection was monitored by culturing vaginal samples collected every 2-7 days following reinfection.
Serovar D was both more virulent (longer duration of infection) and immunogenic (higher level of circulating and vaginal IgG and higher incidence of IgA in vaginal secretions) in the mouse genital tract. Although both serovars induced cross-reacting antibodies during the course of primary infection, prior infection with serovar H resulted in only a slight reduction in the median duration of infection against homotypic reinfection (p approximately 0.10), while prior infection with serovar D resulted in significant reduction in the median duration of infection against both homotypic (p < 0.01) and heterotypic reinfection (p < 0.01) when compared to primary infection in age and conditions matched controls.
Serovar D infection resulted in significant homotypic and heterotypic protection against reinfection, while primary infection with serovar H resulted in only slight homotypic protection. In addition to being the first demonstration of acquired heterotypic immunity between human oculogenital serovars, the differences in the level and extent of this immunity could in part explain the stable difference in serovar prevalence among human isolates.
沙眼衣原体是全球引起女性生殖道感染最常见的性传播细菌病原体。人类会发生同一血清型的再次感染以及不同血清型的多重感染。利用雌性沙眼衣原体生殖道感染的小鼠模型，我们确定了感染属于两个血清型（D和H）的沙眼衣原体人眼-生殖器菌株后，是否会诱导针对再次感染的同型和/或异型保护，这两种血清型在小鼠模型的感染过程中已显示出显著差异。
远交系CF-1小鼠在初次感染血清型D或H菌株两个月后，经阴道再次感染这些菌株之一。在初次感染后评估细胞免疫和血清学状态，包括定量和定性方面，并在再次感染后每2 - 7天收集阴道样本进行培养，以监测感染过程。
血清型D在小鼠生殖道中更具致病性（感染持续时间更长）且更具免疫原性（循环和阴道IgG水平更高，阴道分泌物中IgA发生率更高）。虽然两种血清型在初次感染过程中都会诱导交叉反应抗体，但先前感染血清型H仅导致同型再次感染的中位感染持续时间略有缩短（p约为0.10），而与年龄和条件匹配的对照组的初次感染相比，先前感染血清型D导致同型（p < 0.01）和异型再次感染（p < 0.01）的中位感染持续时间显著缩短。
血清型D感染导致对再次感染有显著的同型和异型保护，而血清型H的初次感染仅导致轻微的同型保护。除了首次证明人眼-生殖器血清型之间获得性异型免疫外，这种免疫水平和程度的差异可能部分解释了人类分离株中血清型流行率的稳定差异。
