Besselsen David G, Becker Michael D, Henderson Kenneth S, Wagner April M, Banu Laila A, Shek William R
University Animal Care, University of Arizona, Tucson, USA.
Comp Med. 2007 Feb;57(1):66-73.
Fecal shedding and transmission of mouse parvovirus 1 (MPV) to naive sentinels, breeding mates, and progeny were assessed. Neonatal SCID and BALB/c mice inoculated with MPV were evaluated over 24 wk; several mice from each strain were mated once during this period. Fecal MPV loads for each cage were determined weekly by quantitative polymerase chain reaction (PCR) analysis, and all mice were evaluated by quantitative PCR analysis of lymphoid tissues and seroconversion to MPV antigens in immunocompetent mice. Results indicated persistently high fecal shedding of MPV in SCID mice throughout the evaluation period sufficient to allow transmission to sentinels, naive breeding partners, and the progeny of infected male mice and naive partners. Lymphoid tissue viral loads in the progeny of infected female SCID mice were high at weaning but low at 6 wk of age. Infected BALB/c mice shed high levels of MPV in feces for 3 wk postinoculation, with seroconversion only in sentinels exposed during the first 2 wk postinoculation. Thereafter the feces of infected BALB/c mice and the lymphoid tissues of sentinels, naive breeding partners, and progeny intermittently contained extremely low levels of MPV DNA. Although pregnancy and lactation did not increase viral shedding in BALB/c mice, MPV exposure levels were sufficient to induce productive infection in some BALB/c progeny. These data indicate that the adaptive immune response suppresses, but does not eliminate, MPV shedding; this suppression is sufficient to inhibit infection of weanling and adult mice but allows productive infection of some progeny.
评估了小鼠细小病毒1型（MPV）向未接触过该病毒的哨兵小鼠、繁殖配偶及后代的粪便排出及传播情况。对接种MPV的新生SCID和BALB/c小鼠进行了24周的评估；在此期间，每个品系的几只小鼠进行了一次交配。每周通过定量聚合酶链反应（PCR）分析确定每个笼子的粪便MPV载量，并通过对淋巴组织进行定量PCR分析以及对免疫活性小鼠中MPV抗原的血清转化情况对所有小鼠进行评估。结果表明，在整个评估期内，SCID小鼠的粪便中MPV持续大量排出，足以传播给哨兵小鼠、未接触过该病毒的繁殖伙伴以及感染雄性小鼠与未接触过该病毒的伙伴所生的后代。感染的雌性SCID小鼠后代的淋巴组织病毒载量在断奶时较高，但在6周龄时较低。接种后3周内，感染的BALB/c小鼠粪便中排出大量MPV，仅在接种后前2周接触过病毒的哨兵小鼠中出现血清转化。此后，感染的BALB/c小鼠的粪便以及哨兵小鼠、未接触过该病毒的繁殖伙伴和后代的淋巴组织中偶尔含有极低水平的MPV DNA。虽然怀孕和哺乳并未增加BALB/c小鼠的病毒排出量，但MPV接触水平足以在一些BALB/c后代中引发有 productive infection。这些数据表明，适应性免疫反应可抑制但不能消除MPV的排出；这种抑制足以抑制断奶小鼠和成年小鼠的感染，但允许一些后代发生 productive infection。
