Grant C K, Essex M, Gardner M B, Hardy W D
Cancer Res. 1980 Mar;40(3):823-9.
Forty-two kittens and 28 adult cats were placed as tracers in leukemia cluster environments in contact with resident cats, 30% of which were persistently infected with feline leukemia virus (FeLV). After 7 months exposure, FeLV viremia had been detected in 71% of the tracer kittens, although only 55% of these remained persistently infected; in the same period, 11% of tracer adults became infected, but by 2 years the figure reached 43%. Mean latent periods before detection of viremia were 3.4 +/- 1.8 (S.D.) and 13.0 +/- 5.9 months for kittens and adults, respectively. First detection of FeLV infection was accompanied by a sharp although transient drop in peripheral white blood cell numbers, and infection onset triggered the humoral immune response which was comprised of separate antibodies with virus-neutralizing and tumor lysis activities. High titers of virus-neutralizing antibody appeared in transiently viremic cats immediately following elimination of viremia; this antibody was rarely detected in cats that remained persistently viremic. Lytic complement-dependent antibody to feline oncornavirus-associated cell membrane antigen appeared in most cats 1 to 2 weeks after FeLV infection was first detected, and subsequently high titers of this antibody remained in both transiently and persistently infected cats. If the rate of FeLV infection was summarized by using viremia and/or antibody appearance, then 95% of the kittens became infected within 1 year and 61% of the adults within 2 years. Adult cats are, therefore, susceptible to FeLV infection following long-term natural exposure, and their apparent resistance cannot be attributed to a protective humoral immune response that developed immediately after exposure commenced.
42只小猫和28只成年猫被作为追踪对象放置在白血病聚集环境中，与常住猫接触，其中30%的常住猫持续感染猫白血病病毒（FeLV）。暴露7个月后，在71%的追踪小猫中检测到FeLV病毒血症，尽管其中只有55%的小猫持续感染；同一时期，11%的追踪成年猫被感染，但到2年时这一数字达到43%。小猫和成年猫在检测到病毒血症之前的平均潜伏期分别为3.4±1.8（标准差）和13.0±5.9个月。首次检测到FeLV感染时，外周白细胞数量会急剧但短暂下降，感染开始会引发体液免疫反应，该反应由具有病毒中和和肿瘤溶解活性的不同抗体组成。在病毒血症消除后，短暂病毒血症的猫立即出现高滴度的病毒中和抗体；在持续病毒血症的猫中很少检测到这种抗体。在首次检测到FeLV感染后1至2周，大多数猫出现针对猫肿瘤病毒相关细胞膜抗原的溶细胞补体依赖性抗体，随后在短暂感染和持续感染的猫中都保持高滴度。如果用病毒血症和/或抗体出现情况来总结FeLV感染率，那么95%的小猫在1年内被感染，61%的成年猫在2年内被感染。因此，成年猫在长期自然暴露后易感染FeLV，它们明显的抵抗力不能归因于暴露开始后立即产生的保护性体液免疫反应。
