Fadly A M, Smith E J
USDA, Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, Michigan 48823, USA.
Poult Sci. 1997 Jul;76(7):968-73. doi: 10.1093/ps/76.7.968.
The role of contact and genetic transmission of endogenous virus-21 (EV21) on response of chickens to avian leukosis virus (ALV) infection and tumors was studied. F1 progeny of a cross between RPRL late-feathering (LF) line EV21+ males and RPRL early feathering (EF) line 15B1 females harboring or lacking EV21 were used. The EF chicks lacking EV21 were inoculated with a field strain of subgroup A ALV at hatch and contact exposed to LF, EV21+ hatchmates for various time intervals. In a second experiment, EV21 contact-exposed and unexposed EF chicks as well as LF, EV21+ hatchmates were inoculated with ALV at various ages. Chickens were tested for ALV-induced viremia and antibody and were observed for tumors until 24 wk of age. Antibody to EV21 in EF chickens contact-exposed to LF, EV21+ hatchmates varied from 10 to 65%, and was detected by 10 wk of age. By 24 wk of age, ALV-induced viremia and tumors in EF chickens varied from 5 to 30%, and from 15 to 32%, respectively, regardless of exposure to EV21. The incidence of ALV-induced tumors was significantly higher in LF chickens genetically infected with EV21 than in EV21 contact-exposed or unexposed EF chickens, but only in chickens inoculated with ALV at hatch. The data suggest that contact infection with EV21 has no influence on ALV infection and tumors. The data also suggest that genetic transmission of EV21 may increase susceptibility of chickens to ALV infection and tumors following infection with ALV at hatch, but not at 4 wk of age or older.
研究了内源性病毒21（EV21）的接触传播和基因传递对鸡对禽白血病病毒（ALV）感染及肿瘤反应的作用。使用了RPRL晚羽（LF）品系EV21阳性雄性与携带或不携带EV21的RPRL早羽（EF）品系15B1雌性杂交的F1后代。缺乏EV21的EF雏鸡在出雏时接种A亚群ALV田间毒株，并在不同时间间隔与携带EV21的LF同窝雏鸡接触。在第二个实验中，将接触和未接触EV21的EF雏鸡以及携带EV21的LF同窝雏鸡在不同年龄接种ALV。检测鸡的ALV诱导的病毒血症和抗体，并观察肿瘤直至24周龄。接触携带EV21的LF同窝雏鸡的EF鸡中，EV21抗体的比例在10%至65%之间，在10周龄时可检测到。到24周龄时，无论是否接触EV21，EF鸡中ALV诱导的病毒血症和肿瘤的比例分别在5%至30%和15%至32%之间。在基因上感染EV21的LF鸡中，ALV诱导的肿瘤发生率显著高于接触或未接触EV21的EF鸡，但仅在出雏时接种ALV的鸡中如此。数据表明，与EV21的接触感染对ALV感染和肿瘤没有影响。数据还表明，EV21的基因传递可能会增加鸡在出雏时感染ALV后对ALV感染和肿瘤的易感性，但在4周龄及以上时则不会。
