Grunhaus A, Cho S, Horwitz M S
Department of Micrbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461.
Virology. 1994 May 1;200(2):535-46. doi: 10.1006/viro.1994.1216.
The adenovirus type 2 (Ad2) early region 3 (E3) codes for a 19-kDa glycoprotein (gp19) that associates with the class I major histocompatibility (MHC) heavy chain in the endoplasmic reticulum (ER) and prevents the transport of class I MHC protein products to the cell surface. It has been shown previously in tissue culture that this reduction in class I MHC expression allows infected cells to escape detection by class I MHC restricted CD8+ cytotoxic T-lymphocytes (CTL). We now report the results of studies on the effects of Ad2/gp19 expression on virulence in vivo. Since we wanted to isolate the effect of Ad2/gp19 from the effects of other Ad E3 region gene products and human Ads do not replicate in the mouse, we cloned the Ad2/gp19 open reading frame (ORF) into the HindIII C region of WR vaccinia virus (VV). Two VV recombinants were constructed by inserting the Ad2/gp19 ORF in either an expressing (V-e19(+)) or a non-expressing (V-e19(-)) orientation under control of the VV P7.5 promoter. The V-e19(+)recombinant expressed Ad2/gp19 in infected tissue and could be co-precipitated with an antibody to the class I MHC antigen Kd. However, intracerebral or intranasal infections of BALB/c (H-2d), BALB.G (H-2g), or C3H (H-2k) mice showed that Ad2/gp19 expression by V-e19(+) had no significant effect either on viral lethality or on its ability to replicate in vivo when compared to V-e19(-). Furthermore, the nature of the CD8+ CTL response to a V-e19(+)-induced pneumonia in (H-2d) mice was unchanged by Ad2/gp19 expression. Modulating the CD8+ CTL response, by interfering with infected target presentation, may not be important in the control of VV replication or virulence in vivo when other aspects of the immune response to viral infection are not altered. However, the two VV recombinants V-e19(+) and V-e19(-) were both equally attenuated (10-fold) when compared to wild-type VV. This attenuation, which has been reported previously for an intracerebral infection, is believed to be caused by the disruption of a 37-kDa ORF in the VV HindIII C region. Interestingly, our studies showed that the attenuation is not accompanied by a reduction in viral titers in infected tissue.
2型腺病毒（Ad2）早期区域3（E3）编码一种19kDa的糖蛋白（gp19），该蛋白在内质网（ER）中与I类主要组织相容性（MHC）重链结合，并阻止I类MHC蛋白产物转运至细胞表面。先前在组织培养中已表明，I类MHC表达的这种降低使受感染细胞能够逃避I类MHC限制性CD8 +细胞毒性T淋巴细胞（CTL）的检测。我们现在报告关于Ad2/gp19表达对体内毒力影响的研究结果。由于我们想将Ad2/gp19的作用与其他Ad E3区域基因产物的作用区分开来，且人腺病毒不在小鼠体内复制，我们将Ad2/gp19开放阅读框（ORF）克隆到WR痘苗病毒（VV）的HindIII C区域。通过在VV P7.5启动子控制下以表达（V-e19(+)）或非表达（V-e19(-)）方向插入Ad2/gp19 ORF构建了两个VV重组体。V-e19(+)重组体在受感染组织中表达Ad2/gp19，并且可以与I类MHC抗原Kd的抗体共沉淀。然而，对BALB/c（H-2d）、BALB.G（H-2g）或C3H（H-2k）小鼠进行脑内或鼻内感染表明，与V-e19(-)相比，V-e19(+)表达Ad2/gp19对病毒致死率或其在体内复制的能力均无显著影响。此外，Ad2/gp19表达并未改变（H-2d）小鼠对V-e19(+)诱导的肺炎的CD8 + CTL反应的性质。当对病毒感染的免疫反应的其他方面未改变时，通过干扰受感染靶标的呈递来调节CD8 + CTL反应在体内控制VV复制或毒力方面可能并不重要。然而，与野生型VV相比，两个VV重组体V-e19(+)和V-e19(-)的毒力均同等减弱（10倍）。这种减弱先前已报道与脑内感染有关，据信是由VV HindIII C区域中一个37kDa ORF的破坏引起的。有趣的是，我们的研究表明这种减弱并不伴随着受感染组织中病毒滴度的降低。
