Hainaut P, Vaira D, Francois C, Calberg-Bacq C M
Département de Microbiologie, Université de Liège, Belgium.
Arch Virol. 1990;113(1-2):35-52. doi: 10.1007/BF01318351.
Host-virus relationships were examined in mice from the two mouse mammary tumor virus (MMTV)-infected strains SWISS MB+ and RIII, which harbour the same MMTV variant, and from the derived sublines Swiss MB- and RIIIf, which were freed of milk-borne MMTV by foster-nursing. These two strains are not phylogenetically related, the SWISS strain bearing the endogenous Mtv-3 locus in its DNA. In RIII and SWISS MB+ mice, the incidence of early mammary tumors, which was of 96% and 8%, respectively, was correlated to the level of MMTV expression in milk. In the SWISS MB-line, a non-coordinate expression of the provirus associated with the Mtv-3 locus was observed in the mammary glands, the salivary glands and the spleen. This expression was not tumorigenic and was characterized by the presence of the p28 gag antigen and the absence of the gp52 env antigen, except, however, in mammary glands of elder mice where traces of gp52 were found. In the mammary glands of SWISS MB+ mice, the expression of the Mtv-3 locus was masked by large amounts of antigens resulting from exogenous virus expression. RIIIf mice were MMTV-negative. Viral antigens coexisted with anti-MMTV antibodies in the serum of infected and tumor-bearing mice, but not in the form of immune complexes as verified by a method that allowed to detect specific antigen-containing-soluble immune complexes. An anti-MMTV serum reactivity was also detected in SWISS MB- and RIIIf mice. However, the serum response was higher in the two SWISS lines than in the two RIII lines. Except in tumor-bearing mice, the anti-MMTV response was not significantly modified by the presence of exogenous virus and thus resulted essentially from exposure to endogenous MMTV expression. In experimental infection studies, RIII mice were more susceptible to MMTV infection than SWISS mice. The correlation between resistance to MMTV infection and serum response to endogenous MMTV expression, suggests that the non-tumorigenic expression of an endogenous provirus can protect at least partially, against exogenous MMTV infection.
在两种感染小鼠乳腺肿瘤病毒（MMTV）的品系SWISS MB+和RIII的小鼠中研究了宿主与病毒的关系，这两个品系携带相同的MMTV变体，还研究了通过寄养摆脱乳汁传播的MMTV的衍生亚系Swiss MB-和RIIIf。这两个品系在系统发育上没有亲缘关系，SWISS品系的DNA中带有内源性Mtv-3位点。在RIII和SWISS MB+小鼠中，早期乳腺肿瘤的发生率分别为96%和8%，这与乳汁中MMTV的表达水平相关。在SWISS MB系中，在乳腺、唾液腺和脾脏中观察到与Mtv-3位点相关的前病毒的非协调表达。这种表达不具有致瘤性，其特征是存在p28 gag抗原且不存在gp52 env抗原，不过在老年小鼠的乳腺中发现了微量的gp52。在SWISS MB+小鼠的乳腺中，Mtv-3位点的表达被外源性病毒表达产生的大量抗原所掩盖。RIIIf小鼠为MMTV阴性。在感染和患肿瘤小鼠的血清中，病毒抗原与抗MMTV抗体共存，但不是以免疫复合物的形式存在，这通过一种能够检测含特定抗原的可溶性免疫复合物的方法得到了证实。在SWISS MB-和RIIIf小鼠中也检测到了抗MMTV血清反应性。然而，两个SWISS系中的血清反应高于两个RIII系。除了患肿瘤的小鼠外，外源性病毒的存在并没有显著改变抗MMTV反应，因此其基本上是由接触内源性MMTV表达引起的。在实验性感染研究中，RIII小鼠比SWISS小鼠更容易受到MMTV感染。对MMTV感染的抵抗力与对内源性MMTV表达的血清反应之间的相关性表明，内源性前病毒的非致瘤性表达至少可以部分保护机体免受外源性MMTV感染。
