Abelson murine leukemia virus-induced tumors elicit antibodies against a host cell protein, P50
Abelson murine leukemia virus-induced tumors elicit antibodies against a host cell protein, P50
复制标题
Abelson 鼠白血病病毒诱导的肿瘤引发针对宿主细胞蛋白 P50 的抗体
DOI：
10.1128/jvi.36.2.547-555.1980
复制
发表时间：
1980
影响因子：
5.4
通讯作者：
D. Baltimore
中科院分区：
文献类型：
--
作者：
V. Rotter;O. Witte;R. Coffman;D. Baltimore
给BALB/c小鼠注射Abelson小鼠白血病病毒(A-MuLV)转化的同基因细胞系，肿瘤通常是致死的。在荷瘤小鼠的血清中，以及在排斥它们的肿瘤的小鼠的血清中，有一种抗体免疫沉淀了来自[35S]-蛋氨酸标记的A-MuLV转化的BALB/c细胞的特定蛋白。该蛋白不是先前鉴定的A-MuLV特异性蛋白(P120)，而是一种50000分子量的蛋白(P50)。这种血清也可以免疫沉淀P120，但没有其他蛋白可由它们重复沉淀。一种已被证明染色正常B淋巴细胞的单抗(RA3-2C2)也选择性地免疫沉淀P50。在A-MuLV转化的多种小鼠品系的淋巴样细胞和成纤维细胞中均存在P50。其中一株A-MuLV转化的细胞株P50水平很低，为C57L来源的L1-2肿瘤。这种肿瘤以前被C57L小鼠排斥，并被用来生产抗P120(抗ABT)血清。P50不是Moloney MuLV蛋白，在非A-MuLV转化的正常细胞中低水平表达，可能是A-MuLV转化选择性增加其浓度的宿主细胞蛋白。P50被磷酸化，用间接免疫荧光法，抗p50血清对A-MuLV转化的活细胞进行染色。该蛋白质没有糖基化，也没有通过乳过氧化物酶催化的碘化标记。因此，P50在细胞定位和性质上与P120非常相似，但它在体外不显示Protein Kinase活性。该蛋白在A-MuLV转化子中选择性增强，在同基因动物中具有很强的抗原性，提示它是一种独特的具有重要功能的蛋白。
When BALB/c mice were injected with a syngeneic cell line transformed by Abelson murine leukemia virus (A-MuLV), the tumor was usually lethal. In sera from tumor-bearing mice, and at highest levels in sera from mice that reject their tumors, was an antibody that immunoprecipitates a specific protein from [35S]-methionine-labeled A-MuLV-transformed BALB/c cells. This protein was not the previously characterized A-MuLV-specific protein (P120) but a 50,000-molecular-weight protein (P50). Such sera may also immunoprecipitate P120, but no other protein was reproducibly precipitated by them. A monoclonal antibody (RA3-2C2) that has been shown to stain normal B-lymphocytes also selectively immunoprecipitated P50. P50 was present in A-MuLV-transformed lymphoid and fibroblastic cells of a variety of mouse strains. One A-MuLV-transformed cell line had a very low P50 level, the L1-2 tumor of C57L origin. This tumor was previously shown to be rejected by C57L mice and is used to produce anti-P120 (anti-AbT) sera. P50 was not a Moloney MuLV protein and was found at low levels in normal cells of cells transformed by agents other than A-MuLV; thus, it was probably a host cell protein whose concentration was selectively accentuated by A-MuLV transformation. P50 was phosphorylated and, by using indirect immunofluorescence, anti-P50 serum stained live A-MuLV-transformed cells. The protein was not glycosylated and did not label by lactoperoxidase-catalyzed iodination. Thus, P50 was very like P120 in its cellular localization and properties, but it did not exhibit proptein kinase activity in vitro. The selective accentuation of this protein in A-MuLV transformants and its strong antigenicity in syngeneic animals suggest that it is a unique and functionally important protein.