Snyder H W, Singhal M C, Zuckerman E E, Jones F R, Hardy W D
Virology. 1983 Dec;131(2):315-27. doi: 10.1016/0042-6822(83)90500-7.
The feline oncornavirus-associated cell membrane antigen (FOCMA) on the surface of feline lymphosarcoma (LSA) cells is defined as the target(s) recognized in immunofluorescence (IFA) tests by antibody in sera of cats relatively resistant to development of FeLV (feline leukemia virus) LSA and FeSV (feline sarcoma virus) fibrosarcoma. The specificities of antibodies in cat FOCMA-typing sera and the nature of the LSA antigens recognized were investigated in the present study. FOCMA sera obtained from viremic cats were separable into at least two classes : those which contained antibodies against the envelope glycoprotein (gp70) of subgroup C FeLV and those which did not contain antibodies against any subgroup of FeLV. The first class of sera could be further subdivided into three groups: those whose FOCMA reactivity could be completely absorbed, partially absorbed, or not absorbed by FeLV-C antigens. The second class of sera could be further subdivided into two groups: those whose FOCMA reactivity could be partially absorbed and those whose activity could not be absorbed by FeLV-C. The results indicate that the FOCMA reactivity exhibited by some viremic cat sera can be partially, if not entirely, attributed to antibodies not crossreactive with FeLV virion antigens. A consistent property of all FOCMA sera in this study is the ability to bind to 70-kDa proteins on the surface of LSA cells. Staphylococcus aureus V8 protease partial digest maps of 70-kDa proteins purified from 12 primary feline LSAs (five FeLV positive and seven FeLV negative) all showed 18-, 14-, and 10-kDa fragments. V8 maps of FeLV-C gp70 showed similarly sized fragments while the maps of the RD114, FeLV-A, and FeLV-B gp70s were distinct. However, in a subgroup-specific radioimmunoassay for FeLV-C gp70-related antigens, the LSA 70-kDa proteins were found to be serologically related to, but distinct from, FeLV-C gp70. The results on the antigenic variations among LSA 70-kDa proteins and the antibodies which bind them are entirely consistent with previous studies indicating heterogeneity among FOCMA determinants.
猫淋巴肉瘤（LSA）细胞表面的猫肿瘤病毒相关细胞膜抗原（FOCMA）被定义为在免疫荧光（IFA）试验中，相对不易发生猫白血病病毒（FeLV）LSA和猫肉瘤病毒（FeSV）纤维肉瘤的猫血清中的抗体所识别的靶标。本研究调查了猫FOCMA分型血清中抗体的特异性以及所识别的LSA抗原的性质。从病毒血症猫获得的FOCMA血清可分为至少两类：一类含有针对C亚群FeLV包膜糖蛋白（gp70）的抗体，另一类不含有针对任何FeLV亚群的抗体。第一类血清可进一步细分为三组：其FOCMA反应性可被FeLV-C抗原完全吸收、部分吸收或不被吸收的血清。第二类血清可进一步细分为两组：其FOCMA反应性可被部分吸收的血清和其活性不能被FeLV-C吸收的血清。结果表明，一些病毒血症猫血清表现出的FOCMA反应性，即使不能完全，也可部分归因于与FeLV病毒粒子抗原无交叉反应的抗体。本研究中所有FOCMA血清的一个一致特性是能够结合LSA细胞表面的70 kDa蛋白。从12例原发性猫LSA（5例FeLV阳性和7例FeLV阴性）中纯化的70 kDa蛋白的金黄色葡萄球菌V8蛋白酶部分消化图谱均显示出18 kDa、14 kDa和10 kDa的片段。FeLV-C gp70的V8图谱显示出大小相似的片段，而RD114、FeLV-A和FeLV-B gp70的图谱则不同。然而，在针对FeLV-C gp70相关抗原的亚群特异性放射免疫分析中，发现LSA 70 kDa蛋白与FeLV-C gp70在血清学上相关，但又有所不同。关于LSA 70 kDa蛋白之间的抗原变异以及与之结合的抗体的结果，与先前表明FOCMA决定簇存在异质性的研究完全一致。
