Bright R K, Shearer M H, Kennedy R C
Department of Virology and Immunology, Southwest Foundation for Biomedical Research, San Antonio, TX.
Clin Exp Immunol. 1994 Jun;96(3):491-9. doi: 10.1111/j.1365-2249.1994.tb06056.x.
Baculovirus-derived recombinant simian virus 40 large tumour antigen (SV40 T-ag) was used to immunize BALB/c, C57Bl/6 and CB6/F1 mice and their anti-SV40 T-ag antibody responses were examined for the ability to bind synthetic peptides representing six predicted B cell epitopes on SV40 T-ag. In C57Bl/6 mice, anti-SV40 T-ag antibodies failed to bind any of the six SV40 T-ag peptides. However, the antibody responses induced in both BALB/c and CB6/F1 mice recognized synthetic peptides corresponding to two distinct epitopes (amino acids 690-708 and 660-679, respectively) associated with the carboxyl-terminal half of SV40 T-ag. In addition, murine MoAbs (BALB/c) generated to native SV40 T-ag, and previously characterized as recognizing the carboxyl-terminus of SV40 T-ag by deletion mutant analysis, also bound the synthetic peptide (residues 690-708) defining the carboxyl-terminus of SV40 T-ag. These data indicate that the antibody responses induced in BALB/c and CB6/F1 mice by immunization with baculovirus-derived recombinant SV40 T-ag are capable of recognizing sequential carboxyl-terminal epitopes on SV40 T-ag defined by peptides 690-708 and 660-679, respectively. No statistically significant differences in anti-SV40 T-ag antibody titres were observed between the three inbred mouse strains. These data suggested that the fine specificities of the anti-SV40 T-ag responses as assessed by synthetic peptide binding were different in the three inbred strains of mice examined. Finally, in vivo tumour challenge studies comparing recombinant SV40 T-ag with the two carboxyl-terminus peptide epitopes indicated that some tumour immunity was induced in BALB/c, but not CB6/F1 mice, by immunization with peptide 690-708 conjugated to a carrier protein. These studies suggest that the carboxyl-terminal region of SV40 T-ag represents a continuous sequential epitope involved in both the antibody response to SV40 T-ag and tumour immunity in BALB/c mice.
杆状病毒衍生的重组猿猴病毒40大肿瘤抗原（SV40 T-ag）用于免疫BALB/c、C57Bl/6和CB6/F1小鼠，并检测它们的抗SV40 T-ag抗体反应结合代表SV40 T-ag上六个预测B细胞表位的合成肽的能力。在C57Bl/6小鼠中，抗SV40 T-ag抗体未能结合六个SV40 T-ag肽中的任何一个。然而，在BALB/c和CB6/F1小鼠中诱导的抗体反应识别了与SV40 T-ag羧基末端一半相关的两个不同表位（分别为氨基酸690 - 708和660 - 679）对应的合成肽。此外，针对天然SV40 T-ag产生的鼠单克隆抗体（BALB/c），通过缺失突变分析先前被鉴定为识别SV40 T-ag的羧基末端，也结合了定义SV4 T-ag羧基末端的合成肽（残基690 - 708）。这些数据表明，用杆状病毒衍生的重组SV40 T-ag免疫BALB/c和CB6/F1小鼠诱导的抗体反应能够识别分别由肽690 - 708和660 - 679定义的SV40 T-ag上的连续羧基末端表位。在这三个近交系小鼠品系之间未观察到抗SV40 T-ag抗体滴度的统计学显著差异。这些数据表明，在所检测的三个近交系小鼠中，通过合成肽结合评估的抗SV40 T-ag反应的精细特异性不同。最后，将重组SV40 T-ag与两个羧基末端肽表位进行比较的体内肿瘤攻击研究表明，用与载体蛋白偶联的肽690 - 708免疫在BALB/c小鼠中诱导了一些肿瘤免疫，但在CB6/F1小鼠中未诱导。这些研究表明，SV40 T-ag的羧基末端区域代表一个连续的序列表位，参与了对SV40 T-ag的抗体反应和BALB/c小鼠的肿瘤免疫。
