van der Most R G, Murali-Krishna K, Whitton J L, Oseroff C, Alexander J, Southwood S, Sidney J, Chesnut R W, Sette A, Ahmed R
Department of Microbiology and Immunology, University of California, Los Angeles School of Medicine 90024, USA.
Virology. 1998 Jan 5;240(1):158-67. doi: 10.1006/viro.1997.8934.
Antiviral cytotoxic T-cells are critical for control of lymphocytic choriomeningitis virus (LCMV) infection in mice. In H-2b mice, the antiviral response is directed against three Db-restricted epitopes in the viral nucleoprotein (NP396-404) and glycoprotein (GP276-286 and GP33-41). Our present data revealed a clear hierarchy among these three epitopes, in which NP396-404 is immunodominant, followed by GP33-41 and GP276-286, respectively. In order to identify additional CTL epitopes in the LCMV nucleoprotein and glycoprotein, we used the motifs for Db2- and Kb-binding peptides, combined with MHC class I-binding assays. Out of 23 Db motif-fitting peptides, we identified 4 Db binders, one of which (GP92-101) turned out to be a new CTL epitope. Among 28 Kb motif-fitting peptides, 12 bound Kb, and one of these (NP205-212) was a CTL epitope. Both newly identified CTL peptides were recognized by LCMV-immune splenocytes after secondary in vitro stimulation. Both peptides bound their MHC class I molecules with intermediate affinity (470 and 170 nM for GP92-101 and NP205-212, respectively). Responses against these peptides were weaker than the responses against the three major epitopes. None of the high affinity binders were new epitopes, suggesting that high affinity binders are either immunodominant epitopes or no epitopes at all. Thus, analysis of 51 Kb and Db motif-fitting peptides yielded 2 new, subdominant epitopes. Immunization of C57BL/6 mice with these peptides, or vaccinia virus recombinants expressing these epitopes as minigenes, protected against chronic LCMV infection, demonstrating that immunization with subdominant epitopes can confer protection against chronic viral infection.
抗病毒细胞毒性T细胞对于控制小鼠淋巴细胞性脉络丛脑膜炎病毒（LCMV）感染至关重要。在H-2b小鼠中，抗病毒反应针对病毒核蛋白（NP396-404）和糖蛋白（GP276-286和GP33-41）中的三个Db限制性表位。我们目前的数据揭示了这三个表位之间存在明显的等级关系，其中NP396-404具有免疫优势，其次分别是GP33-41和GP276-286。为了鉴定LCMV核蛋白和糖蛋白中的其他CTL表位，我们使用了Db2和Kb结合肽的基序，并结合MHC I类结合试验。在23个符合Db基序的肽中，我们鉴定出4个Db结合物，其中一个（GP92-101）被证明是一个新的CTL表位。在28个符合Kb基序的肽中，12个与Kb结合，其中一个（NP205-212）是CTL表位。在体外二次刺激后，新鉴定的两种CTL肽均被LCMV免疫的脾细胞识别。两种肽都以中等亲和力结合其MHC I类分子（GP92-101和NP205-212的亲和力分别为470和170 nM）。针对这些肽的反应比针对三个主要表位的反应弱。高亲和力结合物均不是新表位，这表明高亲和力结合物要么是免疫优势表位，要么根本不是表位。因此，对51个符合Kb和Db基序的肽进行分析产生了2个新的、次优势表位。用这些肽或表达这些表位作为小基因的痘苗病毒重组体免疫C57BL/6小鼠，可预防慢性LCMV感染，这表明用次优势表位免疫可提供针对慢性病毒感染的保护。
