Studies on the T-cell epitopes of herpesviruses

在病毒中和所需补体糖蛋白B(GB)的单抗存在下，获得了牛疱疹病毒1型(BHV1)逃逸突变株。该突变体对其他3种抗GB的单抗也有抵抗力，这些单抗表现出补体非依赖性中和活性。目前正在分析该突变体的Gb的氨基酸取代情况。同时，以突变体感染的原代培养物为靶点，研究突变株感染牛的外周血淋巴细胞的细胞毒活性，以研究氨基酸替代是否会影响T细胞的识别能力。为了开发更有效、更安全的牛传染性鼻气管炎疫苗，对牛进行了含杆状病毒表达的GC和/或GD亚单位疫苗的鼻腔免疫。在疫苗中加入霍乱毒素B亚单位作为粘膜佐剂。用疫苗滴鼻免疫的牛在鼻腔分泌物中产生针对BHV1的中和抗体，并在攻击BHV1的105.0PFU后勉强排出病毒。用107.8PFU的病毒攻击牛，表现出较轻的临床症状和较少的病毒脱落，小鼠滴入表达奥杰斯基病病毒(ADV)gD的质粒，在气管和肺冲洗液中产生抗病毒抗体，并抵抗致死量病毒的鼻内攻击。鼻腔给药的小鼠也能抵抗病毒的攻击。由于在小鼠鼻腔分泌物、气管肺泡灌洗液和血清中未检测到抗原性，呼吸道粘膜细胞表达的GC可能诱导细胞免疫以保护小鼠免受攻击。

An escape mutant of bovine herpesvirus 1 (BHV1) was obtained in the presence of monoclonal antibody against glycoprotein B (gB) , which required complement for virus neutralization. The mutant was also resistant to other 3 monoclonal antibodies against gB,which exhibited complement-independent neutralizing activity. Amino acid substitution of gB of the mutant is now being analyzed. The cytotoxic activity of peripheral blood lymphocytes from BHV1-infected cattle is also being investigated using the mutant-infected primary culture as a target to study whether the amino acid substitution affects recognition by T cells.To develope more effective and safer vaccine against infectious bovine rhinotracheitis, intranasal immunization of cattle with subunit vaccines containing baculovirus-expressed gC and/or gD of BHV1 was performed. Cholera toxin B subunit was added to the vaccines as amucosal adjuvant. Cattle immunized intranasally with the vaccines produced neutralizing antibodies against BHV1 in the nasal secresions and scarecely shed the virus after challenge with 105.0PFU of BHV1. When cattle were challenged with 107.8PFU of the virus, they showed less severity of clinical signs and less virus shedding.Mice intranasally administrated with plasmid expressing gD of Aujeszky's disease virus (ADV) produced antibodies against the virus in the trachea-lung washes and resisted to intranasal challenge with a lethal dose of the virus. Mice intranasally administrated with gC-expressing plasmid also resisted to the virus challenge. Since no antiody was detected in the nasal secresions, trachea-lung washes or serum of the mice, gC expressed in the respiratory mucosal cells may induce cellular immunity to protect from the challenge.