Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
Fish Shellfish Immunol. 2020 Sep;104:279-288. doi: 10.1016/j.fsi.2020.06.002. Epub 2020 Jun 4.
Glycoprotein is an important immunogenic protein of Hirame novirhabdovirus (HIRRV). In this study, the full-length and N-/C-terminal portions of glycoprotein were recombinantly expressed (rG, rGn and rGc protein), and the induced immune responses were investigated in flounder (Paralichthys olivaceus) model. The results showed that compared to PBS control, rG, rGn and rGc proteins and inactivated HIRRV suspension (iVS) could all stimulate significant increases of flounder CD4-1, CD4-2 T lymphocytes and surface IgM positive (sIgM) B lymphocytes in peripheral blood, spleen and head kidney (p < 0.05). However, no significant differences of the percentages of CD4-1 or CD4-2 T lymphocytes were observed among three protein vaccination groups (p > 0.05). iVS could induce the highest mean levels of CD4 T lymphocytes in peripheral blood and spleen. For sIgM B lymphocytes, the average peak percentages in rG and rGc groups were higher than rGn group. Moreover, significant increases of specific serum IgM against HIRRV or rG protein were observed in iVS, rG, rGn and rGc groups, but rG group exhibited the highest mean level. Furthermore, rG protein induced the highest titer of neutralizing antibodies against HIRRV, followed by iVS. Meanwhile, the challenge test showed that the relative percent survival (RPS) of rG, rGn, rGc and iVS groups were 75.0%, 35.7%, 53.6% and 60.7%, respectively. These results revealed that the full-length G protein would be a more effective subunit vaccine candidate against HIRRV infection.
糖蛋白是牙鲆虹彩病毒（HIRRV）的一种重要免疫原性蛋白。本研究中，重组表达了糖蛋白全长和 N-/C-末端部分（rG、rGn 和 rGc 蛋白），并在牙鲆模型中研究了诱导的免疫反应。结果表明，与 PBS 对照组相比，rG、rGn 和 rGc 蛋白以及灭活 HIRRV 悬浮液（iVS）均能刺激牙鲆外周血、脾脏和头肾中 CD4-1、CD4-2 T 淋巴细胞和表面免疫球蛋白 M 阳性（sIgM）B 淋巴细胞显著增加（p<0.05）。然而，在三种蛋白免疫组中，CD4-1 或 CD4-2 T 淋巴细胞的百分比没有显著差异（p>0.05）。iVS 能诱导外周血和脾脏中 CD4 T 淋巴细胞的最高平均水平。对于 sIgM B 淋巴细胞，rG 和 rGc 组的平均峰值百分比高于 rGn 组。此外，在 iVS、rG、rGn 和 rGc 组中均观察到针对 HIRRV 或 rG 蛋白的特异性血清 IgM 显著增加，但 rG 组的平均水平最高。此外，rG 蛋白诱导针对 HIRRV 的中和抗体效价最高，其次是 iVS。同时，攻毒试验表明，rG、rGn、rGc 和 iVS 组的相对存活率（RPS）分别为 75.0%、35.7%、53.6%和 60.7%。这些结果表明全长 G 蛋白可能是一种更有效的虹彩病毒亚单位疫苗候选物。
