Kim Nam-Hyung, Ha Eun-Jin, Ko Dae-Sung, Choi Kang-Seuk, Kwon Hyuk-Joon
Laboratory of Poultry Medicine, Seoul National University, Seoul, South Korea.
Research Institute for Veterinary Science, College of Veterinary Medicine, BK21 for Veterinary Science, Seoul, South Korea.
Front Vet Sci. 2020 Nov 6;7:598610. doi: 10.3389/fvets.2020.598610. eCollection 2020.
Fowl typhoid is caused by serovar Gallinarum biovar Gallinarum (SG), and live attenuated, rough vaccine strains have been used. Both humoral and cellular immune responses are involved in protection, but the humoral responses to different forms of SG antigens are unclear. In this study, we compared humoral responses to a killed oil-emulsion (OE) smooth vaccine (SG002) and its rough mutant vaccine (SR2-N6) strains using proteomics techniques. We identified two immunogenic outer membrane proteins (OmpA and OmpX), and the selected linear epitopes were successfully applied in peptide-ELISA. Our peptide- and total OMP-ELISAs were used to compare the temporal humoral responses to various SG antigens: OE SG002 and SR2-N6; live, killed [PBS-suspension (PS) and OE)] and mixed (live and PS) formulations of another rough vaccine strain (SG 9R); and orally challenge with a field strain. Serum antibodies to the linear epitopes of OmpA and OmpX lasted only for the first 2 weeks, but serum antibodies against OMPs increased over time. The rough strain (SR2-N6) and mixed SG 9R induced higher serum antibody titers than the smooth strain (SG002) and single SG 9R (OE, live and PS SG 9R), respectively. Infection with the field strain delayed the serum antibody response by ~2 weeks. Mucosal immunity was not induced by any formulation, except for infection with the field strain after SG 9R vaccination. Thus, our results may be useful to understand humoral immunity against various SG antigens and to improve vaccine programs and serological diagnosis in the field.
禽伤寒由鸡沙门氏菌生物变种鸡亚种（SG）引起，一直使用的是减毒活粗糙疫苗株。体液免疫和细胞免疫反应均参与保护过程，但对不同形式的SG抗原的体液免疫反应尚不清楚。在本研究中，我们使用蛋白质组学技术比较了对灭活油乳剂（OE）光滑疫苗（SG002）及其粗糙突变疫苗（SR2-N6）株的体液免疫反应。我们鉴定出两种免疫原性外膜蛋白（OmpA和OmpX），并将所选的线性表位成功应用于肽酶联免疫吸附测定（ELISA）。我们的肽ELISA和总外膜蛋白ELISA用于比较对各种SG抗原的时间性体液免疫反应：OE SG002和SR2-N6；另一种粗糙疫苗株（SG 9R）的活疫苗、灭活疫苗[磷酸盐缓冲液悬浮液（PS）和OE]以及混合疫苗（活疫苗和PS）制剂；以及用一株野毒株进行口服攻毒。针对OmpA和OmpX线性表位的血清抗体仅在最初2周内存在，但针对外膜蛋白的血清抗体随时间增加。粗糙菌株（SR2-N6）和混合SG 9R分别比光滑菌株（SG002）和单一SG 9R（OE、活疫苗和PS SG 9R）诱导出更高的血清抗体滴度。用野毒株感染使血清抗体反应延迟约2周。除了在SG 9R疫苗接种后用野毒株感染外，任何制剂均未诱导黏膜免疫。因此，我们的结果可能有助于了解针对各种SG抗原的体液免疫，并改善该领域的疫苗计划和血清学诊断。
