Plasmid DNA encoding neutralizing human monoclonal antibody without enhancing activity protects against dengue virus infection in mice

• 作者: Surachet Benjathummarak Atsushi Yamanaka Thanyaluk Krasae Chonlatip Pipattanaboon Subenya Injampa Pannamthip Pitaksajjakul Pongrama Ramasoota
• 来源期刊: 亚太热带医药杂志（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: Original Articles
• 页码范围: 299-308
• 页数: 10页
• 语种: 英文
• DOI: 10.4103/1995-7645.320520

摘要

Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus (DENV) without enhancing activity in BALB/c mice. Methods: We constructed pFUSE-based vectors (pFUSE_1G7C2_hVH and pFUSE_1G7C2_hVL) containing genes encoding the variable domains of the heavy or light chain of the anti-dengue virus antibody 1G7C2, a human IgG1 that has been characterized for its neutralizing activity to DENV-1-4. Leucine (L) at positions 234 and 235 on the Fc CH2 domain in pFUSE_1G7C2_hVH was mutated to alanine (A) (LALA mutation) by site direct mutagenesis, and the new plasmid was termed pFUSE_1G7C2_hVH_LALA. An equal amount of pFUSE_1G7C2_hVL and 1G7C2_hG1-LALA plasmids were co-transfected into Chinese hamster ovary cells (CHO-K1) and a single dose of 100 μg 1G7C2_hG1-LALA plasmid was intramuscularly injected, followed by electroporation in BALB/c mice. The secreted 1G7C2_hG1-LALA antibodies in cell culture supernatant and mouse serum were examined for their biological functions, neutralization and enhancing activity. Results: The co-transfection of heavy- and light-chain 1G7C2_hG1-LALA plasmids in CHO-K1 cells produced approximately 3900 ng/mL human IgG and neutralized 90％-100％ all four DENV, with no enhancing activity. Furthermore, the modified human IgG was produced more than 1000 ng/mL in mouse serum on day 7 post plasmid injection and showed cross-neutralization to four DENV serotypes. Subsequently, antibody production and neutralization decreased rapidly. Nevertheless, the secreted neutralizing 1G7C2_hG1-LALA in mouse serum demonstrated complete absence of enhancing activities to all DENV serotypes. Conclusions: These findings reveal that a new modified 1G7C2_hG1-LALA expressing plasmid based on gene transfer is a possible therapeutic antibody candidate against DENV infection.