Heterodimeric Bispecific Single Chain Variable Fragments (scFv) Killer Engagers (BiKEs) Enhance NK-cell Activity...

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Natural killer (NK) cells are crucial for tumor immunosurveillance.
• Cancer stem cells (CSCs) drive tumor growth and relapse, expressing CD133.
• Targeting CSCs is vital for effective cancer therapy.

Purpose of the Study:

• To develop a novel bispecific antibody (16×133 BiKE) to enhance NK cell-mediated killing of CSCs.
• To investigate the efficacy of targeting CD133 on CSCs using this bispecific antibody.
• To explore a new immunotherapy strategy for carcinoma.

Main Methods:

• Genetic splicing of DNA fragments from scFv antibodies targeting CD16 (NK cells) and CD133 (CSCs).
• Creation of the bispecific antibody 16×133 BiKE.
• In vitro cytotoxicity assays (chromium-51 release) and flow cytometry analysis.

Main Results:

• 16×133 BiKE significantly enhanced NK cell-mediated killing of CD133+ colorectal carcinoma cells (Caco-2).
• The drug increased NK cell cytotoxicity even against NK-resistant cells with low CD133 expression (Daudi cell line).
• Co-culture with the drug increased NK cell degranulation and Interferon-γ production.

Conclusions:

• Bispecific antibodies can effectively recruit the innate immune system to eliminate CSCs.
• The anti-CD133 scFv is a promising component for bispecific and trispecific antibody platforms in cancer therapy.
• This strategy offers a potential new avenue for treating carcinomas.