Page 14 - ebook

[E. Immunology] E-7

Strengthening the cytotoxic immunogenic response against

PD-L1 overexpressing cancer with anti-PD-L1 and anti-CD3

conjugated nanoparticles-based bispecific T cell engager

loaded with R848 (TLR7/TLR8) agonists

Ramesh Duwa¹, Ram Hari Pokharel², Simmyung Yook¹*, Jae Hoon Chang²*

¹Department of Pharmacy, Keimyung University, Daegu 42601, Korea, ²Department of Pharmacy, Yeungnam

University, Gyeongbuk 38541, Korea

Bispecific nanoparticles (NPs) are a modular platform for cancer immunotherapeutic strategies that have the

specificity to recognize two different epitopes. They can redirect the T cell to lyse tumor cells by blocking two
different signaling pathways. In this study, R848-loaded bispecific poly(lactic-co-glycolic acid) NPs conjugated with

anti-CD3 and anti-PD-L1 (bis-R848-PLGA-NPs) were developed to block PD-1/PD-L1 pathway with anti-PD-L1 and
CD3 receptor of T cell with anti-CD3 antibodies. Ultimately, these interactions allow to bring T cells in close proximity

to the tumor cells. Finally, the release of R848 from PLGA-NPs activates the dendritic cells through TLR-8 that
enhanced the activation of T cells. The particle size of Bis-R848-PLGA-NPs was 172.7 ± 3.1nm with -18.2 ± 1.5mV

zeta potential. The loading capacity of R848 in the PLGA-NPs was 5.1 ± 0.2%. In vitro studies showed maximum
internalization of bis-R848-PLGA-NPs in SK-OV3 and B16F10 cell lines due to the high PD-L1 expression.
Furthermore, the total amount of CD4+ and CD8+ T cells, and cytokines (granzyme B, perforin, IFN-Y, IL-10) at

tumor-infiltrating lymphocytes of tumor-bearing C57BL/6 mice was increased in bis-R848-PLGA-NPs treated mice

compared to control group. Thus, these results suggest that bis-R848-PLGA-NPs can be a potential targeted
immunotherapeutic agent against PD-L1 overexpressing cancer.