# Polyclonal antibodies selectively inhibit tumor growth and invasion and synergize with immune checkpoint inhibitors

## TL;DR

Polyclonal antibodies can inhibit tumor growth and work well with immune checkpoint inhibitors to fight cancer.

## Contribution

Glyco-humanized polyclonal antibodies show therapeutic potential and synergize with checkpoint inhibitors in multiple cancer models.

## Key findings

- Polyclonal antibodies target tumors without harming healthy tissues.
- They synergize with anti–PD-L1 to prevent metastases in cancer models.
- Glyco-humanized pAb show efficacy in xenografted mice with human tumors.

## Abstract

Heterologous polyclonal antibodies (pAb) were shown to possess oncolytic properties a century ago with reported clinical responses. More recent preclinical models confirmed pAb efficacy, though their ability to tackle complex target antigens reduces susceptibility to tumor escape. Owing to the recent availability of glyco-humanized pAb (GH-pAb) with acceptable clinical toxicology profile, we revisited use of pAb in oncology and highlighted their therapeutic potential against multiple cancer types. Murine antitumor pAb were generated after repeated immunization of rabbits with murine tumor cell lines from hepatocarcinoma, melanoma, and colorectal cancers. Antitumor pAb recognized and showed cytotoxicity against their targets without cross-reactivity with healthy tissues. In vivo, pAb are effective alone; moreover, these pAb synergize with immune checkpoint inhibitors like anti–PD-L1 in several cancer models. They elicited an antitumor host immune response and prevented metastases. The anticancer activity of pAb was also confirmed in xenografted NMRI nude mice using GH-pAb produced by repeated immunization of pigs with human tumor cell lines. In conclusion, the availability of bioengineered GH-pAb allows for revisiting of passive immunotherapy with oncolytic pAb to fight against solid tumor and cancer metastasis.

<p>Tumor cell-targeting glyco-humanized polyclonal&nbsp;antibodies have potential&nbsp;against circulating and&nbsp;solid tumors and synergize&nbsp;with immune checkpoint inhibitors.</p>