A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.

Several T cell immune checkpoint blockade therapies have shown initial successes in multiple cancers. However, significant issues remain, including tumor relapse, severe toxicities, and a lack of efficacy in most patients. SIRPα, commonly known as the "do not eat me signal", is a monocyte...

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Main Authors: Keifer G Kurtz, Irina Lebedeva, Stephanie A Pierre, David Andrew, Yu-Rou Liao, Daisy Ambriz, Olivia Vergnolle, Leyi Shen, Elizabeth Nyakatura, Manuel Baca, David A Scheinberg
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0321169
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author Keifer G Kurtz
Irina Lebedeva
Stephanie A Pierre
David Andrew
Yu-Rou Liao
Daisy Ambriz
Olivia Vergnolle
Leyi Shen
Elizabeth Nyakatura
Manuel Baca
David A Scheinberg
author_facet Keifer G Kurtz
Irina Lebedeva
Stephanie A Pierre
David Andrew
Yu-Rou Liao
Daisy Ambriz
Olivia Vergnolle
Leyi Shen
Elizabeth Nyakatura
Manuel Baca
David A Scheinberg
author_sort Keifer G Kurtz
collection DOAJ
description Several T cell immune checkpoint blockade therapies have shown initial successes in multiple cancers. However, significant issues remain, including tumor relapse, severe toxicities, and a lack of efficacy in most patients. SIRPα, commonly known as the "do not eat me signal", is a monocyte checkpoint cell surface protein. Agents that block the interaction of CD47 with SIRPα have recently shown clinical success in combination with monoclonal antibody therapy to potentiate macrophage phagocytosis of tumors. However, significant toxicities and logistical issues are associated with CD47-targeted agents due to the expression of CD47 on all human cells. In contrast, SIRPα has expression limited to myelomonocytic cells, meaning highly specific SIRPα blocking agents might reduce these toxicities and avoid the target antigen sink. Herein, we generated a high affinity and highly specific SIRPα-targeting monoclonal antibody, F05, that has enhanced SIRPα binding and reduced SIRPβ and SIRPγ binding capacity when compared to other available SIRPα antibodies. Furthermore, we show F05 reprograms immunosuppressive macrophages toward a phagocytic profile in vitro. F05 demonstrated efficacy in solid tumor animal models, providing a rationale for further development of the antibody.
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spelling doaj-art-2694684b6af5487dbea8a43e3720499e2025-08-20T03:14:02ZengPublic Library of Science (PLoS)PLoS ONE1932-62032025-01-01205e032116910.1371/journal.pone.0321169A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.Keifer G KurtzIrina LebedevaStephanie A PierreDavid AndrewYu-Rou LiaoDaisy AmbrizOlivia VergnolleLeyi ShenElizabeth NyakaturaManuel BacaDavid A ScheinbergSeveral T cell immune checkpoint blockade therapies have shown initial successes in multiple cancers. However, significant issues remain, including tumor relapse, severe toxicities, and a lack of efficacy in most patients. SIRPα, commonly known as the "do not eat me signal", is a monocyte checkpoint cell surface protein. Agents that block the interaction of CD47 with SIRPα have recently shown clinical success in combination with monoclonal antibody therapy to potentiate macrophage phagocytosis of tumors. However, significant toxicities and logistical issues are associated with CD47-targeted agents due to the expression of CD47 on all human cells. In contrast, SIRPα has expression limited to myelomonocytic cells, meaning highly specific SIRPα blocking agents might reduce these toxicities and avoid the target antigen sink. Herein, we generated a high affinity and highly specific SIRPα-targeting monoclonal antibody, F05, that has enhanced SIRPα binding and reduced SIRPβ and SIRPγ binding capacity when compared to other available SIRPα antibodies. Furthermore, we show F05 reprograms immunosuppressive macrophages toward a phagocytic profile in vitro. F05 demonstrated efficacy in solid tumor animal models, providing a rationale for further development of the antibody.https://doi.org/10.1371/journal.pone.0321169
spellingShingle Keifer G Kurtz
Irina Lebedeva
Stephanie A Pierre
David Andrew
Yu-Rou Liao
Daisy Ambriz
Olivia Vergnolle
Leyi Shen
Elizabeth Nyakatura
Manuel Baca
David A Scheinberg
A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
PLoS ONE
title A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
title_full A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
title_fullStr A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
title_full_unstemmed A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
title_short A human antibody specific for SIRPα reprograms macrophages and promotes antibody mediated anti-cancer activity.
title_sort human antibody specific for sirpα reprograms macrophages and promotes antibody mediated anti cancer activity
url https://doi.org/10.1371/journal.pone.0321169
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