Uncoupling therapeutic from immunotherapy-related adverse effects for safer and effective anti-CTLA-4 antibodies in CTLA4 humanized mice.
Cell Res
; 28(4): 433-447, 2018 Apr.
Article
in En
| MEDLINE
| ID: mdl-29463898
ABSTRACT
Anti-CTLA-4 monoclonal antibodies (mAbs) confer a cancer immunotherapeutic effect (CITE) but cause severe immunotherapy-related adverse events (irAE). Targeting CTLA-4 has shown remarkable long-term benefit and thus remains a valuable tool for cancer immunotherapy if the irAE can be brought under control. An animal model, which recapitulates clinical irAE and CITE, would be valuable for developing safer CTLA-4-targeting reagents. Here, we report such a model using mice harboring the humanized Ctla4 gene. In this model, the clinically used drug, Ipilimumab, induced severe irAE especially when combined with an anti-PD-1 antibody; whereas another mAb, L3D10, induced comparable CITE with very mild irAE under the same conditions. The irAE corresponded to systemic T cell activation and resulted in reduced ratios of regulatory to effector T cells (Treg/Teff) among autoreactive T cells. Using mice that were either homozygous or heterozygous for the human allele, we found that the irAE required bi-allelic engagement, while CITE only required monoallelic engagement. As with the immunological distinction for monoallelic vs bi-allelic engagement, we found that bi-allelic engagement of the Ctla4 gene was necessary for preventing conversion of autoreactive T cells into Treg cells. Humanization of L3D10, which led to loss of blocking activity, further increased safety without affecting the therapeutic effect. Taken together, our data demonstrate that complete CTLA-4 occupation, systemic T cell activation and preferential expansion of self-reactive T cells are dispensable for tumor rejection but correlate with irAE, while blocking B7-CTLA-4 interaction impacts neither safety nor efficacy of anti-CTLA-4 antibodies. These data provide important insights for the clinical development of safer and potentially more effective CTLA-4-targeting immunotherapy.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
CTLA-4 Antigen
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Ipilimumab
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Antineoplastic Agents, Immunological
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Immunotherapy
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Neoplasms
Limits:
Animals
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Female
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Humans
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Male
Language:
En
Journal:
Cell Res
Year:
2018
Type:
Article
Affiliation country:
United States