In-depth cross-validation of human and mouse CD4-specific minibodies for noninvasive PET imaging of CD4cells and response prediction to cancer immunotherapy.

in Theranostics by Stefania Pezzana, Simone Blaess, Jule Kortendieck, Nicole Hemmer, Bredi Tako, Claudia Pietura, Lara Ruoff, Simon Riel, Martin Schaller, Irene Gonzalez-Menendez, Leticia Quintanilla-Martinez, Alessandro Mascioni, Argin Aivazian, Ian Wilson, Andreas Maurer, Bernd J Pichler, Manfred Kneilling, Dominik Sonanini

TLDR

  • This study investigates how CD4T cells help fight cancer. The researchers used a special kind of imaging called PET/MRI to track the movement of CD4T cells in the body. They found that CD4T cells play an important role in cancer immunity and that they can be targeted with special molecules to help fight cancer. The study also found that the imaging approach used in this study can be used to monitor CD4T cells in patients undergoing cancer immunotherapy. This could help doctors better understand how CD4T cells are working in the body and how to target them more effectively.

Abstract

Increasing evidence emphasizes the pivotal role of CD4T cells in orchestrating cancer immunity. Noninvasiveimaging of the temporal dynamics of CD4T cells and their distribution patterns might provide novel insights into their effector and regulator cell functions during cancer immunotherapy (CIT).We conducted a comparative analysis ofZr-labeled anti-mouse (m) and anti-human (h) CD4-targeting minibodies (Mbs) forpositron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4knock-in (hCD4-KI) mouse models.BothZr-CD4-Mbs yielded high radiolabeling efficiencies of >90%, immunoreactivities of >70%, and specificbinding to their target antigens. The specificity oftargeting ofZr-hCD4-Mb was confirmed by PET/MRI, revealing ~4-fold greaterZr-hCD4-Mb uptake in subcutaneous hCD4hematopoietic peripheral blood acute lymphoblastic leukemia tumors (HPB-ALL) than in solid hCD4diffuse histiocytic lymphomas (DHL) andZr-mCD4-Mb uptake in hCD4HPB-ALL tumors. In a comparative cross-validation study in anti-programmed death ligand (αPD-L1)/anti-4-1BB-treated orthotopic PyMT mammary carcinoma-bearing hCD4-KI and WT mice, we detected 2- to 3-fold enhanced species-specificZr-hCD4-Mb orZr-mCD4-Mb uptake within CD4cell-enriched secondary lymphatic organs (lymph nodes and spleens). TheZr-hCD4-Mb uptake in the PyMT tumors was more pronounced in hCD4-KI mice compared to the WT control littermates. Most importantly, MC38 adenocarcinoma-bearing mice treated with a combination of αPD-L1 and anti-lymphocyte-activation gene 3 (αLag-3) antibodies exhibited ~1.4-fold higherZr-mCD4-Mb uptake than mice that were not responsive to therapy or sham-treated mice.CD4 PET/MRI enabled monitoring of the CD4cell distribution in secondary lymphatic organs and the tumor microenvironment, capable of predicting sensitivity to CIT. Our imaging approach will provide deeper insights into the underlying molecular mechanisms of CD4-directed cancer immunotherapies in preclinical mouse models and is applicable for clinical translation.

Overview

  • The study investigates the role of CD4T cells in cancer immunity and compares the outcomes of two anti-CD4 targeting minibodies (Mbs) for positron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4knock-in (hCD4-KI) mouse models. The primary objective is to evaluate the specificity and uptake of the two Mbs in CD4T cells and their distribution patterns in the tumor microenvironment and secondary lymphatic organs. The study aims to provide novel insights into the effector and regulator cell functions of CD4T cells during cancer immunotherapy (CIT).

Comparative Analysis & Findings

  • The study compares the outcomes of two anti-CD4 targeting minibodies (Mbs) for PET/MRI of CD4T cells in human xenografts, syngeneic tumor-bearing WT, and hCD4-KI mouse models. Both Zr-CD4-Mbs yielded high radiolabeling efficiencies of >90%, immunoreactivities of >70%, and specific binding to their target antigens. The specificity of targeting of Zr-hCD4-Mb was confirmed by PET/MRI, revealing ~4-fold greater Zr-hCD4-Mb uptake in subcutaneous hCD4 hematopoietic peripheral blood acute lymphoblastic leukemia tumors (HPB-ALL) than in solid hCD4 diffuse histiocytic lymphomas (DHL) and Zr-mCD4-Mb uptake in hCD4 HPB-ALL tumors. In a comparative cross-validation study in anti-programmed death ligand (αPD-L1)/anti-4-1BB-treated orthotopic PyMT mammary carcinoma-bearing hCD4-KI and WT mice, the study detected 2- to 3-fold enhanced species-specific Zr-hCD4-Mb or Zr-mCD4-Mb uptake within CD4 cell-enriched secondary lymphatic organs (lymph nodes and spleens). The Zr-hCD4-Mb uptake in the PyMT tumors was more pronounced in hCD4-KI mice compared to the WT control littermates. Most importantly, MC38 adenocarcinoma-bearing mice treated with a combination of αPD-L1 and anti-lymphocyte-activation gene 3 (αLag-3) antibodies exhibited ~1.4-fold higher Zr-mCD4-Mb uptake than mice that were not responsive to therapy or sham-treated mice. CD4 PET/MRI enabled monitoring of the CD4 cell distribution in secondary lymphatic organs and the tumor microenvironment, capable of predicting sensitivity to CIT.

Implications and Future Directions

  • The study's findings highlight the importance of CD4T cells in cancer immunity and provide novel insights into their effector and regulator cell functions during CIT. The study's imaging approach can be applied for clinical translation to monitor CD4 cell distribution in patients undergoing CIT. Future research directions could include the development of novel anti-CD4 targeting Mbs with improved specificity and uptake, as well as the investigation of the role of CD4T cells in other types of cancer immunotherapies. Additionally, the study's findings could be used to develop personalized CIT strategies based on the CD4 cell distribution patterns in individual patients.
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