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

• Published in: Theranostics Vol. 14; no. 12; pp. 4582 - 4597
• Main Authors: Pezzana, Stefania, Blaess, Simone, Kortendieck, Jule, Hemmer, Nicole, Tako, Bredi, Pietura, Claudia, Ruoff, Lara, Riel, Simon, Schaller, Martin, Gonzalez-Menendez, Irene, Quintanilla-Martinez, Leticia, Mascioni, Alessandro, Aivazian, Argin, Wilson, Ian, Maurer, Andreas, Pichler, Bernd J, Kneilling, Manfred, Sonanini, Dominik
• Format: Journal Article
• Language: English
• Published: Australia Ivyspring International Publisher 01.01.2024
• Subjects: Animals; CD4-Positive T-Lymphocytes - immunology; Cell Line, Tumor; Female; Humans; Immunotherapy - methods; Magnetic Resonance Imaging - methods; Mice; Neoplasms - diagnostic imaging; Neoplasms - immunology; Neoplasms - therapy; Positron-Emission Tomography - methods; Radioisotopes; Research Paper; Zirconium
• ISSN: 1838-7640; 1838-7640
• DOI: 10.7150/thno.95173

Increasing evidence emphasizes the pivotal role of CD4 T cells in orchestrating cancer immunity. Noninvasive imaging of the temporal dynamics of CD4 T 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 of Zr-labeled anti-mouse (m) and anti-human (h) CD4-targeting minibodies (Mbs) for positron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4 T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4 knock-in (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, we 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. 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.