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J Nucl Med. 2015 Aug;56(8):1258-64. doi: 10.2967/jnumed.114.153338. Epub 2015 May 7.

Immuno-PET of Murine T Cell Reconstitution Postadoptive Stem Cell Transplantation Using Anti-CD4 and Anti-CD8 Cys-Diabodies.

Author information

1
Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California rtavare@mednet.ucla.edu awu@mednet.ucla.edu.
2
Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California.
3
Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California.
4
Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California Howard Hughes Medical Institute at UCLA, Los Angeles, California Department of Microbiology, Immunology and Molecular Genetics at UCLA, Los Angeles, California; and Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA, Los Angeles, California.

Abstract

The proliferation and trafficking of T lymphocytes in immune responses are crucial events in determining inflammatory responses. To study whole-body T lymphocyte dynamics noninvasively in vivo, we generated anti-CD4 and -CD8 cys-diabodies (cDbs) derived from the parental antibody hybridomas GK1.5 and 2.43, respectively, for (89)Zr-immuno-PET detection of helper and cytotoxic T cell populations.

METHODS:

Anti-CD4 and -CD8 cDbs were engineered, produced via mammalian expression, purified using immobilized metal affinity chromatography, and characterized for T cell binding. The cDbs were site-specifically conjugated to maleimide-desferrioxamine for (89)Zr radiolabeling and subsequent small-animal PET/CT acquisition and ex vivo biodistribution in both wild-type mice and a model of hematopoietic stem cell (HSC) transplantation.

RESULTS:

Immuno-PET and biodistribution studies demonstrate targeting and visualization of CD4 and CD8 T cell populations in vivo in the spleen and lymph nodes of wild-type mice, with specificity confirmed through in vivo blocking and depletion studies. Subsequently, a murine model of HSC transplantation demonstrated successful in vivo detection of T cell repopulation at 2, 4, and 8 wk after HSC transplantation using the (89)Zr-radiolabeled anti-CD4 and -CD8 cDbs.

CONCLUSION:

These newly developed anti-CD4 and -CD8 immuno-PET reagents represent a powerful resource to monitor T cell expansion, localization, and novel engraftment protocols. Future potential applications of T cell-targeted immuno-PET include monitoring immune cell subsets in response to immunotherapy, autoimmunity, and lymphoproliferative disorders, contributing overall to preclinical immune cell monitoring.

KEYWORDS:

89Zr; CD4+ and CD8+ T cells; antibody fragments; hematopoietic stem cell transplantation; immuno-PET

Comment in

PMID:
25952734
PMCID:
PMC4859343
DOI:
10.2967/jnumed.114.153338
[Indexed for MEDLINE]
Free PMC Article

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