PT  - JOURNAL ARTICLE
AU  - Richard Tavaré
AU  - Melissa N. McCracken
AU  - Kirstin A. Zettlitz
AU  - Felix B. Salazar
AU  - Tove Olafsen
AU  - Owen N. Witte
AU  - Anna M. Wu
TI  - Immuno-PET of Murine T Cell Reconstitution Postadoptive Stem Cell Transplantation Using Anti-CD4 and Anti-CD8 Cys-Diabodies
AID  - 10.2967/jnumed.114.153338
DP  - 2015 Aug 01
TA  - Journal of Nuclear Medicine
PG  - 1258--1264
VI  - 56
IP  - 8
4099  - http://jnm.snmjournals.org/content/56/8/1258.short
4100  - http://jnm.snmjournals.org/content/56/8/1258.full
SO  - J Nucl Med2015 Aug 01; 56
AB  - 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 89Zr-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 89Zr 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 89Zr-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.