Normal T-cell response and in vivo magnetic resonance imaging of T cells loaded with HIV transactivator-peptide-derived superparamagnetic nanoparticles
Ch. Dodd et al., Normal T-cell response and in vivo magnetic resonance imaging of T cells loaded with HIV transactivator-peptide-derived superparamagnetic nanoparticles, J IMMUNOL M, 256(1-2), 2001, pp. 89-105
The present study analyzed the feasibility of using magnetic resonance imag
ing (MRI) to monitor T-cell homing in vivo after loading T cells with super
paramagnetic iron oxide (CLIO) nanoparticles derivatized with a peptide seq
uence from the transactivator protein (Tat) of HIV-1. T cells were isolated
from C57BL/6 (B6) mice and loaded with 0, 400, 800, 1600, or 8000 ng/ml of
FITC conjugated CLIO-Tat (FITC-CLIO-Tat). There was a dose-dependent uptak
e of FITC-CLIO-Tat by T cells. Stimulation of FITC-CLIO-Tat loaded T cells
with anti-CD3 (0.1 mug/ml) plus IL-2 (5 ng/ml) elicited normal activation a
nd activation-induced cell death (AICD) responses, and normal upregulation
of CD69, ICAM-1 (CD54), L-selectin (CD62L), and Fas. The FITC-CLIO-Tat load
ed T cells (3 X 10(7)) were transferred intravenously (i.v.) into B6 mice a
nd the in vivo MRI of mice was acquired using a spin-echo pulse sequence at
4.7 T with a Bruker Biospec system. Homing of T cells into the spleen was
observed by a decrease in MRI signal intensity within I It after the transf
er, which remained decreased for 2-24 h after transfer. These homing data w
ere confirmed by FACS analysis and biodistribution analysis using I-125-CLI
O-Tat. Thus, T cells can be efficiently loaded with FITC-CLIO-Tat without i
nterfering with their normal activation and AICD, or homing to the spleen,
and the biodistribution of FITC-CLIO-Tat loaded T cells can be monitored in
vivo over time by MRI. (C) 2001 Elsevier Science B.V. All rights reserved.