For PET imaging
studies, tumor-bearing mice were intravenously injected with 89Zr-DFO-isatuximab or 89Zr-DFO-daratumumab (n = 4/group) (5–7.5 MBq; 18.7–25 μg).
For blocking studies (n = 4) blocked mice were co-injected
with a 12-fold excess of unlabeled DFO-isatuximab to block relevant
receptors and demonstrate specific binding of the tracer to CD38.
An additional control group of healthy mice (n =
3) was also included in the experiment. To avoid anomalous biodistribution
caused by the lack of endogenous immunoglobulin G in NSG mice, 500
μg of nonspecific human immunoglobulin G was either coinjected
with the radiolabeled antibody or, in the case of the blocking study,
injected 3 days before the radiotracer. In vivo small
animal PET/CT was performed on an Inveon micro PET/CT instrument (Siemens,
Erlangen, Germany). Mice were anesthetized with 1–2% isoflurane,
and static images were collected for a maximum of 45 min. Images were
analyzed using the Inveon Research Workstation (IRW) software.
studies, tumor-bearing mice were intravenously injected with 89Zr-DFO-isatuximab or 89Zr-DFO-daratumumab (n = 4/group) (5–7.5 MBq; 18.7–25 μg).
For blocking studies (n = 4) blocked mice were co-injected
with a 12-fold excess of unlabeled DFO-isatuximab to block relevant
receptors and demonstrate specific binding of the tracer to CD38.
An additional control group of healthy mice (n =
3) was also included in the experiment. To avoid anomalous biodistribution
caused by the lack of endogenous immunoglobulin G in NSG mice, 500
μg of nonspecific human immunoglobulin G was either coinjected
with the radiolabeled antibody or, in the case of the blocking study,
injected 3 days before the radiotracer. In vivo small
animal PET/CT was performed on an Inveon micro PET/CT instrument (Siemens,
Erlangen, Germany). Mice were anesthetized with 1–2% isoflurane,
and static images were collected for a maximum of 45 min. Images were
analyzed using the Inveon Research Workstation (IRW) software.