Samenvatting
Nanobodies are single-domain, antigen-binding fragments derived from the heavy chain-only antibodies naturally occuring in Camelidae. Here we studied the use of anti-idiotype Nanobodies as an imaging tool in Multiple Myeloma (MM) using the 5T2MM murine model. This model is highly analogous to the human disease and is characterised by tumour expansion in the bone marrow, production and secretion of monoclonal paraprotein and bone lesions. After dromedary immunisation with 5T2MM idiotype we were able to isolate anti-idiotype Nanobodies. Their high affinity and specificity as demonstrated by ELISA, afinity binding assay and FACS analysis. Based on these results we selected the best binder (R3B23) fir further in vivo analyssis.
R3B23 was labeled with 99mTC-tricarbonyl (99mTc-R3B23) for in vivo tracing. Healthy C57Bl/KaLwRij mice or 5T2MM diseased mice were i.v. injected with 99mTc-R3B23. One our post injection the miced were sacrificed and the radioactivity present in deifferent organs and tissues was measured. In the naive mice we observed high kidney and bladder uptake, and very low uptake in the other organs and tissues, indicating fast renal clearance. In the diseased animals, increased radioactivity was detected in all examined organs including blood, liver, spleen and bone. Using 99mTc-R3B23 we monitored disease progression: we scanned the 5T2MM mice by pinhole SPECT and micro-CT scan at different time points starting at week 1 after inoculation with 5T2MM cells into naive mice. Image analysis showed an increased 99mTc-R3B23 uptake starting at week 7 after tumour inoculation. At this time point no circulating M-spile could be detected by capillary electrophoresis.
99mTc-R3B23 was able to monitor therapeutic response in 5T2MM mice. After three weeks treatment with velcade (two days per week) we saw a clear decrease in Nanobody uptake compared to the untreated group.
Our study shows that anti-idiotype Nanobodies are a new, sensitive, sêcific and non-invasive imaging tool in MM and provides the rationale for further studies on their clinical application. In addition Nanobodies can be coupled tot toxic agnets to target the MM cells.
R3B23 was labeled with 99mTC-tricarbonyl (99mTc-R3B23) for in vivo tracing. Healthy C57Bl/KaLwRij mice or 5T2MM diseased mice were i.v. injected with 99mTc-R3B23. One our post injection the miced were sacrificed and the radioactivity present in deifferent organs and tissues was measured. In the naive mice we observed high kidney and bladder uptake, and very low uptake in the other organs and tissues, indicating fast renal clearance. In the diseased animals, increased radioactivity was detected in all examined organs including blood, liver, spleen and bone. Using 99mTc-R3B23 we monitored disease progression: we scanned the 5T2MM mice by pinhole SPECT and micro-CT scan at different time points starting at week 1 after inoculation with 5T2MM cells into naive mice. Image analysis showed an increased 99mTc-R3B23 uptake starting at week 7 after tumour inoculation. At this time point no circulating M-spile could be detected by capillary electrophoresis.
99mTc-R3B23 was able to monitor therapeutic response in 5T2MM mice. After three weeks treatment with velcade (two days per week) we saw a clear decrease in Nanobody uptake compared to the untreated group.
Our study shows that anti-idiotype Nanobodies are a new, sensitive, sêcific and non-invasive imaging tool in MM and provides the rationale for further studies on their clinical application. In addition Nanobodies can be coupled tot toxic agnets to target the MM cells.
| Originele taal-2 | English |
|---|---|
| Pagina's (van-tot) | 14-14 |
| Aantal pagina's | 1 |
| Tijdschrift | Belgian Journal of Hematology |
| Nummer van het tijdschrift | 2013 |
| Status | Published - 24 jan 2013 |
| Evenement | 28th General Annual Meeting of the Belgian Hematological Society - Gent Duur: 24 jan 2013 → 26 jan 2013 |