Skip to main content
Log in

Technetium-99m labelling of the anti-tumour antibody PR1A3 by photoactivation

  • Original article
  • Published:
European Journal of Nuclear Medicine Aims and scope Submit manuscript

Abstract

Irradiation of antibody with ultraviolet light leads to reduction of disulphide bonds. Thus irradiation can be used to generate free thiols prior to direct labelling of antibody with technetium-99m, and has a potential advantage over methods using chemical reducing agents such as mercaptoethanol or tin, in that no purification step is needed to remove excess reducing agent. We have used the photoactivation method developed by Sykes et al. to label the anti-tumour antibody PR1A3 with99mTc. The antibody was irradiated at 300 nm using a Rayonet photochemical reactor with eight RMR3000 lamps. In a typical experiment, the antibody solution was injected into a nitrogen-filled borosilicate glass vial and purged with nitrogen. A degassed solution containing stannous fluoride and methylene diphosphonate was then added to the antibody and the vial was irradiated. Following the irradiation, [99mTc]pertechnetate was injected into the vial and the reaction mixture was incubated for 30 min at room temperature before being analysed by size-exclusion high-pressure liquid chromatography and instant thin-layer chromatography. Labelling yields greater than 95% were obtained using antibody concentrations ranging from 0.5 mg/ml to 5 mg/ml. Irradiation times as short as 5 min and tin to antibody ratios in the range between 11 and 32 µg tin per mg antibody gave high labelling yields. Labelling yields greater than 95% were obtained after storage of the photoactivated antibody at −70° C for several weeks. The stability of the99mTc-labelled photoactivated PR1A3 was similar to that of99mTc-labelled mercaptoethanol-reduced PR1A3. The mean immunoreactive fraction was 77% for the photoactivation-labelled PR1A3, compared to 93% for PR1A3 labelled by mercaptoethanol reduction. Biodistribution studies were carried out using99mTc-photoactivation-labelled PR1A3 or PR1A3 labelled by mercaptoethanol reduction in Balb/c mice and in nude mice with MKN-45 human tumour xenografts. There was no significant difference in tumour uptake between the mice that received photoactivated PR1A3 and those that received mercaptoethanol-reduced PR1A3. There was also no significant difference in uptake in most organs in Balb/c mice; however, the photoactivated antibody cleared more rapidly from the blood, and whole-body clearance was also faster for the photoactivated PR1A3. In conclusion, the photoactivation technique provides a very convenient “one-pot” method for labelling antibodies with99mTc.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Reilly RM. Immunoscintigraphy of tumours using Tc-99m labelled monoclonal antibodies: a review.Nucl Med Commun 1993; 14: 347–359.

    Google Scholar 

  2. Granowska M, Britton KE, Mather SJ, Morris G, Ellison D, Soobramoney S, Talbot IC, Northover JMA. Radioimmunoscintigraphy with Tc-99m labeled monoclonal-antibody, 1A3, in colorectal cancer.Eur J Nucl Med 1993; 20: 690–698.

    Google Scholar 

  3. Granowska M, Britton KE, Mather SJ, Lowe DG, Ellison D, Bomanji J, Burchell J, Taylor-Papadimitriou J, Hudson CR, Shepherd JH. Radioimmunoscintigraphy with technetium-99m-labelled monoclonal antibody, SM3, in gynaecological cancer.Eur J Nucl Med 1993; 20: 483–489.

    Google Scholar 

  4. Eckelman WC, Paik CH, Steigman J. Three approaches to radiolabelling antibodies with99mTc.Nucl Med Biol 1989; 16: 171–176.

    Google Scholar 

  5. Thakur ML, DeFulvio J, Richard MD, Paik CH. Technetium-99m labeled monoclonal antibodies: evaluation of reducing agents.Nucl Med Biol 1991; 18: 227–234.

    Google Scholar 

  6. Hnatowitch DJ, Virzi F, Winnard P, Fogarasi M, Rusckowski M. Investigations of ascorbate for direct labelling of antibodies with technetium-99m.J Nucl Med 1994; 35: 127–134.

    Google Scholar 

  7. Schwarz A, Steinstrasser A. A novel approach to Tc-99m labelled monoclonal antibodies [abstract].J Nucl Med 1987; 28: 721.

    Google Scholar 

  8. Rhodes BA. Direct labeling of proteins with99mTc.Nucl Med Biol 1991; 18: 667–676.

    Google Scholar 

  9. Sykes TR, Woo TK, Qi P, Baum RP, Noujaim AA. Direct labelling of monoclonal antibodies with technetium-99m by a novel photoactivation process [abstract].J Nucl Med 1993; 34: 100P.

  10. Sykes TR, Woo TK, Qi P, Baum RP, Noujaim AA. Photolabelling of proteins with technetium-99m [abstract].Nucl Med Commun 1993; 14: 909.

    Google Scholar 

  11. Mather SJ, Ellison D. Reduction-mediated technetium-99m labeling of monoclonal antibodies.J Nucl Med 1990; 31: 692–697.

    Google Scholar 

  12. Durbin H, Young S, Stewart LM, Wrba F, Rowan AJ, Snary D, Bodmer WF. A novel epitope on carcinoembryonic antigen defined by the clinically relevant antibody PR1A3.Proc Natl Acad Sci USA 1994; 91: 4313–4317.

    Google Scholar 

  13. Burchell J, Gendler S, Taylor-Papadimitriou J, et al. Development and characterization of breast-cancer reactive monoclonal antibodies directed to the core protein of the human milk mucin.Cancer Res 1987; 47: 5476–5482.

    Google Scholar 

  14. Hojo H, Establishment of cultured cell lines of human stomach cancer origin and their morphological characteristics.Niigata Igakukai Zassi 1977; 91: 737–763.

    Google Scholar 

  15. Ellman GL. A colorimetric method for determining low concentrations of mercaptans.Arch Biochem Biophys 1958; 74: 443–450.

    Google Scholar 

  16. Ellman GL. Tissue sulfhydryl groups.Arch Biochem Biophys 1959; 82: 70–77.

    Google Scholar 

  17. Lindmo T, Bunn PA. Determination of the true immunoreactive fraction of monoclonal antibodies after radiolabelling.Methods Enzymol 1986; 121: 678–684.

    Google Scholar 

  18. Hnatowich DJ, Virzi F, Fogarasi M, Rusckowski M, Winnard P Jr. Can a cysteine challenge assay predict the in vivo behavior of99mTc-labeled antibodies?Nucl Med Biol 1994; 21: 1035–1044.

    Google Scholar 

  19. Suppan P.Chemistry and light. Cambridge, UK: The Royal Society of Chemistry; 1994; Chap. 5.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Stalteri, M.A., Mather, S.J. Technetium-99m labelling of the anti-tumour antibody PR1A3 by photoactivation. Eur J Nucl Med 23, 178–187 (1996). https://doi.org/10.1007/BF01731842

Download citation

  • Received:

  • Revised:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01731842

Key words

Navigation