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Vander Borght et al. J Cancer Metastasis Treat 2019;5:57 Journal of Cancer
DOI: 10.20517/2394-4722.2019.0010 Metastasis and Treatment

Original Article Open Access

Monoclonal antibodies to the exon 18 encoded
moiety of NCAM

Ann Vander Borght , Mieke Duysinx , Monique Ummelen , Bernard A.M. van der Zeijst 3
1,2
2
1
1 Department of Genetics and Cell Biology and GROW School for Oncology and Developmental Biology, Maastricht University,
Maastricht, PO Box 616, 6200 MD, The Netherlands.
2 MUbio Products B.V., Maastricht, 6200 EV, The Netherlands.
3 Catherinn B.V., Manuel de Fallapad 1, Rotterdam, 3069 MR, The Netherlands.
Correspondence to: Prof. Bernard A.M. van der Zeijst, Catherinn B.V., Manuel de Fallapad 1, Rotterdam, 3069 MR, The
Netherlands. E-mail: zeijst@lumc.nl

How to cite this article: Vander Borght A, Duysinx M, Ummelen M, van der Zeijst BAM . Monoclonal antibodies to the exon 18
encoded moiety of NCAM. J Cancer Metastasis and Treatment 2019;5:57. http://dx.doi.org/10.20517/2394-4722.2019.0010

Received: 15 Jan 2019 First Decision: 13 Apr 2019 Revised: 15 Apr 2019 Accepted: 21 May 2019 Published: 20 Jul 2019
Science Editor: Ira-Ida Skvortsova Copy Editor: Han-Juan Zhang Production Editor: Jing Yu

Abstract
Aim: Exon 18 expression of NCAM has been recognized as a biomarker for small cell lung cancer (SCLC). To use
this finding for an improved diagnosis of SCLC and personalized treatment of patients, techniques to identify
and quantitate E18, the exon 18 encoded protein moiety of NCAM, are needed. We developed three monoclonal
antibodies for this purpose.

Methods: The his-tagged E18 antigen was expressed in E. coli and, after purification, used to immunize mice.
Hybridoma’s were isolated by standard procedures and tested for their reaction with E18.

Results: Three monoclonal antibodies, MUM-1, MUM-4 and MUM-6 were obtained. They reacted with E18 in
western blots, with SCLC cell line NCI-H82, but not with unrelated his-tagged proteins. Only permeabilized
NCI-H82 cells stained with the antibodies, confirming the intracellular position of E18. Next an enzyme-linked
immunosorbent assay was developed using the earlier isolated monoclonal antibody MUMi-21B2, coated on the
surface of microtiter wells as capture antibody and biotinylated MUM-6 as second antibody. Using streptavidin
conjugated to horse radish peroxidase a linear dose response curve to his-tagged E18 antigen was obtained between
0 and 5 µg/mL with a sensitivity of at least 0.5 µg/mL or 50 ng/well.

Conclusion: Four monoclonal antibodies are available to be used in assays for the identification and quantification of
SCLC biomarker E18. This will enable the development of liquid biopsies to follow the tumor load in patients.

© The Author(s) 2019. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

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