Spontaneous Immunity Against the Receptor Tyrosine Kinase ROR1 in Patients with Chronic Lymphocytic Leukemia

PLoS One. 2015 Nov 12;10(11):e0142310. doi: 10.1371/journal.pone.0142310. eCollection 2015.


Background: ROR1 is a receptor tyrosine kinase expressed in chronic lymphocytic leukemia (CLL) and several other malignancies but absent in most adult normal tissues. ROR1 is considered an onco-fetal antigen. In the present study we analysed spontaneous humoral and cellular immunity against ROR1 in CLL patients.

Materials and methods: Antibodies against ROR1 were analysed in 23 patients and 20 healthy donors by ELISA and Western blot. Purified serum IgG from patients was tested for cytotoxicity against CLL cells using the MTT viability assay. A cellular immune response against ROR1 derived HLA-A2 restricted 9 aa and 16 aa long peptides were analysed using peptide loaded dendritic cells co-cultured with autologous T cells from CLL patients (n = 9) and healthy donors (n = 6). IFN-γ, IL-5 and IL-17A-secreting T cells were assessed by ELISPOT and a proliferative response using a H3-thymidine incorporation assay.

Results: The majority of CLL patients had antibodies against ROR1. Significantly higher titers of anti-ROR1 antibodies were noted in patients with non-progressive as compared to progressive disease. The extracellular membrane-close ROR1 KNG domain seemed to be an immunodominant epitope. Ten patients with high titers of anti-ROR1 binding antibodies were tested for cytotoxicity. Five of those had cytotoxic anti-ROR1 antibodies against CLL cells. ROR1-specific IFN-γ and IL-17A producing T cells could be detected in CLL patients, preferentially in non-progressive as compared to patients with progressive disease (p<0.05).

Conclusion: ROR1 seemed to spontaneously induce a humoral as well as a T cell response in CLL patients. The data support the notion that ROR1 might be a specific neo-antigen and may serve as a target for immunotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies / blood
  • Antibodies / immunology*
  • Antibody-Dependent Cell Cytotoxicity / immunology
  • Blotting, Western
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • HLA-A2 Antigen / immunology
  • Humans
  • Immunity / immunology*
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Interferon-gamma / immunology
  • Interferon-gamma / metabolism
  • Interleukin-17 / immunology
  • Interleukin-17 / metabolism
  • Interleukin-5 / immunology
  • Interleukin-5 / metabolism
  • Leukemia, Lymphocytic, Chronic, B-Cell / blood
  • Leukemia, Lymphocytic, Chronic, B-Cell / diagnosis
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology*
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Peptides / immunology
  • Prognosis
  • Receptor Tyrosine Kinase-like Orphan Receptors / immunology*
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism


  • Antibodies
  • HLA-A2 Antigen
  • Immunoglobulin G
  • Interleukin-17
  • Interleukin-5
  • Peptides
  • Interferon-gamma
  • Receptor Tyrosine Kinase-like Orphan Receptors

Grants and funding

This study was funded by CLL Global Research Foundation (US), award no: 10501033 to Håkan Mellstedt; The Cancer and Allergy Foundation (SE), www.cancerochallergifonden.se, award no: 149351, 149746, 150288 to Håkan Mellstedt; The Swedish Cancer Society (SE), www.cancerfonden.se, award no: CAN 12 0842 to Anders Österborg; The Cancer Society in Stockholm (SE), www.rahfo.se, award no: 121273, 144142 to Anders Österborg; The King Gustaf Vth Jubilee Fund HM (SE), www.rahfo.se, award no: 121332 to Håkan Mellstedt; Vinnova (SE), www.vinnova.se, award no: P36147-1, P37147-1 to Håkan Mellstedt; AFA Insurance (SE), www.afaforsakring.se dnr, award no: 130054 to Anders Österborg; The Karolinska Institute Foundations (SE), www.ki.se, award no: 2011Fobi0061 to Håkan Mellstedt; The Stockholm County Council (SE), www.forskningsstod.vmi.se, award no: 20120051 to Anders Österborg; The Tehran University of Medical sciences FS, The Nanotechnology Network affiliated to The Ministry of Health and Medical Education of Iran, Avicenna Research Institute, www.tums.ac.ir, to Fazel Shokri. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.