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Author Notes:

Correspondence: Jeanne E. Hendrickson, jeanne.hendrickson@yale.edu

Edited by: Gilles Blancho, University of Nantes, France

Reviewed by: Vokaer Benoit

PN, DL, SP, SS, and JH designed the experiments and performed the primary experiments; JL, MS, DG, and DM assisted with the experiments; PN, DL, and JH analyzed the results and made the figures; PN and JH wrote the manuscript; and all authors edited the manuscript.

The authors would like to thank Dr. C. John Luckey and his laboratory members for helpful discussions.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Research Funding:

This work was supported in part by a grant from the Emory Egleston Children’s Center and a grant from the National Institutes of Health (R01 HL126076) to JH and a grant from the National Institutes of Health (T32 HL007974) to Brian Smith, Chair of the Department of Laboratory Medicine at Yale University School of Medicine.


  • Science & Technology
  • Life Sciences & Biomedicine
  • Immunology
  • red blood cell
  • alloimmunization
  • tolerance
  • CD40L blockade
  • T-cells

CD4 Depletion or CD40L Blockade Results in Antigen-Specific Tolerance in a Red Blood Cell Alloimmunization Model

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Journal Title:

Frontiers in Immunology


Volume 8, Number AUG


, Pages 907-907

Type of Work:

Article | Final Publisher PDF


Approximately 3-10% of human red blood cell (RBC) transfusion recipients form alloantibodies to non-self, non-ABO blood group antigens expressed on donor RBCs, with these alloantibodies having the potential to be clinically significant in transfusion and pregnancy settings. However, the majority of transfused individuals never form detectable alloantibodies. Expanding upon observations that children initially transfused with RBCs at a young age are less likely to form alloantibodies throughout their lives, we hypothesized that "non-responders" may not only be ignorant of antigens on RBCs but instead tolerized. We investigated this question in a reductionist murine model, in which transgenic donors express the human glycophorin A (hGPA) antigen in an RBC-specific manner. Although wild-type mice treated with poly IC and transfused with hGPA RBCs generated robust anti-hGPA IgG alloantibodies that led to rapid clearance of incompatible RBCs, those transfused in the absence of an adjuvant failed to become alloimmunized. Animals depleted of CD4 + cells or treated with CD40L blockade prior to initial hGPA RBC exposure, in the presence of poly IC, failed to generate detectable anti-hGPA IgG alloantibodies. These non-responders to a primary transfusion remained unable to generate anti-hGPA IgG alloantibodies upon secondary hGPA exposure and did not prematurely clear transfused hGPA RBCs even after their CD4 cells had returned or their CD40L blockade had resolved. This observed tolerance was antigen (hGPA) specific, as robust IgG responses to transfused RBCs expressing a third-party antigen occurred in all studied groups. Experiments completed in an RBC alloimmunization model that allowed evaluation of antigen-specific CD4 + T-cells (HOD (hen egg lysozyme, ovalbumin, and human duffy b )) demonstrated that CD40L blockade prevented the expansion of ovalbumin 323-339 specific T-cells after HOD RBC transfusion and also prevented germinal center formation. Taken together, our data suggest that recipients may indeed become tolerized to antigens expressed on RBCs, with the recipient's immune status upon initial RBC exposure dictating future responses. Although questions surrounding mechanism(s) and sustainability of tolerance remain, these data lay the groundwork for future work investigating RBC immunity versus tolerance in reductionist models and in humans.

Copyright information:

© 2017 Natarajan, Liu, Patel, Santhanakrishnan, Beitler, Liu, Gibb, Liepkalns, Madrid, Eisenbarth, Stowell and Hendrickson.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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