Contribution of donor-specific antibodies to acute allograft rejection: evidence from B cell-deficient mice

Transplantation. 1998 Jun 15;65(11):1489-93. doi: 10.1097/00007890-199806150-00014.

Abstract

Background: The role of T lymphocytes in acute allograft rejection is well established. The involvement of B lymphocytes in this process, however, is more controversial. A series of reports showed that mice without a functional B-cell compartment rejected allografts with the same kinetics as control animals. In rats, however, alloantibodies were found to play a decisive role in allograft rejection. To provide an explanation for the discrepant results, we readdressed the role of B cells and antibodies in mice with disrupted immunoglobulin mu chain genes. The use of cyclosporine (CsA), which strongly suppresses T cells, allowed us to focus specifically on the function of B cells.

Methods: C57BL/6 mice rendered B cell deficient by targeted disruption of the immunoglobulin mu chain gene (referred to as microMT/microMT mice) and microMT/+ control mice with one functional mu chain were heterotopically transplanted with fully MHC-disparate BALB/c hearts. CsA was administered subcutaneously by Alzet osmotic pumps. Normal and immune serum specific for donor hearts was given to assess the role of antibodies in the rejection process.

Results: Both B cell-deficient microMT/microMT and heterozygous microMT/+ mice were found to reject transplanted hearts within a similar period of time. In contrast, when T cells were partially suppressed with CsA, graft survival was significantly prolonged in microMT/microMT mice as compared with heterozygous controls. Passive transfer of donor-specific immune serum, obtained from microMT/+ animals rejecting allogeneic hearts, to CsA-treated microMT/microMT mice significantly accelerated allograft rejection as opposed to recipients treated with normal serum.

Conclusions: B lymphocytes and antibodies play an important role in acute allograft rejection particularly when the dominant T-cell compartment is partially suppressed.

MeSH terms

  • Animals
  • B-Lymphocytes / physiology
  • Cyclosporine / pharmacology
  • Gene Targeting
  • Graft Rejection / immunology*
  • Heart Transplantation / immunology*
  • Immune Sera / immunology
  • Immunoglobulin G / genetics
  • Immunoglobulin mu-Chains / genetics
  • Immunosuppressive Agents / pharmacology
  • Isoantibodies / immunology*
  • Mice
  • Mice, Inbred BALB C / immunology
  • Mice, Inbred C57BL / genetics
  • Spleen / cytology
  • Spleen / immunology
  • T-Lymphocytes / physiology
  • Time Factors
  • Transplantation, Homologous / immunology

Substances

  • Immune Sera
  • Immunoglobulin G
  • Immunoglobulin mu-Chains
  • Immunosuppressive Agents
  • Isoantibodies
  • Cyclosporine