Anti-CD20 treatment depletes B-cells in blood and lymphatic tissue of cynomolgus monkeys

Transpl Immunol. Oct-Nov 2003;12(1):19-28. doi: 10.1016/S0966-3274(03)00059-5.

Abstract

Introduction: Macaque species offer a valuable model for translational allo-transplantation and tolerance studies. Cardiac allograft vasculopathy in Macaca fascicularis is associated with elaboration of anti-donor antibodies. Since T-independent pathways of B cell activation have been described, and anti-B cell strategies have proven to be a fruitful tolerogenic adjunct in rodent and xenogenic models, here we investigate whether an anti-CD20 antibody (rituximab) would be useful to deplete B-cells in a pre-clinical allo-transplantation setting in macaques.

Methods: Three cynomolgus macaques which had previously rejected a cardiac allograft and one with concurrent subacute vascular rejection were treated weekly with rituximab 20 mg/kg i.v. for 4 and 2 weeks, respectively. B-cell levels (CD19+ cells) were measured by flow cytometry in peripheral blood, spleen, lymph node and bone marrow cells at various intervals after initiation of treatment. B-cells and plasma cells were also analyzed by immunohistochemistry at necropsy in spleen, lymph node, tonsil and thymus tissue sections. Anti-donor antibody titers were measured by flow cytometry.

Results: B-cells expressing CD19 were not detectable in the peripheral blood in any animal within 24 h after initial treatment, or over the ensuing month. At necropsy, the germinal centers in spleen and lymph node were completely depleted of CD20+ B-cells in 2 animals, leaving a hypocellular trabecular pattern around preserved plasma cell follicles. Substantial but incomplete depletion of B-cells was demonstrated in the other 2 animals, in each instance immunohistochemical findings in spleen and lymph node exhibiting higher sensitivity for residual B-cells compared to FACS. Anti-donor antibody titers exhibited kinetics similar to untreated animals over this short follow-up.

Comment: Treatment with anti-CD20 very efficiently depletes peripheral and tissue B-cells but not plasma cells in this macaque species. Biopsy of lymph node is necessary and may be sufficient to assess B-cell clearance in secondary lymphoid organs in this model.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies / blood
  • Antibodies / pharmacology
  • Antibodies, Monoclonal / pharmacology
  • Antibodies, Monoclonal / therapeutic use*
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD19 / analysis
  • Antigens, CD19 / blood
  • Antigens, CD20 / immunology*
  • B-Lymphocytes / chemistry
  • B-Lymphocytes / immunology*
  • Bone Marrow Cells / chemistry
  • CD40 Ligand / immunology
  • Cyclosporine / pharmacology
  • Flow Cytometry
  • Graft vs Host Reaction
  • Heart Transplantation
  • Immunoglobulin G / analysis
  • Immunoglobulin G / immunology
  • Immunoglobulin M / analysis
  • Immunoglobulin M / immunology
  • Immunohistochemistry
  • Lymph Nodes / cytology
  • Lymph Nodes / drug effects
  • Lymphoid Tissue / cytology
  • Lymphoid Tissue / drug effects*
  • Lymphoid Tissue / immunology
  • Macaca fascicularis
  • Male
  • Palatine Tonsil / cytology
  • Palatine Tonsil / drug effects
  • Plasma Cells / cytology
  • Rituximab
  • Spleen / cytology
  • Spleen / drug effects
  • T-Lymphocytes / immunology
  • Thymus Gland / cytology
  • Thymus Gland / drug effects
  • Transplantation, Heterotopic

Substances

  • Antibodies
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD19
  • Antigens, CD20
  • Immunoglobulin G
  • Immunoglobulin M
  • CD40 Ligand
  • Rituximab
  • Cyclosporine