title: In vivo administration of anti-CD3 monoclonal antibodies or immunotoxins in murine recipients of allogeneic T cell-depleted marrow for the promotion of engraftment.
abstract: The role of host anti-donor cells in rejection of fully allogeneic donor T cell-depleted marrow was investigated by using mAb or immunotoxins directed against T cell or NK cell determinants. Immunotoxins consisting of mAb conjugated to a low oligosaccharide-containing fraction of purified ricin toxin A chain (RTA) facilitated in vivo-depletion of target cell populations. BALB/c and DBA/1 donors were selected based upon their expression (BALB/c) or lack of (DBA/1) hemopoietic histocompatibility (Hh1) Ag, which may serve as targets for donor rejection in C57BL/6 hosts. When studies directed toward eliminating CD3+ cells were performed in both systems, injections of intact anti-CD3 mAb or anti-CD3-RTA reproducibly produced the highest engraftment values. The fact that engraftment values obtained with anti-CD3 or anti-CD3-RTA therapy in allogeneic systems were substantially higher than in syngeneic controls suggested that engraftment stimulatory proteins were released upon TCR engagement. Elevated levels of cytokines and a high mortality rate in allogeneic recipients confirmed that this was the case. Nonstimulatory preparations of anti-CD3F(ab')2 fragments and anti-CD3F(ab')2-RTA promoted engraftment of both types of allogeneic marrow, as measured by short term 125I-IUdR assays, suggesting that stimulation was not a prerequisite for engraftment. Recipients of anti-CD3F(ab')2 or anti-CD3F(ab')2-RTA showed a marked reduction of host CD3+ cells as measured by immunofluorescence and flow cytometry. In long term chimerism studies, recipients of Hh1-disparate marrow and anti-CD3F(ab')2 had a dramatic increase in donor cell engraftment as compared to controls, indicating that positive effects on engraftment were long lived. Studies further showed that BALB/c donor cells exhibiting an Hh1 disparity were rejected by host cells expressing NK1.1 or Ly-1 (NK cells and T cells). In contrast, DBA/1 donor cells that were not Hh1-disparate were rejected by cells expressing Ly-1, but not NK1.1 (T cells only). These studies provide definitive data that CD3+ cells participate in the rejection of either Hh1+ or Hh1null T cell-depleted allografts and offer new strategies for alloengraftment using regimens containing nonmitogenic anti-CD3.
authors.affiliation: Department of Pediatrics, University of Minnesota Hospital and Clinic, Minneapolis 55455.
authors.forename: B R
authors.initials: BR
authors.lastname: Blazar
authors.forename: R
authors.initials: R
authors.lastname: Hirsch
authors.forename: R E
authors.initials: RE
authors.lastname: Gress
authors.forename: S F
authors.initials: SF
authors.lastname: Carroll
authors.forename: D A
authors.initials: DA
authors.lastname: Vallera
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D000950:Antigens, Ly / Q000276:immunology; D016026:Bone Marrow Transplantation; D017252:CD3 Complex; D016207:Cytokines / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D000922:Immunotoxins / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051379:Mice; D008815:Mice, Inbred Strains; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D016038:Skin Transplantation; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D017252:CD3 Complex; D016207:Cytokines; D007140:Immunoglobulin Fab Fragments; D000922:Immunotoxins; D011948:Receptors, Antigen, T-Cell