Asunto(s)
Antígenos Heterófilos/inmunología , Isoantígenos/inmunología , Linfocitos T Citotóxicos/inmunología , Animales , Células Cultivadas , Citotoxicidad Inmunológica , Inmunidad Celular , Prueba de Cultivo Mixto de Linfocitos , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Modelos Inmunológicos , Ratas , Ratas Endogámicas WF , Trasplante Heterólogo , Trasplante HomólogoRESUMEN
BACKGROUND: We have previously reported the induction of donor-specific tolerance to cardiac allografts after intrathymic injection of alloantigen with simultaneous administration of antilymphocyte serum treatment to eliminate peripheral T cells. The present study determines whether prolongation of a fully major histocompatibility complex-mismatched cardiac allograft is achieved after a single administration of anti-CD4 monoclonal antibody (MoAb) combined with intrathymic injection of alloantigen. METHODS: Male Buffalo rats were given Lewis splenocytes via the intrathymic or intravenous route in combination with a single administration of anti-CD4 monoclonal antibody (OX-38) or anti-CD8 MoAb (OX-8) or both. Heterotopic cardiac transplantation was performed 21 days after intrathymic alloantigen or MoAb pretreatment or both. Fluorescence-activated cell sorter analysis determined changes in lymphocyte compartment T-cell subsets, and in vitro studies examined recipient cellular reactivity. RESULTS: By 21 days after anti-CD4 MoAb treatment earlier nonspecific immunosuppression had resolved with 80% recovery of peripheral CD4+ T cells and restoration of recipient immunocompetence to allow normal rejection of a cardiac allograft. Combined treatment with intrathymic, but not intravenous, alloantigen plus anti-CD4 MoAb induced donor-specific tolerance to subsequent rat cardiac allografts. However, anti-CD8 MoAb combined with intrathymic alloantigen failed to induce tolerance despite a profound depletion of the CD8+ T-cell subset. CONCLUSIONS: Combined treatment of rats with intrathymic donor alloantigen and a single administration of anti-CD4, but not anti-CD8, MoAb significantly prolongs cardiac allograft survival across a fully major histocompatibility complex mismatched strain combination.
Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Antígenos CD4/inmunología , Trasplante de Corazón , Tolerancia Inmunológica , Isoantígenos/administración & dosificación , Animales , Anticuerpos Monoclonales/inmunología , Recuento de Linfocito CD4 , Antígenos CD8/inmunología , Inyecciones , Isoantígenos/inmunología , Masculino , Cuidados Preoperatorios , Ratas , Ratas Endogámicas ACI , Ratas Endogámicas BUF , Ratas Endogámicas Lew , Timo , Trasplante HomólogoAsunto(s)
Supervivencia de Injerto/inmunología , Trasplante de Corazón/inmunología , Isoantígenos/farmacología , Transfusión de Linfocitos , Animales , Suero Antilinfocítico , Isoantígenos/administración & dosificación , Masculino , Ratas , Ratas Endogámicas ACI , Ratas Endogámicas BUF , Ratas Endogámicas Lew , Reoperación , Bazo , Timo , Factores de Tiempo , Trasplante HomólogoRESUMEN
The interaction between lymphocytes and the resident hepatic macrophage, the Kupffer cell (KC), is relevant to the phenomenon of immune tolerance to Ags entering the liver. Tolerance to Ag administered via the portal vein can be prevented by the rare earth lanthanide metal, gadolinium (Gd). Therefore, we studied the ability of OVA-responsive, H-2d-restricted Th1 clones to proliferate in response to KCs from DBA/2J (H-2d) mice that had been injected with either saline (control) or a Gd solution. Whereas control KCs functioned as effective APCs, KCs from Gd-injected mice (GdKC) were incapable of sustaining the proliferative response of the Th1 clone to the 16 mer of OVA (323-339). This lack of proliferation was determined not to be caused by impaired Ag processing, but rather was the result of IFN-gamma-stimulated nitric oxide (NO) release by the APC: 1) In vitro addition of the nitric oxide synthase (NOS) inhibitor NG-methyl-L-arginine (NMMA) restored the ability of the Gd-treated KC to stimulate clone proliferation. 2) Additional of anti-IFN-gamma, but not anti-IL-2 or anti-IL-4, prevented the induction of NOS in the Gd-exposed KC and was associated with clone proliferation. 3) IFN-gamma levels from clone-GdKC-OVA cocultures closely paralleled the nitrite released by GdKCs. 4) Only the addition of rIFN-gamma, and not IL-2 or IL-4, to cultures of purified GdKCs resulted in the release of nitrite. The results of the study suggest an autocrine loop initiated by the interaction of the clone's TCR with the class II MHC molecule presenting processed OVA on the surface of KC. This interaction stimulates the Th1 lymphocyte to release IFN-gamma, which in turn induces NO release by KCs isolated from Gd-injected mice. This release of NO blocks Th1 proliferation. Such a feedback loop may have particular relevance to Ag-specific tolerance, which is not only induced by the administration of Ag into the portal vein, but is also prevented by Gd pretreatment of the recipient animal.
Asunto(s)
Aminoácido Oxidorreductasas/biosíntesis , Presentación de Antígeno/fisiología , Macrófagos del Hígado/enzimología , Macrófagos del Hígado/inmunología , Células TH1/inmunología , Aminoácido Oxidorreductasas/fisiología , Animales , Células Clonales , Inducción Enzimática/inmunología , Gadolinio/farmacología , Interferón gamma/inmunología , Activación de Linfocitos/inmunología , Linfocinas/biosíntesis , Masculino , Ratones , Ratones Endogámicos DBA , Óxido Nítrico/biosíntesis , Óxido Nítrico Sintasa , Ovalbúmina/inmunología , Células Th2/inmunologíaRESUMEN
We analyzed the role of CD4+ and CD8+ T cells in H-2-disparate skin allograft rejection in the mutant mouse strain C.B-17/Icr scid with severe combined immunodeficiency. On the day of skin allografting, scid mice were adoptively transferred with negatively selected CD4+ or CD8+ splenocytes from normal unsensitized C.B-17/Icr mice. These populations were obtained using a double-mAb--plus--complement elimination protocol using anti-CD4 or anti-CD8 mAb that resulted in no detectable CD4+ or CD8+ cells by FACS and negligible numbers of cytolytic T lymphocytes by limiting dilution analysis in anti-CD8 treated populations. Spleen cells were removed from grafted mice at the time of rejection and were tested in vitro for antidonor reactivity in several assays: mixed lymphocyte culture, cell-mediated lympholysis, and LDA for CTL and for IL-2-producing HTL. The presence of Thy 1.2+, CD4+, or CD8+ cells was determined by FACS. All control C.B-17 mice and scid mice adoptively transferred with nondepleted CD4+, and CD8+ cells rejected skin allografts with similar mean survival times (15.6 +/- 1.5, 18.8 +/- 3.4, 18.0 +/- 5.4, respectively), whereas control scid mice retain skin allografts indefinitely (all greater than 100 days). C.B-17 syngeneic grafts survived indefinitely in all groups. At the time of rejection, splenocytes from scid mice receiving CD4+ cells had negligible donor-specific cytotoxicity in CML and negligible numbers of CTL by LDA, but demonstrated a good proliferative response in MLC and IL-2-producing cells by LDA (frequency = 1/1764). There were no detectable CD8+ cells present by FACS analysis. Conversely, splenocytes from scid mice adoptively transferred with CD8+ cells had strong donor-specific cytotoxicity in CML (58.8% +/- 16.1%) and CTL by LDA (frequency = 1/3448), but no significant proliferation was detected in MLC. There were no detectable CD4+ cells by FACS, but there were small numbers of IL-2-producing cells by LDA (frequency = 1/10,204). These data demonstrate that CD4+ cells adoptively transferred into scid mice are capable of mediating skin allograft rejection in the absence of any detectable CD8+ cells or significant functional cytolytic activity. The adoptive transfer of CD8+ cells also results in skin allograft rejection in the absence of detectable CD4+ cells. The detection of small numbers of IL-2 secreting cells in these mice may indicate that CD(8+)-mediated allograft rejection in this model is dependent on IL-2-secreting CD8+ cells.