The samples were sequentially treated with PBS, aqueous hydrogen peroxide, serum block (bovine serum albumin), the primary anti-CD3 antibody (1/100 dilution), and the secondary antibody biotin-conjugated goat anti-rabbit antibody (DakoCytomation)

The samples were sequentially treated with PBS, aqueous hydrogen peroxide, serum block (bovine serum albumin), the primary anti-CD3 antibody (1/100 dilution), and the secondary antibody biotin-conjugated goat anti-rabbit antibody (DakoCytomation). is not achieved. The impact of TBI on LTs and PBLs is usually discordant, in which as few as 32.4% of CD4+ cells were depleted from the spleen. In addition, despite full lymphocyte recovery in the spleen and PB, lymph nodes have suboptimal recovery. This highlights concerns about residual disease, endogenous contributions to recovery, and residual LT damage following ionizing irradiation. Such methodologies also have direct application to immunosuppressive therapy and other immunosuppressive disorders, such as those associated with viral monitoring. Introduction The therapeutic use of ionizing irradiation is usually routine and is associated with myeloablation and immunosuppression. This is particularly true in the setting of hematopoietic stem cell transplantation (HSCT). Depending upon the dose of irradiation, the extent of the depletion can be quite severe with the potential for prolonged recovery periods and other adverse events, such as interstitial pulmonary pneumonitis. Successful immune reconstitution without increasing the risk of graft-versus-host disease is critical to diminishing the risk of posthematopoietic cell transplant infections, malignancy relapse, and secondary malignancies. Evaluating immune recovery of lymphoid tissues (LTs) following transplantation, immunosuppressive regimens, or viral infections has proven to be problematic without invasive biopsy. Fewer than 2% of the total numbers of lymphocytes are peripheral blood (PB) lymphocytes (PBLs), the majority reside in LTs.1 Hence, small changes in the distribution of cells between PB and LT (eg, LT homing) could have profound effects on PBL counts. We as well as others have established a large animal model for performing gene transfer and HSCT in rhesus macaques.2 This model has allowed us to evaluate immune Mutant IDH1-IN-4 recovery of rhesus macaques transplanted with immunoselected CD34+ cells transduced with retroviral vectors. Most recently, we developed a chimeric lentiviral vector made up of portions of the HIV and the simian immunodeficiency computer virus (SIV) which efficiently transduces rhesus CD34+ cells and expresses enhanced green fluorescent protein (EGFP) as a marker to determine the contributions of the transduced CD34+ cells to various elements of the hematopoietic lineage posttransplant.3 In addition, we have developed a strategy to evaluate noninvasively and in real time the contribution of the CD4+ cell population to LTs using single-photon emission computed tomography (SPECT) imaging.4 This technique has been used to study Mutant IDH1-IN-4 the relationships between the PB and LT pool of CD4+ T cells in healthy and SIV- or simian/human immunodeficiency computer virus (SHIV)-infected animals. In the present study, we have used a combination of SPECT imaging and a radiotracer, 99mTc-labeled rhesus immunoglobulin G1 (rhIgG1) anti-CD4R1 (Fab)2, to longitudinally image CD4+ cell recovery in rhesus macaques following varying doses of total body irradiation (TBI) and reinfusion of vector-transduced, autologous CD34+ cells to determine the impact of these modalities on CD4+ T-cell depletion and recovery. This is especially important in graft rejection, as it has been previously shown that clonable, alloreactive host T cells can be recovered from the spleen of rhesus macaques following hyperfractionated TBI and chemotherapy.5 Methods Animals Eleven rhesus macaques (Web site) were irradiated and transplanted; 7 were imaged pre- and posttransplant, and 6 underwent longitudinal imaging (supplemental Physique 2). Two (ZI10 and ZI12) received a dose of 3 Gy on 2 sequential days (3Gyx2) of TBI (6 Gy total), 3 (ZG21, ZH32, and ZG41) received a dose of 4 Gy on 2 sequential days (4Gyx2) of TBI, and 3 (ZG70, ZI64, and ZJ37) received a dose of 5 Gy on 2 sequential days (5Gyx2) of TBI. ZI10 developed an antibody response to the radiotracer and could not be reimaged posttransplant. ZI64 was euthanized on day 6 Mutant IDH1-IN-4 posttransplant following SPECT imaging and LTs were collected for evaluation. One rhesus macaque (G43) in chronic stage, coinfected with SIV/SHIV lentivirus, with very low PB CD4+ T-cell counts was imaged to serve as a positive control. In addition, 2 long-term transplanted animals (RQ7280 and RQ7387) having received 5Gyx2 TBI Mutant IDH1-IN-4 were imaged. The 4Gyx2 TBI animals were also imaged during mobilization with AMD3100 (Sigma-Aldrich), administered at 1 mg/kg subcutaneously (SQ). Transplant CD34+ cells were immunoselected from a leukapheresis product following granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) mobilization over 5 days as previously described.2 Around the last day of irradiation autologous CD34+ cells were reinfused after being transduced once (multiplicity of contamination [MOI] = Rabbit polyclonal to PSMC3 50) with a SIV/HIV chimeric lentiviral vector expressing EGFP.3 Preparation of F(ab)2 anti-CD4 antibodies To produce rhesus recombinant antibody, CD4R1-OKT4A/rhIgG1, complementarity determining regions (CDRs) representing the anti-CD4 antibody OKT4A6 were grafted onto a rhesus scaffold using the rhesus germline variable region.