About RecombiMAb anti-mouse CD45.2 (LALA-PG) The 104.2-CP063 monoclonal antibody is a recombinant, chimeric version of the original 104.2 antibody. The variable domain sequences are identical, but the constant region includes the Fc silencing mutation variant LALA-PG, rendering it unable to bind endogenous murine Fcγ receptors or C1q to induce antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC). The LALA-PG variant has demonstrated significantly reduced effector function, C1q binding and C3 fixation compared to other common silencing mutations such as the LALA and DANG variants while retaining favorable biophysical and manufacturing properties. Infusion-related toxicities have been observed with anti-CD45 antibodies likely due to effector function of the wild-type antibody. The 104.2 monoclonal antibody reacts with mouse CD45.2 a 180-240 kDa member of the protein tyrosine phosphatase family. CD45.2 is an alloantigen of CD45 and is only expressed by certain mouse strains including C57BL/6, CBA, 129, A, AKR, C58, DBA/1, DBA/2, BALB/c, and C3H/He. The 104.2 monoclonal antibody does not react with leukocytes of CD45.1-expressing mouse strains including DA, SJL/J, RIII, and STS/A. CD45.2 is expressed on all hematopoietic cells except mature erythrocytes and platelets and is thought to be involved in TCR and BCR signal transduction. The 104.2 antibody has been shown to block B cell responses in vitro and reduce serum autoantibody concentration in vivo in SLE-prone mice. 104.2 antibody conjugated to cytotoxic compounds has been shown to deplete hematopoietic cells in-vivo and is a promising targeted conditioning strategy for autologous or allogeneic hematopoietic stem cell transplantation. RecombiMAb anti-mouse CD45.2 (LALA-PG) Specifications IsotypeMouse IgG2a LALA-PG Recommended Isotype Control(s)RecombiMAb mouse IgG2a (LALA-PG) isotype control, anti-hen egg lysozyme Recommended Dilution BufferInVivoPure pH 7.0 Dilution Buffer ImmunogenB10.S mouse thymocytes and splenocytes Reported ApplicationsWestern Blot Flow Cytometry CD45-targeted myeloablative conditioning (antibody drug conjugate) Immunohistochemistry in-vitro CD45.2 blockade in-vivo CD45.2 blockade *Reported for the original 104.2 antibody. For information on in vivo applications, please contact technicalservice@bioxcell.com FormulationPBS, pH 7.0 Contains no stabilizers or preservatives Endotoxin<1EU/mg (<0.001EU/μg) Determined by LAL gel clotting assay Aggregation<5% Determined by SEC Purity>95% Determined by SDS-PAGE Sterility0.2 μm filtration ProductionPurified from mammalian cell supernatant in an animal-free facility PurificationProtein G Molecular Weight150 kDa StorageThe antibody solution should be stored at the stock concentration at 4°C. Do not freeze. Application ReferencesRecombiMAb anti-mouse CD45.2 (LALA-PG) (CLONE: 104.2-CP063)Saha A, Hyzy S, Lamothe T, Hammond K, Clark N, Lanieri L, Bhattarai P, Palchaudhuri R, Gillard GO, Proctor J, Riddle MJ, Panoskaltsis-Mortari A, MacMillan ML, Wagner JE, Kiem HP, Olson LM, Blazar BR (2022). "A CD45-targeted antibody-drug conjugate successfully conditions for allogeneic hematopoietic stem cell transplantation in mice" Blood 139(11):1743-1759. PubMedAllogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment of patients with nonmalignant or malignant blood disorders. Its success has been limited by graft-versus-host disease (GVHD). Current systemic nontargeted conditioning regimens mediate tissue injury and potentially incite and amplify GVHD, limiting the use of this potentially curative treatment beyond malignant disorders. Minimizing systemic nontargeted conditioning while achieving alloengraftment without global immune suppression is highly desirable. Antibody-drug-conjugates (ADCs) targeting hematopoietic cells can specifically deplete host stem and immune cells and enable alloengraftment. We report an anti-mouse CD45-targeted-ADC (CD45-ADC) that facilitates stable murine multilineage donor cell engraftment. Conditioning with CD45-ADC (3 mg/kg) was effective as a single agent in both congenic and minor-mismatch transplant models resulting in full donor chimerism comparable to lethal total body irradiation (TBI). In an MHC-disparate allo-HSCT model, pretransplant CD45-ADC (3 mg/kg) combined with low-dose TBI (150 cGy) and a short course of costimulatory blockade with anti-CD40 ligand antibody enabled 89% of recipients to achieve stable alloengraftment (mean value: 72%). When CD45-ADC was combined with pretransplant TBI (50 cGy) and posttransplant rapamycin, cyclophosphamide (Cytoxan), or a JAK inhibitor, 90% to 100% of recipients achieved stable chimerism (mean: 77%, 59%, 78%, respectively). At a higher dose (5 mg/kg), CD45-ADC as a single agent was sufficient for rapid, high-level multilineage chimerism sustained through the 22 weeks observation period. Therefore, CD45-ADC has the potential utility to confer the benefit of fully myeloablative conditioning but with substantially reduced toxicity when given as a single agent or at lower doses in conjunction with reduced-intensity conditioning.
