Our Published Studies

Studies in the Marasco Laboratory with these mouse models include:

Chang DK, Peterson E, Sun J, Goudie C, Drapkin RI, Liu JF, Matulonis U, Zhu Q and Marasco WA. Anti-CCR4 antibody enhances anti-tumor immunity by modulating tumor-infiltrating Tregs in an ovarian cancer xenograft humanized mouse model. OncoImmunol. 2015 Dec 10;5(3):e1090075. PMID: 27141347

Recent studies have demonstrated that regulatory T cells (Tregs) are recruited to tumor sites where they can suppress antitumor immunity. The chemokine receptor CCR4 is expressed at high levels on functional CD4+CD25+FoxP3+ Tregs and production of the CCR4 ligand CCL22 by tumor cells and tumor-associated macrophages is associated with Treg recruitment to the tumor site. Here, we tested IgG1 and IgG4 isotypes of human anti-CCR4 mAb2-3 for their in vitro activity and in vivo capacity in a NSG mouse model bearing CCL22-secreting ovarian cancer (OvCA) xenograft to modulate Tregs and restore antitumor activity. Both mAb2-3 isotypes blocked in vitro chemoattraction of Tregs to CCL22-secreting OvCA cells. However, they differed in their in vivo mode of action with IgG1 causing Treg depletion and IgG4 blocking migration to the tumors. Primary T cells that were primed with OvCA-pulsed dendritic cells (DCs) demonstrated INFγ secretion that could be enhanced through Treg depletion by mAb2-3. Humanized mice reconstructed with allogeneic tumor-primed T cells (TP-T) were used to evaluate the restoration of OvCA immunity by depletion or blockade of Tregs with mAb2-3. We observed that IgG1 was more potent than IgG4 in inhibiting tumor growth. Mechanism studies demonstrated that mAb2-3 treatment lead to inhibition of IL-2 binding to its receptor. Further studies showed that mAb2-3 induced CD25 shedding (sCD25) from Tregs which lead to a decrease in IL-2-dependent survival. Together, the results demonstrate that mAb2-3 is an agonist antibody that can restore anti-OvCA immunity through modulation of Treg activity.

 

 

Chang DK, Moniz RJ, Xu Z, Sun J, Signoretti S, Zhu Q, Marasco WA. Human anti-CAIX antibodies mediate immune cell inhibition of renal cell carcinoma in vitro and in a humanized mouse model in vivo. Mol Cancer. 2015 Jun 11:14:119. PMID: 26062742

Carbonic anhydrase (CA) IX is a surface-expressed protein that is upregulated by the hypoxia inducible factor (HIF) and represents a prototypic tumor-associated antigen that is overexpressed on renal cell carcinoma (RCC). Therapeutic approaches targeting CAIX have focused on the development of CAIX inhibitors and specific immunotherapies including monoclonal antibodies (mAbs). However, current in vivo mouse models used to characterize the anti-tumor properties of fully human anti-CAIX mAbs have significant limitations since the role of human effector cells in tumor cell killing in vivo is not directly evaluated. Our studies demonstrate the capacity of human anti-CAIX mAbs that inhibit CA enzymatic activity to result in immune-mediated killing of RCC, including nature killer (NK) cell-mediated ADCC, CDC, and macrophage-mediated ADCP. The killing activity correlated positively with the level of CAIX expression on RCC tumor cell lines. In addition, Fc engineering of anti-CAIX mAbs was shown to enhance the ADCC activity against RCC. We also demonstrate that these anti-CAIX mAbs inhibit migration of RCC cells in vitro. Finally, through the implementation of a novel orthotopic RCC model utilizing allogeneic human peripheral blood mononuclear cells in NOD/SCID/IL2Rγ(-/-) mice, we show that anti-CAIX mAbs are capable of mediating human immune response in vivo including tumor infiltration of NK cells and activation of T cells, resulting in inhibition of CAIX(+) tumor growth.

 

 

Hong Chang, Subhabrata Biswas, Aimee St. Clair Tallarico, Phuong Thi Nguyen Sarkis, Shusheng Geng, Madhura M. Panditrao, Quan Zhu and Wayne A. Marasco. Human B-cell ontogeny in humanized NOD/SCID gcnull mice generates a diverse yet auto/poly- and HIV-1 reactive antibody repertoire. Genes and Immunity.  13, 399-410 (July/August 2012) | doi:10.1038/gene.2012.16.  PMID:22592523

Characterization of the human Ab repertoire in mouse models of the human immune system is essential to establish their relevance in translational studies. In this study single human B cells from hNSG mice, engrafted with human cord blood-derived CD34+ stem cells were sorted from bone marrow and periphery at 8–10 months p.e. Human IG variable heavy (VH) and kappa (VK) genes were amplified, cognate VH–VK gene-pairs assembled as single-chain variable fragment-Fc Abs (scFvFcs) and functional studies were performed. Although overall distribution of VH genes approximated the normal human Ab repertoire, analysis of the VH-CDR3 in the mature B-cell subset demonstrated an increase in length and positive charges, suggesting autoimmune characteristics. Additionally, >70% of VK sequences utilized VK4-1, a germline gene associated with autoimmunity. The mature B-cell subset-derived scFvFcs displayed the highest frequency of autoreactivity and polyspecificity, suggesting defects in checkpoint control mechanisms. Furthermore, these scFvFcs demonstrated binding to recombinant HIV envelope corroborating previous observations of poly/autoreactivity in anti-HIVgp140 Abs. These data lend support to the hypothesis that anti-HIV broadly neutralizing antibodies may be derived from auto/polyspecific Abs that escaped immune elimination and that the hNSG mouse could provide a new experimental platform for studying the origin of anti-HIV-neutralizing Ab responses.

Abstract of talk by Hong Chang

 

 Subhabrata Biswas, Hong Chang, Phuong Thi Nguyen Sarkis, Erol Fikrig, Quan Zhu and Wayne A. Marasco.  Humoral immune responses in humanized BLT mice immunized with West Nile virus and HIV-1 envelope proteins are largely mediated via human CD5+ B cells.  Immunology, 2011, 134:419-33.  PMID: 22044090

Immunization studies in BLT mice. A number of strategies including DNA and protein based immunization and use of several adjuvants have been tested in these animal models.  Antigen (HIV gp140 trimer and West Nile Virus E-protein) specific human IgM and IgG have been detected in immunized mouse serum.  We are currently exploring different strategies to induce a more robust adaptive immune response.