There has been a recent surge in research involving “humanized” mice, which both underscores the growing need for and the finding that these human developmental and disease models can provide reliable and validated in vivo systems to study complex biological processes. We are developing humanized mouse models for different areas of investigations including regenerative medicine, cancer immunotherapy and stem cell biology, B-cell developmental biology as well as infectious diseases and related vaccine development. For more information please visit our website at www.humouse.org.
Human B-cell Ontogeny and Vaccine Development
We are constructing different types of “humanized mice” for investigations of B-cell ontogeny and their utility in evaluating infectious diseases and cancer vaccines. In one such model, the “BLT” mouse develop a functional human lymphoid system after human stem cell engraftment. We have shown that a single intramuscular immunization with recombinant viral envelope antigens, e.g., HIVgp140 and West Nile Virus envelope (WNV-E) proteins, together with the immune-stimulatory TLR9 agonist results in seroconversion and secretion of antigen-specific human antibodies. In vitro studies with human T-cells recovered from these mice demonstrate suboptimal proliferative responses and loss of co-stimulatory surface proteins ex vivo that could be partially reversed with human interleukin (IL)-2 and IL-7. We are currently investigating whether CD4 helper T-cell functions which are required for optimal B cell maturation can modulated in vivo by the exogenous delivery of human cytokines/growth factors.
In a second study, we performed on the analysis of single-sorted human B cells from humanized NOD/SCID gc-/- (hNSG) mice at both genetic and functional levels. B cells from different stages of development, from early immature in the bone marrow to naïve mature in the periphery were sorted as single cells, the antibody genes cloned and expressed as single chain antibody fragments (scFvFcs). Sequence analysis of the antibody genes suggested an impairment in the checkpoint control mechanisms based on longer HCDR3 regions with high levels of positive charges found in the peripheral naïve mature B cells, a characteristic of auto/polyreactive antibodies. This observation was functionally confirmed by performing autoantigen binding analysis with the purified scFvFcs. Moreover, our findings of poly/auto reactive antibodies were extended to show that many of these antibodies can also bind with high affinity binding to HIV envelope protein. This suggests that the hNSG model (and BLT/GTL models) can be used to study the ontogeny of anti-HIV antibodies at the molecular level.
Goettel JA, Biswas S, Lexmond WS, Yeste A, Passerini L, Patel B, Yang S, Sun J, Ouahed J, Shouval DS, McCann KJ, Horwitz BH, Mathis D, Milford EL, Notarangelo LD, Roncarolo MG, Fiebiger E, Marasco WA, Bacchetta R, Quintana FJ, Pai SY, Muise AM, Snapper SB. Fatal autoimmunity in mice reconstituted with human hematopoietic stem cells encoding defective FOXP3. Blood. 2015 Jun 18;125(25):3886-95. PMID: 25833964
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, Dec;134(4):419-33. PMID: 22044090
Hong Chang, Subhabrata Biswas, Aimee St.Clair Tallarico, Phuong Thi Nguyen Sarkis, ShushengGeng, Madhura M. Panditrao, QUan Zhu and Wayne A, Marasco. Human B-cell ontogeny in huamized NOD/SCID gcnull mice generates a diverse yet anto/poly- and HIV-1 reactive antibody repertoire. Genes and Immunity. (17 May 2012) | doi:10.1038/gene.2012.16. PMID: 22592523.
Learn more at our Humanized Neonatal Mouse Center (HNMC) at the Harvard Stem Cell Institute (HSCI).