Human B Cell Growth and Differentiation in the Spleen of Immunodeficient Mice

Abstract

Human mAbs (HumAbs) have therapeutic potential against infectious diseases and cancer. Heretofore, their production has been hampered by ethical constraints preventing the isolation of Ag-specific activated B cells by in vivo immunization. Alternatively, severe combined immune deficient (SCID) mice, transplanted i.p. with human (Hu)-PBLs, allow the in vivo stimulation of human Ab responses without the usual constraints. Unfortunately, human B cells only represent a minor fraction of the surviving graft, they are scattered all over the animal body, and thus are hard to isolate for subsequent immortalization procedures. To prevent this dispersion and to provide the human B cells with a niche for expansion and maturation, SCID mice were engrafted with Hu-PBL directly into the spleen. Simultaneously endogenous murine NK cell activity was depleted by treatment with an anti-mouse IL-2 receptor β-chain Ab. During engraftment, human B lymphocytes became activated, divided intensely, and differentiated into plasmacytoid cells. In vivo exposure to a recall Ag after cell transfer induced expansion of Ag-specific B cell clones. One week after inoculation, human B cells were abundant in the spleen and could easily be recovered for fusion with a heteromyeloma line. This resulted in the formation of stable hybridoma cell lines that secreted Ag-specific HumAbs. Thus transplantation of human lymphoid cells in the spleens of immune deficient mice represents a model for the study of human T cell-dependent B cell activation and proves to be an excellent tool for the successful production of HumAbs.

Hepatitis B Virus Core Antigen Binds and Activates Naive Human B Cells In Vivo: Studies with a Human PBL-NOD/SCID Mouse Model

“…This method is based on the combined use of sublethal total-body irradiation (300 rads) and a rat antibody against the mouse interleukin-2 receptor ␤ chain (TM␤1) (20). When human cells are injected directly into the mouse spleen, human B cells become activated, expand vigorously, and transiently become the most prominent subset among the hu-PBL residing in the spleen (2). We have used this model to examine whether HBcAg displays the same unique immunological characteristics for human lymphoid cells that have been observed in the mouse (9,10).…”

“…This route leads to a predominant expansion of T cells, whereas the survival of B cells and their functional expression are minimal. Recently, we discovered that the transfer of hu-PBL directly into the spleens of optimally conditioned NOD/SCID mice led to a vigorous expansion of B cells and their differentiation into plasmacytoid cells (2). By using this hu-PBL-SCID mouse model, we show here that HBc particles (HBcAg) induce the production of HBcAg-binding immunoglobulin M (IgM) in the B cells of unprimed individuals that were transferred into NOD/SCID recipients.…”

Vaccine-induced monoclonal antibodies targeting circumsporozoite protein prevent Plasmodium falciparum infection

“…The cell donor of the PBMCs used to generate the human anti-CSP mAb was selected from a clinical trial (MAL-080) evaluating the RTS,S vaccine at the Center for Vaccinology, Ghent University and Ghent University Hospital. Human B lymphocytes were immortalized as described previously (37). The mAb concentration was determined by measuring UV absorbance at 280 nm (1 mg/ml = 1.4 absorbance units) and by anti-CSP ELISA (25).…”

Plasmacytoid Dendritic Cells of Different Origins Have Distinct Characteristics and Function: Studies of Lymphoid Progenitors versus Myeloid Progenitors

“…The sorted CLPs (3-5 ϫ 10 4 ) and MPs (5-10 ϫ 10 4 ) from B6 Ly5.2 mice were injected IS into the recipient mice (15). For cotransfer of progenitors, CLPs isolated from B6 Ly5.2 mice and MPs isolated from B6 Ly5.1 mice were cotransplanted in the spleen of 5 Gy-irradiated F 1 of B6 Ly5.1 and B6 Ly5.2 mice (Ly5.1 ϩ / Ly5.2 ϩ ).…”