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Improved B cell development in humanized NOD ‐ scid IL2R γ mice transgenically expressing human stem cell factor, granulocyte ‐ macrophage colony ‐ stimulating factor and interleukin ‐ 3

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Immunodeficient mice engrafted with human immune systems support studies of human hematopoiesis and the immune response to human‐specific pathogens. A significant limitation of these humanized mouse models is, however, a severely restricted ability of human B cells to undergo class switching and produce antigen‐specific IgG after infection or immunization.

Methods: In this study, we have characterized the development and function of human B cells in NOD‐scid IL2Rγ (NSG) mice transgenically expressing human stem cell factor (SCF), granulocyte macrophage colony‐stimulating factor (GM‐CSF), and IL‐3 (NSG‐SGM3) following engraftment with human hematopoietic stem cells, autologous fetal liver, and thymic tissues (bone marrow, liver, thymus or BLT model). The NSG‐SGM3 BLT mice engraft rapidly with human immune cells and develop T cells, B cells, and myeloid cells.

Results: A higher proportion of human B cells developing in NSG‐SGM3 BLT mice had a mature/naive phenotype with a corresponding decrease in immature/transitional human B cells as compared to NSG BLT mice. In addition, NSG‐SGM3 BLT mice have higher basal levels of human IgM and IgG as compared with NSG BLT mice. Moreover, dengue virus infection of NSG‐SGM3 BLT mice generated higher levels of antigen‐specific IgM and IgG, a result not observed in NSG BLT mice.

Conclusions: Our studies suggest that NSG‐SGM3 BLT mice show improved human B cell development and permit the generation of antigen‐specific antibody responses to viral infection.

No MeSH data available.


Related in: MedlinePlus

Evaluation of total antibody titers and dengue virus specific antibody responses in NSG BLT and NSG‐SGM3 BLT mice. Mice were bled at 12 weeks post‐implantation of human tissues and total human IgM (A) and human IgG (B) levels (ng/ml) were determined in the plasma of these mice by ELISA. Mice were infected with DENV‐2 and plasma samples were tested to determine DENV‐2 specific IgM (C) and IgG (D) by sandwich ELISA. Each symbol indicates an individual BLT mouse. The results from two independent experiments.
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iid3124-fig-0007: Evaluation of total antibody titers and dengue virus specific antibody responses in NSG BLT and NSG‐SGM3 BLT mice. Mice were bled at 12 weeks post‐implantation of human tissues and total human IgM (A) and human IgG (B) levels (ng/ml) were determined in the plasma of these mice by ELISA. Mice were infected with DENV‐2 and plasma samples were tested to determine DENV‐2 specific IgM (C) and IgG (D) by sandwich ELISA. Each symbol indicates an individual BLT mouse. The results from two independent experiments.

Mentions: A major limitation of humanized mice is their reduced ability to generate human IgG responses. The enhanced human B cell maturation observed in the NSG‐SGM3 BLT mouse model (Fig. 6) suggested that these mice may have an increased ability to undergo Ig class switching. The basal levels of human IgM and IgG in the plasma of resting BLT mice were therefore evaluated at 12 weeks post‐tissue implant. NSG‐SGM3 mice had 5.6‐fold higher levels of human IgM compared to NSG mice (Fig. 7A). Human IgG levels were 4.5‐fold higher in NSG‐SGM3 mice compared to NSG mice (Fig. 7B). Next we infected the mice with DENV‐2 (dengue virus serotype‐2) and assessed the generation of DENV‐2 specific antibodies by sandwich ELISA 4 weeks post‐infection. We previously demonstrated the generation of IgM responses to the inactivated lysates of dengue antigen and the DENV‐2 E (envelope) protein in NSG BLT mice but limited antigen‐specific IgG responses 23. NSG‐SGM3 BLT mice infected with DENV‐2 had significantly higher levels of DENV‐2 specific IgM (Fig. 7C) and increased levels of DENV‐2 specific IgG (Fig. 7D). These data indicate that transgenic expression of SCF, GM‐CSF, and IL‐3 generates higher levels of total human IgM and IgG suggesting improved class switching and induces improved viral antigen‐specific antibody responses.


Improved B cell development in humanized NOD ‐ scid IL2R γ mice transgenically expressing human stem cell factor, granulocyte ‐ macrophage colony ‐ stimulating factor and interleukin ‐ 3
Evaluation of total antibody titers and dengue virus specific antibody responses in NSG BLT and NSG‐SGM3 BLT mice. Mice were bled at 12 weeks post‐implantation of human tissues and total human IgM (A) and human IgG (B) levels (ng/ml) were determined in the plasma of these mice by ELISA. Mice were infected with DENV‐2 and plasma samples were tested to determine DENV‐2 specific IgM (C) and IgG (D) by sandwich ELISA. Each symbol indicates an individual BLT mouse. The results from two independent experiments.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5134721&req=5

iid3124-fig-0007: Evaluation of total antibody titers and dengue virus specific antibody responses in NSG BLT and NSG‐SGM3 BLT mice. Mice were bled at 12 weeks post‐implantation of human tissues and total human IgM (A) and human IgG (B) levels (ng/ml) were determined in the plasma of these mice by ELISA. Mice were infected with DENV‐2 and plasma samples were tested to determine DENV‐2 specific IgM (C) and IgG (D) by sandwich ELISA. Each symbol indicates an individual BLT mouse. The results from two independent experiments.
Mentions: A major limitation of humanized mice is their reduced ability to generate human IgG responses. The enhanced human B cell maturation observed in the NSG‐SGM3 BLT mouse model (Fig. 6) suggested that these mice may have an increased ability to undergo Ig class switching. The basal levels of human IgM and IgG in the plasma of resting BLT mice were therefore evaluated at 12 weeks post‐tissue implant. NSG‐SGM3 mice had 5.6‐fold higher levels of human IgM compared to NSG mice (Fig. 7A). Human IgG levels were 4.5‐fold higher in NSG‐SGM3 mice compared to NSG mice (Fig. 7B). Next we infected the mice with DENV‐2 (dengue virus serotype‐2) and assessed the generation of DENV‐2 specific antibodies by sandwich ELISA 4 weeks post‐infection. We previously demonstrated the generation of IgM responses to the inactivated lysates of dengue antigen and the DENV‐2 E (envelope) protein in NSG BLT mice but limited antigen‐specific IgG responses 23. NSG‐SGM3 BLT mice infected with DENV‐2 had significantly higher levels of DENV‐2 specific IgM (Fig. 7C) and increased levels of DENV‐2 specific IgG (Fig. 7D). These data indicate that transgenic expression of SCF, GM‐CSF, and IL‐3 generates higher levels of total human IgM and IgG suggesting improved class switching and induces improved viral antigen‐specific antibody responses.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Immunodeficient mice engrafted with human immune systems support studies of human hematopoiesis and the immune response to human‐specific pathogens. A significant limitation of these humanized mouse models is, however, a severely restricted ability of human B cells to undergo class switching and produce antigen‐specific IgG after infection or immunization.

Methods: In this study, we have characterized the development and function of human B cells in NOD‐scid IL2Rγ (NSG) mice transgenically expressing human stem cell factor (SCF), granulocyte macrophage colony‐stimulating factor (GM‐CSF), and IL‐3 (NSG‐SGM3) following engraftment with human hematopoietic stem cells, autologous fetal liver, and thymic tissues (bone marrow, liver, thymus or BLT model). The NSG‐SGM3 BLT mice engraft rapidly with human immune cells and develop T cells, B cells, and myeloid cells.

Results: A higher proportion of human B cells developing in NSG‐SGM3 BLT mice had a mature/naive phenotype with a corresponding decrease in immature/transitional human B cells as compared to NSG BLT mice. In addition, NSG‐SGM3 BLT mice have higher basal levels of human IgM and IgG as compared with NSG BLT mice. Moreover, dengue virus infection of NSG‐SGM3 BLT mice generated higher levels of antigen‐specific IgM and IgG, a result not observed in NSG BLT mice.

Conclusions: Our studies suggest that NSG‐SGM3 BLT mice show improved human B cell development and permit the generation of antigen‐specific antibody responses to viral infection.

No MeSH data available.


Related in: MedlinePlus