Dengue virus infection and immune response in humanized RAG2−/−γc−/− (RAG-hu) mice

Abstract

Dengue viral (DENV) pathogenesis and vaccine studies are hampered by the lack of an ideal animal model mimicking human disease and eliciting an adaptive human immune response. Although currently available animal models have been very useful in dissecting some key aspects of disease pathogenesis, a major limitation with these is the lack of a human immune response. In this study, we sought to overcome this difficulty by utilizing a novel mouse model that permits multi-lineage human hematopoiesis and immune response following transplantation with human hematopoietic stem cells. To generate immunocompetent humanized mice, neonatal RAG2(-/-)gamma(c)(-/-) mice were xenografted with human CD34+ hematopoietic stem cells, resulting in de novo development of major functional cells of the human adaptive immune system. To evaluate susceptibility to dengue viral infection, humanized mice were challenged with DEN-2 serotype. Viremia lasting up to 3 weeks was detected in infected mice with viral titers reaching up to 10(6.3) RNA copies/ml. Fever characteristic of dengue was also noted in infected mice. Presence of human anti-dengue antibodies was evaluated using an antibody capture ELISA. Anti-dengue IgM was first detected by 2 weeks post-infection followed by IgG at 6 weeks. Sera from some of the infected mice were also found to be capable of dengue virus neutralization. Infected mouse sera showed reactivity with the viral envelope and capsid proteins in immunoprecipitation assay. These results demonstrate for the first time that humanized mice are capable of dengue viral primary human immune responses thus paving the way for new dengue immunopathogenesis and vaccine studies.

Les souris ne sont pas des hommes et pourtant…

“…Des souris NOD-scid, greffées avec des CPH puis infectées par voie sous-cutanée avec le virus, ce qui mime la transmission par les moustiques, développent des signes cliniques identiques à ceux observés chez l'homme : fièvre, érythème et thrombocytopénie [28]. De même, des souris BRG humanisées ayant reçu une greffon de CPH puis secondairement infectées par le virus de la dengue, développent pendant trois semaines une virémie éle-vée accompagnée d'une fièvre importante [29]. La production précoce d'anticorps de type IgM est suivie de celle d'anticorps IgG, dont certains sont neutralisants.…”

Replacing mouse BAFF with human BAFF does not improve B-cell maturation in hematopoietic humanized mice

“…[4][5][6][7][8] One example of these recipients is the BALB/c-Rag2 null Il2rg null (BRG) strain that, when transplanted with hHSCs, develop human B cells, T cells, and, with varying frequencies, other human hematopoietic cell types. [9][10][11][12][13][14][15][16][17] This strain has been recently modified into BRGS with the introduction of the NOD-derived Sirpa allele (Sirpa NOD indicated that T cells are crucial to B-cell maturation in hu-mice, 16 other studies have suggested that the defects in B-cell maturation and antibody responses observed in hu-mice are caused by an inability of mouse B-cell-activating factor (mBAFF) to aid survival and antigen responses of human B cells. 19,20 B-cell-activating factor (BAFF)/B-lymphocyte stimulator (BlyS) is an important homeostatic factor for B cells in both mice and humans, 21 and a BAFF deficiency in mice and antagonism in humans cause major loss of late transitional and mature B cells.…”

Viral infections in mice with reconstituted human immune system components

“…Dengue virus infection was performed by intraperitoneal, subcutaneous of intravenous injection into HIS mice [62][63][64][65][66]. In most instances dengue serotype 2 viruses were used.…”

“…Dengue virus infection was performed by intraperitoneal, subcutaneous of intravenous injection into HIS mice [62][63][64][65][66]. In most instances dengue serotype however, is dengue hemorrhagic fever after heterologous infection with another dengue virus serotype and it is thought that heterologous antibodies enhance infection by the second phenotype to cause this severe disease [67].…”

“…In most instances dengue serotype however, is dengue hemorrhagic fever after heterologous infection with another dengue virus serotype and it is thought that heterologous antibodies enhance infection by the second phenotype to cause this severe disease [67]. However, in HIS mice primarily IgM responses were so far detected after infection [64,66], and it remains unclear if these could mediate antibody mediated enhancement of heterologous dengue virus infection. Modelling of this disease would be the most valuable application of HIS mice to this viral infection.…”