RESUMEN
BACKGROUND: Staphylococcus aureus can cause serious infections by secreting many superantigen exotoxins in "carrier" or "pathogenic" states. HLA DQ and HLA DR humanized mice have been used as a small animal model to study the role of two molecules during S. aureus infection. However, the contribution of HLA DP to S. aureus infection is unknown yet. METHODS: In this study, we have produced HLA DP401 and HLA DRA0101 humanized mice by microinjection of C57BL/6J zygotes. Neo-floxed IAß+/- mice were crossbred with Ella-Cre and further crossbred with HLA DP401 or HLA-DRA0101 humanized mice. After several rounds of traditional crossbreeding, we finally obtained HLA DP401-IAß-/- and HLA DRA-IAß-/- humanized mice, in which human DP401 or DRA0101 molecule was introduced into IAß-/- mice deficient in endogenous murine MHC class II molecules. A transnasal infection murine model of S. aureus pneumonia was induced in the humanized mice by administering 2 × 108 CFU of S. aureus Newman dropwise into the nasal cavity. The immune responses and histopathology changes were further assessed in lungs in these infected mice. RESULTS: We evaluated the local and systemic effects of S. aureus delivered intranasally in HLA DP401-IAß-/- and HLA DRA-IAß-/- transgenic mice. S. aureus Newman infection significantly increased the mRNA level of IL 12p40 in lungs in humanized mice. An increase in IFN-γ and IL-6 protein was observed in HLA DRA-IAß-/- mice. We observed a declining trend in the percentage of F4/80+ macrophages in lungs in HLA DP401-IAß-/- mice and a decreasing ratio of CD4+ to CD8+ T cells in lungs in IAß-/- mice and HLA DP401-IAß-/- mice. A decreasing ratio of Vß3+ to Vß8+ T cells was also found in the lymph node of IAß-/- mice and HLA DP401-IAß-/- mice. S. aureus Newman infection resulted in a weaker pathological injury in lungs in IAß-/- genetic background mice. CONCLUSION: These humanized mice will be an invaluable mouse model to resolve the pathological mechanism of S. aureus pneumonia and study what role DP molecule plays in S. aureus infection.
Asunto(s)
Genes MHC Clase II , Neumonía Estafilocócica , Ratones , Humanos , Animales , Cadenas alfa de HLA-DR/farmacología , Staphylococcus aureus , Neumonía Estafilocócica/genética , Linfocitos T CD8-positivos , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
BACKGROUND: DRα1-mouse(m)MOG-35-55, a novel construct developed in our laboratory as a simpler and potentially less immunogenic alternative to two-domain class II constructs, was shown previously to target the MIF/CD74 pathway and to reverse clinical and histological signs of experimental autoimmune encephalomyelitis (EAE) in DR*1501-Tg mice in a manner similar to the parent DR2ß1-containing construct. METHODS: In order to determine whether DRα1-mMOG-35-55 could treat EAE in major histocompatibility complex (MHC)-mismatched mice and to evaluate the treatment effect on central nervous system (CNS) inflammation, C57BL/6 mice were treated with DRα1-mMOG-35-55. In addition, gene expression profile was analyzed in spinal cords of EAE DR*1501-Tg mice that were treated with DRα1-mMOG-35-55. RESULTS: We here demonstrate that DRα1-mMOG-35-55 could effectively treat EAE in MHC-mismatched C57BL/6 mice by reducing CNS inflammation, potentially mediated in part through an increased frequency of M2 monocytes in the spinal cord. Microarray analysis of spinal cord tissue from DRα1-mMOG-35-55-treated vs. vehicle control mice with EAE revealed decreased expression of a large number of pro-inflammatory genes including CD74, NLRP3, and IL-1ß and increased expression of genes involved in myelin repair (MBP) and neuroregeneration (HUWE1). CONCLUSION: These findings indicate that the DRα1-mMOG-35-55 construct retains therapeutic, anti-inflammatory, and neuroprotective activities during treatment of EAE across MHC disparate barriers.