The NOD- scid IL2rγ ^null Mouse Model Is Suitable for the Study of Osteoarticular Brucellosis and Vaccine Safety

Abstract

Osteoarticular brucellosis is the most common complication in Brucella-infected humans regardless of age, sex, or immune status. The mechanism of bone destruction caused by Brucella species remained partially unknown due to the lack of a suitable animal model. Here, to study this complication, we explored the suitability of the use of the NOD-scid IL2rγnull mouse to study osteoarticular brucellosis and examined the potential use of this strain to evaluate the safety of live attenuated vaccine candidates. Mice were inoculated intraperitoneally with a single dose of 1 × 104, 1 × 105, or 1 × 106 CFU of B. abortus S19 or the vaccine candidate B. abortus S19ΔvjbR and monitored for the development of side effects, including osteoarticular disease, for 13 weeks. Decreased body temperature, weight loss, splenomegaly, and deformation of the tails were observed in mice inoculated with B. abortus S19 but not in those inoculated with S19ΔvjbR. Histologically, all S19-inoculated mice had a severe dose-dependent inflammatory response in multiple organs. The inflammatory response at the tail was characterized by the recruitment of large numbers of neutrophils, macrophages, and osteoclasts with marked bone destruction. These lesions histologically resembled what is typically observed in Brucella-infected patients. In contrast, mice inoculated with B. abortus S19ΔvjbR did not show significant bone changes. Immunofluorescence, in situ hybridization, and confocal imaging demonstrated the presence of Brucella at the sites of inflammation, both intra- and extracellularly, and large numbers of bacteria were observed within mature osteoclasts. These results demonstrate the potential use of the NOD-scid IL2rγnull mouse model to evaluate vaccine safety and further study osteoarticular brucellosis.

Interaction of Brucella abortus with Osteoclasts: a Step toward Understanding Osteoarticular Brucellosis and Vaccine Safety

“…Although in vitro infection of osteoclasts with various types of live bacteria known to cause bone destruction, including Staphylococcus aureus, Mycobacterium tuberculosis, and Cutibacterium acnes, has been studied (41, 61, 62), the direct interaction of Brucella with osteoclasts has never been investigated. A recent study performed by our laboratory has demonstrated severe bone destruction in the tail vertebrae of NSG mice inoculated with B. abortus S19, with accumulation of a large number of bacteria within mature osteoclasts, an outcome which was not observed during infection with the Brucella vaccine candidate S19⌬vjbR (21). In this study, we demonstrated that only B. abortus 2308 and S19 were able to invade and replicate inside mature osteoclasts.…”

“…In addition to their resorptive activity, osteoclasts regulate osteoblast precursor differentiation and activity as well as immune cell responses (20). Previous investigations from our laboratory using NOD-SCID IL2r␥ null (NSG) mice have demonstrated that infection with B. abortus S19 but not the S19⌬vjbR vaccine candidate induced severe bone resorption with accumulation of myriad bacteria within mature osteoclasts (21). This apparent tropism of Brucella for osteoclasts and the significant amount of bone destruction in the mice, a lesion which is mediated by osteoclast resorptive activity, prompted the investigation of the effect of Brucella infection on these cells.…”

Brucella abortus em Humanos: revisão de literatura

“…Quando a origem da infecção é alimentar a brucelose se assemelha à febre tifoide e os sintomas predominam nas queixas gastrointestinais, casos de ileíte, colite e peritonite bacteriana espontânea já foram relatados (CLEMENTINO et al, 2016). Frequentemente a brucelose humana é associada ao desenvolvimento de doença osteoarticular, com incidência variando de 40% a 80% (KHALAF et al, 2020) e a endocardite infecciosa é a manifestação cardiovascular mais comum, considerada a causa mais associada aos casos letais por brucelose, sendo relatada em 2% dos casos (LAWINSKY et al, 2010). Porém, a endocardite, meningite, artrite, hepatite e abscessos viscerais são complicações mais raramente observadas (CARMICHAEL et al, 1990).…”

Next-Generation Sequencing-Based Identification of Enterobacter hormaechei as Causative Agent of High Mortality Disease in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) Mice

“…Immunodeficient mice are an increasingly popular research model due to their utility in studying human immune responses and cancer, and their use has increased significantly in preclinical research for multiple applications. 5,11,21,24,35,39,45,52 In preclinical studies in areas such as oncology and immunology, immunodeficient mice have been important to the understanding of mechanisms of disease, target identification and validation, and toxicologic effects of compounds. In addition, immunodeficient strains may recapitulate some of the immune dysfunction observed following immunosuppressive conditions in humans, such as chemotherapy, radiation therapy, surgery, infectious disease, or paraneoplastic syndromes, 17,48 and therefore may serve as a better predictor of toxicokinetics and safety in these instances.…”

“…33 In preclinical research, NSG mice have been used to test vaccine safety in the context of immunodeficient patients and the toxicity of human cell-based therapies. 24,45 Based on these research applications, NSG mice and other polygenic variants will likely continue to increase in popularity and value. However, immunodeficient mice created with multiple genetic mutations, including NSG mice, are very expensive to procure and often engrafted with tumors directly harvested from human patients and therefore irreplaceable.…”