The TN3-19.12 monoclonal antibody reacts with mouse, rat, and rabbit TNFα (tumor necrosis factor-alpha) a multifunctional proinflammatory cytokine. TNFα exists as a soluble 17 kDa monomer, which forms homotrimers in circulation or as a 26 kDa membrane-bound form. TNFα belongs to the TNF superfamily of cytokines and signals through its two receptors, TNFR1 and TNFR2 which can be activated by both the soluble trimeric and membrane-bound and forms of TNFα. TNFα is primarily produced by macrophages in response to foreign antigens such as bacteria (lipopolysaccharides viruses, and parasites as well as mitogens and other cytokines but can also be expressed by monocytes, neutrophils, NK cells, CD4 T cells and some specialized dendritic cells. TNFα is known to play key roles in a wide spectrum of biological processes including immunoregulation, cell proliferation, differentiation, apoptosis, antitumor activity, inflammation, anorexia, cachexia, septic shock, hematopoiesis, and viral replication. TNFα dysregulation has been implicated in a variety of diseases, including autoimmune diseases, insulin resistance, and cancer. Mouse and human TNFα share 79% amino acid sequence identity however, mouse TNFα is glycosylated while human TNFα is not. TNFα knockout animals display defects in response to bacterial infection, characterized by defects in forming organized follicular dendritic cell networks and germinal centers with a lack of primary B cell follicles. The TN3-19.12 antibody can neutralize the bioactivity of natural or recombinant TNF-α.'

InVivoMAb anti-mouse/rat/rabbit TNFα (Clone: TN3-19.12)

 Xiong, H., et al. (2016). "Innate Lymphocyte/Ly6C Monocyte Crosstalk Promotes Klebsiella Pneumoniae Clearance." Cell. doi: 10.1016/j.cell.2016.03.017. PubMed

Increasing antibiotic resistance among bacterial pathogens has rendered some infections untreatable with available antibiotics. Klebsiella pneumoniae, a bacterial pathogen that has acquired high-level antibiotic resistance, is a common cause of pulmonary infections. Optimal clearance of K. pneumoniae from the host lung requires TNF and IL-17A. Herein, we demonstrate that inflammatory monocytes are rapidly recruited to the lungs of K. pneumoniae-infected mice and produce TNF, which markedly increases the frequency of IL-17-producing innate lymphoid cells. While pulmonary clearance of K. pneumoniae is preserved in neutrophil-depleted mice, monocyte depletion or TNF deficiency impairs IL-17A-dependent resolution of pneumonia. Monocyte-mediated bacterial uptake and killing is enhanced by ILC production of IL-17A, indicating that innate lymphocytes engage in a positive-feedback loop with monocytes that promotes clearance of pneumonia. Innate immune defense against a highly antibiotic-resistant bacterial pathogen depends on crosstalk between inflammatory monocytes and innate lymphocytes that is mediated by TNF and IL-17A.

Brasseit, J., et al. (2015). "CD4 T cells are required for both development and maintenance of disease in a new mouse model of reversible colitis." Mucosal Immunol. doi: 10.1038/mi.2015.93. PubMed

Current therapies to treat inflammatory bowel diseases have limited efficacy, significant side effects, and often wane over time. Little is known about the cellular and molecular mechanisms operative in the process of mucosal healing from colitis. To study such events, we developed a new model of reversible colitis in which adoptive transfer of CD4+CD45RBhi T cells into Helicobacter typhlonius-colonized lymphopenic mice resulted in a rapid onset of colonic inflammation that was reversible through depletion of colitogenic T cells. Remission was associated with an improved clinical and histopathological score, reduced immune cell infiltration to the intestinal mucosa, altered intestinal gene expression profiles, regeneration of the colonic mucus layer, and the restoration of epithelial barrier integrity. Notably, colitogenic T cells were not only critical for induction of colitis but also for maintenance of disease. Depletion of colitogenic T cells resulted in a rapid drop in tumor necrosis factor alpha (TNFalpha) levels associated with reduced infiltration of inflammatory immune cells to sites of inflammation. Although neutralization of TNFalpha prevented the onset of colitis, anti-TNFalpha treatment of mice with established disease failed to resolve colonic inflammation. Collectively, this new model of reversible colitis provides an important research tool to study the dynamics of mucosal healing in chronic intestinal remitting-relapsing disorders.

Gopinath, S., et al. (2014). "Role of disease-associated tolerance in infectious superspreaders." Proc Natl Acad Sci U S A 111(44): 15780-15785. PubMed

Natural populations show striking heterogeneity in their ability to transmit disease. For example, a minority of infected individuals known as superspreaders carries out the majority of pathogen transmission events. In a mouse model of Salmonella infection, a subset of infected hosts becomes superspreaders, shedding high levels of bacteria (>10(8) cfu per g of feces) but remain asymptomatic with a dampened systemic immune state. Here we show that superspreader hosts remain asymptomatic when they are treated with oral antibiotics. In contrast, nonsuperspreader Salmonella-infected hosts that are treated with oral antibiotics rapidly shed superspreader levels of the pathogen but display signs of morbidity. This morbidity is linked to an increase in inflammatory myeloid cells in the spleen followed by increased production of acute-phase proteins and proinflammatory cytokines. The degree of colonic inflammation is similar in antibiotic-treated superspreader and nonsuperspreader hosts, indicating that the superspreader hosts are tolerant of antibiotic-mediated perturbations in the intestinal tract. Importantly, neutralization of acute-phase proinflammatory cytokines in antibiotic-induced superspreaders suppresses the expansion of inflammatory myeloid cells and reduces morbidity. We describe a unique disease-associated tolerance to oral antibiotics in superspreaders that facilitates continued transmission of the pathogen.

Khmaladze, I., et al. (2014). "Mannan induces ROS-regulated, IL-17A-dependent psoriasis arthritis-like disease in mice." Proc Natl Acad Sci U S A 111(35): E3669-3678. PubMed

Psoriasis (Ps) and psoriasis arthritis (PsA) are poorly understood common diseases, induced by unknown environmental factors, affecting skin and articular joints. A single i.p. exposure to mannan from Saccharomyces cerevisiae induced an acute inflammation in inbred mouse strains resembling human Ps and PsA-like disease, whereas multiple injections induced a relapsing disease. Exacerbation of disease severity was observed in mice deficient for generation of reactive oxygen species (ROS). Interestingly, restoration of ROS production, specifically in macrophages, ameliorated both skin and joint disease. Neutralization of IL-17A, mainly produced by gammadelta T cells, completely blocked disease symptoms. Furthermore, mice depleted of granulocytes were resistant to disease development. In contrast, certain acute inflammatory mediators (C5, Fcgamma receptor III, mast cells, and histamine) and adaptive immune players (alphabeta T and B cells) were redundant in disease induction. Hence, we propose that mannan-induced activation of macrophages leads to TNF-alpha secretion and stimulation of local gammadelta T cells secreting IL-17A. The combined action of activated macrophages and IL-17A produced in situ drives neutrophil infiltration in the epidermis and dermis of the skin, leading to disease manifestations. Thus, our finding suggests a new mechanism triggered by exposure to exogenous microbial components, such as mannan, that can induce and exacerbate Ps and PsA.