Profound reduction of mature B cell numbers, reactivities and serum lg levels in mice which simultaneously carry the XID and CD40 deficiency gense

It has been known for some time that single mutant nude or CD40T mice have apparently normal numbers of cells in the precursor compartments of bone marrow and the mature B cell compartments of the periphery. X-linked immunodeficiency (XID) mice are deficient only in some of the slgM+slgD+ B cells. We have investigated further the contributions of the xid mutation, of the T cell deficiency of nude and of the inability of CD40T B cells to cooperate with T cells in the generation of the precursor and the mature B cell compartments in mice. Double mutant XIDInu and XIDlCD4OT mice have precursor B cell compartments that are no more deficient than the single mutant XID mice. However, the peripheral B cell compartments of both XIDInu and XIDlCD40T are even more deficient than those of single mutant XID mice. While 10% of the peripheral B cells of wild-type or CD40T, one-third of XID and half of XIDInu mice turn over rapidly, as many as threequarters of those in XIDlCD40T are short-lived. Total numbers of slgM+slgD+ B cells in the spleen are at best 1615% of normal mice at 6-8 weeks of age in XID, XIDInu and XIDICD40T mice. They remain that low at 3 months of age in XIDICD40T mice, while in XID mice these peripheral B cells slowly build up in numbers with age. As expected, double mutant XIDlCD40T mice do not respond to the T-dependent antigen keyhole limpet hemocyanin. Only the responses to the T-independent type I antigen, TNP-lipopolysaccharide (LPS), appear to be normal. In vitro, their splenic B cells respond poorly to LPS or to IgM-specific antibody in either the absence or presence of cytokines. Most notably, serum IgM, lgG2b and lgG3 levels are severely depressed, while IgG1, lgG2a and IgA levels are <I0 pglml. The results suggest a model of mature B cell development in which the peripheral, mature B cell compartments are generated in two parallel, not tandemly organized pathways. They could be selected and/or stimulated at the transition from immature to mature B cells: in btk controlled or in CD40 controlled way

Expression of Interleukin-10 in Intestinal Lymphocytes Detected by an Interleukin-10 Reporter Knockin tiger Mouse

SummaryTo identify interleukin-10 (IL-10)-producing cells in vivo, we generated a knockin mouse where an internal ribosome entry site (IRES) green fluorescence protein (GFP) element was inserted immediately before the polyadenylation site of the IL-10 gene. GFP fluorescence in cells from these mice was found to correlate positively with IL-10 protein expression. With this model, we found that after multiple T cell receptor (TCR) stimulations, strong expression of IL-10 was produced specifically by intraepithelial lymphocytes (IEL) in the small intestine and colonic lamina propria lymphocytes (cLPL). We found that anti-CD3 treatment induces T regulatory cell 1 (Tr1)-like cells in small intestinal IEL (sIEL) and led to the accumulation of naturally occurring regulatory T (nTreg) cells in colonic LPL (cLPL). These findings highlight the intestine as a unique site for induction of IL-10-producing T cells, which play a critical role in the regulation of inflammation in the gut

Memory/effector (CD45RBlo) CD4 T cells are controlled directly by IL-10 and cause IL-22–dependent intestinal pathology

Interleukin-10 acts directly on CD45RBlo but not CD45RBhi cells to control colitis upon transfer into Rag1-deficient recipients

IL-10 Signaling Blockade Controls Murine West Nile Virus Infection

West Nile virus (WNV), a mosquito-borne single-stranded RNA flavivirus, can cause significant human morbidity and mortality. Our data show that interleukin-10 (IL-10) is dramatically elevated both in vitro and in vivo following WNV infection. Consistent with an etiologic role of IL-10 in WNV pathogenesis, we find that WNV infection is markedly diminished in IL-10 deficient (IL-10−/−) mice, and pharmacologic blockade of IL-10 signaling by IL-10 neutralizing antibody increases survival of WNV-infected mice. Increased production of antiviral cytokines in IL-10−/− mice is associated with more efficient control of WNV infection. Moreover, CD4+ T cells produce copious amounts of IL-10, and may be an important cellular source of IL-10 during WNV infection in vivo. In conclusion, IL-10 signaling plays a negative role in immunity against WNV infection, and blockade of IL-10 signaling by genetic or pharmacologic means helps to control viral infection, suggesting a novel anti-WNV therapeutic strategy

IL-10 from CD4+CD25−Foxp3−CD127− Adaptive Regulatory T Cells Modulates Parasite Clearance and Pathology during Malaria Infection

The outcome of malaria infection is determined, in part, by the balance of pro-inflammatory and regulatory immune responses. Failure to develop an effective pro-inflammatory response can lead to unrestricted parasite replication, whilst failure to regulate this response leads to the development of severe immunopathology. IL-10 and TGF-β are known to be important components of the regulatory response, but the cellular source of these cytokines is still unknown. Here we have examined the role of natural and adaptive regulatory T cells in the control of malaria infection and find that classical CD4+CD25hi (and Foxp3+) regulatory T cells do not significantly influence the outcome of infections with the lethal (17XL) strain of Plasmodium yoelii (PyL). In contrast, we find that adaptive IL-10-producing, CD4+ T cells (which are CD25−, Foxp3−, and CD127− and do not produce Th1, Th2, or Th17 associated cytokines) that are generated during both PyL and non-lethal P. yoelii 17X (PyNL) infections are able to down-regulate pro-inflammatory responses and impede parasite clearance. In summary, we have identified a population of induced Foxp3− regulatory (Tr1) T cells, characterised by production of IL-10 and down regulation of IL-7Rα, that modulates the inflammatory response to malaria

IL-10 Suppression of NK/DC Crosstalk Leads to Poor Priming of MCMV-Specific CD4 T Cells and Prolonged MCMV Persistence

IL-10 is an anti-inflammatory cytokine that regulates the extent of host immunity to infection by exerting suppressive effects on different cell types. Herpes viruses induce IL-10 to modulate the virus-host balance towards their own benefit, resulting in prolonged virus persistence. To define the cellular and molecular players involved in IL-10 modulation of herpes virus-specific immunity, we studied mouse cytomegalovirus (MCMV) infection. Here we demonstrate that IL-10 specifically curtails the MCMV-specific CD4 T cell response by suppressing the bidirectional crosstalk between NK cells and myeloid dendritic cells (DCs). In absence of IL-10, NK cells licensed DCs to effectively prime MCMV-specific CD4 T cells and we defined the pro-inflammatory cytokines IL-12, IFN-γ and TNF-α as well as NK cell activating receptors NKG2D and NCR-1 to regulate this bidirectional NK/DC interplay. Consequently, markedly enhanced priming of MCMV-specific CD4 T cells in Il10-/-mice led to faster control of lytic viral replication, bu

Differential involvement of p38 mitogen-activated protein kinase kinases MKK3 and MKK6 in T-cell apoptosis

The p38 mitogen-activated protein kinase (p38MAPK) is activated in response to various stimuli, including cellular stress, inflammatory cytokines and cell surface receptors. The activation of p38MAPK is predominantly mediated by the two upstream MAPK kinases MKK3 and MKK6. To study the role of the p38MAPK pathway in vivo, we generated Mkk6(–/–) mice. We examined whether T-cell apoptosis is affected in these mice and in our previously reported Mkk3(–/–) mice. Strikingly, in vivo deletion of double positive thymocytes in Mkk6(–/–) mice was impaired, whereas Mkk3(–/–) mice showed no apparent abnormality. Conversely, CD4(+)T cells from Mkk3(–/–) but not from Mkk6(–/–) mice were resistant to activation-induced cell death and cytokine-withdrawal-induced apoptosis. In peripheral CD4(+)T cells, MKK3 is induced upon stimulation, whereas MKK6 is downregulated. These results suggest a novel mechanism regulating T-cell apoptosis differentially through the p38MAPK pathway by MKK3 and MKK6

IL-10 mediated regulation of liver inflammation during acute murine cytomegalovirus infection.

Various cell types in both lymphoid and non-lymphoid tissues produce the anti-inflammatory cytokine interleukin (IL)-10 during murine cytomegalovirus (MCMV) infection. The functions of IL-10 in the liver during acute infection and the cells that generate this cytokine at this site have not been extensively investigated. In this study, we demonstrate that the production of IL-10 in the liver is elevated in C57BL/6 mice during late acute MCMV infection. Using IL-10 green fluorescence protein (GFP) reporter knock-in mice, designated IL-10-internal ribosomal entry site (IRES)-GFP-enhanced reporter (tiger), NK cells are identified as major IL-10 expressing cells in the liver after infection, along with T cells and other leukocytes. In the absence of IL-10, mice exhibit marked elevations in proinflammatory cytokines and in the numbers of mononuclear cells and lymphocytes infiltrating the liver during this infection. IL-10-deficiency also enhances liver injury without improving viral clearance from this site. Collectively, the results indicate that IL-10-producing cells in the liver provide protection from collateral injury by modulating the inflammatory response associated with MCMV infection