n., submandibular lymph nodes, but not NALTs, were consistently find more clearly stained (Fig. 3, inset). These results taken together demonstrate that the submandibular lymph nodes are the main organ that responds to i.n. injected allergens. To explore the mechanisms of IgG Ab production and compare them with those of IgE Ab production in submandibular lymph nodes, we injected the allergen with or without complete Freund’s adjuvant i.n. once into BALB/c mice (Fig. 4). A significant amount of serum IgE (465.4 ±111.6 ng/mL; mean ± SD; n =9) was induced by one i.n. injection of allergen alone. In contrast, one i.n. injection

of the allergen with adjuvant induced a much smaller amount of serum IgE (172.5 ± 74.7ng/mL; mean ± SD; n =9). This was greater than that (57.6 ± 32.2 ng/mL; mean ± SD; n =9) in mice treated with adjuvant alone or that (40.8 ± 14.8 ng/mL; mean ± SD; n =9) in PBS-injected mice. In contrast, a large amount of serum IgG (1585.4 ± 161.0 μg/mL; mean ± SD; n =9) was induced by one i.n. injection

of the allergen with adjuvant into mice; this amount of serum IgG was greater than R788 cost that obtained after one i.n. injection of adjuvant (1018.2 ±33.2 μg/mL; mean ± SD; n =9) or allergen (904.9 ± 51.2 μg/mL; mean ± SD; n =9) alone, both of which were greater than that (514.7 ± 161.8 μg/mL; mean ± SD; n =9) in PBS-injected mice. These results indicate that one i.n. injection of allergen alone or with adjuvant is suitable for induction of serum IgE or IgG Ab, respectively. To explore which population of cells in the submandibular lymph nodes is involved in the production of IgE Ab in response to the allergen, we separated the cells into macrophage-, lymphocyte-, and granulocyte-rich populations by Percoll density-gradient centrifugation. The yield of cells from the submandibular lymph nodes

was 78–89% (n =9). Fraction 3 (rich in lymphocytes) was the major (93.5 ± 7.2%; mean ± SD; n =9) population, 3-oxoacyl-(acyl-carrier-protein) reductase followed by fraction 2 (rich in macrophages; 1.2 ± 0.1%; mean ± SD; n =9) and fraction 4 (rich in granulocytes; 0.3 ± 0.1%; mean ± SD; n =9) in that order. Fraction 1 (rich in somewhat damaged cells) contained a small number of cells. As we obtained the macrophage-, lymphocyte-, and granulocyte-rich fractions, we incubated various combinations of these cells for 6 days and then assessed the amounts of IgE Ab in the culture media (Fig. 5). Bulk submandibular lymph node cells from mice that had been treated with allergen once i.n. produced a significant amount of IgE Abs (6.2 ± 3.4 ng/mL; mean ± SD; n =9); whereas the lymphocyte-rich (fraction 3) fraction of the lymph node cells did not (1.5 ± 0.8 ng/mL; mean ± SD; n =9). The macrophage-rich (fraction 2) fraction was also inactive (1.1 ± 0.9 ng/mL; mean ± SD; n =9). Of particular interest, IgE Ab production (4.6 ± 2.8 ng/mL; mean ± SD; n =9) was restored by addition of the macrophage-rich fraction to the lymphocyte-rich fraction.

Of note, hepatocytes pulsed in vivo and in vitro with α-GalCer can activate iNKT cells to secrete IL-4 and not IFN-γ [28]. Thus, although not essential, MI-503 mouse hepatocytes could play a role in iNKT cell activation in actively sensitized wild-type mice. There may simply be a network of CD1d+ cells (e.g. dendritic cells, Kuppfer cells or NKT cells themselves) that activate iNKT cells in vivo, as suggested here and elsewhere, via presentation of rapidly accumulating stimulatory lipids after sensitization [28, 32]. Dendritic cells have recently been shown to be

able to potentiate iNKT cell activation in a CD1d-dependent manner even in the context of low levels of lipid antigen [33]. Important questions remain pertaining to the stimulatory hepatic lipids observed here. It is unclear whether the accumulation of stimulatory lipids is the result of an increase in the quantity Staurosporine order of stimulatory hepatic lipids, a change in the quality of pre-existing hepatic lipids or a combination. A quantitative difference would imply migration of lipids from an extra-hepatic site, perhaps the skin at the site of sensitization. A qualitative difference would be mediated by chemical or structural modification of lipids native to

the liver. Although our extracts are sensitive to lipase (N. Dey, K. Lau, M. Szczepanik, P.W. Askenase, unpublished observations), the identity of these lipids is as yet unknown. This determination remains for further studies collaborating with glycolipid biochemists. The lipids may represent a subset of endogenous skin-derived self-lipids that have particular iNKT cell–activating potential. They may be released from the skin following sensitization. Alternatively, these may be hepatic lipids that Urocanase are somehow modified following skin sensitization to provide increased stimulation to iNKT cells. Finally, exogenous glycolipids derived from the host skin microbiota may be involved. While the finding of accumulating stimulatory

hepatic lipids begins to clarify the mystery of rapid iNKT cell response after sensitization, whether the entire role of iNKT cells in CS has been defined remains unclear. For example, we have observed using ELISA assays that serum IFN-γ levels peak approximately 1 day after sensitization in mice (unpublished observations), a finding that remains unexplained in terms of both mechanism and relevance. iNKT cells could potentially account for this. This and other described immune activities of iNKT cells, such as cytotoxicity and influence on regulatory T cells [34], remain unexplored in CS. The implications of these data for other diseases are also unclear and should be investigated further. Finally, these and related data on iNKT cell biology may have implications for a multitude of clinical diseases. For example, IL-4-producing iNKT cells may be therapeutic (e.g. NAFLD) or detrimental (e.g.

HRP-conjugated goat antirabbit IgG (Dingguo Biotechnology, Beijing, China) diluted by 1:10000 was added and incubated for 1 hr at 37°C. The plates were washed four times with PBS before adding diaminobenzidine substrate (Dingguo Biotechnology), 20 M H2SO4 was added to cease the reaction and the OD490nm was measured. A positive control, a negative control and a blank control were always included on each plate. Six BALB/c mice (6–8 weeks of age) were immunized with the purified recombinant protein. For primary immunization, each mouse was s.c.

injected with 50 μg of antigen (recombinant Tamoxifen purchase 56-kDa protein) emulsified in Freund’s complete adjuvant. Ten days later, they were given an i.p. booster injection of HDAC inhibitor 50 μg antigen emulsified in Freund’s incomplete adjuvant. Control mice were injected similarly with PBS emulsified in Freund’s complete adjuvant or incomplete adjuvant. After that, mice were bled and sera were obtained and stored at −20°C. The animal use was reviewed and approved by the Beijing Administrative Committee for Laboratory Animals and the animal care met the standard of the committee. Bleeding of the mice was performed by tail clip after primary immunization and cardiac puncture after booster immunization. To determine

IgG titers of the sera, an IFA test with antigen slides of O. tsutsugamushi Karp was carried out with fluorescein isothiocyanate-conjugated goat antimouse IgG (Kierkegaard & Perry Laboratories, Gaithersburg, MD,

USA). Meanwhile, an ELISA test was also performed as described above. A fragment of 1107 bp that would yield a 46-kDa His-tagged protein with a deletion of 99 amino acid residues at the N terminal and 64 amino acid residues at the C terminal was amplified by PCR and the product was cloned into pET30a. The resulting recombinant plasmid, designated pET30a-Ot56, was detected by both PCR and restriction enzyme digestion (Fig. 1) and was verified by direct DNA sequencing. Analysis by SDS-PAGE showed that a band approximately at 46 kDa, the expected size ADP ribosylation factor for the truncated protein, was observed in E. coli Rossetta cells transformed with pET30a-Ot56 (Fig. 2a). The purified protein appeared as a single band corresponding to the molecular mass of the recombinant protein on SDS-PAGE (Fig. 2b). The amount of protein after purification was 0.7 mg/mL. Immunoblot assay showed that the protein was recognized by O. tsutsugamushi Karp-immunized rabbit serum (Fig. 2c). The recombinant protein was also validated by MALDI-TOF-MS, which revealed that it had 100% identity to 56-kDa protein of O. tsutsugamushi (Fig. 3). Enzyme-linked immunoassay was performed to assess the extent of cross-reactivity of the recombinant protein with the rabbit polyclonal sera described above. All of the sera detected, except sera against O. tsutsugamushi strains TA763, TH1817, Kato, B quintana, A. phagocytophilum, E. chaffeensis and B. bacilliformis were negative (Tables 1,2).

Furthermore, experimental data generated using HVC-infected chimpanzees demonstrate that the miR-122 antisense locked

nucleic acid (LNA) SPC3649 is able to clear both the HCV 1a and the 1b genotypes PD98059 40. These data hold much promise for novel anti-HCV therapies. In the case of HCV-induced inflammation, if the target site for miR-155 in the TNF 3′ UTR was to be blocked, this could provide a new strategy to limit TNF expression and TNF-associated activities. Another approach could be to specifically boost the effect that miR-21 has on PDCD4 and thus also generate an anti-inflammatory effect. These types of studies are worth pursuing, since targeting both miR-155 and miR-122 would effectively boost the resolution of inflammation. A second example where the targeting of miRNAs regulated by TLRs might hold promise is in myelodysplastic syndrome (MDS). MDS results from Compound Library ic50 the ineffective production of myeloid cells from stem cells in the BM and arises at the stage of primitive CD34+ hematopoietic stem/progenitor cells due to ineffective hematopoiesis. One of the most common forms is the 5q-syndrome, which results in the deletion of a segment on chromosome 5, long-arm position 32 (5q32) 41–43. The commonly deleted region at 5q32 contains 40

genes and a number of miRNAs, including miR-145 and miR-146a. Starczynowski et al. 41 found that 5q-MDS individuals had low levels of miR-145 and miR-146a, thereby confirming their deletion 41. A key target for miR-145 is known to be the adapter Mal, which is required for signaling by TLR2 and, especially, TLR4 Adenosine triphosphate 42. As mentioned in the miR-146 section, miR-146 targets IRAK1 and TRAF6. The knockdown of miR-145 and miR-146a or, in particular, the enforced expression of TRAF6 in hematopoietic stem/progenitor cells transplanted into mice results in

thrombocytosis, neutropenia, and megakaryocytic dysplacia 41. These changes lead to the induction/overexpression of pro-inflammatory cytokines, such as IL-6, leading to chronic inflammation, which again appears to promote tumorogenesis in this disease. Other studies, e.g. 43, have failed to find a correlation between 5q-MDS and downregulation of miR-145–miR-146a, however; hence further analysis is needed. Nonetheless, blockade of the Mal/TRAF6 pathway could prove to be therapeutically useful in MDS. Clearly, the targeting of miRNAs for therapeutic purposes is at an early stage; however, given the roles of miR-146a, miR-155, and miR-21 in the control of inflammation, and, in particular, in macrophage function, they remain of interest for future drug development. An important consideration is in vivo validation, and Table 1 summarizes this aspect for these miRNAs. As summarized in Table 1, deletion of miR-155, miR-146, and miR-21 has serious consequences in mice, e.g. autoimmune disease.

Myeloid cells were most commonly confined to massive diffuse pockets around worm migratory tracts (Figure 1a) and to necro-ulcerative areas, the latter especially in neoplastic cases (Figure 1b). Most cases had massive diffuse areas that could not be counted. To a lesser extent, myeloid cells were diffusely scattered throughout the nodules (Table 4). T cells occurred diffusely (Figure 1c) or in a focal/multifocal (Figure 1d)

distribution pattern, predominantly at the periphery of the nodule (Table 5). The number of foci in the most active ×20 field ranged Seliciclib chemical structure from 0 to 18. B cells followed the same distribution within the nodule as T cells (Table 6), but there were fewer of them (Table 7), and they were more confined to focal/multifocal areas (Figure 1e). FoxP3+ cells were detected in 30% of nodules (32% of neoplastic cases and 28% of the non-neoplastic cases), especially in T cell foci, but they were not observed in the normal oesophagus. In most of the S. lupi cases where FoxP3+ cells were detected, the number of cells was very low and was not significantly different from

the normal oesophagus, where no FoxP3+ cells were detected (Table 8). However, three cases (one non-neoplastic and two neoplastic) contained a high power field with more than 10 FoxP3+ cells (up H 89 research buy to 47 cells/0·0625 mm2 in a selected high power field; Figure 1f). High numbers of FoxP3+ cells were observed in the lymph nodes (Table 9, Figure 1g), but no difference was observed between the bronchial and popliteal nodes and between the neoplastic draining mafosfamide (86·44 ± 34·39, mean ± SD/0·0625 mm2) and non-neoplastic draining nodes (85·95 ± 54·55). These FoxP3+ cells were confined to CD3+ areas (Figure 1h). The current study revealed that the predominant inflammatory cells

in S. lupi oesophageal nodules are of myeloid lineage. These cells were identified by a MAC387 antibody, which does not enable differentiation between the different types of myeloid cells. However, based on the histological appearance, the vast majority of myeloid cells were neutrophils. These neutrophils formed pockets of pus around the worm, or they were confined to necro-ulcerative areas in the neoplastic nodules. Alternatively, neutrophils occurred diffusely throughout the nodules. The lymphocytic infiltrates had a prominent focal/multifocal distribution pattern (compared to the myeloid cells), and they were usually peripherally located within nodules. However, in the majority of cases, lymphocytes occurred in a mixed pattern, namely focal/multifocal and diffuse. The relative proportions of leucocytes within S. lupi nodules were different to our initial observations in H&E-stained sections (5). This finding shows the importance of further identification and quantification of cells using immunohistochemistry. There are two possible explanations for the observed difference.

The variety arrhizus possesses two slightly differing copies of the lactate dehydrogenase gene while the var. delemar contains only a single copy, resulting in the production of lactic acid by var. arrhizus and of fumaric-malic acid by var. Erlotinib manufacturer delemar.[19] Genome sequencing of Rhizopus arrhizus var. delemar revealed a dynamic organization of the genome.[38] There is evidence for ancestral whole-genome duplication and numerous recent gene duplications suggesting duplications of genes to be a frequent event.[38] Studies by Min et al. [39] revealed different haploid chromosome numbers for strains now assigned to the same species, (e.g. for R. oligosporus and R. microsporus or R.

arrhizus and R. niveus) that could be explained by duplication events as well. It is also known for other species such as Aspergillus fumigatus that genomes of different individuals of the same species may differ in gene numbers because of duplications and losses.[40] Genomes of two strains of A. fumigatus included 2% of genes that were unique for one of the two strains.[40] Although this result has to be interpreted with care because genome sequence quality is still not high enough to detect all genes, it shows that the absence of buy PS-341 genes is not a priori a basis for separating species. The enzyme assays did not reveal any additional physiological difference between

var. arrhizus and var. delemar and there is no indication for differences in virulence. In general Rhizopus arrhizus is more frequently involved in human infection than R. microsporus. Compared to R. microsporus, R. arrhizus strains were more often positive for siderophore production and they possessed a higher activity for amylases and lipases.[23] Judging from its enzyme profile, R. arrhizus has a high potential to degrade both plant as well as animal material. Morphologically the varieties have been distinguished

on the basis of the position of swellings of the sporangiophore, the length of the sporangiospores, the structure of the rhizoids and the shape of the columella.[17] However, Gryganskyi et al. [20] showed that spore size measurements were insufficient to distinguish var. arrhizus from var. delemar. Sporangiospores of strains of a single variety may differ strongly in their size, while also intra-strain of variability can be high. In addition, sporangiospore size is strongly influenced by temperature and medium[41] and is consequently not considered appropriate to distinguish taxonomic entities. In the literature the var. delemar has mostly been used for strains involved in food production and the var. arrhizus was more often known as an opportunistic human pathogen. Our statistical analyses were based on a relatively small number of strains because 50% of the arrhizus strains and 65% of the delemar strains lack information on the source of isolation.

Thus, influenza infection had no influence on expression of these inhibitory receptors on lung NK cells. CD107a is associated with stored intracellular cytolytic granules in NK cells [29, 30]. CD107a appears at the NK-cell surface when they degranulate their cytolytic contents as a result of activation. Thus, NK-cell degranulation activity is estimated by CD107a expression [29, 30]. NK cells also can produce IFN-γ when activated [31]. Furthermore, treatment with IFN-γ can protect mice from death in a NK-cell-dependent manner at an early stage of influenza infection [32]. We purified lymphocytes from influenza-infected

lung using Percoll gradients, then selleck inhibitor stained the cells with anti-CD3 to exclude T cells and identified those which were NK1.1+, CD122hi, 2B4+, and NKp46+, and therefore likely to be NK cells. We found that a small percentage of these cells were positive for CD107a or IFN-γ (Fig. 2C and D), which was slightly more than by these cells

in uninfected mice (data not shown). By contrast, a CD3−NK1.1+CD122hi2B4+NKp46− population showed extensive Selleckchem GSK458 degranulation (over 90% of the cells), and nearly 15% of this population expressed intracellular IFN-γ during influenza infection (Fig. 2C and D). Cells that lacked CD3, expressed the other NK-cell markers, NK1.1, CD122hi, and 2B4, but not NKp46, were not found in any quantity in uninfected mice (data not shown). Downregulation of NKp46 has been described for human NK cells upon encountering influenza virus in vitro, or after in vivo exposure to influenza [33]. Our results suggest that this may also be the case for NKp46 expressed on mouse NK cells isolated from influenza-infected mice. Thus, it is possible that the CD3−NK1.1+CD122hi2B4+NKp46− cells found in influenza-infected lungs are NK cells that have encountered influenza virus and

have responded with substantial degranulation Astemizole and production of IFN-γ. The NK cells in influenza virus infected lung displayed an activated phenotype, suggesting that they play an active not passive role during influenza infection. To investigate the influence of NK cells on host outcome during influenza infection, we treated mice with anti-asialo GM1 to deplete NK cells in vivo prior to and during influenza infection. Anti-asialo GM1 is effective at depletion of NK cells in vivo [34, 35], as confirmed by our flow cytometric analysis of lung and spleen (Fig. 3A). Interestingly, compared with PBS control mice, depletion of NK cells improved the survival rate (Fig. 3B) and recovery of body weight (Fig. 3C) of surviving animals after influenza virus infection. These results suggested that NK cells may exacerbate pathology induced by influenza infection, leading to a worsened outcome. Our results (Fig. 3) are contradictory to previous reports [24-26] that found that depletion of NK cells increased mouse morbidity and mortality from influenza infection.

“
“Regulatory T (Treg) cells represent one of the main mechanisms of regulating self-reactive immune cells. Treg cells are thought to play a role in down-regulating immune responses to self or allogeneic antigens in the periphery. Although the function of Treg cells has been demonstrated in many experimental settings, the precise mechanisms and antigen specificity often remain unclear. In a hepatitis B e antigen–T-cell receptor (HBeAg-TCR)

double transgenic mouse model, we observed a phenotypically unique (TCR+ CD4−/CD8− CD25+/− GITRhigh PD-1high FoxP3−) HBeAg-specific population that demonstrates immune regulatory function. This HBeAg-specific double-negative regulatory cell population proliferates vigorously in vitro, in contrast to any other known regulatory population, Cisplatin concentration in an interleukin-2-independent manner. The primary function of the immune system

is to protect the self from pathogens. A highly effective and dynamic cellular network has evolved to signal the presence of pathogens and initiate a response that is specific for the invading pathogen while maintaining tolerance to self. Distinguishing between self and non-self is a fundamental property of the immune system and is accomplished by a variety of mechanisms. A function of regulatory T (Treg) cells EPZ-6438 clinical trial is to prevent self-reactive immune cells from damaging self. The Treg cells, particularly CD4+ CD25+ conventional Treg (cTreg) cells, are thought to play a role in down-regulating immune responses to self or allogeneic antigens in the periphery.1–4 Although the function of Treg cells has been shown in a number of in vivo models of autoimmunity and transplantation, the precise mechanism and antigen specificity often remains unclear.5 In 1971 it was first suggested that Treg cells had the ability to transfer antigen-specific tolerance to naive animals.6 Even though a role for regulatory cells during an immune response was widely accepted, the existence of Treg cells was controversial until a specific Celecoxib surface marker was described by Sakaguchi et al.7 Conventional Treg cells constitutively express a variety of cell

markers, such as CD4, CD25, CD45RBlow, CD62 ligand (CD62L), CD103, as well as cytotoxic T-lymphocyte antigen 4 (CTLA-4) and glucocorticoid-induced tumour necrosis factor receptor-related protein (GITR).7–14 Although cTreg cells express CD4+ CD25+, CD25 is not a specific marker for cTreg cells. Other cell markers (i.e. CTLA-4, GITR and CD103) are also not exclusive markers for Treg cells, because in most cases they are up-regulated on effector T cells upon activation. The transcription factor Forkhead box P3 (FoxP3) is predominantly expressed on Treg cells and appears to be expressed at the thymic CD4+/CD8+ stage.15–18 In contrast to the cell surface markers mentioned above, FoxP3 is not observed in non-Treg cells upon activation or differentiation into T helper type 1/ type 2 cells, nor in natural killer T cells.

, 1997). From this study, it was determined that P66 is a voltage-dependent, nonspecific porin with a single channel conductance measuring at 9.6 nS in 1 M KCl, which is indicative of very large 2.6-nm pores (Skare et al., 1997). P66 orthologs

from other Borrelia spp. display similar biophysical characteristics, suggesting that both Lyme disease and relapsing fever spirochetes possess functional P66 orthologs (Barcena-Uribarri et al., 2010). P66 has also been shown to function as an adhesin that binds the mammalian cell receptors, β3 chain and β1 chain integrins (Coburn et al., 1999; Dasatinib clinical trial Defoe & Coburn, 2001; Coburn & Cugini, 2003). It was further demonstrated that β3 integrin binding was mediated by a central region of the P66 protein (residues 142–384; Coburn et al., 1999) and that a single peptide heptamer within this 242-residue region was sufficient for inhibiting attachment of B. burgdorferi to αIIbβ3 integrins (Defoe & 3-deazaneplanocin A cell line Coburn, 2001). Additional verification of P66 as a β3 integrin ligand was also provided by in vivo phage display experiments (Antonara et al., 2007). The virulence-associated cell adhesion properties of P66, in addition to its immunogenicity, have created an intense interest in

P66 as a potential Lyme disease vaccine candidate. Interestingly, indirect immunofluorescence assays (IFA) and cDNA microarray data have demonstrated that P66 is upregulated in fed ticks and in the mammalian host, but not in unfed

ticks (Brooks et al., 2003; Cugini et al., 2003), Pyruvate dehydrogenase suggesting that B. burgdorferi specifically upregulates expression of the protein to aid in host cell attachment and/or tissue dissemination during mammalian infection. The chromosomal P13 protein, which is encoded by ORF bb0034, is a 13-kDa surface antigen first identified in B. burgdorferi strain B313. Strain B313 lacks almost all linear plasmids, which encode a majority of the B. burgdorferi outer surface lipoproteins (Sadziene et al., 1995). Anti-P13 monoclonal antibodies inhibited growth of strain B313 but not wild-type B. burgdorferi cells, suggesting that the abundant outer surface lipoproteins expressed by the linear plasmids in wild-type B. burgdorferi masked P13 epitopes and probably interfered with earlier identification of this integral OMP (Sadziene et al., 1995). Sequence analysis and epitope mapping indicated that P13 is a membrane-integrated protein with three transmembrane regions and a surface-exposed immunogenic loop (Noppa et al., 2001; Pinne et al., 2004). Additionally, combined results from mass spectrometry (MS), in vitro translation, as well as N- and C-terminal amino acid sequencing strongly indicated that P13 is posttranslationally processed at both termini, with an N-terminal modification and a C-terminal 28-residue cleavage (Noppa et al., 2001).

baumannii, and that NK1.1+ cells play a role in the migration of neutrophils into the alveoli of Acinetobacter pneumonia mice. The number of infiltrating macrophages was similar to that in the control mice (Fig. 7B). Small numbers of NK cells were observed up until Day 7 in mice injected selleck chemicals llc with the anti-NK1.1 Ab (Fig. 7C). To elucidate the role played by NK1.1+ cells in the migration of neutrophils, the

expression level of chemokines was measured in the lung tissues of anti-NK1.1 Ab-injected mice with pneumonia. RT-PCR was used to detect CXC chemokine mRNAs in lung tissues, as CXC chemokines are chemotactic for neutrophils. As shown in Figure 8A, lung tissues from control mice constantly expressed KC (CXCL1) mRNA, even after Acinetobacter infection; however, the KC levels in mice injected with anti-NK1.1 Ab were lower than those in the control mice on Days 1 and 3. In addition to KC mRNA levels, the amount

of KC protein in the BAL fluid was measured by ELISA (Fig. 8B). There was no significant difference in the level of KC in the BAL fluid between anti-NK1.1 Ab-injected mice and control Ab-injected mice on Day 0. The level of KC in the BAL fluid of the control Ab-injected and anti-NK1.1 Ab-injected mice increased substantially following Acinetobacter challenge, reaching maximum levels in control mice on Day 1, before returning to normal on Day 5. However, KC levels in anti-NK1.1 Ab-injected mice were maximal on Day 3, although they remained lower than those in control mice from Day 1 to Day 5. Nosocomial infection with A. baumannii pneumonia is DOK2 an increasing threat because of high mortality rates and antibiotic resistance Afatinib supplier (6, 26–28). However, little is known about host defense against respiratory infection by this pathogen (9, 11, 29, 30). To investigate the pathology and the responses of immunocompetent cells to A. baumannii, we analyzed the cells infiltrating the lungs of mice with A. baumannii pneumonia and examined their role in the immune response. Normal healthy C57BL/6 mice inoculated i.n. with <108 CFU A. baumannii

completely eliminated the pathogen within 3 days, and the inflamed lungs recovered within 7 days (Figs 1, 2). However, large numbers of neutrophils infiltrated the alveoli of mice with Acinetobacter pneumonia (Fig. 3). Increased numbers of macrophages, NK cells, αβT cells, and γδT cells were also observed up until 3 days post-inoculation, decreasing to normal levels thereafter (Fig. 3 and data not shown). Few NKT cells were detected in the alveoli, and the numbers of these cells were constant after A. baumannii infection (Fig. 3D). These results are consistent with earlier observations (11). Next, we examined the effects of neutrophils on the elimination of A. baumannii using mice depleted of neutrophils by i.p. injection of an anti-Gr1 Ab. Neutrophils play an important role in host defense against bacterial pathogens (31, 32). A.