Another DC subset, the plasmacytoid DCs, induces peripheral tolerance under non-inflammatory conditions in the spleen and lymph nodes [12]. Further studies on DC subsets in the lungs are necessary to distinguish the role of DCs in asthma and design more effective preventative or therapeutic strategies for asthma [12]. Both DCs and FcγR are implicated in the development of allergic airway inflammation in bronchial asthma. FcRs on APCs and DCs and their signalling also play important roles in the development and control of the pathogenesis of asthma. The present report demonstrates that manipulation of the inhibitory FcR pathway is

a practical therapeutic means for controlling allergic airway inflammation. Targeting IgG-Fc and FcγRIIb Talazoparib purchase on CD11c+ DC is a promising therapeutic strategy in allergic asthma. We appreciate the advice and expertise of Drs Tetsuya Takagawa and Kentarou Minagawa. We would also like to thank Drs Kazumi Kaneshiro, Haruko Shinke, Emi Kuramoto, Yuko Kono, Akihiro Sakashita, Natsumi Hara, Nobuko Hazeki, Keiko Okuno, Suya Okamoto and Daisuke Tamura for their helpful discussions. HKI 272 This study was supported by KAKENHI (19790557). M. Yoshida was supported, in part, by grants for the Global Center of Excellence (COE) Program ‘Global Center of Excellence for Education

and Research on Signal Transduction Medicine in the Coming Generation’ from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, The Mother and Child Health Foundation and the Long-range Research Initiative of Japan Chemical Industry Association. The authors declare no conflicts of interest. Amylase “
“Accumulating evidence shows that galectins play roles in the initiation and resolution phases of inflammatory responses by promoting anti-

or proinflammatory effects. This study investigated the presence of three members of the galectin family (galectin-1, -3 and -9) in induced sputum samples of asthma patients, as well as their possible implication in the immunopathogenesis of human asthma. Levels of interleukin (IL)-5, IL-13, and galectins were determined in leucocytes isolated from induced sputum samples by reverse transcription–polymerase chain reaction (RT–PCR) immunofluorescence and flow cytometry. High levels of IL-5 and IL-13 mRNA were detected in sputum cells from asthma patients. In parallel, immunoregulatory proteins galectin-1 and galectin-9 showed a reduced expression on macrophages from sputum samples compared with cells from healthy donors. In-vitro immunoassays showed that galectin-1 and galectin-9, but not galectin-3, are able to induce the production of IL-10 by peripheral blood mononuclear cells from healthy donors. These findings indicate that macrophages from sputum samples of asthma patients express low levels of galectin-1 and galectin-9, favouring the exacerbated immune response observed in this disease.

, Montgomery, TX, USA) for 30 min on ice and finally washed with 1% BSA–PBS. Multi-colour flow cytometry was performed on a fluorescence activated cell sorter (FACS)Canto,

interfaced Selleckchem Navitoclax to a FacsDiva software (BD Biosciences, San Jose, CA, USA) and analysed through Flow-Jo software version 8·8·3 (Three Star Inc., Ashland, OR, USA). The binding of the antibody to the cells incubated with the different plasma samples was measured and the percentage of binding-inhibition calculated according to the background staining (cells incubated without plasma). A cartoon showing the principles of the assay is presented in Fig. 1. Purified PBMCs were thawed and stained with the following conjugated monoclonal antibodies: CD19-Alexa 488, interleukin (IL)-21R-phycoerythrin (PE), CD27-peridinin chlorophyll-cyanin 5·5 (PerCP-Cy5·5), Selleckchem Idelalisib CD21-allophycocyanin (APC), IgD-H7 (all from BD Biosciences) and the CD10-PE-Cy7 (Biolegend, San Diego, CA, USA). The frequencies of MA (defined as CD10–CD21–) and DN (defined as CD27–IgD–) B cell subpopulations were calculated from total CD19+ B cells. Multi-colour flow cytometry was performed on a FACSCanto,

interfaced to a FacsDiva software (BD Biosciences) and analysed through Flow-Jo software version 8·8·3 (Three Star Inc.). Plasma IL-21 titres were measured using the human IL-21 platinum ELISA kit (eBioscience, San Diego, CA, USA), following the manufacturer’s instructions. The Mann–Whitney U-test and Spearman’s correlation were used for all analyses. A P-value <0·05 was considered statistically significant. GraphPad Prism software for Windows was used to perform the analyses. The ALA titres before and after flu vaccination were quantitated as described in the Materials and methods and in Fig. 1. Before vaccination, significantly lower ALA titres were found in the

HIV group compared to KT and HC check (P < 0·0001) (Fig. 2a), while no significant difference was found between the KT and the HC groups (P > 0·05) (Fig. 2a). Interestingly, after vaccination individuals in both the HIV and KT groups increased ALA titres substantially compared to HC (P = 0·0001 and P = 0·0002, respectively) (Fig. 2b). Between HIV and KT, the biggest increase was recorded in the HIV group (P = 0·0008) (Fig. 2c). HC increased ALA titres only slightly compared to HIV and KT (P = 0·0001 and P = 0·0003, respectively (Fig. 2c). Fifteen per cent of the HIV-1-infected individuals (10 of 65) were having a viraemic blip at the time of vaccination (Table 1). However, this did not relate to any of the parameters analysed as confirmed by Spearman’s correlation (P > 0·05). Moreover, the CD4+ T cell counts were similar in the viramic and aviraemic patients (P > 0·05).

Such differences may be one of the causes of cell tropism for PrPSc accumulation, and furthermore, might result in the prion strain-specific PrPSc accumulation pattern in the brain. Species specificity in cell-free conversion has been reported

(14, 23), and the products preserve strain-specific properties (24). These data suggest that the cell-free conversion reaction mimics some aspects of in vivo conversion of PrPC into PrPSc. In this study, we demonstrated that the effect of reducing conditions and removal of Cys residues on binding and conversion differed among prion strains; indeed, these may mirror prion strain properties in vivo. In fact, classification of the five prion strains BAY 57-1293 by their binding and the conversion efficiencies correlated well with classification according to their biological and biochemical properties. Therefore, the

in vivo properties of each strain likely correlate with their conversion capacity. Binding and conversion assays may thus aid in the classification of prion strains. Reduction of the www.selleckchem.com/products/BMS-777607.html intramolecular disulfide bond did not interfere with binding of PrPSc to MoPrP and conversion of MoPrP into PrPres. However, substitution of Cys with Ser in MoPrP inhibited binding and conversion of the ME7 and Obihiro strains and conversion of the Chandler and 79A strains. Therefore, Cys residues may play a key role in the conversion and binding of Chandler and 79A, ME7, and Obihiro PrPSc. However, we cannot rule out the possibility that such a substitution alters the tertiary structure

of the prion protein. Addition of DTT significantly increased the ZD1839 conversion efficiencies of MoPrP and the Cys-less mutant driven by mBSE PrPSc. This suggests that the effect of DTT may be mediated by a mechanism other than cleaving of the disulfide bond in MoPrP. DTT diminishes the carbohydrate binding activity of a Cys-less mutant of pigpen as well as inhibiting the intact molecule (25). Therefore, in an mBSE-seeded cell-free conversion, DTT may improve the efficiency of mBSE-seeded conversion independently of the reduction of disulfide bonds. In summary, reducing conditions did not inhibit conversion in vitro and markedly increased mBSE-seeded conversion. This suggests that cell-free conversion under reducing conditions mimics the conversion of PrPC into PrPSc within endosomes and lysosomes. In addition, classification of prion strains by their efficiency at binding and conversion of both MoPrP and its Cys-less mutant in the absence and presence of DTT correlates well with classification based on biological and biochemical properties. Therefore, the cell-free conversion assay may be useful in discriminating between prion strains. We are grateful to Dr.

2, lower panel E and F). These results demonstrated that the T cells now harboured a mutant and a wild-type sequence, confirming the in vivo reversal of the mutation in one allele of the ADA gene. We also measured ADA activity at this time (Table 2, 50 months old) and found that RBC had some (although still very low compared with a healthy control) and continued to show a modest but lower levels of dAXP than previously observed. However, this ADA selleck chemicals activity was almost 3 times higher when compared to reference values (Table 2, age 50 months). This suggested that the revertant T cells could have contributed to mildly improve the immune function in the patient allowing him to survive

longer. For ADA-deficient patients in whom immune reconstitution by HSCT or GT is not feasible, ERT with PEG-ADA is an option that leads to rapid improvement in lymphocyte counts within several weeks to few months after the initiation of therapy [13, 17]; this has been used also even in situations in which

a somatic mosaicism caused by a reversion of an inherited mutation is detected. At the age of 50 months, our patient was not eligible for HSCT or GT therefore, we started him on ERT at the dose of 30 U/kg of weight, and just after 2 weeks, the ADA activity in PBL increased from 0.9 to 12.6 nmol/h per mg and dAXP decreased from 10.4% to 2.7% (not shown). However, difficulties Mdm2 antagonist in adherence to treatment led to some fluctuations in ADA activity and dAXP; therefore, we increased the dose to 50 U/kg after 10 months of treatment, and

this quickly led to normal ADA activity and undetectable dAXP (not shown). To monitor the treatment with PEG-ADA, we phenotyped all main lymphocyte populations in PB at several intervals after the initiation of therapy. As mentioned earlier, by the age of 50 months, SPTLC1 our patient had normal PBL counts with normal CD3+, CD8+ and CD16/56+ NK lymphocytes, and although CD4+ T cells also increased, they were still below normal values; in contrast, CD19+ B cells remained unchanged (Table 1, age 50 months). After 2 weeks on PEG-ADA we observed a rapid increase in PBL counts exceeding the reference values for the patient’s age, including CD3+, CD8+ T cells as well as NK cells (12,637, 10,880, 2154 and 1643 cells/μl, respectively; see Fig. 3). CD4+ T cells also increased to normal values but transiently (1284 cells/μl); moreover, CD19+ B cells also increased yet these always remained below normal (25 cells/μl). Interestingly, lymphocyte (and subset) counts returned to normal or just below normal after 3 months of therapy and remained stable for the next 14 months (Fig. 3). These results demonstrated that the ERT resulted in a transient expansion in total counts for most lymphocyte populations in PB. The mature pool of T lymphocytes in PB in humans is comprised of clonally derived TCRαβ+ and TCRγδ+ T cells in a proportion of 90% vs.

RoVs were present throughout the year, with two peaks in March/April in the spring and in October/December in winter (Fig. 1). The objectives of this study were to investigate the prevalence and determine the G/P genotypes of RoVs isolated from patients with acute gastroenteritis in Seoul, Korea. Although sanitation conditions have improved globally, the relative

prevalence of RoV diarrhoea may still be increasing in developed countries including EPZ015666 ic50 Japan and Korea (7,10). In our study, 1423 fecal specimens were collected from children hospitalized with diarrhea, 269 (18.9%) of which were positive for RoVs. RoVs were the most frequently detected viral agent in stool samples from children less than three years of age presenting with acute gastroenteritis, as has been shown in previous global studies and reports from Korea (2,11,12).

RoV is the leading cause of acute gastroenteritis world wide, the incidence of RoV gastroenteritis being higher than of Norovirus gastroenteritis (2,13). Studies in Asia have demonstrated RoV in 45%–66.7% of diarrheal cases (11,14,15). In this study most of the globally common RoVs (G1, G2, G3, and G4) and other types (G8 and G9) were detected. Genotype G1 was observed to be broadly circulating in Korea, with overall incidences of  54.3%. This result is in agreement with the earlier findings that G1 was the most prevalent strain (45–81%) regardless of geographical area or season CSF-1R inhibitor in Korea (16). Human G9 RoVs have recently been highlighted as the fifth most common strain in circulation. In this study, G9s

were infrequently identified (1%); much less than in reports from other Asian (54.8%–91.6%) and European (7.4%) countries (14,17,18). Analysis of P types indicated that P[8] was predominant, followed by P[6], P[4], P[9], and P[10]. This result is consistent with previous data that the most prevalent P type was P[8] in Korea and other countries (29,21,20). Genotype P[9] and P[10] were detected less frequently and have also been detected in previous studies in the region (11,20,23). In fact, More than 42 G/P combinations have been observed in at least one RoV case. Only a relatively small number of these combinations have been frequently reported in humans Dichloromethane dehalogenase and genotypes G1P[8], G2P[4], G3P[8] and G4P[8] comprise nearly half of all the RoV infections in the world (7,23). In this study, G1P[8], G2P[4], and G3P[8] made up 47.6% of RoV genotypes, which suggests there were many kinds of RoV strains circulating in this region and period in Korea. Characterization of >2700 stool specimens world-wide for which both G and P types have been determined has revealed that the most prevalent strain is G1P[8], followed by strains G4P[8], G2P[4], and G3P[8][30]. G9P[8], G9P[4], G9P[9], and G9P[6] were also detected in 10.4%, 1.1%, 0.4%, and 0.4% of specimens, respectively.

When T cells are removed from the influence of such cells, normal T-cell responses are restored. We show that tumour necrosis factor 1 (TNFR1) signalling is a critical checkpoint in the development of such Mϕ, as TNFR1−/− Mϕ are unable to suppress T-cell proliferation. This deficit in antigen-presenting cells results in a lack of production of prostaglandin E2 (PGE2) and nitric oxide, which are critical effector mechanisms that inhibit T-cell division. However, TNFR1 signalling is not required for the inhibitory function of Mϕ because we could circumvent the requirement for this receptor, by maturing Mϕ in the

presence of exogenous interferon-γ and PGE2. This produced TNFR1−/− Mϕ that inhibited T-cell proliferation and indicates that TNFR1 delivers a signal selleck products that is necessary for the development Selleck MG-132 but not the execution

of this function. Organ-specific autoimmune diseases, such as multiple sclerosis and inflammatory eye disease, are co-ordinated by the activation of autoantigen-specific T cells, which are recruited specifically to sites of disease.1,2. The release of inflammatory mediators leads to a leucocyte influx that consists of a complex mixture of cell types.3,4 For example, at the peak of experimental autoimmune uveoretinitis (EAU), the murine model of human inflammatory eye disease, we observe a heterogeneous population of cells including CD11b+ cells, which form the largest fraction of the immune cells present, with significant numbers of CD4+ T cells and smaller numbers of CD8+ T cells also detected.5–7 In this environment, the large majority of CD11b+ cells are usually described as macrophages (Mϕ); they release inflammatory mediators and act as professional antigen-presenting cells (APCs).8–10 They can stimulate autoantigen-specific CD4+ T cells, by presenting MHC class II-restricted

peptides and we have recently reported that Mϕ derived from the inflamed retina of mice with EAU can act as myeloid regulatory cells, inhibiting T-cell proliferation while allowing normal antigen-specific T-cell cytokine production.10 One important cytokine produced by Bcl-w activated Mϕ is tumour necrosis factor-α (TNF-α) and the expression of one of its receptors, TNFR1, is necessary for the normal development of organ-specific autoimmunity.11,12 Blocking signals through this receptor produces a number of important changes in Mϕ function, including the abrogation of nitric oxide (NO) release following interferon-γ (IFN-γ) stimulation,11 with a concomitant reduction in tissue damage. In murine EAU, the loss of TNFR1 signalling is also associated with a dramatic reduction in CD11b+ cell trafficking to the target organ, but an increase in the relative proportion of CD4+ cells within the target organ,10 suggesting that the control of T-cell proliferation by myeloid CD11b+ cells in EAU may be dependent on TNFR1 signalling.

Furthermore, in addition to the noncanonical pathway, type I IFNs activate MAPK and PI3K

signaling leading to activation of the transcription factors AP-1 and CREB and to the activation of the mTOR complex with profound impact on, for example, T-cell biology [100]. Importantly, the activation of all the factors mentioned above is context dependent and can be both pro- or anti-inflammatory and pro- or anti-apoptotic. As STAT3 is known to be critical for the generation of Th17 cells [101, 102], it is therefore possible that Th17-cell differentiation IWR 1 can be supported by noncanonical IFNAR-mediated STAT3 activation. In addition, it is also possible that type I IFN may support IL-17 production by participating in the induction of the production of cytokines, such as IL-6, that are important for Th17-cell differentiation [103]. Type I IFN (IFN-β) treatment has been used successfully in patients with MS for many years. However, the mechanisms underlying the therapeutic efficacy of type I IFN are still not

well understood. Studies showing that IFN-β limits Th17-cell development by inducing IL-27 and downregulating RORc, IL-17A, and IL-23R in T cells [89, 104] prompted the idea that type I IFN was beneficial in the context of MS by antagonizing deleterious Th17-cell responses. However, 10–50% of patients with MS do not respond to IFN-β therapy, and recent studies in animal models suggest that the outcome Ivacaftor of IFN-β treatment may depend on the Th1 versus Th17 phenotype of the disease. IFN-β was found to be effective in reducing EAE symptoms induced by transfer of Th1 cells whereas it actually aggravated

the disease induced by Th17 cells [105]. These findings were mirrored by the situation in humans, as IFN-β nonresponders had higher serum levels of IL-17F than responders [105]. It may therefore be that the therapeutic Meloxicam efficacy of type I IFN in MS does not rely on a direct inhibition of Th17 responses, but on a more complex context-dependent action, for example in the regulation of Th1- and Th17-driven inflammation. Alternatively, some of the positive effects of IFN-β therapy in MS may be due to the effect of IFN-β on the blood–brain barrier [106]. The relative efficacy of IFN-β treatment for Th17-driven diseases can also be questioned based on the results in ulcerative colitis patients, as IFN-β therapy nonresponders have been shown to have higher production of IL-17 by lamina propria T cells before treatment than responders [107]. Taken together, all these data suggest that type I IFN may not directly antagonize Th17 responses and that, under some conditions as may be the case in SLE, both arms of the immune system, that is type I IFN and Th17 responses, may actually cooperate to promote disease. Type I IFN expression is mediated by three members of the IRF family of transcription factors, IRF3, IRF5, and IRF7.

e. interaction with MHC class Ilow cells, might be a priming signal for NK cells whereas NKG2D engagement is a triggering signal. To test this hypothesis we did coincubation, transplantation and chromium release experiments comparing several lymphoma cell lines that differed with regard to MHC class I and NKG2D-L expression (Table 1). MHC class Ilow but not MHC class Ihigh cells caused NK-cell activation in inoculated WT mice and in coincubation experiments (Table 1). However, NK-cell activation by MHC class Ilow cells was not sufficient for mediating cytotoxicity and tumor elimination. Both, cytotoxicity in vitro

and rejection in vivo additionally required NKG2D-L expression by the target cells. Thus, all tumor cell BGB324 order lines showed the same requirements for NK-cell function as the myc-B and myc-E cell lines (Fig. 4A, Table 1). The dependence

of in vitro cytotoxicity on “missing self” could be overcome PD0325901 ic50 by pre-activating NK cells with IL-15 in vitro or with DC injected into the NK-cell donors. Notably, this treatment could not restore cytotoxicity if target cells did not express NKG2D-L (Table 1). Since effector functions of NK cells from clinically-unapparent λ-myc mice were reduced but could be restored by in vitro activation with CpG-ODN (Fig. 2C) that are strong NK-cell stimulators 31, 32, we examined whether NK cell-activating agents may delay tumor development in vivo through an NK cell-mediated mechanism. We therefore treated clinically unapparent λ-myc mice with CpG-ODN 1668 for several weeks. Treated animals exhibited a statistically significant survival benefit (p<0.005; Fig. 5). To uncover the role of NK cells in this system, we depleted λ-myc mice of NK cells by using Ab during CpG-ODN treatment. No statistically significant delay of tumor development was observed in these animals as

compared with λ-myc mice that did not receive CpG-ODN. Since NK-cell depletion was sufficient for reversing the CpG-ODN-induced effect, the CpG-mediated survival RVX-208 benefit is dependent on NK-cell activation although an additional effect of T cells cannot be completely precluded. In summary, NK-cell activation can delay endogenous lymphoma growth when applied during early steps of tumorigenesis. The observation that MHC class I recovery and loss of NKG2D-L may contribute to tumor escape suggests that NK cells play a role in immune surveillance of lymphomas. However, despite showing an activated phenotype, NK cells from tumor-bearing λ-myc transgenic mice failed to exert effector functions such as cytotoxicity against NK-sensitive targets and IFN-γ expression. Impaired NK-cell functions have also been described in cancer patients 33, 34. For example, lower levels of NCR and reduced lytic activity were reported for NK cells of patients with acute myeloid leukemia 33. Controversial results were obtained in tumor transplantation models of the mouse.

In the thymus, CCRL1 is abundant in cTECs but not mTECs or thymocytes [20]. In fetal mice, CCRL1 regulates the migration of thymocyte precursors before vascularization [19]. It has been reported that CCRL1 deficiency results in thymus enlargement in adult mice, in association with altered thymocyte development and autoimmunity [21]. Thus, CCRL1 is important for optimal thymus homeostasis and normal thymocyte development. To analyze the expression of CCRL1 in TECs during embryogenesis,

Ribeiro et al. [18] use CCRL1-EGFP-knockin mice, in which EGFP is expressed under the control of CCRL1 gene expression [20]. By crossing CCRL1-EGFP-knockin mice with IL-7-YFP-transgenic EPZ-6438 research buy mice, and by flow cytometry analysis of embryonic TECs, the authors show that CCRL1 expression progressively increases during fetal cTEC development. The emergence of CCRL1-EGFPhigh cells, which are class II MHChigh CD40high cTECs, is diminished in RAG2/IL2Rγ double-deficient mice, in which thymocyte development is arrested at an early stage. From these results, the authors conclude that CCRL1high cTECs represent late-appearing mature cTECs, and that the development of those mature cTECs is regulated by

the signals provided by developing this website thymocytes. These results agree with previous reports showing that thymocyte-derived signals are necessary for the late maturation of cTECs [4-6]. Ribeiro et al. [18] also show that CCRL1+UEA1–CD80– cTECs isolated from E15.5 fetal thymus give rise to UEA1+CD80+ mTECs, when cultured in the presence of RANK and CD40 stimulation in RTOCs, suggesting that CCRL1+ fetal cTECs contain mTEC progenitor activity. These results agree with the recent reports discussed above showing that pTECs progress through a stage in which they express cTEC-associated molecules before diversifying into mTECs [11, 14-16] (Fig. 1). Perhaps very more interestingly, Ribeiro et al. [18] go beyond the confirmation of other studies to report that CCRL1-EGFPlow cells in the thymus are not restricted to CD205+ Ly51+ cTECs but also contain UEA1+ mTECs, despite the fact that CCRL1-EGFPhigh cells are

limited to cTECs but not mTECs. The CCRL1-EGFPlow CD80+ UEA1+ mTECs were detectable only after birth. Gene expression analysis showed that this late-appearing subpopulation of mTECs, which was identified by the CCRL1-EGFPlow CD80+ phenotype, contained large amounts of Aire and RANK mRNAs but a nondetectable amount of CCL21 mRNA. Ribeiro et al. [18] further demonstrate that the combination of RANK and CD40 signals, the ligands of which are produced by positively selected thymocytes [8, 10], is important for the development of CCRL1-EGFPlow mTECs. Thus, the analysis of CCRL1-EGFP reporter mice suggests a novel heterogeneity in postnatal mTECs. It has been shown that mTECs are heterogeneous in terms of the expression of various molecules, including class II MHC, CD80, Aire, and CCL21 [22-26]. White et al.

BamHI-BamHI fragments hybridized Midostaurin cost with the probe D were ligated into the same site of pUC19, and the resulting plasmids transformed in E. coli H1717. Positive clones were selected by colony blot hybridization with the same probe, and one of the recombinant plasmids, termed pVMB1, was extracted (Fig. 2). The nucleotide sequence of the 5121-bp fragment from pVMB1 was determined by primer

walking. Two entire ORF located divergently were identified; these were named mhuAB (V. mimicus heme utilization). The two other partial genes (orf1 and orf4) were not relevant to iron acquisition or iron-regulated gene expression. As shown in Figure 3a, each of the mhuA and mhuB genes possesses the predicted RBS and promoter elements (−35 and −10). Potential Fur boxes sharing 15/19 and 12/19 base matches with the E. coli consensus Fur box (24) are located in the upstream regions of mhuA and mhuB, respectively, overlapping with the −35 elements. Although the normal initiation codon (AUG) was missing at the predicted start position of mhuB transcript, an alternative initiation codon, UUG (25), was found in seven bases downstream of the RBS. V. mimicus has been reported to produce 77-kDa (IutA) and 80-kDa IROMP, whose N-terminal amino acid sequences have been determined to be EEQTLFDEMV and EQQSQFNEVV,

respectively (9, 10). An amino acid sequence compatible with the latter EPZ-6438 order was found in the N-terminal portion of the deduced amino acid sequence of MhuA. To gain better separation of the IROMP, SDS-PAGE was carried out under the conditions shown in Figure 3b. As a result, the IROMP were separated into five protein bands, and the N-terminal amino acid sequences of the smallest band and a second large-molecular weight band corresponded with those of 77-kDa IutA (Fig. 3b, lane 1, open arrowhead) and 80-kDa MhuA (Fig. 3b, lane 1, solid arrowhead), respectively. The functions of the three other IROMP are at present unknown.

The protein product of mhuA shared homology with the heme/hemoglobin receptors of Vibrio species (11, 12, 26), ranging from 33% to 62% identity and from 52% to 80% similarity (Table 2). Selected proteins were aligned with MhuA (Fig. Bay 11-7085 4). A probable TonB box (28NEVVVTA34) present in MhuA, which is thought to interact physically with TonB protein, was similar in amino acid sequence to those in the heme/hemoglobin receptors of other Vibrio species (1, 27). Furthermore, MhuA possesses FRTP and NPNL amino acid boxes characteristic of the bacterial heme/hemoglobin receptors (28). However, the conserved histidine residue between FRTP and NPNL boxes (corresponding to His-461 in the Yersinia enterocolitica HemR, a receptor for heme/heme-containing proteins) (28) was not found in MhuA.