![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Jean-François Popoff, and
Jenefer M. Blackwell*
Cambridge Institute for Medical Research and Department of Medicine, Wellcome Trust/MRC Building, University of Cambridge School of Clinical Medicine, Addenbrookes Hospital, Hills Road, Cambridge CB2 2XY, United Kingdom
Received 30 January 2007/ Returned for modification 10 May 2007/ Accepted 28 June 2007
 |
ABSTRACT |
|---|
 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
MATERIALS AND METHODS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
10-Mb interval distal to D1Mit80 and proximal to D1Mit44 on chromosome 1 that carries the Slc11a1 gene. BALB/c (BALB) Slc11a1mutant mice and their congenic C.D2-Vil6 Slc11a1 wild-type counterparts were bred in-house. Their derivation is as previously described (40), with C.D2-Vil6 carrying a congenic interval of 1.5 Mb from Tnp1 to Vil1 derived from DBA/2 mice. Mice were bred and maintained under specific-pathogen-free conditions. All breeding and procedures were carried out under license and United Kingdom Government Home Office regulations. Slc11a1 transfected cell lines. RAW264.7 macrophage cell lines stably transfected with wild-type (clones 7.5R and WT3) or mutant (clones 10S and MUT12) alleles at Slc11a1 were made in our laboratory as previously described (6, 49). The RAW264.7 macrophage cell line has an endogenous copy of the mutant allele from which the protein is expressed at low level (44) through mis-targeting and degradation (49). The presence of the transgene was verified by sequencing across the mutation site using primers that distinguished the intronless transgene from the endogenous genomic allele. RAW264.7 cell lines were maintained in 25-cm2 tissue culture flasks in RPMI 1640 supplemented with 10% fetal calf serum (Life Technologies), 50 U of penicillin/ml, 50 µg of streptomycin/ml, and 2 mM L-glutamine (hereafter referred to as complete RPMI).
Bone marrow-derived macrophages and DCs. DCs and macrophages were derived from proliferating mouse bone marrow progenitors from Slc11a1 mutant (B10 or BALB) or wild-type (B10.L-Lsh or C.D2-Vil6) mice as indicated in the text, legends, and figures. Bone marrow was taken from femurs and tibia of 6- to 10-week-old mice. Macrophages were cultured in 95-mm bacteriological dishes (1 x 107 to 3 x 107 cells/dish) in complete RPMI, supplemented with 1 µM 2-mercaptoethanol (Life Technologies), 25 mM HEPES (Sigma), and 30% L-cell supernatant (derived from L929 mouse fibroblasts). Culture medium was renewed after 5 days, and cells were used between days 10 and 15. DCs were cultured in flat bottomed six-well plates (1 x 106 to 3 x 106 cells/well). The culture medium was complete RPMI, supplemented with 1 µM 2-mercaptoethanol, 25 mM HEPES, 20 ng of recombinant interleukin-4 (rIL-4)/ml, and 10 ng of rGM-CSF/ml (Peprotech). Half of the culture medium was renewed at days 2, 5, and 9. DCs were recovered from day 5 onward. At day 9, nonadherent DCs were separated by transfer into new six-well dishes. DCs were supplemented with new media and cytokines on alternate days and utilized between days 10 and 15. To demonstrate purity, DCs were labeled with anti-mouse CD11c-fluorescein isothiocyanate (FITC) monoclonal antibody HL3 (MAb HL3; BD Pharmingen) at a 1/200 dilution and analyzed by flow cytometry (FACScan; Becton Dickinson).
Quantification of MHC class II and CD40 expression.
Quantification of MHC class II molecules and CD40 expressed on the plasma membrane of macrophages and DCs was performed on live cells by flow cytometry. Cells were transferred into 14-ml polypropylene snap cap tubes (Falcon) and incubated with 10 U of recombinant gamma interferon (rIFN-
; Life Technologies)/ml and/or 100 ng of lipopolysaccharide (LPS)/ml (Sigma [from Escherichia coli O127:B8]) for different time intervals as indicated. Macrophages were washed in phosphate-buffered saline (PBS) and incubated for 30 min with 1% fetal calf serum-0.1% NaN3 in cold PBS (fluorescence-activated cell sorting [FACS] buffer). DCs were washed in PBS and preincubated in 10% normal mouse serum (Sigma) and 2.5 µg of mouse Fc block (2.4G2; BD Pharmingen)/ml in FACS buffer for 30 min. This blocking step was essential to avoid binding of MAb to Fc receptors. Cells were then incubated for 30 min with (i) rat R-PE anti-mouse I-A/I-E (1:100, clone M5/114.15.2; BD Pharmingen), (ii) PE anti-mouse CD40 (1:100, clone 3/23; BD Pharmingen), or (iii) with the same concentration of PE-rat immunoglobulin G2a (IgG2a), isotype standard (clone R35-95; BD Pharmingen). DCs were coincubated with FITC-conjugated anti-mouse CD11c (1:200, clone HL3; BD Pharmingen) or with the same concentration of FITC-conjugated hamster IgG, group 1, 
isotype standard (G235-2356; BD Pharmingen). After being washed with cold PBS, cells were analyzed by flow cytometry.
Slc11a1 detection by flow cytometry. DCs, macrophages, and the control B-cell line WEH231 were fixed for 20 min on ice in 4% paraformaldehyde, washed in FACS buffer, and blocked in blocking buffer (PBS, 0.1% saponin, 5% milk [Marvel]) for 1 h. Cells were incubated for 2 h at ambient temperature with a rabbit polyclonal antibody (1:200) prepared (1) against recombinant fusion protein corresponding to amino acids 1 to 82 of murine Slc11a1 (a gift from C. Howard Barton, University of Southampton, Southampton, United Kingdom). This antibody recognizes a mature 90- to 100-kDa fully glycosylated Slc11a1 protein in transfected COS cells, as well as the 45-kDa precursor (1). Cells were washed in PBS-0.1% saponin three times and then incubated with secondary Alexa Fluor 488 goat anti-rabbit IgG (Molecular Probes) at a 1/200 dilution for 2 h at ambient temperature in PBS-0.1% saponin-1% milk. Cells were then washed three times in PBS-0.1% saponin. After a final wash in PBS, cells were analyzed by flow cytometry.
Confocal microscopy.
CD11c+ unstimulated DCs or DCs stimulated for 24 h with 10 ng of LPS/ml were isolated by using a MoFlo (Dako) high-performance cell sorter. Cells were blocked by using 10% mouse normal mouse serum and Fc block and then stained for 30 min on ice in FACS buffer with FITC-conjugated anti-mouse CD11c (1:200, clone HL3; BD Pharmingen) or the appropriate FITC hamster IgG, group 1, isotype standard (G235-2356; BD Pharmingen). After a sorting step, DCs were cytospun onto polylysine-coated slides to a density of 5 x 104/spot, air dried for 5 min, and fixed in 4% paraformaldehyde for 25 min. Single staining for Slc11a1 was performed as follows. Slides were washed three times in PBS-0.05% Tween (PBST) and blocked for 1 h at room temperature in PBS-0.1% Triton X-100-5% milk (Marvel) (blocking buffer). After three washes in PBST, the cells were incubated with polyclonal rabbit anti-mouse Slc11a1 (N-terminal antibody [1] at 1:200 dilution) in blocking buffer for 2 h at ambient temperature. This was followed by three washes in PBST and incubation with secondary Alexa Fluor 488 goat anti-rabbit IgG (Molecular Probes) at 1/400 dilution in blocking buffer for 2 h. Slides were washed three times in PBST, rinsed with PBS, air dried, and mounted (Vectashield). Cells were viewed with a Nikon Optiphot-2 epifluorescence microscope coupled to a Bio-Rad MRC 1000 confocal laser scanning attachment (Bio-Rad Laboratories, Ltd., Hemel Hempsted, United Kingdom). Images were collected by using Lasersharp 2000 software. For colocalization studies, slides were double stained for Slc11a1 (as described above) and early or late endosomal/lysosomal markers. Briefly, cells were blocked (as described above) and coincubated with polyclonal rabbit anti-mouse Slc11a1 (N-terminal antibody at a 1:200 dilution) and goat anti-EEA1 polyclonal antibody (1:100; Santa Cruz) or rat anti-Lamp1 MAb (1:100, clone 1D4B; Developmental Studies Hybridoma Bank, Iowa City, IA) in blocking buffer overnight at 4°C. After three washes in PBST, cells were incubated with secondary antibodies Alexa Fluor 594 goat anti-rat IgG (Molecular Probes) and Alexa Fluor 594 donkey anti-goat IgG (Molecular Probes) for Lamp-1 and EEA1 detection, respectively. Incubation was for 2 h in PBS-0.1% Triton X-100-1% milk. Slides were washed, mounted, and analyzed as described above.
TaqMan quantitative RT-PCR.
DCs were stimulated for various time intervals with 1 µg of LPS/ml prior to depletion by negative selection of Gr-1-positive cells as follows. Cells were incubated with biotinylated anti-mouse Ly-6G (Gr-1) (RB6-8C5; BD Pharmingen), followed by BD Imag Streptavidin Particles Plus-DM (BD Pharmingen), according to manufacturer's instructions. Macrophage contamination was minimized by harvesting nonadherent cells. This method of culture routinely yielded 75 to 85% CD11c+ cells by FACScan analysis (data not shown) prior to elimination of GR1+/CD11c– cells, which further improved CD11c+ purity. We did not use CD11c+ selection for Slc11a1 TaqMan analysis since we wanted to avoid the activation of CD11c+ cells through purification. The Gr-1-positive fraction was removed by using a BD IMagnet, the Gr-1-negative cells extracted in TRIzol (Invitrogen) and RNA pellets resuspended in RNase-free water. Prior to reverse transcription (RT), RNA was DNase treated by using DNA-free (Ambion, Austin, TX) according to the manufacturer's instructions, 1.6 µg of oligo(dT)15 was added, and the sample was denatured at 70°C for 10 min. RNA was reverse transcribed with 10 U of Super RT (HT Biotechnology, Ltd., Cambridge, United Kingdom) per µg of total RNA, 1xx Super RT buffer, a 1 mM concentration of each deoxynucleotide triphosphate, and 40 U of RNaseOUT (Invitrogen) at 42°C for 40 min. Relative quantitation of specific cDNA species to rodent GAPDH (glyceraldehyde-3-phosphate dehydrogenase) endogenous control (Applied Biosystems) was conducted on the ABI 7700 (PE Applied Biosystems, Warrington, United Kingdom) using TaqMan chemistry and the comparative CT method with separate tubes. Sequences for primers and probes were as follows: Slc11a1, forward (5'-GCTGTCATGCAGGAGTTT-3'), reverse (5'-GCGCCATGATGCACGAA-3'), and probe (5'-ATGGCTTTGCTCATCCGGCCG-3'); and IL-10, forward (5'-GCCCAGAAATCAAGGAGCATT-3'), reverse (5'-GCTCCACTGCCTTGCTCTTATT-3'), and probe (5'-AGGCGCTGTCATCGATTTCTCCCCT-3'). IL-12 reagents were purchased from Applied Biosystems. Relative quantification of signal per cell was determined by subtracting the CT for the target gene from the CT for GAPDH. The relative expression levels were compared to an internal control and are expressed as 2–
CT.
Antigen-presenting cell assays.
Ovalbumin (OVA)-specific DO11.10 or Leishmania homologue of the receptor for activated C kinase (LACK)-specific LMR7.5 (a gift from N. Glaichenhaus) T-cell hybridomas were plated in complete medium at 105 cells/well in 96-well U-bottom plates. 10S and 7.5R or MUT12 and WT3 pairs of transfected macrophage lines (see above) prestimulated with 25 U of IFN-/ml for 24 h were added at 0.5 x 105 cells/well. Unstimulated or prestimulated (24 h, 100 ng of LPS/ml) DCs were used at 0.25 x 105 cells/well. Chicken OVA peptide 323-339 (ISQAVHAAHAEINEAGR), albumin from chicken egg white (Sigma), or recombinant LACK protein (46) were added at the indicated concentrations in complete medium, and cells were stimulated for 24 h at 37°C in 5% CO2 prior to harvesting the supernatants for the detection of IL-2 by enzyme-linked immunosorbent assay. As expected, the incubation of DCs or macrophages with antigen, or T cells alone with antigen did not generate IL-2 (data not shown).
Statistics. Unpaired, two-tailed Student t tests were used for between-group comparisons. Differences between experimental groups were considered significant for P values of <0.05.
|
RESULTS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
/ml upregulated the expression of Slc11a1 at the mRNA level (Fig. 1A). Macrophages stably transfected with wild-type Slc11a1 (7.5R) showed higher relative expression of Slc11a1 mRNA than macrophages stably transfected with mutant Slc11a1 (10S). However, stimulation of CD11C+ DCs derived from Slc11a1 wild-type C.D2-Vil6 bone marrow with 20 U of IFN-/ml did not increase expression of Slc11a1 mRNA (Fig. 1B). These DCs did, however, show increased expression of Slc11a1 mRNA in response to 24 h of stimulation with 1 µg of LPS/ml (Fig. 1B). We therefore used stimulation with 1 µg of LPS/ml in a more comprehensive comparison of Slc11a1 mRNA expression in DCs derived from pairs of congenic mice on BALB and B10 genetic backgrounds (Fig. 1C and D). BALB background mice were more responsive to LPS stimulation than DCs derived from B10 background mice, but there was equivalent expression (P > 0.05) of Slc11a1 in DCs derived from Slc11a1 wild-type mice compared to mutant mice at all time points.
|
|
to IL-4 cytokine responses) in antigen-specific T-cell responses during the course of infection in vivo (31, 34, 38, 45). Other studies (12) have demonstrated that the My-D88 and non-MyD88 pathway-induced IL-10 production by macrophages and DCs can suppress endogenous IL-12 p70, thereby inhibiting Th1 development. We hypothesize, therefore, that the difference in bias toward Th1 versus Th2 responses in vivo in Slc11a1 congenic mouse strains could be due to differences in endogenous IL-12 versus IL-10 induction in macrophages or DCs. Using TaqMan quantitative RT-PCR, we examined IL-12 and IL-10 mRNA levels in CD11c+ DCs derived from BALB and B10 background congenic mice after stimulation with LPS (Fig. 3). DCs derived from Slc11a1 wild-type and mutant mice on BALB and B10 genetic backgrounds upregulated IL-12 mRNA responses to equivalent degrees (Fig. 3A and B), peaking at 15 h poststimulation and returning to baseline at 36 h. DCs derived from B10 background mice made a more vigorous IL-10 response (Fig. 3D) compared to BALB background mice (Fig. 3C), with sustained expression in DCs derived from all mice at 36 h poststimulation. Since the outcome of the Th1 cell response in vivo might reflect the balance between endogenous IL-10 and IL-12 responses, we also calculated the ratios of IL-10 to IL-12 mRNA as a measure of the potential for inhibition of Th1 induction. This revealed a significant trend for higher IL-10:IL-12 ratios at baseline and 15 h after LPS stimulation in DCs derived from the Slc11a1 mutant than in DCs from wild-type mice (Fig. 3E and F). This bias in IL-10 response by DCs could contribute to the inhibition of Th1 responses in Slc11a1 mutant mice in vivo and therefore lead to a bias toward a Th2 response in these mice.
|
|
|
were highly proficient at processing and presenting LACK protein to this T-cell hybridoma, whereas the antigen-presenting cell function of mutant transfectants was poor (Fig. 5B). Similar differences were observed when the processing and presentation of LACK protein to LACK-specific T cells for a second pair (WT3 versus MUT12) (49) of separately derived wild-type and mutant stably transfected RAW264.7 macrophage cell lines were compared (data not shown).
|
|
DISCUSSION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Several studies have indicated that, in addition to a T-cell-independent influence on innate immunity and early resistance to infection with L. donovani (13), S. enterica serovar Typhimurium (42), and Mycobacterium spp. (25, 27), Slc11a1 also exerts an effect on Th1:Th2 bias in vivo (31, 34, 38, 45). This includes influences on Th1:Th2 bias after primary infection with L. donovani (31), serovar Typhimurium (38), and M. bovis (34), as well as an ability to bias the immune response to exogenous antigen delivered to the immune system using attenuated serovar Typhimurium AroA mutant as a vaccine vehicle (45). Although these effects have previously been related to differences in the cytokine and chemokine milieu, MHC class II expression, and antigen processing after interaction of these pathogens with Slc11a1 wild-type or mutant macrophages, our demonstration that myeloid CD11c+ DCs from Slc11a1 wild-type mice versus mutant mice display a parallel range of pleiotropic effects could be important in light of the unique role played by DCs in initiating primary immune responses by stimulating immunologically naive T cells (3). In the context of autoimmune disease such as type 1 diabetes in NOD mice, it is the wild-type allele at Slc11a1 that promotes a Th1 response and has been associated with disease (29, 33). Given their enhanced ability to process protein antigens in the immature state and the bias toward IL-12 in the immature state and upon early activation, wild-type DCs could contribute to the initial priming of autoreactive T cells in type 1 diabetes. This would be consistent with studies demonstrating Slc11a1 expression at RNA and protein levels in pancreatic islets (8, 21). Intriguingly, however, DCs are also the cells that prime CD25+ CD4+ regulatory T cells that suppress type 1 diabetes (47). It is of interest, therefore, that it was the protective effect of the mutant allele derived from C57BL/10 (B10) and bred onto the NOD background that first highlighted Slc11a1 as a putative candidate gene for type 1 diabetes (29). Our demonstration here of a reduced capacity to process antigen, a reduced ability to respond to activation signals in terms of MHC class II expression, and a bias toward IL-10 relative to IL-12 production by unstimulated or immature DCs is consistent with a possible role for immature DCs from Slc11a1 mutant mice in priming a protective regulatory T-cell response in relation to development of type 1 diabetes (16). A similar balance of roles for DCs in priming proinflammatory Th1 versus Th2 and/or regulatory T cells might also occur in humans, where the functional promoter polymorphism at SLC11a1 has two major alleles that drive high and low expression (43). The high-expresser SLC11A1 allele is associated with human type 1 diabetes (23), whereas the low-expresser allele is associated with high IL-10 responses in peripheral blood mononuclear cells stimulated with LPS (2) and with protection from type 1 diabetes (7, 23). Additional work will be required to further define the role of DC subsets from Slc11a1 wild-type and mutant mice in regulating type 1 versus type 2 or regulatory T-cell responses in relation to the important role of this gene in regulating susceptibility to infectious and autoimmune diseases.
The difference in the ability to process protein antigens in DCs from Slc11a1 mutant mice versus congenic wild-type mice is interesting in relation to the primary function of Slc11a1 as a proton-dependent divalent cation transporter localized to the membranes of late endosomes and lysosomes. Two functions that might influence the processing and presentation of antigens are (i) endocytosis and early endosomal fusion events involving, in particular, MHC class II-containing multivesicular bodies, and (ii) the role of divalent cation-dependent metalloproteinases in antigen processing. A role for Slc11a1 in promoting endosomal fusion events in well established, particularly in relation to the fusion of microbe-containing phagosomes with the late endosome/lysosome compartment (22, 28, 44). Whether Slc11a1 similarly influences the delivery of protein antigens to late endosomes, lysosomes, or multivesicular bodies for processing has yet to be established. A possible role for Slc11a1 in regulating metalloproteinase activity lies at the core of the current debate as to whether Slc11a1 is a proton/divalent cation symporter that transports divalent cations out of the late endosomal lysosomal compartment along a proton gradient (30) or a proton/divalent cation antiporter that delivers divalent cations to this compartment against a proton gradient (24, 35, 36). Our most recent data using yeast complementation (M. Techau, M. Seaman, and J. M. Blackwell, unpublished data) support our original observation using cRNA-injected frog oocytes (24) that Slc11a1 functions as an antiporter. A role for Slc11a1 in promoting metalloproteinase-dependent antigen processing would be consistent with antiport function and is a testable hypothesis in further studies.
Here we have demonstrated that, in addition to its expression in macrophages and polymorphonuclear leukocytes, Slc11a1 is expressed in late endosomes and lysosomes of CD11c+ myeloid DCs, where it similarly exerts pleiotropic effects on cytokine transcription, MHC class II molecule expression, and the processing of protein antigens for presentation to T cells. These observations have important implications for future studies designed to determine how this important gene regulates susceptibility to both infectious and autoimmune diseases in humans.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
Published ahead of print on 9 July 2007.
Present address: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
|
REFERENCES |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
| 1. | Atkinson, P. G. P., and C. H. Barton. 1998. Ectopic expression of Nramp1 in COS-1 cells modulates iron accumulation. FEBS Lett. 425:239-242.[CrossRef][Medline] |
| 2. | Awomoyi, A. A., A. Marchant, J. M. Howson, K. P. McAdam, J. M. Blackwell, and M. J. Newport. 2002. Interleukin-10, polymorphism in SLC11A1 (formerly NRAMP1), and susceptibility to tuberculosis. J. Infect. Dis. 186:1804-1814. |
| 3. | Banchereau, J., and R. M. Steinman. 1998. Dendritic cells and the control of immunity. Nature 392:245-252.[CrossRef][Medline] |
| 4. | Barrera, L. F., I. Kramnik, E. Skamene, and D. Radzioch. 1997. I-A beta gene expression regulation in macrophages derived from mice susceptible or resistant to infection with M. bovis BCG. Mol. Immunol. 34:343-355.[CrossRef][Medline] |
| 5. | Barton, C. H., J. K. White, T. I. A. Roach, and J. M. Blackwell. 1994. NH2-terminal sequence of macrophage-expressed natural resistance-associated macrophage protein (Nramp) encodes a proline/serine-rich putative Src homology 3-binding domain. J. Exp. Med. 179:1683-1687. |
| 6. | Barton, C. H., S. H. Whitehead, and J. M. Blackwell. 1995. Nramp transfection transfers Ity/Lsh/Bcg-related pleiotropic effects on macrophage activation: influence on oxidative burst and nitric oxide pathways. Mol. Med. 1:267-279.[Medline] |
| 7. | Bassuny, W. M., K. Ihara, N. Matsuura, S. Ahmed, H. Kohno, R. Kuromaru, K. Miyako, and T. Hara. 2002. Association study of the NRAMP1 gene promoter polymorphism and early-onset type 1 diabetes. Immunogenetics 54:282-285.[CrossRef][Medline] |
| 8. | Blackwell, J. M., T. Goswami, C. A. W. Evans, D. Sibthorpe, N. Papo, J. K. White, S. Searle, E. N. Miller, C. S. Peacock, H. Mohammed, and M. Ibrahim. 2001. SLC11A1 (formerly NRAMP1) and disease. Cell. Microbiol. 3:773-784.[CrossRef][Medline] |
| 9. | Blackwell, J. M., H.-R. Jiang, and J. K. White. 2004. Role of Nramp family in pro-inflammatory diseases, p.53-64. In M. F. M. Cellier and P. Gros (ed.), The Nramp family. Kluwer Academic/Landes, New York, NY. |
| 10. | Blackwell, J. M., S. Searle, H. Mohamed, and J. K. White. 2003. Divalent cation transport and susceptibility to infectious and autoimmune disease: continuation of the Ity/Lsh/Bcg/Nramp1/Slc11a1 gene story. Immunol. Lett. 85:197-203.[CrossRef][Medline] |
| 11. | Blackwell, J. M., S. Toole, M. King, P. Dawda, T. I. Roach, and A. Cooper. 1988. Analysis of Lsh gene expression in congenic B10.L-Lshr mice. Curr. Top. Microbiol. Immunol. 137:301-309. |
| 12. | Boonstra, A., R. Rajsbaum, M. Holman, R. Marques, C. Asselin-Paturel, J. P. Pereira, E. E. Bates, S. Akira, P. Vieira, Y. J. Liu, G. Trinchieri, and A. O'Garra. 2006. Macrophages and myeloid dendritic cells, but not plasmacytoid dendritic cells, produce IL-10 in response to MyD88- and TRIF-dependent TLR signals, and TLR-independent signals. J. Immunol. 177:7551-7558. |
| 13. | Bradley, D. J. Genetic control of natural resistance to Leishmania donovani. Nature 250:353-354, 1974. |
| 14. | Bradley, D. J., B. A. Taylor, J. Blackwell, E. P. Evans, and J. Freeman. 1979. Regulation of Leishmania populations within the host. III. Mapping of the locus controlling susceptibility to visceral leishmaniasis in the mouse. Clin. Exp. Immunol. 37:7-14.[Medline] |
| 15. | Brown, D. H., W. LaFuse, and B. S. Zwilling. 1995. Cytokine-mediated activation of macrophages from Mycobacterium bovis BCG-resistant and -susceptible mice: differential effects of corticosterone on antimycobacterial activity and expression of the Bcg gene (candidate Nramp). Infect. Immun. 63:2983-2988.[Abstract] |
| 16. | Bruder, D., A. M. Westendorf, W. Hansen, S. Prettin, A. D. Gruber, Y. Qian, H. von Boehmer, K. Mahnke, and J. Buer. 2005. On the edge of autoimmunity: T-cell stimulation by steady-state dendritic cells prevents autoimmune diabetes. Diabetes 54:3395-3401. |
| 17. | Buschman, E., and E. Skamene. 2001. From Bcg/Lsh/Ity to Nramp1: three decades of search and research. Drug Metab. Dispos. 29:471-473. |
| 18. | Canonne-Hergaux, F., J. Calafat, E. Richer, M. Cellier, S. Grinstein, N. Borregaard, and P. Gros. 2002. Expression and subcellular localization of NRAMP1 in human neutrophil granules. Blood 100:268-275. |
| 19. | Caron, J., L. Lariviere, M. Nacache, M. Tam, M. M. Stevenson, C. McKerly, P. Gros, and D. Malo. 2006. Influence of Slc11a1 on the outcome of Salmonella enterica serovar Enteritidis infection in mice is associated with Th polarization. Infect. Immun. 74:2787-2802. |
| 20. | Cellier, M., C. Shustik, W. Dalton, E. Rich, J. Hu, D. Malo, E. Schurr, and P. Gros. 1997. Expression of the human NRAMP1 gene in professional primary phagocytes: studies in blood cells and in HL-60 promyelocytic leukemia. J. Leukoc. Biol. 61:96-105.[Abstract] |
| 21. | Clifford, K. S., and M. J. MacDonald. 2000. Survey of mRNAs encoding zinc transporters and other metal complexing proteins in pancreatic islets of rats from birth to adulthood: similar patterns in the Sprague-Dawley and Wistar BB strains. Diabetes Res. Clin. Pract. 49:77-85.[CrossRef][Medline] |
| 22. | de Chastellier, C., C. Frehel, C. Offredo, and E. Skamene. 1993. Implication of phagosome-lysosome fusion in restriction of Mycobacterium avium growth in bone marrow macrophages from genetically resistant mice. Infect. Immun. 61:3775-3784. |
| 23. | Esposito, L., N. J. Hill, L. E. Pritchard, F. Cucca, C. Muxworthy, M. E. Merriman, A. Wilson, C. Julier, M. Delepine, J. Tuomilehto, E. Tuomilehto-Wolf, C. Ionesco-Tirgoviste, L. Nistico, R. Buzzetti, P. Pozzilli, M. Ferrari, E. Bosi, F. Pociot, J. Nerup, C. Bain, J. A. Todd, et al. 1998. Genetic analysis of chromosome 2 in type 1 diabetes: analysis of putative loci IDDM7, IDDM12, and IDDM13 and candidate genes NRAMP1 and IA-2 and the interleukin-1 gene cluster. Diabetes 47:1797-1799.[Medline] |
| 24. | Goswami, T., A. Bhattacharjee, P. Babal, S. Searle, E. Moore, M. Li, and J. M. Blackwell. 2001. Natural-resistance-associated macrophage protein 1 is an H+/bivalent cation antiporter. Biochem. J. 354:511-519.[CrossRef][Medline] |
| 25. | Goto, Y., E. Buschman, and E. Skamene. 1989. Regulation of host resistance to Mycobacterium intracellulare in vivo and in vitro by the Bcg gene. Immunogenetics 30:218-221.[CrossRef][Medline] |
| 26. | Govoni, G., S. Vidal, M. Cellier, P. Lepage, D. Malo, and P. Gros. 1995. Genomic structure, promoter sequence, and induction of expression of the mouse Nramp1 gene in macrophages. Genomics 27:9-19.[CrossRef][Medline] |
| 27. | Gros, P., E. Skamene, and A. Forget. 1981. Genetic control of natural resistance to Mycobacterium bovis (BCG) in mice. J. Immunol. 127:2417-2421.[Abstract] |
| 28. | Gruenheid, S., E. Pinner, M. Desjardins, and P. Gros. 1997. Natural resistance to infections with intracellular pathogens: the Nramp1 protein is recruited to the membrane of the phagosome. J. Exp. Med. 185:717-730. |
| 29. | Hill, N. J., P. A. Lyons, N. Armitage, J. A. Todd, L. S. Wicker, and L. B. Peterson. 2000. NOD Idd5 locus controls insulitis and diabetes and overlaps the orthologous CTLA4/IDDM12 and NRAMP1 loci in humans. Diabetes 49:1744-1747.[Abstract] |
| 30. | Jabado, N., A. Jankowski, S. Dougaparsad, V. Picard, S. Grinstein, and P. Gros. 2000. Natural resistance to intracellular infections: natural resistance-associated macrophage protein 1 (Nramp1) functions as a pH-dependent manganese transporter at the phagosomal membrane. J. Exp. Med. 192:1237-1248. |
| 31. | Kaye, P. M., and J. M. Blackwell. 1989. Lsh, antigen presentation and the development of CMI. Res. Immunol. 140:810-815.[CrossRef][Medline] |
| 32. | Kaye, P. M., N. K. Patel, and J. M. Blackwell. 1988. Acquisition of cell-mediated immunity to Leishmania. II. LSH gene regulation of accessory cell function. Immunology 65:17-22.[Medline] |
| 33. | Kissler, S., P. Stern, K. Takahashi, K. Hunter, L. B. Peterson, and L. S. Wicker. 2006. In vivo RNA interference demonstrates a role for Nramp1 in modifying susceptibility to type 1 diabetes. Nat. Genet. 38:479-483.[CrossRef][Medline] |
| 34. | Kramnik, I., D. Radzioch, and E. Skamene. 1994. T-helper 1-like subset selection in Mycobacterium bovis bacillus Calmette-Gurin-infected resistant and susceptible mice. Immunology 81:618-625.[Medline] |
| 35. | Kuhn, D. E., B. D. Baker, W. LaFuse, and B. S. Zwilling. 1999. Differential iron transport into phagosomes isolated from the RAW264.7 macrophage cell lines transfected with Nramp1Gly169 or Nramp1Asp169. J. Leukoc. Biol. 66:113-119.[Abstract] |
| 36. | Kuhn, D. E., W. P. Lafuse, and B. S. Zwilling. 2001. Iron transport into Mycobacterium avium-containing phagosomes from an Nramp1(Gly169)-transfected RAW264.7 macrophage cell line. J. Leukoc. Biol. 69:43-49. |
| 37. | Lafuse, W. P., G. R. Alvarez, and B. S. Zwilling. 2000. Regulation of Nramp1 mRNA stability by oxidants and protein kinase C in RAW264.7 macrophages expressing Nramp1(Gly169). Biochem. J. 351:687-696.[CrossRef][Medline] |
| 38. | Lalmanach, A. C., A. Montagne, P. Menanteau, and F. Lantier. 2001. Effect of the mouse Nramp1 genotype on the expression of IFN-gamma gene in early response to Salmonella infection. Microbes Infect. 3:639-644.[CrossRef][Medline] |
| 39. | Lang, T., E. Prina, D. Sibthorpe, and J. M. Blackwell. 1997. Nramp1 transfection transfers Ity/Lsh/Bcg-related pleiotropic effects on macrophage activation: influence on antigen processing and presentation. Infect. Immun. 65:380-386.[Abstract] |
| 40. | Mock, B. A., D. L. Holiday, D. P. Cerretti, S. C. Darnell, A. D. O'Brien, and M. Potter. 1994. Construction of a series of congenic mice with recombinant chromosome 1 regions surrounding the genetic loci for resistance to intracellular parasites (Ity, Lsh, and Bcg), DNA repair responses (Rep-1), and the cytoskeletal protein villin (Vil). Infect. Immun. 62:325-328. |
| 41. | Plant, J., and A. A. Glynn. 1979. Locating salmonella resistance gene on mouse chromosome 1. Clin. Exp. Immunol. 37:1-6.[Medline] |
| 42. | Plant, J., and A. A. Glynn. 1974. Natural resistance to Salmonella infection, delayed hypersensitivity, and Ir genes in different strains of mice. Nature 248:345-347.[CrossRef][Medline] |
| 43. | Searle, S., and J. M. Blackwell. 1999. Evidence for a functional repeat polymorphism in the promoter of the human NRAMP1 gene that correlates with autoimmune versus infectious disease susceptibility. J. Med. Genet. 36:295-299. |
| 44. | Searle, S., N. A. Bright, T. I. A. Roach, P. G. P. Atkinson, C. H. Barton, R. H. Meloen, and J. M. Blackwell. 1998. Localisation of Nramp1 in macrophages: modulation with activation and infection. J. Cell Sci. 111:2855-2866.[Abstract] |
| 45. | Soo, S.-S., B. Villarreal Ramos, C. M. Khan, C. E. Hormaeche, and J. M. Blackwell. 1998. Genetic control of immune response to recombinant antigens carried by an attenuated Salmonella typhimurium vaccine strain: Nramp1 influences T-helper subset responses and protection against leishmanial challenge. Infect. Immun. 66:1910-1917. |
| 46. | Stober, C., U. Lange, M. T. M. Roberts, A. Alcami, and J. M. Blackwell. 2005. IL-10 from regulatory T cells determines vaccine efficacy in murine Leishmania major infection. J. Immunol. 175:2517-2524. |
| 47. | Tarbell, K. V., S. Yamazaki, K. Olson, P. Toy, and R. M. Steinman. 2004. CD25+ CD4+ T cells, expanded with dendritic cells presenting a single autoantigenic peptide, suppress autoimmune diabetes. J. Exp. Med. 199:1467-1477. |
| 48. | Vidal, S. M., D. Malo, K. Vogan, E. Skamene, and P. Gros. 1993. Natural resistance to infection with intracellular parasites: isolation of a candidate for Bcg. Cell 73:469-485.[CrossRef][Medline] |
| 49. | White, J. K., A. Stewart, J. F. Popoff, S. Wilson, and J. M. Blackwell. 2004. Incomplete glycosylation and defective intracellular targeting of mutant solute carrier family 11 member 1 (Slc11a1). Biochem. J. 382:811-819.[CrossRef][Medline] |
| 50. | Winzler, C., P. Rovere, M. Rescigno, F. Granucci, G. Penna, L. Adorini, V. S. Zimmermann, J. Davoust, and P. Ricciardi-Castagnoli. 1997. Maturation stages of mouse dendritic cells in growth factor-dependent long-term cultures. J. Exp. Med. 185:317-328. |
| 51. | Wojciechowski, W., J. DeSanctis, E. Skamene, and D. Radzioch. 1999. Attenuation of MHC class II expression in macrophages infected with Mycobacterium bovis bacillus Calmette-Guerin involves class II transactivator and depends on the Nramp1 gene. J. Immunol. 163:2688-2696. |
| 52. | Zwilling, B. S., L. Vespa, and M. Massie. 1987. Regulation of I-A expression by murine peritoneal macrophages: differences linked to the Bcg gene. J. Immunol. 138:1372-1376.[Abstract] |
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|
