| 1. |
- Shabani, Mahdi, et al.
(författare)
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Ligation of human Fc receptor like-2 (FCRL2) by monoclonal antibodies downregulates B cell receptor mediated signaling
- 2014
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Ingår i: Immunology. - Stockholm : Karolinska Institutet, Dept of Oncology-Pathology. - 0019-2805 .- 1365-2567.
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Tidskriftsartikel (refereegranskat)abstract
- B cell antigen receptor (BCR) signaling and its regulation through negative and positive regulators are critical for balancing B cell response and function. Human Fc receptor like-2 (FCRL2), a member of the newly identified FCRL family, could influence B cell signaling due to possession of both immunoreceptor tyrosine-based activation and inhibitory motifs (ITAM and ITIM). Since the natural ligand of FCRL2 has not been identified yet, we generated FCRL2-specific monoclonal antibodies (mAbs) and employed them to investigate the influence of FCRL2 stimulation on BCR signaling in a FCRL2-expressing B cell line. Two anti-FCRL2 mAb-producing hybridoma clones (5A7-E7 and 3D8-G8) were selected. None of the mAbs displayed any cross-reactivity with the other members of the FCRL family including recombinant FCRL1, 3, 4 and 5, as tested by FACS and ELISA techniques. Engagement of the FCRL2 by these mAbs resulted in significant inhibition of BCR signaling mediators such as calcium mobilization and phosphorylation of the MAP kinases Erk, p38 and Jnk MAP. These findings indicate that the FCRL2 ITIM motifs are functional and the anti-FCRL2 mAbs may mimic the natural ligand of FCRL2 by induction of inhibitory signals in B cells.
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| 2. |
- Ehinger, Magnus, et al.
(författare)
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Influence of CD4 or CD8 deficiency on collagen-induced arthritis
- 2001
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 103:3, s. 291-300
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Tidskriftsartikel (refereegranskat)abstract
- The role of T cells in the mouse collagen-induced arthritis (CIA) model for rheumatoid arthritis is not clarified, and different results have been reported concerning the role of CD4 and CD8 T cells. To address this issue, we have investigated B10.Q mice deficient for CD4 or CD8. The mice lacking CD4 were found to be less susceptible to disease, but not completely resistant, whereas the CD8 deficiency had no significant impact on the disease. No difference in the development of late occurring relapses was noted. Interestingly, the CD4-deficient mice had a severely reduced response to the glycosylated form of the immunodominant type II collagen (CII) 256–270 peptide whereas the response to the non-glycosylated peptide was not significantly different. Furthermore, CD4-deficient mice had lower antibody responses to CII, explaining the lower disease susceptibility. In comparison with previously reported results, it is apparent that the lack of CD4 molecules has a different impact on CIA if present on different genetic backgrounds, findings that could possibly be related to the occurrence of different disease pathways of CIA in different mouse strains.
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| 3. |
- Ellmark, Peter, et al.
(författare)
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Pre-assembly of the extracellular domains of CD40 is not necessary for rescue of mouse B cells from anti-immunoglobulin M-induced apoptosis
- 2003
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 108:4, s. 452-457
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Tidskriftsartikel (refereegranskat)abstract
- CD40 is a tumour necrosis factor receptor (TNFR) family member of central importance for the adaptive immune system. To elucidate the functional role of the different extracellular domains of CD40, we have created a set of truncated CD40 molecules where domains, or parts of domains, have been removed. These CD40 proteins, which contain a peptide tag in the N-terminal end, have been expressed in a murine B-cell line, WEHI 231. It was found that ligation of these engineered CD40 proteins via the peptide tag, was sufficient to rescue as well as to promote proliferation of apoptotic WEHI 231 cells, even when all the extracellular domains of CD40 were absent. Our results suggest that pre association of CD40 in the cell membrane plays no critical role for the CD40 signalling pathway. Furthermore, our data imply that conformational changes initiated in the extracellular domains of CD40 are not essential for signal transduction.
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| 4. |
- Jarefors, Sara, et al.
(författare)
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Lyme borreliosis reinfection: might it be explained by gender difference in immune response?
- 2006
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 118:2, s. 224-235
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Tidskriftsartikel (refereegranskat)abstract
- Lyme borreliosis is a tick-borne disease often manifesting as a circular skin lesion. This cutaneous form of the disease is known as erythema migrans. In a 5-year follow-up study in southern Sweden, 31 of 708 individuals initially diagnosed with erythema migrans and treated with antibiotics were found to be reinfected with Borrelia burgdorferi. Although men and women were tick-bitten to the same extent, 27 of the 31 reinfected individuals were women, all of whom were over 44 years of age. The aim of this study was to determine whether this discrepancy in gender distribution could be a result of differences in immunological response. Twenty single-infected and 21 reinfected women and 18 single-infected and three reinfected men were included in the study. None of the participants showed any sign of an ongoing B. burgdorferi infection, and thus the habitual response was captured. Lymphocytes were separated from blood and stimulated with antigens. The secretion of interleukin (IL)-4, IL-6, IL-10, interferon (IFN)-γ and tumour necrosis factor (TNF)-α was measured by enzyme-linked immunosorbent assay (ELISA), enzyme-linked immunosorbent spot-forming cell assay (ELISPOT) or Immulite. No difference was detected in cytokine secretion between single-infected and reinfected individuals. We also compared the immunological response in men and women, regardless of the number of B. burgdorferi infections. Women displayed a significantly higher spontaneous secretion of all cytokines measured. The ratios of IL-4:IFN-γ and IL-10:TNF-α were significantly higher in women. Gender differences in immune reactivity might in part explain the higher incidence of reinfection in women. The higher IL-4:IFN-γ and IL-10:TNF-α ratios seen in women indicate that postmenopausal women have T helper type 2 (Th2)-directed reactivity with impaired inflammatory responses which might inhibit the elimination of spirochetes.
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| 5. |
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| 6. |
- Maruvada, Ravi, et al.
(författare)
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Effects of complement regulators bound to Escherichia coli K1 and Group B Streptococcus on the interaction with host cells
- 2008
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 124, s. 265-276
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli K1 and Group B Streptococcus (GBS) are the most common bacteria that cause meningitis during the neonatal period. Complement, the first line of defence in the host, acts on these bacteria to opsonize with various components of complement for subsequent presentation to phagocytes. To counteract these opsonization effects, E. coli and GBS bind to the complement regulators C4 binding protein and Factor H, respectively. Nonetheless, the deposition of complement components on these two bacteria from neonatal serum and their effect on the host cell interaction is unclear. Here we demonstrated that the deposition of complement proteins from adult serum prevented the invasion of E. coli into human brain microvascular endothelial cells, whereas the invasion of GBS was enhanced. In contrast, treatment with cord serum had no effect on the invasion of both these bacteria. We also examined the effect of the deposited complement proteins on phagocytosis using THP-1 cells and THP-1 cells differentiated into macrophages. Escherichia coli treated with adult serum neither attached nor entered these cells, whereas GBS was phagocytosed and survived efficiently. We further demonstrate that the inhibitory effect of complement proteins is the result of the bound complement inhibitors C4b-binding protein, in the case of E. coli, and Factor H, in the case of GBS. Taken together, these results suggest that E. coli and GBS utilize contrasting mechanisms of complement-mediated interactions with their target cells for successful establishment of disease.
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| 7. |
- Månsson, Anne, et al.
(författare)
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A distinct Toll-like receptor repertoire in human tonsillar B cells, directly activated by PamCSK, R-837 and CpG-2006 stimulation.
- 2006
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 118:Jun 16, s. 539-548
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Tidskriftsartikel (refereegranskat)abstract
- Toll-like receptors (TLRs) recognize specific pathogen-associated molecular patterns (PAMPs), which subsequently trigger innate immunity. Recent data also suggest a role for TLRs in the direct activation of adaptive immune cells. In the present study, the expression and function of TLR1-TLR10 were characterized in purified human tonsillar B cells, focusing on differences among CD19(+) CD38(-) CD27(-) (naive B cells), CD19(+) IgD(-) CD27- [germinal centre (GC) B cells] and CD19(+) CD38(-)CD27(+) (memory B cells) cells. The study was also designed to compare the TLR expression in B cells obtained from infected and hyperplastic tonsils that served as controls. The results demonstrated a distinct repertoire of TLRs, in which TLR1, TLR2, TLR7, TLR9 and TLR10 predominated. No differences were found among naive, GC and memory B cells. Tonsillar infection did not substantially alter the TLR expression profile in ex vivo-isolated B-cell subsets. Purified CD19+ B cells stimulated with Pam(3)CSK(4), R-837 and CpG oligodeoxynucleotide (ODN) 2006, via TLR1/TLR2, TLR7 and TLR9, respectively, showed an induction of interleukin-6 secretion and an up-regulated expression of human leucocyte antigen (HLA)-DR. Collectively, the present study demonstrates that B cells exhibit constitutively high levels of specific TLRs, which are not developmentally regulated during the B-cell differentiation process. Ongoing microbial infections, such as chronic tonsillitis, do not appear to affect the TLR profile in B cells. Furthermore, the distinct expression of TLRs allows B cells to.respond directly to the cognate PAMPs. This further emphasizes the role of TLRs in directly activating adaptive immune cells.
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| 8. |
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| 9. |
- Rydberg, Camilla, et al.
(författare)
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Toll-like receptor agonists induce inflammation and cell death in a model of head and neck squamous cell carcinomas
- 2009
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 128:1, s. 600-611
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Tidskriftsartikel (refereegranskat)abstract
- P>Toll-like receptors (TLRs) are increasingly implicated in the pathogenesis of cancer. The present study describes TLR expression and function in healthy and malignant airway epithelial cells. The squamous cell carcinoma cell line Detroit-562 was compared with the healthy bronchial epithelial cell line NL-20 and primary human nasal epithelial cells (HNECs). TLR2, TLR3 and TLR5 were present in primary head and neck squamous cell carcinomas (HNSCCs). Consistent with this, Detroit-562 expressed TLR2, TLR3 and TLR5, whereas NL-20 expressed mainly TLR3 and HNECs expressed TLR2-5. In Detroit-562, Pam(3)CSK(4), poly(I:C) and flagellin, ligands for TLR2, TLR3 and TLR5, respectively, induced an up-regulation of intercellular adhesion molecule 1 (ICAM-1), an increase in interleukin (IL)-6 and IL-8 secretion and a decrease in cell viability. Additionally, poly(I:C) affected IL-1 beta production and the migratory behaviour of Detroit-562. NL-20 responded with a slight increase in IL-8 secretion upon poly(I:C) stimulation. Poly(I:C) induced a small increase in IL-1 beta, IL-6 and IL-8 production in HNECs, while Pam(3)CSK(4) increased viability. The TLR signalling was transcription-dependent, but the pathways involved differed among TLRs as well as cells. In Detroit-562, TLR2 and TLR5 activation was mediated via c-jun N-terminal kinase (JNK)-, p38-, phosphatidylinositol 3-kinase (PI3K)- and nuclear factor (NF)-kappa B-related pathways, while TLR3 was dependent on NF-kappa B. In NL-20, TLR3 signalled via p38, and in HNECs, NF-kappa B, JNK and extracellular signal-regulated kinase (ERK) appeared to be involved. We found that TLR agonists induced a robust response in HNSCCs, characterized by generation of inflammation and cell death. A similar response was not seen in normal epithelial cells. Thus, the TLR system should be considered an important target in future antitumour immunotherapy.
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