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DQB1*0602 rather than DRB1*1501 confers susceptibility to multiple sclerosis-like disease induced by proteolipid protein (PLP).

Kaushansky N, Altmann DM, David CS, Lassmann H, Ben-Nun A - J Neuroinflammation (2012)

Bottom Line: Due to strong linkage disequilibrium in HLA-II region, it has been hard to establish precisely whether the functionally relevant effect derives from the DRB1*1501, DQA1*0102-DQB1*0602, or DRB5*0101 loci of HLA-DR15 haplotype, their combinations, or their epistatic interactions.Moreover, that DQB1*0602, but not DRB1*1501, determines disease-susceptibility to PLP in HLA-transgenics, suggests a potential differential, functional role for DQB1*0602 as a predisposing allele in MS.This, together with previously demonstrated disease-susceptibility to MBP and MOG in DRB1*1501-transgenics, also suggests a differential role for DRB1*1501 and DQB1*0602 depending on target antigen and imply a potential complex 'genotype/target antigen/phenotype' relationship in MS heterogeneity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel.

ABSTRACT

Background: Multiple sclerosis (MS) is associated with pathogenic autoimmunity primarily focused on major CNS-myelin target antigens including myelin basic protein (MBP), proteolipidprotein (PLP), myelin oligodendrocyte protein (MOG). MS is a complex trait whereby the HLA genes, particularly class-II genes of HLA-DR15 haplotype, dominate the genetic contribution to disease-risk. Due to strong linkage disequilibrium in HLA-II region, it has been hard to establish precisely whether the functionally relevant effect derives from the DRB1*1501, DQA1*0102-DQB1*0602, or DRB5*0101 loci of HLA-DR15 haplotype, their combinations, or their epistatic interactions. Nevertheless, most genetic studies have indicated DRB1*1501 as a primary risk factor in MS. Here, we used 'HLA-humanized' mice to discern the potential relative contribution of DRB1*1501 and DQB1*0602 alleles to susceptibility to "humanized" MS-like disease induced by PLP, one of the most prominent and encephalitogenic target-antigens implicated in human MS.

Methods: The HLA-DRB1*1501- and HLA-DQB1*0602-Tg mice (MHC-II(-/-)), and control non-HLA-DR15-relevant-Tg mice were immunized with a set of overlapping PLP peptides or with recombinant soluble PLP for induction of "humanized" MS-like disease, as well as for ex-vivo analysis of immunogenic/immunodominant HLA-restricted T-cell epitopes and associated cytokine secretion profile.

Results: PLP autoimmunity in both HLA-DR15-Tg mice was focused on 139-151 and 175-194 epitopes. Strikingly, however, the HLA-DRB1*1501-transgenics were refractory to disease induction by any of the overlapping PLP peptides, while HLA-DQB1*0602 transgenics were susceptible to disease induction by PLP139-151 and PLP175-194 peptides. Although both transgenics responded to both peptides, the PLP139-151- and PLP175-194-reactive T-cells were directed to Th1/Th17 phenotype in DQB1*0602-Tg mice and towards Th2 in DRB1*1501-Tg mice.

Conclusions: While genome studies map a strong MS susceptibility effect to the region of DRB1*1501, our findings offer a rationale for potential involvement of pathogenic DQ6-associated autoimmunity in MS. Moreover, that DQB1*0602, but not DRB1*1501, determines disease-susceptibility to PLP in HLA-transgenics, suggests a potential differential, functional role for DQB1*0602 as a predisposing allele in MS. This, together with previously demonstrated disease-susceptibility to MBP and MOG in DRB1*1501-transgenics, also suggests a differential role for DRB1*1501 and DQB1*0602 depending on target antigen and imply a potential complex 'genotype/target antigen/phenotype' relationship in MS heterogeneity.

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Cytokine secretion profile of phPLP139-151, 175-194, and 257-276-primed LNC derived from immunized DRB1*1501- or DQB1*0602-Tg mice. HLA-DRB1*1501- and DQB1*0602-Tg mice were immunized by s.c. injection of 150 μg phPLP139-151, phPLP175-194 or phPLP257-276 (as control) in CFA. Ten days later, draining LNC (pooled from 3 mice) were cultured for 48 h without or with the immunizing peptide, respectively, and supernatants were analyzed for the secretion of indicated cytokines. Values presented (pg/ml) are after background (without antigen) cytokines were subtracted. The results represent three experiments done in triplicates, and are the mean cytokine concentration ± SE.
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Figure 5: Cytokine secretion profile of phPLP139-151, 175-194, and 257-276-primed LNC derived from immunized DRB1*1501- or DQB1*0602-Tg mice. HLA-DRB1*1501- and DQB1*0602-Tg mice were immunized by s.c. injection of 150 μg phPLP139-151, phPLP175-194 or phPLP257-276 (as control) in CFA. Ten days later, draining LNC (pooled from 3 mice) were cultured for 48 h without or with the immunizing peptide, respectively, and supernatants were analyzed for the secretion of indicated cytokines. Values presented (pg/ml) are after background (without antigen) cytokines were subtracted. The results represent three experiments done in triplicates, and are the mean cytokine concentration ± SE.

Mentions: The finding that phPLP139-151 and phPLP175-194 were encephalitogenic only in DQB1*0602 but not in DRB1*1501 Tg mice, despite their ability to stimulate quantitatively similar T cell responses in both Tg lines demanded further investigation. We therefore analyzed the Th1/Th2/Th17 cytokine profiles associated with the T-cell reactivity to phPLP139-151 and phPLP175-194 by both Tg lines. The phPLP139-151- and phPLP175-194-primed LNCs derived from DRB1*1501- or DQB1*0602-Tg mice were stimulated ex-vivo with the relevant priming peptide, and cytokines secreted into the supernatants were analyzed. Figure 5 shows that reactivity against phPLP139-151 and phPLP175-194 in DQB1*0602-Tg mice was explicitly pro-inflammatory, with variably high secretion of IL-2, IFNγ, IL-17 and TNFα by PLP139-151- or PLP175-194-reactive T-cells, respectively, and relatively low IL-4 and IL-10. This Th1/Th17 cytokine profile (Figure 5) correlates with the encephalitogenic capacity of phPLP139-151 and phPLP175-194 in-DQB1*0602-Tg mice (Table 2, Figure 4). Moreover, the consistently lower secretion of IL-17 and IL-2 by phPLP139-151- compared to phPLP175-194- primed LNCs derived from DQB1*0602-Tg mice, is consistent with the lower encephalitogenic potential of phPLP139-151 compared to phPLP175-194 in DQB1*0602-Tg mice (Table 2 &Figure 4). In contrast to DQB1*0602-Tg mice, the cytokine profile of the DRB1*1501-derived primed LNCs against the relevant priming peptide, phPLP139-151 or phPLP175-194, was of a more anti-inflammatory type, with low IL-2, IFNγ, TNFα and IL-17, and with secretion of IL-4 by PLP139-151-reactive T-cells (Figure 5). Thus, the Th2 phenotype of the phPLP139-151-reactive T-cells, and the very low secretion of pro-inflammatory cytokines by phPLP175-194-reactive T-cells derived from DRB1*1501-Tg mice may explain the relative resistance of these mice to EAE induction by phPLP139-151 or by phPLP175-194.


DQB1*0602 rather than DRB1*1501 confers susceptibility to multiple sclerosis-like disease induced by proteolipid protein (PLP).

Kaushansky N, Altmann DM, David CS, Lassmann H, Ben-Nun A - J Neuroinflammation (2012)

Cytokine secretion profile of phPLP139-151, 175-194, and 257-276-primed LNC derived from immunized DRB1*1501- or DQB1*0602-Tg mice. HLA-DRB1*1501- and DQB1*0602-Tg mice were immunized by s.c. injection of 150 μg phPLP139-151, phPLP175-194 or phPLP257-276 (as control) in CFA. Ten days later, draining LNC (pooled from 3 mice) were cultured for 48 h without or with the immunizing peptide, respectively, and supernatants were analyzed for the secretion of indicated cytokines. Values presented (pg/ml) are after background (without antigen) cytokines were subtracted. The results represent three experiments done in triplicates, and are the mean cytokine concentration ± SE.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
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Figure 5: Cytokine secretion profile of phPLP139-151, 175-194, and 257-276-primed LNC derived from immunized DRB1*1501- or DQB1*0602-Tg mice. HLA-DRB1*1501- and DQB1*0602-Tg mice were immunized by s.c. injection of 150 μg phPLP139-151, phPLP175-194 or phPLP257-276 (as control) in CFA. Ten days later, draining LNC (pooled from 3 mice) were cultured for 48 h without or with the immunizing peptide, respectively, and supernatants were analyzed for the secretion of indicated cytokines. Values presented (pg/ml) are after background (without antigen) cytokines were subtracted. The results represent three experiments done in triplicates, and are the mean cytokine concentration ± SE.
Mentions: The finding that phPLP139-151 and phPLP175-194 were encephalitogenic only in DQB1*0602 but not in DRB1*1501 Tg mice, despite their ability to stimulate quantitatively similar T cell responses in both Tg lines demanded further investigation. We therefore analyzed the Th1/Th2/Th17 cytokine profiles associated with the T-cell reactivity to phPLP139-151 and phPLP175-194 by both Tg lines. The phPLP139-151- and phPLP175-194-primed LNCs derived from DRB1*1501- or DQB1*0602-Tg mice were stimulated ex-vivo with the relevant priming peptide, and cytokines secreted into the supernatants were analyzed. Figure 5 shows that reactivity against phPLP139-151 and phPLP175-194 in DQB1*0602-Tg mice was explicitly pro-inflammatory, with variably high secretion of IL-2, IFNγ, IL-17 and TNFα by PLP139-151- or PLP175-194-reactive T-cells, respectively, and relatively low IL-4 and IL-10. This Th1/Th17 cytokine profile (Figure 5) correlates with the encephalitogenic capacity of phPLP139-151 and phPLP175-194 in-DQB1*0602-Tg mice (Table 2, Figure 4). Moreover, the consistently lower secretion of IL-17 and IL-2 by phPLP139-151- compared to phPLP175-194- primed LNCs derived from DQB1*0602-Tg mice, is consistent with the lower encephalitogenic potential of phPLP139-151 compared to phPLP175-194 in DQB1*0602-Tg mice (Table 2 &Figure 4). In contrast to DQB1*0602-Tg mice, the cytokine profile of the DRB1*1501-derived primed LNCs against the relevant priming peptide, phPLP139-151 or phPLP175-194, was of a more anti-inflammatory type, with low IL-2, IFNγ, TNFα and IL-17, and with secretion of IL-4 by PLP139-151-reactive T-cells (Figure 5). Thus, the Th2 phenotype of the phPLP139-151-reactive T-cells, and the very low secretion of pro-inflammatory cytokines by phPLP175-194-reactive T-cells derived from DRB1*1501-Tg mice may explain the relative resistance of these mice to EAE induction by phPLP139-151 or by phPLP175-194.

Bottom Line: Due to strong linkage disequilibrium in HLA-II region, it has been hard to establish precisely whether the functionally relevant effect derives from the DRB1*1501, DQA1*0102-DQB1*0602, or DRB5*0101 loci of HLA-DR15 haplotype, their combinations, or their epistatic interactions.Moreover, that DQB1*0602, but not DRB1*1501, determines disease-susceptibility to PLP in HLA-transgenics, suggests a potential differential, functional role for DQB1*0602 as a predisposing allele in MS.This, together with previously demonstrated disease-susceptibility to MBP and MOG in DRB1*1501-transgenics, also suggests a differential role for DRB1*1501 and DQB1*0602 depending on target antigen and imply a potential complex 'genotype/target antigen/phenotype' relationship in MS heterogeneity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel.

ABSTRACT

Background: Multiple sclerosis (MS) is associated with pathogenic autoimmunity primarily focused on major CNS-myelin target antigens including myelin basic protein (MBP), proteolipidprotein (PLP), myelin oligodendrocyte protein (MOG). MS is a complex trait whereby the HLA genes, particularly class-II genes of HLA-DR15 haplotype, dominate the genetic contribution to disease-risk. Due to strong linkage disequilibrium in HLA-II region, it has been hard to establish precisely whether the functionally relevant effect derives from the DRB1*1501, DQA1*0102-DQB1*0602, or DRB5*0101 loci of HLA-DR15 haplotype, their combinations, or their epistatic interactions. Nevertheless, most genetic studies have indicated DRB1*1501 as a primary risk factor in MS. Here, we used 'HLA-humanized' mice to discern the potential relative contribution of DRB1*1501 and DQB1*0602 alleles to susceptibility to "humanized" MS-like disease induced by PLP, one of the most prominent and encephalitogenic target-antigens implicated in human MS.

Methods: The HLA-DRB1*1501- and HLA-DQB1*0602-Tg mice (MHC-II(-/-)), and control non-HLA-DR15-relevant-Tg mice were immunized with a set of overlapping PLP peptides or with recombinant soluble PLP for induction of "humanized" MS-like disease, as well as for ex-vivo analysis of immunogenic/immunodominant HLA-restricted T-cell epitopes and associated cytokine secretion profile.

Results: PLP autoimmunity in both HLA-DR15-Tg mice was focused on 139-151 and 175-194 epitopes. Strikingly, however, the HLA-DRB1*1501-transgenics were refractory to disease induction by any of the overlapping PLP peptides, while HLA-DQB1*0602 transgenics were susceptible to disease induction by PLP139-151 and PLP175-194 peptides. Although both transgenics responded to both peptides, the PLP139-151- and PLP175-194-reactive T-cells were directed to Th1/Th17 phenotype in DQB1*0602-Tg mice and towards Th2 in DRB1*1501-Tg mice.

Conclusions: While genome studies map a strong MS susceptibility effect to the region of DRB1*1501, our findings offer a rationale for potential involvement of pathogenic DQ6-associated autoimmunity in MS. Moreover, that DQB1*0602, but not DRB1*1501, determines disease-susceptibility to PLP in HLA-transgenics, suggests a potential differential, functional role for DQB1*0602 as a predisposing allele in MS. This, together with previously demonstrated disease-susceptibility to MBP and MOG in DRB1*1501-transgenics, also suggests a differential role for DRB1*1501 and DQB1*0602 depending on target antigen and imply a potential complex 'genotype/target antigen/phenotype' relationship in MS heterogeneity.

Show MeSH
Related in: MedlinePlus