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Germline deletion of β2 microglobulin or CD1d reduces anti-phospholipid antibody, but increases autoantibodies against non-phospholipid antigens in the NZB/W F1 model of lupus.

Singh RR, Yang JQ, Kim PJ, Halder RC - Arthritis Res. Ther. (2013)

Bottom Line: Since CD1d is known to bind and present phospholipid antigens to T cells, we asked if the deficiency of β2m or CD1d will impact the development of anti-phospholipid antibodies as compared to other aspects of lupus autoimmunity.Whereas β2m° BWF1 mice had reduced serum IgG, they had increased mortality, nephritis, serum IgG anti-DNA antibody and RF as compared to heterozygous and wild-type littermates.Such CD1d dependence of anti-CL antibody production is not mediated by CD1d/glycolipid-reactive iNKT cells, as these cells reduced the production of RF and anti-DNA antibodies but had no effect on anti-CL antibodies.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: β2-microglobulin (β2m) is required for the surface expression of MHC class I and class I-like proteins such as CD1d, Qa1 and neonatal Fc receptor (FcRn), all of which may impact the development of autoimmunity. Since CD1d is known to bind and present phospholipid antigens to T cells, we asked if the deficiency of β2m or CD1d will impact the development of anti-phospholipid antibodies as compared to other aspects of lupus autoimmunity.

Methods: We introgressed the β2m- genotype onto the NZB and NZW backgrounds for 12 to 14 generations to generate genetically lupus-susceptible (NZB/NZW)F1 (BWF1) mice that are β2m-deficient (β2m°). Circulating immunoglobulins (Ig), rheumatoid factor (RF), anti-DNA and anti-cardiolipin (anti-CL) antibodies, and renal disease were analyzed in these and CD1d-deficient (CD1d°) BWF1 mice that we had previously generated.

Results: Whereas β2m° BWF1 mice had reduced serum IgG, they had increased mortality, nephritis, serum IgG anti-DNA antibody and RF as compared to heterozygous and wild-type littermates. These effects were recapitulated in CD1d° BWF1 mice, except that they also had increased serum IgG as compared to control littermates. Intriguingly, both β2m° and CD1d° mice had lower serum anti-CL antibody levels than in control littermates. Such CD1d dependence of anti-CL antibody production is not mediated by CD1d/glycolipid-reactive iNKT cells, as these cells reduced the production of RF and anti-DNA antibodies but had no effect on anti-CL antibodies.

Conclusions: We report a novel dichotomous role of β2m and CD1d, whereby these molecules differently regulate autoimmunity against phospholipid versus non-phospholipid autoantigens.

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Related in: MedlinePlus

Serum anti-cardiolipin (anti-CL) antibodies are decreased in β2 microglobulin-deficient (β2m°) and CD1d-deficient (CD1d°) BWF1 mice. (a-c) β2m° or CD1d° BWF1 mice and control littermates (β2m+/+ or β2m+/-, designated as β2m+; and CD1d+/+ or CD1d+/-, designated as CD1d+) were bled and serum samples tested for serum immunoglobulin G (IgG) anti-CL antibodies: (a) 4-month-old β2m+ (n = 88) and β2m° (n = 32); (b) 6- to 8-month-old β2m+ (n = 75) and β2m° (n = 14); (c) 7- to 8-month-old CD1d+ (n = 57) and CD1d° (n = 26) mice. Each symbol represents a single mouse, and horizontal bars represent the mean U/ml for the group. The negative control mean ± SD values for anti-CL antibody in six normal BALB/c mice was 15.1 ± 5.2 U/ml. *P <0.01, Student's t-test.
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Figure 5: Serum anti-cardiolipin (anti-CL) antibodies are decreased in β2 microglobulin-deficient (β2m°) and CD1d-deficient (CD1d°) BWF1 mice. (a-c) β2m° or CD1d° BWF1 mice and control littermates (β2m+/+ or β2m+/-, designated as β2m+; and CD1d+/+ or CD1d+/-, designated as CD1d+) were bled and serum samples tested for serum immunoglobulin G (IgG) anti-CL antibodies: (a) 4-month-old β2m+ (n = 88) and β2m° (n = 32); (b) 6- to 8-month-old β2m+ (n = 75) and β2m° (n = 14); (c) 7- to 8-month-old CD1d+ (n = 57) and CD1d° (n = 26) mice. Each symbol represents a single mouse, and horizontal bars represent the mean U/ml for the group. The negative control mean ± SD values for anti-CL antibody in six normal BALB/c mice was 15.1 ± 5.2 U/ml. *P <0.01, Student's t-test.

Mentions: Preliminary analyses of autoantibodies using ELISA and western blot showed that a variety of antibodies against cellular and nuclear antigens were higher in β2m° BWF1 mice than in control littermates (data not shown). Surprisingly, however, no β2m° BWF1 mice had anti-CL antibodies above the cutoff level (mean + 4 (SD) OD in normal BALB/c mice). Subsequent analysis in a large cohort of mice showed that 6 to 10% of β2m° BWF1 mice compared to 36 to 39% of control littermates were positive for IgG anti-CL antibodies at different ages (P <0.01, Fisher's exact test). Levels of serum anti-phospholipid antibody were significantly lower in β2m° BWF1 mice than in control littermates (Figure 5a, b). These data suggest a contribution of β2m in the production of anti-CL antibodies in BWF1 mice.


Germline deletion of β2 microglobulin or CD1d reduces anti-phospholipid antibody, but increases autoantibodies against non-phospholipid antigens in the NZB/W F1 model of lupus.

Singh RR, Yang JQ, Kim PJ, Halder RC - Arthritis Res. Ther. (2013)

Serum anti-cardiolipin (anti-CL) antibodies are decreased in β2 microglobulin-deficient (β2m°) and CD1d-deficient (CD1d°) BWF1 mice. (a-c) β2m° or CD1d° BWF1 mice and control littermates (β2m+/+ or β2m+/-, designated as β2m+; and CD1d+/+ or CD1d+/-, designated as CD1d+) were bled and serum samples tested for serum immunoglobulin G (IgG) anti-CL antibodies: (a) 4-month-old β2m+ (n = 88) and β2m° (n = 32); (b) 6- to 8-month-old β2m+ (n = 75) and β2m° (n = 14); (c) 7- to 8-month-old CD1d+ (n = 57) and CD1d° (n = 26) mice. Each symbol represents a single mouse, and horizontal bars represent the mean U/ml for the group. The negative control mean ± SD values for anti-CL antibody in six normal BALB/c mice was 15.1 ± 5.2 U/ml. *P <0.01, Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672782&req=5

Figure 5: Serum anti-cardiolipin (anti-CL) antibodies are decreased in β2 microglobulin-deficient (β2m°) and CD1d-deficient (CD1d°) BWF1 mice. (a-c) β2m° or CD1d° BWF1 mice and control littermates (β2m+/+ or β2m+/-, designated as β2m+; and CD1d+/+ or CD1d+/-, designated as CD1d+) were bled and serum samples tested for serum immunoglobulin G (IgG) anti-CL antibodies: (a) 4-month-old β2m+ (n = 88) and β2m° (n = 32); (b) 6- to 8-month-old β2m+ (n = 75) and β2m° (n = 14); (c) 7- to 8-month-old CD1d+ (n = 57) and CD1d° (n = 26) mice. Each symbol represents a single mouse, and horizontal bars represent the mean U/ml for the group. The negative control mean ± SD values for anti-CL antibody in six normal BALB/c mice was 15.1 ± 5.2 U/ml. *P <0.01, Student's t-test.
Mentions: Preliminary analyses of autoantibodies using ELISA and western blot showed that a variety of antibodies against cellular and nuclear antigens were higher in β2m° BWF1 mice than in control littermates (data not shown). Surprisingly, however, no β2m° BWF1 mice had anti-CL antibodies above the cutoff level (mean + 4 (SD) OD in normal BALB/c mice). Subsequent analysis in a large cohort of mice showed that 6 to 10% of β2m° BWF1 mice compared to 36 to 39% of control littermates were positive for IgG anti-CL antibodies at different ages (P <0.01, Fisher's exact test). Levels of serum anti-phospholipid antibody were significantly lower in β2m° BWF1 mice than in control littermates (Figure 5a, b). These data suggest a contribution of β2m in the production of anti-CL antibodies in BWF1 mice.

Bottom Line: Since CD1d is known to bind and present phospholipid antigens to T cells, we asked if the deficiency of β2m or CD1d will impact the development of anti-phospholipid antibodies as compared to other aspects of lupus autoimmunity.Whereas β2m° BWF1 mice had reduced serum IgG, they had increased mortality, nephritis, serum IgG anti-DNA antibody and RF as compared to heterozygous and wild-type littermates.Such CD1d dependence of anti-CL antibody production is not mediated by CD1d/glycolipid-reactive iNKT cells, as these cells reduced the production of RF and anti-DNA antibodies but had no effect on anti-CL antibodies.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: β2-microglobulin (β2m) is required for the surface expression of MHC class I and class I-like proteins such as CD1d, Qa1 and neonatal Fc receptor (FcRn), all of which may impact the development of autoimmunity. Since CD1d is known to bind and present phospholipid antigens to T cells, we asked if the deficiency of β2m or CD1d will impact the development of anti-phospholipid antibodies as compared to other aspects of lupus autoimmunity.

Methods: We introgressed the β2m- genotype onto the NZB and NZW backgrounds for 12 to 14 generations to generate genetically lupus-susceptible (NZB/NZW)F1 (BWF1) mice that are β2m-deficient (β2m°). Circulating immunoglobulins (Ig), rheumatoid factor (RF), anti-DNA and anti-cardiolipin (anti-CL) antibodies, and renal disease were analyzed in these and CD1d-deficient (CD1d°) BWF1 mice that we had previously generated.

Results: Whereas β2m° BWF1 mice had reduced serum IgG, they had increased mortality, nephritis, serum IgG anti-DNA antibody and RF as compared to heterozygous and wild-type littermates. These effects were recapitulated in CD1d° BWF1 mice, except that they also had increased serum IgG as compared to control littermates. Intriguingly, both β2m° and CD1d° mice had lower serum anti-CL antibody levels than in control littermates. Such CD1d dependence of anti-CL antibody production is not mediated by CD1d/glycolipid-reactive iNKT cells, as these cells reduced the production of RF and anti-DNA antibodies but had no effect on anti-CL antibodies.

Conclusions: We report a novel dichotomous role of β2m and CD1d, whereby these molecules differently regulate autoimmunity against phospholipid versus non-phospholipid autoantigens.

Show MeSH
Related in: MedlinePlus