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B cell activating factor (BAFF) and T cells cooperate to breach B cell tolerance in lupus-prone New Zealand Black (NZB) mice.

Chang NH, Cheung YH, Loh C, Pau E, Roy V, Cai YC, Wither J - PLoS ONE (2010)

Bottom Line: Treatment of NZB sHEL recipient mice with TACI-Ig reduced NZB dTg B cell survival following adoptive transfer, confirming the role of BAFF in this process.In contrast, T cell blockade had a minimal effect on B cell survival, but inhibited anti-HEL antibody production.The findings suggest that the modest BAFF elevations in NZB mice are sufficient to perturb B cell tolerance, particularly when acting in concert with B cell functional abnormalities and T cell help.

View Article: PubMed Central - PubMed

Affiliation: Arthritis Centre of Excellence, Toronto Western Research Institute, Toronto, Ontario, Canada.

ABSTRACT
The presence of autoantibodies in New Zealand Black (NZB) mice suggests a B cell tolerance defect however the nature of this defect is unknown. To determine whether defects in B cell anergy contribute to the autoimmune phenotype in NZB mice, soluble hen egg lysozyme (sHEL) and anti-HEL Ig transgenes were bred onto the NZB background to generate double transgenic (dTg) mice. NZB dTg mice had elevated levels of anti-HEL antibodies, despite apparently normal B cell functional anergy in-vitro. NZB dTg B cells also demonstrated increased survival and abnormal entry into the follicular compartment following transfer into sHEL mice. Since this process is dependent on BAFF, BAFF serum and mRNA levels were assessed and were found to be significantly elevated in NZB dTg mice. Treatment of NZB sHEL recipient mice with TACI-Ig reduced NZB dTg B cell survival following adoptive transfer, confirming the role of BAFF in this process. Although NZB mice had modestly elevated BAFF, the enhanced NZB B cell survival response appeared to result from an altered response to BAFF. In contrast, T cell blockade had a minimal effect on B cell survival, but inhibited anti-HEL antibody production. The findings suggest that the modest BAFF elevations in NZB mice are sufficient to perturb B cell tolerance, particularly when acting in concert with B cell functional abnormalities and T cell help.

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NZB dTg B cells appear functionally anergic in-vitro.(A) Sorted B cells from IgTg and dTg B6 or NZB mice were stimulated in-vitro with increasing concentrations of HEL (0 to 1 µg/ml) together with a submitogenic concentration of LPS (50 ng/mL). B cell proliferation was measured by [3H]-thymidine incorporation at 36 h by pulsing the cells overnight with 1 µCi/well. Uptake of [3H]-thymidine was quantified using a scintillation counter and expressed as mean cpm ± SD of triplicate wells. Results are representative of three independent experiments. (B) The percentage of CD86+ cells was measured 16 h after stimulation with 1 µg/ml HEL, gating on the B220+IgMa+ population.
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pone-0011691-g002: NZB dTg B cells appear functionally anergic in-vitro.(A) Sorted B cells from IgTg and dTg B6 or NZB mice were stimulated in-vitro with increasing concentrations of HEL (0 to 1 µg/ml) together with a submitogenic concentration of LPS (50 ng/mL). B cell proliferation was measured by [3H]-thymidine incorporation at 36 h by pulsing the cells overnight with 1 µCi/well. Uptake of [3H]-thymidine was quantified using a scintillation counter and expressed as mean cpm ± SD of triplicate wells. Results are representative of three independent experiments. (B) The percentage of CD86+ cells was measured 16 h after stimulation with 1 µg/ml HEL, gating on the B220+IgMa+ population.

Mentions: Anergic B cells do not proliferate and demonstrate impaired induction of CD86 in response to antigenic stimulation [29], [30]. Therefore, sorted B cells were stimulated in-vitro with various concentrations of HEL together with a sub-mitogenic concentration of LPS. As shown in Figure 2A, B cells from both B6 and NZB IgTg mice showed a strong proliferative response to HEL in a concentration-dependent fashion. In contrast, neither B6 nor NZB dTg B cells proliferated in response to any of the concentrations of HEL tested, suggesting that NZB dTg B cells are equivalently anergic to their B6 counterparts. Consistent with this observation, induction of CD86 expression following overnight incubation with HEL was similarly reduced for B6 and NZB dTg B cells, as compared to corresponding IgTg controls (Figure 2B). Thus, B cells from NZB dTg mice are both phenotypically and functionally anergic.


B cell activating factor (BAFF) and T cells cooperate to breach B cell tolerance in lupus-prone New Zealand Black (NZB) mice.

Chang NH, Cheung YH, Loh C, Pau E, Roy V, Cai YC, Wither J - PLoS ONE (2010)

NZB dTg B cells appear functionally anergic in-vitro.(A) Sorted B cells from IgTg and dTg B6 or NZB mice were stimulated in-vitro with increasing concentrations of HEL (0 to 1 µg/ml) together with a submitogenic concentration of LPS (50 ng/mL). B cell proliferation was measured by [3H]-thymidine incorporation at 36 h by pulsing the cells overnight with 1 µCi/well. Uptake of [3H]-thymidine was quantified using a scintillation counter and expressed as mean cpm ± SD of triplicate wells. Results are representative of three independent experiments. (B) The percentage of CD86+ cells was measured 16 h after stimulation with 1 µg/ml HEL, gating on the B220+IgMa+ population.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2908288&req=5

pone-0011691-g002: NZB dTg B cells appear functionally anergic in-vitro.(A) Sorted B cells from IgTg and dTg B6 or NZB mice were stimulated in-vitro with increasing concentrations of HEL (0 to 1 µg/ml) together with a submitogenic concentration of LPS (50 ng/mL). B cell proliferation was measured by [3H]-thymidine incorporation at 36 h by pulsing the cells overnight with 1 µCi/well. Uptake of [3H]-thymidine was quantified using a scintillation counter and expressed as mean cpm ± SD of triplicate wells. Results are representative of three independent experiments. (B) The percentage of CD86+ cells was measured 16 h after stimulation with 1 µg/ml HEL, gating on the B220+IgMa+ population.
Mentions: Anergic B cells do not proliferate and demonstrate impaired induction of CD86 in response to antigenic stimulation [29], [30]. Therefore, sorted B cells were stimulated in-vitro with various concentrations of HEL together with a sub-mitogenic concentration of LPS. As shown in Figure 2A, B cells from both B6 and NZB IgTg mice showed a strong proliferative response to HEL in a concentration-dependent fashion. In contrast, neither B6 nor NZB dTg B cells proliferated in response to any of the concentrations of HEL tested, suggesting that NZB dTg B cells are equivalently anergic to their B6 counterparts. Consistent with this observation, induction of CD86 expression following overnight incubation with HEL was similarly reduced for B6 and NZB dTg B cells, as compared to corresponding IgTg controls (Figure 2B). Thus, B cells from NZB dTg mice are both phenotypically and functionally anergic.

Bottom Line: Treatment of NZB sHEL recipient mice with TACI-Ig reduced NZB dTg B cell survival following adoptive transfer, confirming the role of BAFF in this process.In contrast, T cell blockade had a minimal effect on B cell survival, but inhibited anti-HEL antibody production.The findings suggest that the modest BAFF elevations in NZB mice are sufficient to perturb B cell tolerance, particularly when acting in concert with B cell functional abnormalities and T cell help.

View Article: PubMed Central - PubMed

Affiliation: Arthritis Centre of Excellence, Toronto Western Research Institute, Toronto, Ontario, Canada.

ABSTRACT
The presence of autoantibodies in New Zealand Black (NZB) mice suggests a B cell tolerance defect however the nature of this defect is unknown. To determine whether defects in B cell anergy contribute to the autoimmune phenotype in NZB mice, soluble hen egg lysozyme (sHEL) and anti-HEL Ig transgenes were bred onto the NZB background to generate double transgenic (dTg) mice. NZB dTg mice had elevated levels of anti-HEL antibodies, despite apparently normal B cell functional anergy in-vitro. NZB dTg B cells also demonstrated increased survival and abnormal entry into the follicular compartment following transfer into sHEL mice. Since this process is dependent on BAFF, BAFF serum and mRNA levels were assessed and were found to be significantly elevated in NZB dTg mice. Treatment of NZB sHEL recipient mice with TACI-Ig reduced NZB dTg B cell survival following adoptive transfer, confirming the role of BAFF in this process. Although NZB mice had modestly elevated BAFF, the enhanced NZB B cell survival response appeared to result from an altered response to BAFF. In contrast, T cell blockade had a minimal effect on B cell survival, but inhibited anti-HEL antibody production. The findings suggest that the modest BAFF elevations in NZB mice are sufficient to perturb B cell tolerance, particularly when acting in concert with B cell functional abnormalities and T cell help.

Show MeSH
Related in: MedlinePlus