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Siglecg limits the size of B1a B cell lineage by down-regulating NFkappaB activation.

Ding C, Liu Y, Wang Y, Park BK, Wang CY, Zheng P, Liu Y - PLoS ONE (2007)

Bottom Line: The expansion of B1a B cells in the peritoneal correlated with enhanced activation of NFkappaB and was ablated by an IKK inhibitor.Our data revealed a critical role for Siglec G-NFkappaB pathway in regulating B1a B cell lineage.These data lead to a novel model of B1a lineage development that explains a large array of genetic data in this field.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunotherapy, Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America.

ABSTRACT

Background: B1 B cells are believed to be a unique lineage with a distinct developmental pathway, function and activation requirement. How this lineage is genetically determined remained largely obscure.

Methods and principal findings: Using the Siglecg-deficient mice with a knockin of green-fluorescent protein encoding sequence, we show here that, although the Siglecg gene is broadly expressed at high levels in all stages and/or lineages of B cells tested and at lower levels in other lineages, its deletion selectively expanded the B1a B cell lineages, including the frequency of the B1 cell progenitor in the bone marrow and the number of B1a cells in the peritoneal cavity, by postnatal expansion. The expansion of B1a B cells in the peritoneal correlated with enhanced activation of NFkappaB and was ablated by an IKK inhibitor.

Conclusion and significance: Our data revealed a critical role for Siglec G-NFkappaB pathway in regulating B1a B cell lineage. These data lead to a novel model of B1a lineage development that explains a large array of genetic data in this field.

Show MeSH
Selective expansion of peritoneal cavity B1a cells in mice with targeted mutation of the Siglecg gene.A. Expansion of B1a, but not B1b subsets. The top panel shows the profile of B cells among peritoneal lavages of 10 weeks old mutant and age-matched WT controls, while the lower panel shows summary data involving 10 mice per group. This experiment has been repeated 5 times involving a total of 10–12 mice per group. C. Serum concentration of different isotypes of Ig, note substantial increase of IgM and decrease of IgG1 in the mutant mice. Data shown in the lower panels are Means+SEM, with 20 mice per group. D. Adaptive B cell response in WT and the Siglecg-deficient mice. The WT and Siglecg-deficient mice were immunized with 200 µg of OVA in complete Freunds' adjuvants (CFA) on day 0, boosted with the same amounts of OVA on day 7. Sera were collected on day 1, 7 and 14 for measurement of anti-OVA antibodies by ELISA using the OVA-coated plate. Data shown are means+SEM of optical density, n = 6. Sera were used at 1∶500 dilutions for the ELISA.
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pone-0000997-g002: Selective expansion of peritoneal cavity B1a cells in mice with targeted mutation of the Siglecg gene.A. Expansion of B1a, but not B1b subsets. The top panel shows the profile of B cells among peritoneal lavages of 10 weeks old mutant and age-matched WT controls, while the lower panel shows summary data involving 10 mice per group. This experiment has been repeated 5 times involving a total of 10–12 mice per group. C. Serum concentration of different isotypes of Ig, note substantial increase of IgM and decrease of IgG1 in the mutant mice. Data shown in the lower panels are Means+SEM, with 20 mice per group. D. Adaptive B cell response in WT and the Siglecg-deficient mice. The WT and Siglecg-deficient mice were immunized with 200 µg of OVA in complete Freunds' adjuvants (CFA) on day 0, boosted with the same amounts of OVA on day 7. Sera were collected on day 1, 7 and 14 for measurement of anti-OVA antibodies by ELISA using the OVA-coated plate. Data shown are means+SEM of optical density, n = 6. Sera were used at 1∶500 dilutions for the ELISA.

Mentions: Given the wide-spread expression of Siglecg, we determined whether targeted mutation of the gene affects the development of different compartments of the hematopoeitic cells by flow cytometry. As shown in table 1, the compositions of the major hematopoeitic subsets, including HSC, T cells, myeloid cells, dendritic cells and different stages of B cells, were comparable between the WT and the mutant mice. Surprisingly, we have observed a 5-fold increase in the size of B1a cells in the peritoneal, although the number of B1b subset was unchanged (Fig. 2A). The number of B1a cells in the spleen, however, did not differ in adult mice (Fig. 2B lower panel and table 1), although a two fold expansion of spleen B1 B cells can be observed at two weeks (Fig. 2B, upper panel).


Siglecg limits the size of B1a B cell lineage by down-regulating NFkappaB activation.

Ding C, Liu Y, Wang Y, Park BK, Wang CY, Zheng P, Liu Y - PLoS ONE (2007)

Selective expansion of peritoneal cavity B1a cells in mice with targeted mutation of the Siglecg gene.A. Expansion of B1a, but not B1b subsets. The top panel shows the profile of B cells among peritoneal lavages of 10 weeks old mutant and age-matched WT controls, while the lower panel shows summary data involving 10 mice per group. This experiment has been repeated 5 times involving a total of 10–12 mice per group. C. Serum concentration of different isotypes of Ig, note substantial increase of IgM and decrease of IgG1 in the mutant mice. Data shown in the lower panels are Means+SEM, with 20 mice per group. D. Adaptive B cell response in WT and the Siglecg-deficient mice. The WT and Siglecg-deficient mice were immunized with 200 µg of OVA in complete Freunds' adjuvants (CFA) on day 0, boosted with the same amounts of OVA on day 7. Sera were collected on day 1, 7 and 14 for measurement of anti-OVA antibodies by ELISA using the OVA-coated plate. Data shown are means+SEM of optical density, n = 6. Sera were used at 1∶500 dilutions for the ELISA.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC1994585&req=5

pone-0000997-g002: Selective expansion of peritoneal cavity B1a cells in mice with targeted mutation of the Siglecg gene.A. Expansion of B1a, but not B1b subsets. The top panel shows the profile of B cells among peritoneal lavages of 10 weeks old mutant and age-matched WT controls, while the lower panel shows summary data involving 10 mice per group. This experiment has been repeated 5 times involving a total of 10–12 mice per group. C. Serum concentration of different isotypes of Ig, note substantial increase of IgM and decrease of IgG1 in the mutant mice. Data shown in the lower panels are Means+SEM, with 20 mice per group. D. Adaptive B cell response in WT and the Siglecg-deficient mice. The WT and Siglecg-deficient mice were immunized with 200 µg of OVA in complete Freunds' adjuvants (CFA) on day 0, boosted with the same amounts of OVA on day 7. Sera were collected on day 1, 7 and 14 for measurement of anti-OVA antibodies by ELISA using the OVA-coated plate. Data shown are means+SEM of optical density, n = 6. Sera were used at 1∶500 dilutions for the ELISA.
Mentions: Given the wide-spread expression of Siglecg, we determined whether targeted mutation of the gene affects the development of different compartments of the hematopoeitic cells by flow cytometry. As shown in table 1, the compositions of the major hematopoeitic subsets, including HSC, T cells, myeloid cells, dendritic cells and different stages of B cells, were comparable between the WT and the mutant mice. Surprisingly, we have observed a 5-fold increase in the size of B1a cells in the peritoneal, although the number of B1b subset was unchanged (Fig. 2A). The number of B1a cells in the spleen, however, did not differ in adult mice (Fig. 2B lower panel and table 1), although a two fold expansion of spleen B1 B cells can be observed at two weeks (Fig. 2B, upper panel).

Bottom Line: The expansion of B1a B cells in the peritoneal correlated with enhanced activation of NFkappaB and was ablated by an IKK inhibitor.Our data revealed a critical role for Siglec G-NFkappaB pathway in regulating B1a B cell lineage.These data lead to a novel model of B1a lineage development that explains a large array of genetic data in this field.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunotherapy, Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America.

ABSTRACT

Background: B1 B cells are believed to be a unique lineage with a distinct developmental pathway, function and activation requirement. How this lineage is genetically determined remained largely obscure.

Methods and principal findings: Using the Siglecg-deficient mice with a knockin of green-fluorescent protein encoding sequence, we show here that, although the Siglecg gene is broadly expressed at high levels in all stages and/or lineages of B cells tested and at lower levels in other lineages, its deletion selectively expanded the B1a B cell lineages, including the frequency of the B1 cell progenitor in the bone marrow and the number of B1a cells in the peritoneal cavity, by postnatal expansion. The expansion of B1a B cells in the peritoneal correlated with enhanced activation of NFkappaB and was ablated by an IKK inhibitor.

Conclusion and significance: Our data revealed a critical role for Siglec G-NFkappaB pathway in regulating B1a B cell lineage. These data lead to a novel model of B1a lineage development that explains a large array of genetic data in this field.

Show MeSH