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A crucial role for the p110delta subunit of phosphatidylinositol 3-kinase in B cell development and activation.

Clayton E, Bardi G, Bell SE, Chantry D, Downes CP, Gray A, Humphries LA, Rawlings D, Reynolds H, Vigorito E, Turner M - J. Exp. Med. (2002)

Bottom Line: Mice lacking the p110delta catalytic subunit of phosphatidylinositol 3-kinase have reduced numbers of B1 and marginal zone B cells, reduced levels of serum immunoglobulins, respond poorly to immunization with type II thymus-independent antigen, and are defective in their primary and secondary responses to thymus-dependent antigen. p110delta(-/-) B cells proliferate poorly in response to B cell receptor (BCR) or CD40 signals in vitro, fail to activate protein kinase B, and are prone to apoptosis. p110delta function is required for BCR-mediated calcium flux, activation of phosphlipaseCgamma2, and Bruton's tyrosine kinase.Thus, p110delta plays a critical role in B cell homeostasis and function.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Lymphocyte Signaling and Development, Molecular Immunology Programme, The Babraham Institute, Babraham, Cambridge CB2 4AT, United Kingdom.

ABSTRACT
Mice lacking the p110delta catalytic subunit of phosphatidylinositol 3-kinase have reduced numbers of B1 and marginal zone B cells, reduced levels of serum immunoglobulins, respond poorly to immunization with type II thymus-independent antigen, and are defective in their primary and secondary responses to thymus-dependent antigen. p110delta(-/-) B cells proliferate poorly in response to B cell receptor (BCR) or CD40 signals in vitro, fail to activate protein kinase B, and are prone to apoptosis. p110delta function is required for BCR-mediated calcium flux, activation of phosphlipaseCgamma2, and Bruton's tyrosine kinase. Thus, p110delta plays a critical role in B cell homeostasis and function.

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Immune function in p110δ mutant mice. (A) Serum Ig levels in naive mice were measured by ELISA. (B) DNP-specific Ig of the indicated isotypes were determined by ELISA of “preimmune” collected before immunization, and “immune” sera collected 7 d after immunization with DNP-Ficoll. (C) DNP-specific Ig was measured in preimmune serum, and in serum taken 7 and 21 d after immunization with DNP-KLH. Mice were then reimmunized at 21 d and bled 7 d later to measure the secondary response. In each set of graphs, the relative unit (absorbance) value for individual control animals is represented by a filled circle, individual p110δ-deficient mice are represented by open circles. Bars represent the average and SD for the group. In the TD responses, arrows represent the points at which mice were immunized (days 1 and 21). P values denote the levels of significance between sera of control and p110δ−/− mice as determined by the Student's t test. a, P < 0.01; b, P < 0.05; c, not significant; d, P < 0.001. (D) Quantitation of germinal center formation in spleens taken 10 d after immunization. The results are expressed as the ratio of PNA+ germinal centers/B220+ follicles. Black bar, wild type; white bar, mutant. Data was compiled from two control mice and four mutant mice. (E) Flow cytometric analysis of lymphocytes from Peyer's patches. Activated B cells are gated as B220+ GL7+, the numbers refer to the percentage of lymphocytes falling within the indicated gate.
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fig3: Immune function in p110δ mutant mice. (A) Serum Ig levels in naive mice were measured by ELISA. (B) DNP-specific Ig of the indicated isotypes were determined by ELISA of “preimmune” collected before immunization, and “immune” sera collected 7 d after immunization with DNP-Ficoll. (C) DNP-specific Ig was measured in preimmune serum, and in serum taken 7 and 21 d after immunization with DNP-KLH. Mice were then reimmunized at 21 d and bled 7 d later to measure the secondary response. In each set of graphs, the relative unit (absorbance) value for individual control animals is represented by a filled circle, individual p110δ-deficient mice are represented by open circles. Bars represent the average and SD for the group. In the TD responses, arrows represent the points at which mice were immunized (days 1 and 21). P values denote the levels of significance between sera of control and p110δ−/− mice as determined by the Student's t test. a, P < 0.01; b, P < 0.05; c, not significant; d, P < 0.001. (D) Quantitation of germinal center formation in spleens taken 10 d after immunization. The results are expressed as the ratio of PNA+ germinal centers/B220+ follicles. Black bar, wild type; white bar, mutant. Data was compiled from two control mice and four mutant mice. (E) Flow cytometric analysis of lymphocytes from Peyer's patches. Activated B cells are gated as B220+ GL7+, the numbers refer to the percentage of lymphocytes falling within the indicated gate.

Mentions: In nonimmunized P110δ−/− mice the levels of serum IgM, IgG1, IgG2a, and IgG3 and were significantly reduced, whereas IgG2b and IgA were in the normal range (Fig. 3 A). To determine the ability of p110δ−/− mice to mount humoral responses, we immunized p110δ−/− mice with the T cell–independent type II antigen, DNP-Ficoll. The hapten-specific IgM response of p110δ−/− mice after immunization was significantly reduced when compared with that of control mice, similarly, the levels of DNP-specific IgG3 produced were significantly lower in p110δ−/− mice (Fig. 3 B). The primary response to thymus-dependent (TD) antigens was measured 7 d after administration of DNP-KLH. Wild-type littermate mice produced IgM, IgG1 IgG2a, IgG2b, and IgG3 antibodies against DNP (Fig. 3 C). By contrast, p110δ−/− mice produced significantly less anti-DNP antibody of these subclasses. By 21 d after the primary immunization antigen specific Ig levels had generally fallen and reimmunization of control animals with DNP-KLH led to a secondary response. Although mice lacking p110δ produced antigen-specific Ig, there was a significant defect in the production of antigen-specific Ig of all subclasses tested (Fig. 3 C). Analysis of germinal center formation in the spleen after immunization revealed a reduction in the p110δ−/− mice (Fig. 3 D). Those germinal centers that were found were often atypical in size or location (unpublished data). This defect was underscored by a reduction in the number of Peyer's patches on the small intestine from 7.75 ± 1.7 in control mice (n = 4) to 4 ± 1.2 in p110δ−/− mice (n = 4). Furthermore, the Peyer's patches were smaller in the mutant mice and staining of B lymphocytes with GL7, an activation antigen expressed on germinal center B cells, also revealed a defect in p110δ−/− mice (Fig. 3 E).


A crucial role for the p110delta subunit of phosphatidylinositol 3-kinase in B cell development and activation.

Clayton E, Bardi G, Bell SE, Chantry D, Downes CP, Gray A, Humphries LA, Rawlings D, Reynolds H, Vigorito E, Turner M - J. Exp. Med. (2002)

Immune function in p110δ mutant mice. (A) Serum Ig levels in naive mice were measured by ELISA. (B) DNP-specific Ig of the indicated isotypes were determined by ELISA of “preimmune” collected before immunization, and “immune” sera collected 7 d after immunization with DNP-Ficoll. (C) DNP-specific Ig was measured in preimmune serum, and in serum taken 7 and 21 d after immunization with DNP-KLH. Mice were then reimmunized at 21 d and bled 7 d later to measure the secondary response. In each set of graphs, the relative unit (absorbance) value for individual control animals is represented by a filled circle, individual p110δ-deficient mice are represented by open circles. Bars represent the average and SD for the group. In the TD responses, arrows represent the points at which mice were immunized (days 1 and 21). P values denote the levels of significance between sera of control and p110δ−/− mice as determined by the Student's t test. a, P < 0.01; b, P < 0.05; c, not significant; d, P < 0.001. (D) Quantitation of germinal center formation in spleens taken 10 d after immunization. The results are expressed as the ratio of PNA+ germinal centers/B220+ follicles. Black bar, wild type; white bar, mutant. Data was compiled from two control mice and four mutant mice. (E) Flow cytometric analysis of lymphocytes from Peyer's patches. Activated B cells are gated as B220+ GL7+, the numbers refer to the percentage of lymphocytes falling within the indicated gate.
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Related In: Results  -  Collection

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fig3: Immune function in p110δ mutant mice. (A) Serum Ig levels in naive mice were measured by ELISA. (B) DNP-specific Ig of the indicated isotypes were determined by ELISA of “preimmune” collected before immunization, and “immune” sera collected 7 d after immunization with DNP-Ficoll. (C) DNP-specific Ig was measured in preimmune serum, and in serum taken 7 and 21 d after immunization with DNP-KLH. Mice were then reimmunized at 21 d and bled 7 d later to measure the secondary response. In each set of graphs, the relative unit (absorbance) value for individual control animals is represented by a filled circle, individual p110δ-deficient mice are represented by open circles. Bars represent the average and SD for the group. In the TD responses, arrows represent the points at which mice were immunized (days 1 and 21). P values denote the levels of significance between sera of control and p110δ−/− mice as determined by the Student's t test. a, P < 0.01; b, P < 0.05; c, not significant; d, P < 0.001. (D) Quantitation of germinal center formation in spleens taken 10 d after immunization. The results are expressed as the ratio of PNA+ germinal centers/B220+ follicles. Black bar, wild type; white bar, mutant. Data was compiled from two control mice and four mutant mice. (E) Flow cytometric analysis of lymphocytes from Peyer's patches. Activated B cells are gated as B220+ GL7+, the numbers refer to the percentage of lymphocytes falling within the indicated gate.
Mentions: In nonimmunized P110δ−/− mice the levels of serum IgM, IgG1, IgG2a, and IgG3 and were significantly reduced, whereas IgG2b and IgA were in the normal range (Fig. 3 A). To determine the ability of p110δ−/− mice to mount humoral responses, we immunized p110δ−/− mice with the T cell–independent type II antigen, DNP-Ficoll. The hapten-specific IgM response of p110δ−/− mice after immunization was significantly reduced when compared with that of control mice, similarly, the levels of DNP-specific IgG3 produced were significantly lower in p110δ−/− mice (Fig. 3 B). The primary response to thymus-dependent (TD) antigens was measured 7 d after administration of DNP-KLH. Wild-type littermate mice produced IgM, IgG1 IgG2a, IgG2b, and IgG3 antibodies against DNP (Fig. 3 C). By contrast, p110δ−/− mice produced significantly less anti-DNP antibody of these subclasses. By 21 d after the primary immunization antigen specific Ig levels had generally fallen and reimmunization of control animals with DNP-KLH led to a secondary response. Although mice lacking p110δ produced antigen-specific Ig, there was a significant defect in the production of antigen-specific Ig of all subclasses tested (Fig. 3 C). Analysis of germinal center formation in the spleen after immunization revealed a reduction in the p110δ−/− mice (Fig. 3 D). Those germinal centers that were found were often atypical in size or location (unpublished data). This defect was underscored by a reduction in the number of Peyer's patches on the small intestine from 7.75 ± 1.7 in control mice (n = 4) to 4 ± 1.2 in p110δ−/− mice (n = 4). Furthermore, the Peyer's patches were smaller in the mutant mice and staining of B lymphocytes with GL7, an activation antigen expressed on germinal center B cells, also revealed a defect in p110δ−/− mice (Fig. 3 E).

Bottom Line: Mice lacking the p110delta catalytic subunit of phosphatidylinositol 3-kinase have reduced numbers of B1 and marginal zone B cells, reduced levels of serum immunoglobulins, respond poorly to immunization with type II thymus-independent antigen, and are defective in their primary and secondary responses to thymus-dependent antigen. p110delta(-/-) B cells proliferate poorly in response to B cell receptor (BCR) or CD40 signals in vitro, fail to activate protein kinase B, and are prone to apoptosis. p110delta function is required for BCR-mediated calcium flux, activation of phosphlipaseCgamma2, and Bruton's tyrosine kinase.Thus, p110delta plays a critical role in B cell homeostasis and function.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Lymphocyte Signaling and Development, Molecular Immunology Programme, The Babraham Institute, Babraham, Cambridge CB2 4AT, United Kingdom.

ABSTRACT
Mice lacking the p110delta catalytic subunit of phosphatidylinositol 3-kinase have reduced numbers of B1 and marginal zone B cells, reduced levels of serum immunoglobulins, respond poorly to immunization with type II thymus-independent antigen, and are defective in their primary and secondary responses to thymus-dependent antigen. p110delta(-/-) B cells proliferate poorly in response to B cell receptor (BCR) or CD40 signals in vitro, fail to activate protein kinase B, and are prone to apoptosis. p110delta function is required for BCR-mediated calcium flux, activation of phosphlipaseCgamma2, and Bruton's tyrosine kinase. Thus, p110delta plays a critical role in B cell homeostasis and function.

Show MeSH
Related in: MedlinePlus