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2B4 Is Dispensable for T-Dependent B Cell Immune Responses, but Its Deficiency Leads to Enhanced T-Independent Responses Due to an Increase in Peritoneal Cavity B1b Cells.

Ray A, Yuan CY, Miller NM, Mei H, Dittel BN - PLoS ONE (2015)

Bottom Line: We found that the splenic cellularity in Cd244-/- mice was significantly reduced due to a reduction in both CD4 T cells and follicular (Fo) B cells; whereas, the number of peritoneal cavity B cells was increased.When we evaluated T-independent immune responses, we found that antigen-specific IgM and IgG3 were elevated in the serum following immunization.These data indicate that 2B4 dampens T-independent B cell responses due to a reduction in peritoneal cavity B cells, but has minimal impact on T-dependent B cell responses.

View Article: PubMed Central - PubMed

Affiliation: Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin, United States of America.

ABSTRACT
The signaling lymphocyte activation molecule (SLAM) family plays important roles in adaptive immune responses. Herein, we evaluated whether the SLAM family member 2B4 (CD244) plays a role in immune cell development, homeostasis and antibody responses. We found that the splenic cellularity in Cd244-/- mice was significantly reduced due to a reduction in both CD4 T cells and follicular (Fo) B cells; whereas, the number of peritoneal cavity B cells was increased. These findings led us to examine whether 2B4 modulates B cell immune responses. When we examined T-dependent B cell responses, while there was no difference in the kinetics or magnitude of the antigen-specific IgM and IgG1 antibody response there was a reduction in bone marrow (BM) memory, but not plasma cells in Cd244-/- mice. When we evaluated T-independent immune responses, we found that antigen-specific IgM and IgG3 were elevated in the serum following immunization. These data indicate that 2B4 dampens T-independent B cell responses due to a reduction in peritoneal cavity B cells, but has minimal impact on T-dependent B cell responses.

No MeSH data available.


The cellularity and absolute number of CD4 T cells is reduced in the spleen of Cd244-/- mice.The absolute number of mononuclear (A), CD11b+ (B), CD11c+ (C), NK1.1+ (D), TCRβ+ (E), TCRβ+CD4+ (F), TCRβ+CD8+ (G) and CD4+Foxp3+ (H) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. The percentage of CD11b+ (I), CD11c+ (J), NK1.1+ (K), TCRβ+ (L), TCRβ+CD4+ (M), TCRβ+CD8+ (N) and CD4+Foxp3+ (O) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. Data are shown as the mean ± SE of four mice. *p<0.05.
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pone.0137314.g001: The cellularity and absolute number of CD4 T cells is reduced in the spleen of Cd244-/- mice.The absolute number of mononuclear (A), CD11b+ (B), CD11c+ (C), NK1.1+ (D), TCRβ+ (E), TCRβ+CD4+ (F), TCRβ+CD8+ (G) and CD4+Foxp3+ (H) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. The percentage of CD11b+ (I), CD11c+ (J), NK1.1+ (K), TCRβ+ (L), TCRβ+CD4+ (M), TCRβ+CD8+ (N) and CD4+Foxp3+ (O) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. Data are shown as the mean ± SE of four mice. *p<0.05.

Mentions: In our mouse colony, we found that Cd244-/- mice had a significant reduction in splenic cellularity (Fig 1A). This finding was not reported in the original study describing the Cd244-/- mice [12]. In this same study, it was reported that a global deficiency in 2B4 did not alter the frequency (percentage) of CD3+, CD4+, CD8+, CD11b+, CD19+ nor NK1.1+ cells in the spleen [12]. However, the percentage does not reflect changes in absolute cell number. Thus, we repeated the splenic phenotyping and calculated absolute numbers of cells to determine the specific immune cell populations that are reduced in Cd244-/- mice in our colony. We found no difference in the absolute number of CD11b+ myeloid cells (Fig 1B), CD11c+ dendritic cells (Fig 1C) or NK1.1+ NK cells (Fig 1D) between WT and Cd244-/- mice. In contrast, there was a significant reduction in αβ T cells in the spleen (Fig 1E). Further analysis revealed that the reduction was due to lower numbers of CD4+ T cells (Fig 1F). In addition, while a trend for lower numbers of CD8+ T cells (p = 0.1) (Fig 1G) and CD4+Foxp3+ T regulatory cells (p = 0.11) (Fig 1H) was observed in Cd244-/- mice, it did not reach significance. When we examined the percentage of the above immune cell populations in the spleen, the non-significant increase in CD11b+ myeloid cells (p = 0.06) was reflected in a significant increase in percentage of total CD11b+ cells (Fig 1I) and percentage of the CD11b+ dendritic (Fig 1J) and NK cells (Fig 1K) subsets. Interestingly, even though significance was observed for absolute number there was no difference in the percentage of αβ T cells (Fig 1L) or CD4 T cells (Fig 1M). In addition, there was no difference in the percentage of CD8 T cells (Fig 1N) or in Treg (Fig 1O). It is not clear why we observed an increase in the percentage of myeloid cells that was not seen in the original report describing Cd244-/- mice, but likely reflects differences in composition of the microbiota in the two animal colonies. Nevertheless, our findings that significant differences in percentages is not reflected by the absolute cell number highlights why only analyzing changes in the percentages of specific cell subsets can be misleading.


2B4 Is Dispensable for T-Dependent B Cell Immune Responses, but Its Deficiency Leads to Enhanced T-Independent Responses Due to an Increase in Peritoneal Cavity B1b Cells.

Ray A, Yuan CY, Miller NM, Mei H, Dittel BN - PLoS ONE (2015)

The cellularity and absolute number of CD4 T cells is reduced in the spleen of Cd244-/- mice.The absolute number of mononuclear (A), CD11b+ (B), CD11c+ (C), NK1.1+ (D), TCRβ+ (E), TCRβ+CD4+ (F), TCRβ+CD8+ (G) and CD4+Foxp3+ (H) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. The percentage of CD11b+ (I), CD11c+ (J), NK1.1+ (K), TCRβ+ (L), TCRβ+CD4+ (M), TCRβ+CD8+ (N) and CD4+Foxp3+ (O) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. Data are shown as the mean ± SE of four mice. *p<0.05.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4554987&req=5

pone.0137314.g001: The cellularity and absolute number of CD4 T cells is reduced in the spleen of Cd244-/- mice.The absolute number of mononuclear (A), CD11b+ (B), CD11c+ (C), NK1.1+ (D), TCRβ+ (E), TCRβ+CD4+ (F), TCRβ+CD8+ (G) and CD4+Foxp3+ (H) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. The percentage of CD11b+ (I), CD11c+ (J), NK1.1+ (K), TCRβ+ (L), TCRβ+CD4+ (M), TCRβ+CD8+ (N) and CD4+Foxp3+ (O) cells in the spleen of WT and Cd244-/- mice was determined by flow cytometry. Data are shown as the mean ± SE of four mice. *p<0.05.
Mentions: In our mouse colony, we found that Cd244-/- mice had a significant reduction in splenic cellularity (Fig 1A). This finding was not reported in the original study describing the Cd244-/- mice [12]. In this same study, it was reported that a global deficiency in 2B4 did not alter the frequency (percentage) of CD3+, CD4+, CD8+, CD11b+, CD19+ nor NK1.1+ cells in the spleen [12]. However, the percentage does not reflect changes in absolute cell number. Thus, we repeated the splenic phenotyping and calculated absolute numbers of cells to determine the specific immune cell populations that are reduced in Cd244-/- mice in our colony. We found no difference in the absolute number of CD11b+ myeloid cells (Fig 1B), CD11c+ dendritic cells (Fig 1C) or NK1.1+ NK cells (Fig 1D) between WT and Cd244-/- mice. In contrast, there was a significant reduction in αβ T cells in the spleen (Fig 1E). Further analysis revealed that the reduction was due to lower numbers of CD4+ T cells (Fig 1F). In addition, while a trend for lower numbers of CD8+ T cells (p = 0.1) (Fig 1G) and CD4+Foxp3+ T regulatory cells (p = 0.11) (Fig 1H) was observed in Cd244-/- mice, it did not reach significance. When we examined the percentage of the above immune cell populations in the spleen, the non-significant increase in CD11b+ myeloid cells (p = 0.06) was reflected in a significant increase in percentage of total CD11b+ cells (Fig 1I) and percentage of the CD11b+ dendritic (Fig 1J) and NK cells (Fig 1K) subsets. Interestingly, even though significance was observed for absolute number there was no difference in the percentage of αβ T cells (Fig 1L) or CD4 T cells (Fig 1M). In addition, there was no difference in the percentage of CD8 T cells (Fig 1N) or in Treg (Fig 1O). It is not clear why we observed an increase in the percentage of myeloid cells that was not seen in the original report describing Cd244-/- mice, but likely reflects differences in composition of the microbiota in the two animal colonies. Nevertheless, our findings that significant differences in percentages is not reflected by the absolute cell number highlights why only analyzing changes in the percentages of specific cell subsets can be misleading.

Bottom Line: We found that the splenic cellularity in Cd244-/- mice was significantly reduced due to a reduction in both CD4 T cells and follicular (Fo) B cells; whereas, the number of peritoneal cavity B cells was increased.When we evaluated T-independent immune responses, we found that antigen-specific IgM and IgG3 were elevated in the serum following immunization.These data indicate that 2B4 dampens T-independent B cell responses due to a reduction in peritoneal cavity B cells, but has minimal impact on T-dependent B cell responses.

View Article: PubMed Central - PubMed

Affiliation: Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin, United States of America.

ABSTRACT
The signaling lymphocyte activation molecule (SLAM) family plays important roles in adaptive immune responses. Herein, we evaluated whether the SLAM family member 2B4 (CD244) plays a role in immune cell development, homeostasis and antibody responses. We found that the splenic cellularity in Cd244-/- mice was significantly reduced due to a reduction in both CD4 T cells and follicular (Fo) B cells; whereas, the number of peritoneal cavity B cells was increased. These findings led us to examine whether 2B4 modulates B cell immune responses. When we examined T-dependent B cell responses, while there was no difference in the kinetics or magnitude of the antigen-specific IgM and IgG1 antibody response there was a reduction in bone marrow (BM) memory, but not plasma cells in Cd244-/- mice. When we evaluated T-independent immune responses, we found that antigen-specific IgM and IgG3 were elevated in the serum following immunization. These data indicate that 2B4 dampens T-independent B cell responses due to a reduction in peritoneal cavity B cells, but has minimal impact on T-dependent B cell responses.

No MeSH data available.