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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 T-dependent B cell response is unaltered in Cd244-/- mice.WT (closed symbol) and Cd244-/- (open symbol) mice were immunized (i.p.) with the T-dependent antigen NP-CGG (30 μg) that was alum precipitated. Blood was collected on days 0, 7, 10, 14, 28 and 42, and NP-specific IgM (A) and IgG1 (B) titers were determined by ELISA. The O.D. value for NP-specific IgM at the 1:800 dilution and NP-specific IgG1 at the 1:20,000 dilution are shown. Data shown are the mean ± SE of 8 mice for days 0 and 7; 7 mice for days 10, 14 and 28; and 4 mice for day 41. (C) The absolute number of memory (B220+IgD-NP(24)+CD38+), plasma cells (B220+IgD-IgM-IgG+NP(24)+CD138+) and germinal center (B220+GL-7+) B cells were determined in the spleen on days 11 (top panels) and 42 (middle panels) and in the BM on day 42 by flow cytometry. Data are shown as the mean ± SE of four mice. (D) Expression of 2B4 was evaluated on memory and germinal center B cell from WT and Cd244-/- mice 10 days after immunization. Histograms display overlaid staining profiles from the biotin negative control (shaded), WT mice (thin line) and Cd244-/- mice (thick line). Data shown are from one representative mouse of three. *p<0.05.
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pone.0137314.g004: The T-dependent B cell response is unaltered in Cd244-/- mice.WT (closed symbol) and Cd244-/- (open symbol) mice were immunized (i.p.) with the T-dependent antigen NP-CGG (30 μg) that was alum precipitated. Blood was collected on days 0, 7, 10, 14, 28 and 42, and NP-specific IgM (A) and IgG1 (B) titers were determined by ELISA. The O.D. value for NP-specific IgM at the 1:800 dilution and NP-specific IgG1 at the 1:20,000 dilution are shown. Data shown are the mean ± SE of 8 mice for days 0 and 7; 7 mice for days 10, 14 and 28; and 4 mice for day 41. (C) The absolute number of memory (B220+IgD-NP(24)+CD38+), plasma cells (B220+IgD-IgM-IgG+NP(24)+CD138+) and germinal center (B220+GL-7+) B cells were determined in the spleen on days 11 (top panels) and 42 (middle panels) and in the BM on day 42 by flow cytometry. Data are shown as the mean ± SE of four mice. (D) Expression of 2B4 was evaluated on memory and germinal center B cell from WT and Cd244-/- mice 10 days after immunization. Histograms display overlaid staining profiles from the biotin negative control (shaded), WT mice (thin line) and Cd244-/- mice (thick line). Data shown are from one representative mouse of three. *p<0.05.

Mentions: It was previously shown that SAP plays an essential role in T cell:B cell cognate interactions in the germinal center [28], indicating that SLAM molecules are involved in antibody production to T-dependent antigens. While a role for SLAM (CD150), was implicated in germinal center reactions [28], it is possible that other SLAM family members also play a regulatory role. To determine whether 2B4 regulates T-dependent antibody production, we immunized with NP-CGG and quantitated serum antigen-specific IgM and IgG1 on days 0, 7, 10, 14, 28 and 42. While there was a trend for WT B cells to produce higher levels of both IgM (Fig 4A) and IgG1 (Fig 4B), there was no significant difference as compared to Cd244-/- mice at any of the time points examined. When we quantitated memory B cells, we found no alteration in their number in the spleen on day 7 (data not shown) or on days 11 and 42 following immunization (Fig 4C). In contrast, BM memory cells were reduced on day 42 in Cd244-/- mice (Fig 4C). Consistent with similar levels of antigen-specific Ig, we found no difference in the number of plasma cells or germinal center B cells between WT and Cd244-/- mice at the timepoints examined in the spleen and BM (Fig 4C). Thus even though Fo B cells are reduced in Cd244-/- mice this only led to a minimal impact on the magnitude of the T-dependent antibody response. In addition, we did not observe 2B4 expression by splenic memory or germinal center B cells using flow cytometry on day 11 post-NP-CGG immunization (Fig 4D). The reduction in BM memory B cells is an interesting finding that could reflect a role for 2B4 in their migration from the spleen. In addition, 2B4 could be important in memory B cell maintenance specifically in the BM niche.


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 T-dependent B cell response is unaltered in Cd244-/- mice.WT (closed symbol) and Cd244-/- (open symbol) mice were immunized (i.p.) with the T-dependent antigen NP-CGG (30 μg) that was alum precipitated. Blood was collected on days 0, 7, 10, 14, 28 and 42, and NP-specific IgM (A) and IgG1 (B) titers were determined by ELISA. The O.D. value for NP-specific IgM at the 1:800 dilution and NP-specific IgG1 at the 1:20,000 dilution are shown. Data shown are the mean ± SE of 8 mice for days 0 and 7; 7 mice for days 10, 14 and 28; and 4 mice for day 41. (C) The absolute number of memory (B220+IgD-NP(24)+CD38+), plasma cells (B220+IgD-IgM-IgG+NP(24)+CD138+) and germinal center (B220+GL-7+) B cells were determined in the spleen on days 11 (top panels) and 42 (middle panels) and in the BM on day 42 by flow cytometry. Data are shown as the mean ± SE of four mice. (D) Expression of 2B4 was evaluated on memory and germinal center B cell from WT and Cd244-/- mice 10 days after immunization. Histograms display overlaid staining profiles from the biotin negative control (shaded), WT mice (thin line) and Cd244-/- mice (thick line). Data shown are from one representative mouse of three. *p<0.05.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4554987&req=5

pone.0137314.g004: The T-dependent B cell response is unaltered in Cd244-/- mice.WT (closed symbol) and Cd244-/- (open symbol) mice were immunized (i.p.) with the T-dependent antigen NP-CGG (30 μg) that was alum precipitated. Blood was collected on days 0, 7, 10, 14, 28 and 42, and NP-specific IgM (A) and IgG1 (B) titers were determined by ELISA. The O.D. value for NP-specific IgM at the 1:800 dilution and NP-specific IgG1 at the 1:20,000 dilution are shown. Data shown are the mean ± SE of 8 mice for days 0 and 7; 7 mice for days 10, 14 and 28; and 4 mice for day 41. (C) The absolute number of memory (B220+IgD-NP(24)+CD38+), plasma cells (B220+IgD-IgM-IgG+NP(24)+CD138+) and germinal center (B220+GL-7+) B cells were determined in the spleen on days 11 (top panels) and 42 (middle panels) and in the BM on day 42 by flow cytometry. Data are shown as the mean ± SE of four mice. (D) Expression of 2B4 was evaluated on memory and germinal center B cell from WT and Cd244-/- mice 10 days after immunization. Histograms display overlaid staining profiles from the biotin negative control (shaded), WT mice (thin line) and Cd244-/- mice (thick line). Data shown are from one representative mouse of three. *p<0.05.
Mentions: It was previously shown that SAP plays an essential role in T cell:B cell cognate interactions in the germinal center [28], indicating that SLAM molecules are involved in antibody production to T-dependent antigens. While a role for SLAM (CD150), was implicated in germinal center reactions [28], it is possible that other SLAM family members also play a regulatory role. To determine whether 2B4 regulates T-dependent antibody production, we immunized with NP-CGG and quantitated serum antigen-specific IgM and IgG1 on days 0, 7, 10, 14, 28 and 42. While there was a trend for WT B cells to produce higher levels of both IgM (Fig 4A) and IgG1 (Fig 4B), there was no significant difference as compared to Cd244-/- mice at any of the time points examined. When we quantitated memory B cells, we found no alteration in their number in the spleen on day 7 (data not shown) or on days 11 and 42 following immunization (Fig 4C). In contrast, BM memory cells were reduced on day 42 in Cd244-/- mice (Fig 4C). Consistent with similar levels of antigen-specific Ig, we found no difference in the number of plasma cells or germinal center B cells between WT and Cd244-/- mice at the timepoints examined in the spleen and BM (Fig 4C). Thus even though Fo B cells are reduced in Cd244-/- mice this only led to a minimal impact on the magnitude of the T-dependent antibody response. In addition, we did not observe 2B4 expression by splenic memory or germinal center B cells using flow cytometry on day 11 post-NP-CGG immunization (Fig 4D). The reduction in BM memory B cells is an interesting finding that could reflect a role for 2B4 in their migration from the spleen. In addition, 2B4 could be important in memory B cell maintenance specifically in the BM niche.

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.