Limits...
The role of ACAID and CD4+CD25+FOXP3+ regulatory T cells on CTL function against MHC alloantigens.

Saban DR, Cornelius J, Masli S, Schwartzkopff J, Doyle M, Chauhan SK, Peck AB, Grant MB - Mol. Vis. (2008)

Bottom Line: However, while Treg expansion was observed, these cells did not directly mediate the CTL inhibition.Furthermore, we found that ACAID induction leads to the expansion and proliferation of CD4(+) and CD8(+) T cells while ACAID expression is associated with a diminishment in T cell percentages due to proliferation impairment.However, our data suggest that Treg do not directly inhibit CTL activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA. daniel.saban@schepens.harvard.edu

ABSTRACT

Purpose: Anterior chamber associated immune deviation (ACAID) is an antigen-specific form of peripheral immune tolerance that is induced to exogenous antigens placed in the ocular anterior chamber, which leads to a suppression in delayed-type hypersensitivity (DTH). Considerable work has been done on ACAID induction to major histocompatibility (MHC) alloantigens. However, its role on cytotoxic T lymphocyte (CTL) activity is currently unknown.

Methods: C57BL/6 (H-2(b)) mice received an intracameral (IC) inoculation with BALB/c (H-2(d)) splenocytes. Splenic CD4(+) and CD8(+) T cell populations were characterized by flow cytometry and proliferation assays during induction and expression phases of ACAID. Percentages of CD4(+)CD25(+)FoxP3(+) T regulatory cells (Treg) were also followed. Lastly, CTL function was measured at various time points during ACAID expression, and Treg were added to identify potential alterations in CTL function.

Results: CD4(+) and CD8(+) T cell percentages and proliferation increased in the spleen during ACAID induction but then sharply decreased in response to an allospecific immunization. Expression of ACAID also exhibited a significant drop in CTL function. However, while Treg expansion was observed, these cells did not directly mediate the CTL inhibition.

Conclusions: ACAID mediates an inhibition of CTL function against MHC alloantigens. Furthermore, we found that ACAID induction leads to the expansion and proliferation of CD4(+) and CD8(+) T cells while ACAID expression is associated with a diminishment in T cell percentages due to proliferation impairment. Lastly, Treg also expand during ACAID induction. However, our data suggest that Treg do not directly inhibit CTL activity.

Show MeSH

Related in: MedlinePlus

Intracameral inoculation leads to an increase in CD4+CD25+FoxP3+ Treg. A: Flow cytometry was used to enumerate Treg in the spleen. Triple-stained splenocytes for CD4+, CD25+, and FoxP3+ were first gated on CD4+ (left) and then measured for CD25 and FoxP3 (center, right). B: ACAID induction leads to an increase in Treg in the spleen. Spleens were harvested and enumerated for Treg percentages in naïve mice or in IC inoculated mice on days 4, 8, and 12 (n=3 per time point). An asterisk indicates a statistically significant increase (p<0.5) in percentage over the naïve control. The statistical significance was calculated via Student’s t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2605729&req=5

f3: Intracameral inoculation leads to an increase in CD4+CD25+FoxP3+ Treg. A: Flow cytometry was used to enumerate Treg in the spleen. Triple-stained splenocytes for CD4+, CD25+, and FoxP3+ were first gated on CD4+ (left) and then measured for CD25 and FoxP3 (center, right). B: ACAID induction leads to an increase in Treg in the spleen. Spleens were harvested and enumerated for Treg percentages in naïve mice or in IC inoculated mice on days 4, 8, and 12 (n=3 per time point). An asterisk indicates a statistically significant increase (p<0.5) in percentage over the naïve control. The statistical significance was calculated via Student’s t-test.

Mentions: The reduced levels of proliferation, especially in CD4+ T cells, suggested a role for CD4+CD25+FoxP3+ T regulatory cells (Treg) as these cells are well known for their ability to suppress T cell proliferation [15]. To examine this possibility, spleen cells from naïve mice or from IC inoculated mice on days 4, 8, and 12, were collected, and the CD4+CD25+FoxP3+ T cell populations enumerated using flow cytometry (Figure 3A). These time points allowed us to focus on the induction of ACAID, particularly where the marked suppression of CD4+ proliferation was observed around day 12. As presented in Figure 3B, IC inoculated mice exhibited significantly increased levels of Treg cells on day 12 (p<0.05) relative to those exhibited by naive mice.


The role of ACAID and CD4+CD25+FOXP3+ regulatory T cells on CTL function against MHC alloantigens.

Saban DR, Cornelius J, Masli S, Schwartzkopff J, Doyle M, Chauhan SK, Peck AB, Grant MB - Mol. Vis. (2008)

Intracameral inoculation leads to an increase in CD4+CD25+FoxP3+ Treg. A: Flow cytometry was used to enumerate Treg in the spleen. Triple-stained splenocytes for CD4+, CD25+, and FoxP3+ were first gated on CD4+ (left) and then measured for CD25 and FoxP3 (center, right). B: ACAID induction leads to an increase in Treg in the spleen. Spleens were harvested and enumerated for Treg percentages in naïve mice or in IC inoculated mice on days 4, 8, and 12 (n=3 per time point). An asterisk indicates a statistically significant increase (p<0.5) in percentage over the naïve control. The statistical significance was calculated via Student’s t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2605729&req=5

f3: Intracameral inoculation leads to an increase in CD4+CD25+FoxP3+ Treg. A: Flow cytometry was used to enumerate Treg in the spleen. Triple-stained splenocytes for CD4+, CD25+, and FoxP3+ were first gated on CD4+ (left) and then measured for CD25 and FoxP3 (center, right). B: ACAID induction leads to an increase in Treg in the spleen. Spleens were harvested and enumerated for Treg percentages in naïve mice or in IC inoculated mice on days 4, 8, and 12 (n=3 per time point). An asterisk indicates a statistically significant increase (p<0.5) in percentage over the naïve control. The statistical significance was calculated via Student’s t-test.
Mentions: The reduced levels of proliferation, especially in CD4+ T cells, suggested a role for CD4+CD25+FoxP3+ T regulatory cells (Treg) as these cells are well known for their ability to suppress T cell proliferation [15]. To examine this possibility, spleen cells from naïve mice or from IC inoculated mice on days 4, 8, and 12, were collected, and the CD4+CD25+FoxP3+ T cell populations enumerated using flow cytometry (Figure 3A). These time points allowed us to focus on the induction of ACAID, particularly where the marked suppression of CD4+ proliferation was observed around day 12. As presented in Figure 3B, IC inoculated mice exhibited significantly increased levels of Treg cells on day 12 (p<0.05) relative to those exhibited by naive mice.

Bottom Line: However, while Treg expansion was observed, these cells did not directly mediate the CTL inhibition.Furthermore, we found that ACAID induction leads to the expansion and proliferation of CD4(+) and CD8(+) T cells while ACAID expression is associated with a diminishment in T cell percentages due to proliferation impairment.However, our data suggest that Treg do not directly inhibit CTL activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA. daniel.saban@schepens.harvard.edu

ABSTRACT

Purpose: Anterior chamber associated immune deviation (ACAID) is an antigen-specific form of peripheral immune tolerance that is induced to exogenous antigens placed in the ocular anterior chamber, which leads to a suppression in delayed-type hypersensitivity (DTH). Considerable work has been done on ACAID induction to major histocompatibility (MHC) alloantigens. However, its role on cytotoxic T lymphocyte (CTL) activity is currently unknown.

Methods: C57BL/6 (H-2(b)) mice received an intracameral (IC) inoculation with BALB/c (H-2(d)) splenocytes. Splenic CD4(+) and CD8(+) T cell populations were characterized by flow cytometry and proliferation assays during induction and expression phases of ACAID. Percentages of CD4(+)CD25(+)FoxP3(+) T regulatory cells (Treg) were also followed. Lastly, CTL function was measured at various time points during ACAID expression, and Treg were added to identify potential alterations in CTL function.

Results: CD4(+) and CD8(+) T cell percentages and proliferation increased in the spleen during ACAID induction but then sharply decreased in response to an allospecific immunization. Expression of ACAID also exhibited a significant drop in CTL function. However, while Treg expansion was observed, these cells did not directly mediate the CTL inhibition.

Conclusions: ACAID mediates an inhibition of CTL function against MHC alloantigens. Furthermore, we found that ACAID induction leads to the expansion and proliferation of CD4(+) and CD8(+) T cells while ACAID expression is associated with a diminishment in T cell percentages due to proliferation impairment. Lastly, Treg also expand during ACAID induction. However, our data suggest that Treg do not directly inhibit CTL activity.

Show MeSH
Related in: MedlinePlus