Abatacept (Cytotoxic T Lymphocyte Antigen 4-Fragment Crystallizable) Reduces Allergic Inflammation of Ovalbumin-Sensitized Mice.

2022 ◽  
pp. 194589242110723
Author(s):  
Jaein Chung ◽  
Mi-Ra Choi ◽  
Min Gyu Kim ◽  
Soo Kyoung Park ◽  
Yong Min Kim
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Allergic Inflammation ◽  
Control Group ◽  
Western Blot Assay ◽  
Lymphocyte Antigen ◽  
Cluster Of Differentiation

Background Abatacept (Aba) is a cytotoxic T-lymphocyte antigen-4 and fragment crystallizable fusion protein. Aba blocks B7/Cluster of differentiation 28 - cytotoxic T-lymphocyte antigen-4 costimulatory pathway, inhibits cluster of differentiation 4+ T-cell activation, and is used as an anti-inflammatory drug. Objectives We conducted this study to assess the effectiveness of Aba in the treatment of allergic rhinitis (AR) in a mouse model. Methods We divided 40 four-week-old BALB/c mice into four groups: control group ( n = 10), positive control group (AR, n = 10), Aba group (AR + Aba, n = 10), and dexamethasone group (AR + Dex, n = 10). Mice in each group were challenged intranasally with daily ovalbumin (OVA) administration. Episodes of sneezing and nose rubbing were counted. Mice were sacrificed on day 42 and cytokines were measured in nasal lavage fluid. Nasal mucosae of five mice from each group were used for reverse transcriptase-polymerase chain reaction and western blot assay. Samples were collected from five mice from each group for histological analysis. Results Symptoms of AR significantly improved in the AR + Aba and AR + Dex groups compared with the AR group. Fewer eosinophils and goblet cells were seen in the AR + Aba and AR + Dex groups compared with the AR group. Both the AR + Aba and AR + Dex groups showed a significant decrease in nasal T helper 2 cytokine levels, including interleukin (IL)-4, IL-5, IL-13 and T cell activation related IL-17A, and interferon gamma (IFN- γ). Total immunoglobulin (Ig) E and OVA-specific IgG1 levels were also significantly lower in the AR + Aba and AR + Dex groups. OVA-specific IgE level was also significantly lower in the AR + Aba than AR group. Conclusions Aba suppresses allergic inflammation and appears to be a good treatment for AR.

scholarly journals Cytotoxic T Lymphocyte Antigen 4 (CTLA4) Blockade Accelerates the Acute Rejection of Cardiac Allografts in CD28-deficient Mice: CTLA4 Can Function Independently of CD28

1998 ◽  
Vol 188 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Hua Lin ◽  
Jeffrey C. Rathmell ◽  
Gary S. Gray ◽  
Craig B. Thompson ◽  
Jeffrey M. Leiden ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Graft Rejection ◽  
Allograft Rejection ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Wild Type ◽  
Lymphocyte Antigen ◽  
Deficient Mice

Cytotoxic T lymphocyte antigen 4 (CTLA4) appears to negatively regulate T cell activation. One mechanism by which CTLA4 might antagonize T cell function is through inhibition of CD28 signaling by competing for their shared ligands B7-1 and B7-2. In addition, CTLA4 ligation could initiate a signaling cascade that inhibits T cell activation. To address whether CTLA4 could inhibit immune responses in the absence of CD28, rejection of heart allografts was studied in CD28-deficient mice. H-2q hearts were transplanted into allogeneic wild-type or CD28-deficient mice (H-2b). Graft rejection was delayed in CD28-deficient compared with wild-type mice. Treatment of wild-type recipients with CTLA4-immunoglobulin (Ig), or with anti–B7-1 plus anti–B7-2 mAbs significantly prolonged allograft survival. In contrast, treatment of CD28-deficient mice with CTLA4-Ig, anti–B7-1 plus anti–B7-2 mAbs, or a blocking anti-CTLA4 mAb induced acceleration of allograft rejection. This increased rate of graft rejection was associated with more severe mononuclear cell infiltration and enhanced levels of IFN-γ and IL-6 transcripts in donor hearts of untreated wild-type and CTLA4-Ig– or anti-CTLA4 mAb–treated CD28-deficient mice. Thus, the negative regulatory role of CTLA4 extends beyond its potential ability to prevent CD28 activation through ligand competition. Even in the absence of CD28, CTLA4 plays an inhibitory role in the regulation of allograft rejection.

scholarly journals Ligation of Cytotoxic T Lymphocyte Antigen-4 to T Cell Receptor Inhibits T Cell Activation and Directs Differentiation into Foxp3+Regulatory T Cells

2012 ◽  
Vol 287 (14) ◽  
pp. 11098-11107 ◽  
Author(s):  
Jozsef Karman ◽  
Ji-Lei Jiang ◽  
Nathan Gumlaw ◽  
Hongmei Zhao ◽  
Juanita Campos-Rivera ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Cell Receptor ◽  
Lymphocyte Antigen

scholarly journals Cytotoxic T Lymphocyte Antigen 4 (Ctla-4) Engagement Delivers an Inhibitory Signal through the Membrane-Proximal Region in the Absence of the Tyrosine Motif in the Cytoplasmic Tail

1999 ◽  
Vol 190 (6) ◽  
pp. 765-774 ◽  
Author(s):  
Chiaki Nakaseko ◽  
Shoichiro Miyatake ◽  
Tomohiko Iida ◽  
Satoru Hara ◽  
Ryo Abe ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Interleukin 2 ◽  
Cytoplasmic Tail ◽  
Proximal Region ◽  
Lymphocyte Antigen ◽  
Membrane Proximal Region

Cytotoxic T lymphocyte antigen 4 (CTLA-4) is a T cell costimulation receptor that delivers inhibitory signals upon activation. Although the tyrosine-based motif (165YVKM) within its cytoplasmic tail has been shown to associate in vitro with Src homology 2 domain–containing tyrosine phosphatase (SHP-2) and phosphatidylinositol 3 kinase upon phosphorylation, the mechanism of negative signaling remains unclear. Here, we report a new mechanism of negative signaling based on the analysis of murine T cell clones transfected with various mutants of CTLA-4. Upon T cell activation by cross-linking with anti-CD3 and anti-CD28 antibodies, CTLA-4 engagement inhibited both proliferation and interleukin 2 production in tyrosine mutants as well as in wild-type CTLA-4 transfectants. Furthermore, the mutant CTLA-4 lacking most of the cytoplasmic region strongly suppressed interleukin 2 production as well. These data suggest that negative signals by CTLA-4 could be mediated through the membrane-proximal region of CTLA-4 but not through the YVKM motif and that the association of CTLA-4 with SHP-2 is not required for CTLA-4–mediated suppression of T cell activation.

scholarly journals B7-1 Engagement of Cytotoxic T Lymphocyte Antigen 4 Inhibits T Cell Activation in the Absence of CD28

1998 ◽  
Vol 188 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Francesca Fallarino ◽  
Patrick E. Fields ◽  
Thomas F. Gajewski
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Cell Function ◽  
Cytotoxic T Lymphocyte ◽  
Cell Receptor ◽  
Inhibitory Effect ◽  
Lymphocyte Antigen

Ligation of cytotoxic T lymphocyte antigen 4 (CTLA4) appears to inhibit T cell responses. Four mechanisms have been proposed to explain the inhibitory activity of CTLA4: competition for B7-1 and B7-2 binding by CD28; sequestration of signaling molecules away from CD28 via endocytosis; delivery of a signal that antagonizes a CD28 signal; and delivery of a signal that antagonizes a T cell receptor (TCR) signal. As three of these potential mechanisms involve functional antagonism of CD28, an experimental model was designed to determine whether CTLA4 could inhibit T cell function in the absence of CD28. TCR transgenic/recombinase activating gene 2–deficient/CD28–wild-type or CD28-deficient mice were generated and immunized with an antigen-expressing tumor. Primed T cells from both types of mice produced cytokines and proliferated in response to stimulator cells lacking B7 expression. However, whereas the response of CD28+/+ T cells was augmented by costimulation with B7-1, the response of the CD28−/− T cells was strongly inhibited. This inhibition was reversed by monoclonal antibody against B7-1 or CTLA4. Thus, CTLA4 can potently inhibit T cell activation in the absence of CD28, indicating that antagonism of a TCR-mediated signal is sufficient to explain the inhibitory effect of CTLA4.

scholarly journals Induction of Cytotoxic T Lymphocyte Antigen 4 (Ctla-4) Restricts Clonal Expansion of Helper T Cells

2001 ◽  
Vol 194 (7) ◽  
pp. 893-902 ◽  
Author(s):  
Alden M. Doyle ◽  
Alan C. Mullen ◽  
Alejandro V. Villarino ◽  
Anne S. Hutchins ◽  
Frances A. High ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Clonal Expansion ◽  
Negative Regulator ◽  
Lymphocyte Antigen ◽  
Cell Divisions

Cytotoxic T lymphocyte antigen (CTLA)-4 plays an essential role in immunologic homeostasis. How this negative regulator of T cell activation executes its functions has remained controversial. We now provide evidence that CTLA-4 mediates a cell-intrinsic counterbalance to restrict the clonal expansion of proliferating CD4+ T cells. The regulation of CTLA-4 expression and function ensures that, after ∼3 cell divisions of expansion, most progeny will succumb to either proliferative arrest or death over the ensuing three cell divisions. The quantitative precision of the counterbalance hinges on the graded, time-independent induction of CTLA-4 expression during the first three cell divisions. In contrast to the limits imposed on unpolarized cells, T helper type 1 (Th1) and Th2 effector progeny may be rescued from proliferative arrest by interleukin (IL)-12 and IL-4 signaling, respectively, allowing appropriately stimulated progeny to proceed to the stage of tissue homing. These results suggest that the cell-autonomous regulation of CTLA-4 induction may be a central checkpoint of clonal expansion of CD4+ T cells, allowing temporally and spatially restricted growth of progeny to be dictated by the nature of the threat posed to the host.

scholarly journals B7-1 or B7-2 Is Required to Produce the Lymphoproliferative Phenotype in Mice Lacking Cytotoxic T Lymphocyte–associated Antigen 4 (CTLA-4)

1999 ◽  
Vol 189 (2) ◽  
pp. 435-440 ◽  
Author(s):  
Didier A. Mandelbrot ◽  
Alexander J. McAdam ◽  
Arlene H. Sharpe
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Lymphocyte Activation ◽  
Lymphoproliferative Disease ◽  
Inhibitory Function ◽  
B7 Molecules

The costimulatory molecules B7-1 and B7-2 regulate T lymphocyte activation by delivering activating signals through CD28 and inhibitory signals through cytotoxic T lymphocyte–associated antigen 4 (CTLA-4). The importance of CTLA-4–mediated inhibition was demonstrated by the uncontrolled T cell activation and lymphoproliferative disease that develops in CTLA-4–deficient (−/−) mice. To examine the role of B7 signaling in the activation of CTLA-4–deficient T cells, we bred CTLA-4−/− mice with mice lacking B7-1, B7-2, or both B7 molecules. The CTLA-4/B7-1−/− and the CTLA-4/B7-2−/− mice develop lymphoproliferation and enhanced T cell activation. Mice lacking CTLA-4, B7-1, and B7-2 have a normal life-span, and do not have lymphocytic infiltrates in any organs, or increased T cell activation. Therefore, the two B7 molecules have overlapping functions, since either B7-1 or B7-2 alone can cause the CTLA-4−/− phenotype. Elimination of both B7-1 and B7-2 from the CTLA-4– deficient mouse abrogates the lymphocyte activation and disease, and does not reveal evidence for additional stimulatory CD28 ligands. The CTLA-4−/− phenotype can be reproduced with anti-CD28 antibody in mice lacking CTLA-4, B7-1, and B7-2, but wild-type mice are unaffected by the same treatment. This suggests that the inhibitory function of CTLA-4 can overcome strong CD28-mediated signaling in vivo.

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