Low affinity binding of an LFA-3/IgG1 fusion protein to CD2<sup>+</sup>T cells is independent of cell activation

Majeau, Gerard R.; Whitty, Adrian; Yim, Kalvin; Meier, Werner; Hochman, Paula S.

doi:10.3109/15419069909010808

Cited by 30 publications

(28 citation statements)

References 25 publications

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“…The percentage of CD2 hi cells was approximately 35% higher in the CD45R0 + compared with the CD45R0 -subset and the number of brightly stained alefacept-positive cells was approximately 25% higher in the CD45R0 + subset. These results show that, although the affinity of alefacept for CD2 is independent of T cell activation [30], the level of CD2 expression and hence the binding of alefacept is elevated following activation. The proportionally higher number of activated CD2 hi CD45R0 + compared to CD45R0 -T cells could explain the selective targeting of the CD45R0 + population by NK cells in the presence of alefacept.…”

Section: Alefacept Binding Is Higher On Activated Cd45r0 + Cellsmentioning

confidence: 76%

“…It has previously been reported that CD2 is up-regulated following PBMC stimulation with CD3 mAb [1] and stimulated T cells also display enhanced expression of a number of adhesion markers including CD2, LFA-1 and LFA-2 [40,41]. However, so-called 'naive' and 'memory' CD4 + T cells subsets have been shown to bind LFA-3 to a comparable extent [42], and alefacept binding affinity to T cells is not affected by T cell activation [30]. In the present work we show that, as expected, CD2 was upregulated at the cell surface on activated T lymphocytes [1], and also that alefacept binding increased after CD3 stimulation, consistent with the up-regulation of CD2 expression [30].…”

Section: Discussionmentioning

confidence: 99%

“…CD2-based interventions have also been employed in tumor therapy [27]. Alefacept (human LFA-3-Ig fusion protein) previously referred to as LFA3TIP and Amevive, is a fusion protein consisting of the first extracellular domain of LFA-3 fused to the human IgG 1 hinge, C H 2 and C H 3 domains [18,24,[28][29][30][31]. The fusion protein prolongs cardiac allograft survival in primates [18] and has recently undergone phase II and phase III clinical trials for the treatment of chronic plaque psoriasis [32], a disease characterized by infiltration of memory effector type lymphocytes.…”

Section: Introductionmentioning

confidence: 99%

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Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells

et al. 2003

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Modulation of the immune response using immunoglobulin fusion proteins has shown great promise for clinical immunotherapy of autoimmune diseases. Alefacept is an immunoglobulin fusion protein composed of the first extracellular domain of human LFA-3 fused to the hinge, C H 2 and C H 3 domains of human IgG 1 . Alefacept has previously been reported to inhibit T cell proliferation. Here, we analyzed the effects of alefacept on lymphocytes in vitro and characterized the role of autologous NK cells in its mechanism of action. Alefacept, but not a C H 2 binding mutant of Alefacept, inhibited CD3-induced T cell proliferation only in the presence of live NK cells, consistent with an important role for Fc + R engagement. Alefacept caused preferential depletion of CD69+ T cell subsets. Cytotoxicity assays revealed that alefacept, but not the C H 2 binding mutant, induced NK cell-mediated death of activated T cells and sorting into CD45R0 + and CD45RA + subpopulations showed that lymphocyte deletion occurred preferentially in the CD45R0 + subset. Activated CD45R0 + cells expressed higher levels of CD2 than CD45R0 -cells, providing a possible explanation for the selective targeting of this subset. Our results suggest that selective targeting of CD45R0 + T cells by NK cells represents a potential therapeutic mechanism of action of alefacept.

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Section: Alefacept Binding Is Higher On Activated Cd45r0 + Cellsmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells

et al. 2003

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“…Antibodystained cells were washed twice prior to analysis. Alefacept binding modified from Majeau et al (7). Alefacept was labeled with 0.8 FITC/alefacept.…”

Section: Human Peripheral Blood Lymphocytes (Pbl)-inmentioning

confidence: 99%

“…It is hypothesized that alefacept both reduces deleterious effector functions of activated T cells by blocking interaction of CD2 with CD58 and deletes autoaggressive T cells through FcR-dependent killing. When CD16A is the activating FcR each of the individual interactions of alefacept is low affinity with a K d of 1.5 M for the CD2-CD58 interaction and K d of 0.91 M for the Fc-CD16 interaction (5)(6)(7)(8). How these solution affinities relate to interactions in an adhesion area is not clear.…”

mentioning

confidence: 99%

Quantification and Modeling of Tripartite CD2-, CD58FC Chimera (Alefacept)-, and CD16-mediated Cell Adhesion

Dustin

Starr

Coombs

et al. 2007

Journal of Biological Chemistry

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Alefacept is a chimeric protein combining CD58 immunoglobulin-like domain 1 with human IgG1 Fc. Alefacept mediates adhesion by bridging CD2 on T cells to activating Fc receptors on effector cells, but the equilibrium binding parameters have not been determined. Alefacept mediated T cell killing by NK cells and adhesion between CD2-and CD16-expressing cells at an optimum concentration of 100 nM. We introduce novel measurements with supported planer bilayers, from which key twodimensional and three-dimensional parameters can be determined by data fitting. Alefacept competitively inhibited cell bilayer adhesion mediated by the CD2-CD58 interaction. Alefacept mediated maximal adhesion of CD2 ؉ T cells to CD16B, an Fc receptor, in planar bilayers at 500 nM. A mechanistic model for alefacept-mediated cell-bilayer adhesion allowed fitting of the data and determination of two-dimensional binding parameters. These included the density of bonds in the adhesion area, which grew to maintain a consistent average bond density of 200 molecules/m 2 and two-dimensional association constants of 3.1 and 630 m 2 for bivalently and monovalently bound forms of alefacept, respectively. The maximum number of CD16 bound and the fit value of 4,350 CD2 per cell are much lower than the 40,000 CD2 per cell measured with anti-CD2 Fab. These results suggest that additional information is needed to correctly predict Alefacept-mediated bridge formation.Immunoadhesins are biopharmaceuticals that take the basic framework of antibodies and replace the antigen-binding domain with the ectodomain of adhesion molecules (1, 2). The common fragment of IgG (Fc) portion is thought to link to immune effector mechanisms to destroy cancer cells and or over-reactive immune cells. One example of this approach is the drug alefacept, which combines the CD2 binding domain of the adhesion molecule CD58 (LFA-3) with human IgG1 Fc in a single polypeptide chain. Alefacept is approved for treatment of psoriasis. Alefacept mediates reduction of circulating memory T cells in patients and mediates Fc receptor (FcR) 2 -dependent cell-mediated killing of T cells in vitro (3, 4). It is hypothesized that alefacept both reduces deleterious effector functions of activated T cells by blocking interaction of CD2 with CD58 and deletes autoaggressive T cells through FcR-dependent killing. When CD16A is the activating FcR each of the individual interactions of alefacept is low affinity with a K d of 1.5 M for the CD2-CD58 interaction and K d of 0.91 M for the Fc-CD16 interaction (5-8). How these solution affinities relate to interactions in an adhesion area is not clear.These interactions are proposed to take place in the twodimensional interface between cells, but there are only limited data on such interactions and no quantitative data on formation of the trimolecular bridges as proposed for alefacept. Determining such parameters in a model system would be a first step to development of a system of two-dimensional pharmacology to better predict in vivo behavior in cell-cell conta...

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Treatment of Psoriasis With Alefacept

et al. 2003

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Low affinity binding of an LFA-3/IgG1 fusion protein to CD2⁺T cells is independent of cell activation

Cited by 30 publications

References 25 publications

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells

Quantification and Modeling of Tripartite CD2-, CD58FC Chimera (Alefacept)-, and CD16-mediated Cell Adhesion

Treatment of Psoriasis With Alefacept

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Low affinity binding of an LFA-3/IgG1 fusion protein to CD2+T cells is independent of cell activation

Cited by 30 publications

References 25 publications

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0+ human T cells

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0+ human T cells

Quantification and Modeling of Tripartite CD2-, CD58FC Chimera (Alefacept)-, and CD16-mediated Cell Adhesion

Treatment of Psoriasis With Alefacept

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Product

Resources

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Low affinity binding of an LFA-3/IgG1 fusion protein to CD2⁺T cells is independent of cell activation

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells

Alefacept selectively promotes NK cell‐mediated deletion of CD45R0⁺ human T cells