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Laminin 5 in the human thymus: control of T cell proliferation via alpha6beta4 integrins.

Vivinus-Nebot M, Ticchioni M, Mary F, Hofman P, Quaranta V, Rousselle P, Bernard A - J. Cell Biol. (1999)

Bottom Line: In addition to a linear staining of subcapsular basal laminae, the three mAbs give a disperse staining in the parenchyma restricted to the medullary area on a subset of stellate epithelial cells and vessel structures.We also found that laminin 5 may influence mature human thymocyte expansion; while bulk laminin and laminin 2, when cross-linked, are comitogenic with a TCR signal, cross-linked laminin 5 has no effect.This is accompanied by a particular pattern of inhibition of early tyrosine kinases, including Zap 70 and p59(fyn) inhibition, but not overall inhibition of p56(lck).

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Sant¿e et de la Recherche M¿edicale, U343, Nice 06202, France.

ABSTRACT
Laminin 5 (alpha3beta3gamma2) distribution in the human thymus was investigated by immunofluorescence on frozen sections with anti-alpha3, -beta3, and -gamma2 mAbs. In addition to a linear staining of subcapsular basal laminae, the three mAbs give a disperse staining in the parenchyma restricted to the medullary area on a subset of stellate epithelial cells and vessel structures. We also found that laminin 5 may influence mature human thymocyte expansion; while bulk laminin and laminin 2, when cross-linked, are comitogenic with a TCR signal, cross-linked laminin 5 has no effect. By contrast, soluble laminin 5 inhibits thymocyte proliferation induced by a TCR signal. This is accompanied by a particular pattern of inhibition of early tyrosine kinases, including Zap 70 and p59(fyn) inhibition, but not overall inhibition of p56(lck). Using a mAb specific for alpha6beta4 integrins, we observed that while alpha3beta1 are known to be uniformly present on all thymocytes, alpha6beta4 expression parallels thymocyte maturation; thus a correspondence exists between laminin 5 in the thymic medulla and alpha6beta4 on mature thymocytes. Moreover, the soluble Ab against alpha6beta4 inhibits thymocyte proliferation and reproduces the same pattern of tyrosine kinase phosphorylation suggesting that alpha6beta4 is involved in laminin 5-induced modulation of T cell activation.

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Effects of anti-α6 chain mAb S3-41, added, either in  cross-linked or soluble form, on thymocyte proliferation. (a) S3-41  or GOH3 and CD3 were cross-linked on plastic from culture  wells as indicated in Fig. 2 before adding the thymocyte suspension. (b) CD3 was first cross-linked on plastic from culture wells.  FCS in culture medium was incubated for 2 h at 37°C to saturate  the plastic, before adding IL-2, S3-41, or GOH3 in solution and  the thymocyte suspension. The indicated mAbs were added at  10 μg/ml.
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Figure 8: Effects of anti-α6 chain mAb S3-41, added, either in cross-linked or soluble form, on thymocyte proliferation. (a) S3-41 or GOH3 and CD3 were cross-linked on plastic from culture wells as indicated in Fig. 2 before adding the thymocyte suspension. (b) CD3 was first cross-linked on plastic from culture wells. FCS in culture medium was incubated for 2 h at 37°C to saturate the plastic, before adding IL-2, S3-41, or GOH3 in solution and the thymocyte suspension. The indicated mAbs were added at 10 μg/ml.

Mentions: Anti-α6 antibodies were used in proliferation assays performed on human thymocytes. To determine which laminin 5 receptor is involved in the modulation of thymocyte proliferation, we used GOH3 mAb which recognizes all α6 chains and S3-41 mAb which is α6β4 specific. As previously described (58, 66), the anti-α6 mAb GOH3 immobilized on culture wells delivered a strong costimulus for thymocyte proliferation in the presence of cross-linked CD3 mAb (Fig. 8 a). Under the same conditions, S3-41 delivered a weak proliferative costimulus to thymocytes when compared with GOH3. Moreover, there was no additive or synergistic effect when the two mAbs GOH3 and S3-41 were immobilized on plates with a CD3 mAb. When anti-α6 mAbs were used in soluble form, we observed that only S3-41 inhibited proliferation of thymocytes stimulated via the CD3–TCR complex (Fig. 8 b). Inhibition was very efficient with S3-41 (50%). We tested the same soluble mAbs on thymocytes stimulated with a mitogenic pair of CD2 mAbs (GT2 + D66) (Fig. 9 a), the CD28 mAb and immobilized CD3 mAb (Fig. 9 b), or the CD28 mAb and rIL-2 (Fig. 9 c). Again, an inhibitory effect was seen only when thymocytes were stimulated via the CD3–TCR pathway.


Laminin 5 in the human thymus: control of T cell proliferation via alpha6beta4 integrins.

Vivinus-Nebot M, Ticchioni M, Mary F, Hofman P, Quaranta V, Rousselle P, Bernard A - J. Cell Biol. (1999)

Effects of anti-α6 chain mAb S3-41, added, either in  cross-linked or soluble form, on thymocyte proliferation. (a) S3-41  or GOH3 and CD3 were cross-linked on plastic from culture  wells as indicated in Fig. 2 before adding the thymocyte suspension. (b) CD3 was first cross-linked on plastic from culture wells.  FCS in culture medium was incubated for 2 h at 37°C to saturate  the plastic, before adding IL-2, S3-41, or GOH3 in solution and  the thymocyte suspension. The indicated mAbs were added at  10 μg/ml.
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Related In: Results  -  Collection

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Figure 8: Effects of anti-α6 chain mAb S3-41, added, either in cross-linked or soluble form, on thymocyte proliferation. (a) S3-41 or GOH3 and CD3 were cross-linked on plastic from culture wells as indicated in Fig. 2 before adding the thymocyte suspension. (b) CD3 was first cross-linked on plastic from culture wells. FCS in culture medium was incubated for 2 h at 37°C to saturate the plastic, before adding IL-2, S3-41, or GOH3 in solution and the thymocyte suspension. The indicated mAbs were added at 10 μg/ml.
Mentions: Anti-α6 antibodies were used in proliferation assays performed on human thymocytes. To determine which laminin 5 receptor is involved in the modulation of thymocyte proliferation, we used GOH3 mAb which recognizes all α6 chains and S3-41 mAb which is α6β4 specific. As previously described (58, 66), the anti-α6 mAb GOH3 immobilized on culture wells delivered a strong costimulus for thymocyte proliferation in the presence of cross-linked CD3 mAb (Fig. 8 a). Under the same conditions, S3-41 delivered a weak proliferative costimulus to thymocytes when compared with GOH3. Moreover, there was no additive or synergistic effect when the two mAbs GOH3 and S3-41 were immobilized on plates with a CD3 mAb. When anti-α6 mAbs were used in soluble form, we observed that only S3-41 inhibited proliferation of thymocytes stimulated via the CD3–TCR complex (Fig. 8 b). Inhibition was very efficient with S3-41 (50%). We tested the same soluble mAbs on thymocytes stimulated with a mitogenic pair of CD2 mAbs (GT2 + D66) (Fig. 9 a), the CD28 mAb and immobilized CD3 mAb (Fig. 9 b), or the CD28 mAb and rIL-2 (Fig. 9 c). Again, an inhibitory effect was seen only when thymocytes were stimulated via the CD3–TCR pathway.

Bottom Line: In addition to a linear staining of subcapsular basal laminae, the three mAbs give a disperse staining in the parenchyma restricted to the medullary area on a subset of stellate epithelial cells and vessel structures.We also found that laminin 5 may influence mature human thymocyte expansion; while bulk laminin and laminin 2, when cross-linked, are comitogenic with a TCR signal, cross-linked laminin 5 has no effect.This is accompanied by a particular pattern of inhibition of early tyrosine kinases, including Zap 70 and p59(fyn) inhibition, but not overall inhibition of p56(lck).

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Sant¿e et de la Recherche M¿edicale, U343, Nice 06202, France.

ABSTRACT
Laminin 5 (alpha3beta3gamma2) distribution in the human thymus was investigated by immunofluorescence on frozen sections with anti-alpha3, -beta3, and -gamma2 mAbs. In addition to a linear staining of subcapsular basal laminae, the three mAbs give a disperse staining in the parenchyma restricted to the medullary area on a subset of stellate epithelial cells and vessel structures. We also found that laminin 5 may influence mature human thymocyte expansion; while bulk laminin and laminin 2, when cross-linked, are comitogenic with a TCR signal, cross-linked laminin 5 has no effect. By contrast, soluble laminin 5 inhibits thymocyte proliferation induced by a TCR signal. This is accompanied by a particular pattern of inhibition of early tyrosine kinases, including Zap 70 and p59(fyn) inhibition, but not overall inhibition of p56(lck). Using a mAb specific for alpha6beta4 integrins, we observed that while alpha3beta1 are known to be uniformly present on all thymocytes, alpha6beta4 expression parallels thymocyte maturation; thus a correspondence exists between laminin 5 in the thymic medulla and alpha6beta4 on mature thymocytes. Moreover, the soluble Ab against alpha6beta4 inhibits thymocyte proliferation and reproduces the same pattern of tyrosine kinase phosphorylation suggesting that alpha6beta4 is involved in laminin 5-induced modulation of T cell activation.

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