Toll-like receptors (TLR) are pattern recognition receptors (PRRs) expressed on many different cells types and initiate immune responses via recognition of pathogen-associated molecular patterns. Gamma/delta (γ/δ) T cells are unconventional T lymphocytes, thought to form a bridge between the innate and acquired immune systems. Stimulation through the γ/δ TCR is required for activation, although it is known that at least one ligand for human (γ/δ) T cells can stimulate either through the TCR or through a PRR known as NKG2D. Human (γ/δ) T cells express at least 4 TLRs while bovine (γ/δ) T cells express at least one (TLR2, which senses bacterial lipoproteins). Our objectives were to analyse TLR gene expression (by qRT PCR) of ex vivo resting (γ/δ) T cells and compare this to their in vitro activated phenotype (by mitogen and/or TLR ligands). In addition, we investigated TLR expression in response to in vitro chlamydial antigenic stimulation in naive and immune sheep, since initial observations have shown recall responses in a specific subpopulation of (γ/δ) T cells in immune animals. We demonstrate expression of the complete repertoire of ovine TLR genes by these cells, except TLR5, which was absent in the majority of samples. However each TLR showed differential relative expression in (γ/δ) T cells depending on the stimulus, with TLRs 2, 4 and 6 being the most abundant overall. Resting cells demonstrated highest expression of all TLRs. In naive animals, the highest TLR expression was achieved by stimulation with LPS, with chlamydial antigen stimulation moderately upregulating TLR expression and mitogenic stimulation correlated to the lowest expression. In immune animals the non proliferating (parental) (γ/δ) T cells showed the highest expression of TLRs in response to antigen, whereas among the proliferating T cells TLR expression was variable. Knowledge of TLR expression will allow us to develop hypotheses regarding how these cells sense infection and become activated.

Expression of toll-like receptors by ovine WC1 gamma delta T cells / M. Rocchi, L. Turin, M. Connelly, G. Entrican, C. Baldwin - In: 10th International Veterinary Immunology Symposium, Milan, Italy 2013[s.l] : IZS-Unimi, 2013 Aug. - pp. 61-62 (( Intervento presentato al 10. convegno International Veterinary Immunology Symposium tenutosi a Milano nel 2013.

Expression of toll-like receptors by ovine WC1 gamma delta T cells

L. Turin
Secondo
;
2013

Abstract

Toll-like receptors (TLR) are pattern recognition receptors (PRRs) expressed on many different cells types and initiate immune responses via recognition of pathogen-associated molecular patterns. Gamma/delta (γ/δ) T cells are unconventional T lymphocytes, thought to form a bridge between the innate and acquired immune systems. Stimulation through the γ/δ TCR is required for activation, although it is known that at least one ligand for human (γ/δ) T cells can stimulate either through the TCR or through a PRR known as NKG2D. Human (γ/δ) T cells express at least 4 TLRs while bovine (γ/δ) T cells express at least one (TLR2, which senses bacterial lipoproteins). Our objectives were to analyse TLR gene expression (by qRT PCR) of ex vivo resting (γ/δ) T cells and compare this to their in vitro activated phenotype (by mitogen and/or TLR ligands). In addition, we investigated TLR expression in response to in vitro chlamydial antigenic stimulation in naive and immune sheep, since initial observations have shown recall responses in a specific subpopulation of (γ/δ) T cells in immune animals. We demonstrate expression of the complete repertoire of ovine TLR genes by these cells, except TLR5, which was absent in the majority of samples. However each TLR showed differential relative expression in (γ/δ) T cells depending on the stimulus, with TLRs 2, 4 and 6 being the most abundant overall. Resting cells demonstrated highest expression of all TLRs. In naive animals, the highest TLR expression was achieved by stimulation with LPS, with chlamydial antigen stimulation moderately upregulating TLR expression and mitogenic stimulation correlated to the lowest expression. In immune animals the non proliferating (parental) (γ/δ) T cells showed the highest expression of TLRs in response to antigen, whereas among the proliferating T cells TLR expression was variable. Knowledge of TLR expression will allow us to develop hypotheses regarding how these cells sense infection and become activated.
Settore VET/05 - Malattie Infettive degli Animali Domestici
ago-2013
Università degli Studi di Milano
Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/227160
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