Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors

There is strong evidence that class I MHC-restricted parasite-specific CD8+ CTL protect cattle against the protozoan parasite Theileria parva. As part of an effort to develop a subunit vaccine for the induction of these responses, we have investigated the factors involved in the generation of T. par...

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Main Authors: Taracha, E.L.N., Awino, Elias, McKeever, Declan J.
Format: Journal Article
Language:Inglés
Published: 1997
Subjects:
Online Access:https://hdl.handle.net/10568/28924
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author Taracha, E.L.N.
Awino, Elias
McKeever, Declan J.
author_browse Awino, Elias
McKeever, Declan J.
Taracha, E.L.N.
author_facet Taracha, E.L.N.
Awino, Elias
McKeever, Declan J.
author_sort Taracha, E.L.N.
collection Repository of Agricultural Research Outputs (CGSpace)
description There is strong evidence that class I MHC-restricted parasite-specific CD8+ CTL protect cattle against the protozoan parasite Theileria parva. As part of an effort to develop a subunit vaccine for the induction of these responses, we have investigated the factors involved in the generation of T. parva-specific CTL in cattle. Purified populations of bovine immune and naive CD8+ T cells were cocultured with autologous T. parva-infected lymphoblasts (TpL) in the presence or absence of immune CD4+ T cells or cytokine preparations. Neither population developed CTL activity when cultured with TpL alone, whereas incorporation of immune CD4+ T cells in the cultures supported the generation of parasite-specific CTL from both immune and naive CD8+ precursors. The helper function of parasite-specific CD4+ T cells for immune, but not naive, CTL precursors could be replaced by CD4+ T cells responding to an unrelated Ag or by the addition of T cell growth factors or recombinant bovine IL-2. In experiments with two-chamber culture plates, in which cocultures of CD4+ and CD8+ T cells with TpL were separated by a semipermeable membrane, CTL activity was observed to develop only in immune precursor populations. Hence, although bovine T. parva-specific CD8+ memory T cells need no helper signals other than IL-2 for activation, their naive counterparts require close contact with responding parasite-specific CD4+T cells. This may reflect essential receptor-ligand interactions, or alternatively, a requirement for more stringent microenvironmental cytokine conditions.
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spelling CGSpace289242022-01-29T16:19:20Z Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors Taracha, E.L.N. Awino, Elias McKeever, Declan J. theileria parva antigens immunity There is strong evidence that class I MHC-restricted parasite-specific CD8+ CTL protect cattle against the protozoan parasite Theileria parva. As part of an effort to develop a subunit vaccine for the induction of these responses, we have investigated the factors involved in the generation of T. parva-specific CTL in cattle. Purified populations of bovine immune and naive CD8+ T cells were cocultured with autologous T. parva-infected lymphoblasts (TpL) in the presence or absence of immune CD4+ T cells or cytokine preparations. Neither population developed CTL activity when cultured with TpL alone, whereas incorporation of immune CD4+ T cells in the cultures supported the generation of parasite-specific CTL from both immune and naive CD8+ precursors. The helper function of parasite-specific CD4+ T cells for immune, but not naive, CTL precursors could be replaced by CD4+ T cells responding to an unrelated Ag or by the addition of T cell growth factors or recombinant bovine IL-2. In experiments with two-chamber culture plates, in which cocultures of CD4+ and CD8+ T cells with TpL were separated by a semipermeable membrane, CTL activity was observed to develop only in immune precursor populations. Hence, although bovine T. parva-specific CD8+ memory T cells need no helper signals other than IL-2 for activation, their naive counterparts require close contact with responding parasite-specific CD4+T cells. This may reflect essential receptor-ligand interactions, or alternatively, a requirement for more stringent microenvironmental cytokine conditions. 1997 2013-05-06T07:01:45Z 2013-05-06T07:01:45Z Journal Article https://hdl.handle.net/10568/28924 en Limited Access Journal of Immunology;159: 4539-4545
spellingShingle theileria parva
antigens
immunity
Taracha, E.L.N.
Awino, Elias
McKeever, Declan J.
Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title_full Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title_fullStr Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title_full_unstemmed Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title_short Distinct CD4 + T cell helper requirements in Theileria parva-immune and -naive bovine CTL precursors
title_sort distinct cd4 t cell helper requirements in theileria parva immune and naive bovine ctl precursors
topic theileria parva
antigens
immunity
url https://hdl.handle.net/10568/28924
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AT mckeeverdeclanj distinctcd4tcellhelperrequirementsintheileriaparvaimmuneandnaivebovinectlprecursors