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Characterization of phenotype related responsiveness of peripheral blood lymphocytes from Eimeria tenella infected chickens
Author(s) -
BREED DOMINIQUE G.J.,
SCHETTERS THEO P.M.,
VERHOEVEN NICOLE A.P.,
VERMEULEN ARNO N.
Publication year - 1997
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.1997.d01-174.x
Subject(s) - biology , antigen , cytokine , cd8 , immunology , immune system , monoclonal antibody , stimulation , antibody , eimeria , cytotoxic t cell , t lymphocyte , in vitro , microbiology and biotechnology , endocrinology , biochemistry
We have previously shown that the proportion of CD8‐expressing T cells (CD8 bright+ and CD4 + CD8 dim+ cells) in the peripheral blood of chickens increases around 8 days after a primary infection with Eimeria tenella oocysts. The increase in the CD8 + eight cells coincides with enhanced responses after in vitro stimulation with parasite antigen. In the study described here, the responsiveness of these day 8 PBL was further characterized by determining their capacity to proliferate and to produce cytokine (IFN‐γ) upon stimulation with E. tenella sporozoite antigen, or non‐specific stimuli like T cell growth factor (TCGF) and anti‐CD3 monoclonal antibody (MoAb). Comparing the responsiveness of infected responder (day 8) and control chickens, non‐specific triggering induced cytokine production in cells from infected animals and proliferation in cells from control animals. When triggered with E. tenella sporozoite antigen, lymphocytes from infected chickens responded with proliferation and cytokine production, in contrast to lymphocytes from control animals that did not respond. The phenotype of the lymphocytes involved in the parasite‐specific proliferation and cytokine production, was characterized in a blocking assay using MoAb directed against the CD4 or CD8 molecule. The results suggest that CD8 bright+ as well as CD4 + (CD4 + CD8 dim+ and possible CD4 + , single positive) lymphocytes are responsible for the IFN‐γ production measured after stimulation with parasite antigen, whereas the specific proliferative response appears to be caused by CD4 + (CD4 + CD8 dim+ and possibly CD4 + , single positive) lymphocytes. We speculate that the CD8 bright+ cells, present in the circulation around 8 days after a primary E. tenella infection, act as effector cells in protective immune responses, whereas CD4 + cells play an important helper function in these responses .