Characterization of phenotype related responsiveness of peripheral blood lymphocytes from Eimeria tenella infected chickens

Abstract

We have previously shown that the proportion of CD8-expressing T cells (CD8bright+ and CD4+ CD8dim+ 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-gamma) 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 CD8bright+ as well as CD4+ (CD4+ CD8dim+ and possible CD4+, single positive) lymphocytes are responsible for the IFN-gamma production measured after stimulation with parasite antigen, whereas the specific proliferative response appears to be caused by CD4+ (CD4+ CD8dim+ and possibly CD4+ single positive) lymphocytes. We speculate that the CD8bright+ 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.

Responses to dietary levels of methionine in broilers medicated or vaccinated against coccidia under Eimeria tenella-challenged condition

“…The selective elimination of CD8 + cells resulted in the exacerbation of disease as evidenced by increased oocyst shedding after secondary infection with E. tenella or E. acervulina [ 32 ] . It is known that CD4 + cells play an important helper function in protective immune responses, and CD8 + cells act as effector cells in these processes [ 33 ]. Both CD4+ and CD8+ cells are responsible for the IFN-γ production [ 33 ].…”

“…It is known that CD4 + cells play an important helper function in protective immune responses, and CD8 + cells act as effector cells in these processes [ 33 ]. Both CD4+ and CD8+ cells are responsible for the IFN-γ production [ 33 ]. IFN-γ production is higher in chicks infected with Eimeria species compared with non-infected chicks, and higher levels of IFN-γ coincide with a protective immune response to the infection [ 27 ].…”

Recent Advances in Biology and Immunobiology ofEimeriaSpecies and in Diagnosis and Control of Infection with These Coccidian Parasites of Poultry

“…The fraction of antigens that produced the highest T-cell proliferation and macrophage-activating activity, when administered as a vaccine, also yielded chickens with the lowest cecal lesion scores after challenge (20).…”

“…Because T-cell-stimulatory antigens appear to be the most relevant to protective immunity, T-cell proliferation assays (using T cells from recovering chickens) and IFN-␥ production have been used to screen for protective antigens against E. tenella infections (20). The fraction of antigens that produced the highest T-cell proliferation and macrophage-activating activity, when administered as a vaccine, also yielded chickens with the lowest cecal lesion scores after challenge (20).…”

CD4+CD8dim T lymphocytes exhibit enhanced cytokine expression, proliferation and cytotoxic activity in response to HCMV and HIV-1 antigens

“…Moreover, Bagot et al [13] have demonstrated the presence of tumor-specific, MHC class I-restricted, cytotoxic CD4 + CD8 dim T cell clones inside cutaneous infiltrates from patients with cutaneous T cell lymphoma. In monkeys, swine and chicken, species that have markedly more abundant circulating CD4 + CD8 dim T cells than humans, the CD4 + CD8 dim subset appears to have both helper and cytotoxic functions [16][17][18]. were stimulated with CMV lysate as described in Sect.…”