T cell activation by Theileria annulata-infected macrophages correlates with cytokine production

Abstract

SUMMARYA major feature of the pathology induced by Theileria annulata is acute lymphocytic proliferation, and this study investigates the mechanisms underlying the intrinsic ability of T. anniilata-infecXed monocyles to induce naive autoiogous T cells to proliferate. Different 7". aiinulata-'mkcted clones expressed different but constant levels of MHC class II, varying from < 10 x 10' to 1-5 x 10niolecules/celK as measured by saturation binding. However, no correlation was found between the level of MHC class IT expression and levels of induced T ceil proliferation. Theileria animtatainfected cell lines and clones were assayed for cytokine mRNA expression by reverse transcriplionpolymerase chain reaction (RT-PCR). The infected cells assayed produced mRNA specific for IL-la. \L-\fi. lL-6, IL-10 and tumour necrosis factor-alpha (TNF-a). but not IL-2 or lL-4. One clone (clone G)did not produce mRNA for TNF-f>. The degree of Tcell proliferation induced by infected cells was directly correlated with the amount of mRNA produced for the T cell stimulatory cytokines IL-la and IL-6, as assessed by a semiquantitative technique. In contrast, cells infected with the related parasite T. parva produced mRNA for IL-la, IL-2, IL-4, IL-IO and interferon-gamma (IFN-7). Since T. /5(^/rv«-infected cells also induce naive autologous T cell proliferation, it seems likely that the production oflL-Ifi by cells infected with either parasite is a major signal for the induction of non-specific T cell proliferation.

Molecular and pathological studies on natural cases of bovine theileriosis

“…In contrary with our results Brown et al (1995) showed that cells infected with T. annulata produce high levels of inflammatory cytokines especially TNF-a, which is a potent inducer of fever and also leads to anemia, muscle wasting and necrosis. T. annulata leads to production of various T cell-stimulatory and inflammatory cytokines which are responsible for immunopathological lesions observed during infection.…”

“…T. annulata leads to production of various T cell-stimulatory and inflammatory cytokines which are responsible for immunopathological lesions observed during infection. Increased production of IL-10 which showed similar findings with our results leads to reduced efficiency of immune response against infected cells (Brown et al 1995).…”

“…T. annulata induced production of various T cell stimulatory and inflammatory cytokines which may be responsible for immunopathological symptoms observed Dayne's et al 1990;O'Garra and Murphy 1994). However, Brown et al (1995) showed increased response of IL-2, IL-4, IL-10, TNF-a and INF-c which showed contrary results with our TNF-a and INF-c results. In the present study the level of TNF-a in individual animals varies from higher value (1028 pg/100 lg protein) to as low as 500 pg/100 lg protein.…”

“…In the present study the level of TNF-a in individual animals varies from higher value (1028 pg/100 lg protein) to as low as 500 pg/100 lg protein. Brown et al (1995) suggested that cells infected with T. annulata produce high levels of inflammatory cytokines especially TNF-a which was a potent source of fever. INF-c mainly produced from T. annulata stimulated T-cells and not from infected cells.…”

Variation in clinical markers in cattle naturally infected with bovine tropical theileriosis

“…BTT accounts for high mortality rates in dairy cattle with over 200 million animals exposed to risk (Radostits et al 1994;Sudan et al 2014). The global annual losses due to BTT are estimated to be of US$800 million (Brown et al 1995) while in India alone, the disease accounts for an approximate annual loss of US$384.3 million (Minjauw and McLeod 2003). To add up to the agony, animals with chronic cases of BTT show almost similar types of signs and symptoms with that of other arthropod vector borne diseases like trypanosomiosis, anaplasmosis and babesiosis.…”