Quantitative estimation of suppressor/cytotoxic and helper T cells during acute and chronic Plasmodium berghei infection

Abstract

SummaryIn the present study, the percentage of lymphocyte subpopuiations and their relation to T cell subsets was estimated during acute and chronic Plasmodium berghei malaria. During acute infection, a decreased percentage of T lymphocytes was observed, whereas no change was observed during chronic infection. However, no change in the percentage of B cells was observed in both types of infection. The T cell population was characterized by an increased percentage of T suppressor cytotoxic (CD8+) cells and a decreased percentage of T helper cells (CD4+) during acute infection. This resulted in an inversion ofthe CD8+/CD4+ cell ratio. During chronic infection no change in the CD8'*" cell percentage was observed; however some increase in CD4+ cell percentage was observed in later stages. Thus failure ofthe immune system to overcome acute infection may be due to an increase in T suppressor cells, and maintenance of parasites at subpatent levels during chronic infection may involve the normal CD8+/CD4+ cell ratio with some increase in CD4+ cells.

Methnaridine is an orally bioavailable, fast‐killing and long‐acting antimalarial agent that cures Plasmodium infections in mice

“…Analysis of T cell frequency in splenocytes isolated on day 4 in vehicle‐treated mice revealed significant CD4 + T cell lymphopenia compared with uninfected controls (Figure 6a). Early leukopenia, particularly for CD4 + T cells, is a well‐known phenomenon during Plasmodium infection (Hviid & Kemp, 2000; Wangoo, Kaur, Ganguly, Bhatti, & Mahajan, 1990). Following methnaridine treatment, the level of CD4 + T cells was significantly elevated, indicating that a sufficient number of T cells was raised inside the host to fight the associated infection (Figure 6a).…”

“…CD4 + T cells play a central role in the immune response to malaria (Reece et al, 2004). T lymphopenia is a well‐established feature of P. falciparum malaria in early infection (also seen in murine malaria), although its cause remains unclear (Helmby, Jonsson, & Troye‐Blomberg, 2000; Hviid et al, 1997; Hviid & Kemp, 2000; Wangoo, Kaur, Ganguly, Bhatti, & Mahajan, 1990). In this study, following the treatment with methnaridine, the CD4 + T cell ratio was significantly elevated compared with the vehicle‐treated controls.…”

Immunomodulatory effects of testosterone and letrozole during Plasmodium berghei ANKA infection

“…In addition, we detected a low CD4 + /CD8 + ratio in both infected groups treated with testosterone indicating that CD8 + cells increased. This unbalanced CD4 + /CD8 + T-cell ratio affects the control of parasites during Pb ANKA infection ( Wangoo et al., 1990 ), which somewhat explains the increased parasitemia in these groups. Finally, CD8 + T cells play an important role in neuropathology and mortality in cerebral malaria ( Qin et al., 2021 ; Liang et al., 2022 ).…”