Mechanisms Underlying the Induction of Regulatory T cells and Its Relevance in the Adaptive Immune Response in Parasitic Infections

Abstract

To fulfill its function, the immune system must detect and interpret a wide variety of signals and adjust the magnitude, duration, and specific traits of each response during the complex host-parasite relationships in parasitic infections. Inflammation must be tightly regulated since uncontrolled inflammation may be as destructive as the triggering stimulus and leads to immune-mediated tissue injury.During recent years, increasing evidence points to regulatory T cells (Tregs) as key anti-inflammatory cells, critically involved in limiting the inflammatory response. Herein, we review the published information on the induction of Tregs and summarize the most recent findings on Treg generation in parasitic diseases.

Increased Accumulation of Regulatory Granulocytic Myeloid Cells in Mannose Receptor C Type 1-Deficient Mice Correlates with Protection in a Mouse Model of Neurocysticercosis

“…Using murine NCC, we have characterized the kinetics of the immune response during parasitic infection in which the initial immune response is biased toward a Th1 type of inflammatory immune response (10,14). As the disease progresses, it turns into a mixed Th1, Th2, and Th3 (Treg) type of response similar to that in human NCC, which emanates from a heterogeneous mix of both myeloid and lymphoid subsets (10)(11)(12)15).…”

The Role of Regulatory CD4+ CD25+ T Cell Subset in Host Homeostasis during Protozoan Infection: An Overview

“…In trypanosomiasis, the persistent infections are accompanied by a profound immunosuppression (reviewed by Adalid-Peralta et al [38]). …”

“…During African trypanosomiasis, it has been reported that the expansion of Treg cells is responsible for parasite tolerance from the moment of establishment of infection and continuing during chronic stage [38].…”

“…Schizonts rupture releasing merozoites into the blood stream [48] that easily adhere to and infect red blood cells (RBC). Inside RBC the parasite expands exponentially, developing into the trophozoite stage [38], divide asexually into mature schizonts (erythrocytic schizogony), which in turn rupture the RBC and the merozoite form is released into the blood stream, consequently infecting other RBC, perpetuating the infection [18]. Some of the merozoites forms may develop into male and female gametocytes, the sexual erythrocytic stages.…”

<italic>Helicobacter pylori </italic>Infection: Regulatory T Cells and Their Participation in the Immune Response

“…CD4+CD25 high Treg cells are the best-described subset. A key characteristic of CD4+CD25 high Treg cells is its ability to induce anergy in vitro and suppress immune responses (28,29). Some studies suggest that CD4+CD25 high Treg cells inhibit proliferation of effector CD4+CD25-T cells and CD8+ T cells by arresting the proliferation of these cells at G1-S interphase of the cell cycle (30).…”