Immune Responses in Leishmaniasis: An Overview

Abstract

Leishmaniasis is a parasitic, widespread, and neglected disease that affects more than 90 countries in the world. More than 20 Leishmania species cause different forms of leishmaniasis that range in severity from cutaneous lesions to systemic infection. The diversity of leishmaniasis forms is due to the species of parasite, vector, environmental and social factors, genetic background, nutritional status, as well as immunocompetence of the host. Here, we discuss the role of the immune system, its molecules, and responses in the establishment, development, and outcome of Leishmaniasis, focusing on innate immune cells and Leishmania major interactions.

Biochemical Properties of Parasite Virulence Factor: Lesson Learned from Leishmania

“…Considering this is very critical to the disease formation, due to the fact that (1) the Leishmania parasites live inside the host's cellular innate immune cell named macrophages and (2) it really need to avert the inhabited macrophages from processing them further and ends with killing them [47]. Lipophosphoglycan also has a duty in (1) facilitating resistance and preventing activation of the complement system armamentarium, (2) inhibiting host's oxidative burst response, and also (3) initiating an adequate inflammation and (4) preventing the natural killer T cells realizing that the host's macrophage is already infected with the Leishmania parasite [25,48]. There may be an association between the immune cell's response to Leishmania and the exact cell stage/subset being evaluated, with differentiated macrophages being more permissive to infection in vitro than the monocytes.…”

“…In order to keep away from destruction and killing by the immune cells and also to facilitate its thrive, the Leishmania actually 'disguise' itself inside its host's immune cells [46,48]. This safe location actually facilitates them to circumvent the work of the humoral immune feedback because in this situation, the pathogen is keep safe inside an intact cell that belongs to their host's and actually not in blood vessels where open blood flow is likely to increase its contact with the immune cells.…”

“…Regularly, a phagocytotic cell, e.g., macrophage, will internalize and further kill a pathogen covered within an enclosed endosome and in order to do so, they then pervade this endosome with certain enzymes which will digest the pathogen [25,[46][47][48]. However, in the case of Leishmania, these enzymes of macrophage have no effect to the parasite.…”

“…A key factor in elongating infection is by way of the reticence of the adaptive immune cells [48][49][50]. This took place primarily during the intracellular inhabition phases, when amastigotes search for newly prone uninfected macrophages and then infecting them [44,51,52].…”

Mechanobiology of immune cells: Messengers, receivers and followers in leishmaniasis aiding synthetic devices

“…Because of intricate defense mechanisms, promastigotes can survive in macrophages and undergo dimorphic change to amastigote form ( Maspi et al, 2016 ). There are broadly two forms of responses post infection, T Helper Cell Type 1 (Th1) and T Helper Cell Type 2 (Th2) which helps in parasite killing and survival respectively ( Costa-da-silva et al, 2022 ). The immune response will be discussed in the subsequent sections.…”