Immunology of lymphatic filariasis

Abstract

The immune responses to filarial parasites encompass a complex network of innate and adaptive cells whose interaction with the parasite underlies a spectrum of clinical manifestations. The predominant immunological feature of lymphatic filariasis is an antigen - specific Th2 response and an expansion of IL-10 producing CD4+ T cells that is accompanied by a muted Th1 response. This antigen specific T cell hypo-responsiveness appears to be crucial for the maintenance of the sustained, long-standing infection often with high parasite densities. While the correlates of protective immunity to lymphatic filariasis are still incompletely understood, primarily due to the lack of suitable animal models to study susceptibility, it is clear that T cells and to a certain extent B cells are required for protective immunity. Host immune responses, especially CD4+ T cell responses clearly play a role in mediating pathological manifestations of LF, including lymphedema, hydrocele and elephantiasis. The main underlying defect in the development of clinical pathology appears to be a failure to induce T cell hypo-responsiveness in the face of antigenic stimulation. Finally, another intriguing feature of filarial infections is their propensity to induce bystander effects on a variety of immune responses, including responses to vaccinations, allergens and to other infectious agents. The complexity of the immune response to filarial infection therefore provides an important gateway to understanding the regulation of immune responses to chronic infections, in general.

Systemic Cytokine Profiles in Strongyloides stercoralis Infection and Alterations following Treatment

“…This is classically exemplified in animal models of helminth infection, wherein proinflammatory responses, including type 1 and type 17 responses, are down-modulated and type 2 and anti-inflammatory responses are typically upregulated (16,17). This has been shown to be true in human helminth (soil-transmitted and vector-borne) infections as well (18)(19)(20). However, scant data exist on the immune response engendered by the relatively common helminth parasite S. stercoralis.…”

In-vitro Evaluation of Thymol Derived from Trachyspermum ammi against Acetaminophen Induced Hepatotoxicity Towards Lymphatic Filariasis Therapeutics

“…Existing data support the involvement of pro-inflammatory cytokines namely Interleukin-6 (IL-6) and Interleukin-8 (IL-8) were significantly elevated in LF [2], which plays a key role in the initiation of irreversible swelling, fibrosis [11,12] and regenerative processes of hepatic structure and function [13,14]. Hence, we investigated the potential abilities of thymol against hepatotoxicity, bacterial infection; oxidative stress, elevated cytokines and inflammatory markers expression in response to paracetamol induced effects in WRL-68 liver cells.…”

Human Ascariasis Increases the Allergic Response and Allergic Symptoms

“…The immune response elicited by these infections differs depending on the type of parasite, lifecycle, host age, burden of co-infections (polyparasitism), and parasite loads. However, all share as hallmarks an increase in circulating IgE levels, peripheral and intestinal eosinophilia, and the activation of genes and cytokine networks related to type 2 immunity and immunomodulation [1,2].…”