The role of microbiome in mast cells mediated induction of protective and pathological responses

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2023
Thesis identifier
  • T16566
Person Identifier (Local)
  • 202065379
Qualification Level
Qualification Name
Department, School or Faculty
  • Helminth infections predominantly occur in countries with inadequate environmental sanitation. Around 1.5 million people are infected with different helminth species including hookworms, roundworms, and whipworms. Roundworms are commonly isolated in human, and in particular a zoonotic nematode, T. spiralis is crucially important as it infects humans through food chain by consumption of undercooked meat such as pork, or game meat causing diseases which lead to an increased burdens in economy especially medical, educational costs. The need to find suitable, accurate and cost-effective diagnostic approaches, as well as the way to strengthening natural protective and pathological immune responses driven by MCs against T. spiralis is fundamental to pave that way to control and minimizing the risk of infections. Study of the effect of gut microbiome on immune responses is at its early stage, and only few studies have suggested that the presence of microbiome can affect immune responses. In this study we firstly evaluated the effect of microbiome on helminth induced protective and pathological immune responses driven by mast cells during T. spiralis infection. Secondly, we analysed the specificity and relevance of ELISA in the detection of T. spiralis infection, as well as the stability of T. spiralis antigens in contaminated meat during food preparations. In animal model, treated WT C57 and W-sh/-sh mice were given 25mg/L of enrofloxacin in drinking 7 days prior infection with T. spiralis, then all treated and untreated mice were infected with 400 T. spiralis muscle larvae, and animals were euthanised at 7 and 14 (d.p.i). In this in vitro study, blood samples and T. spiralis specific antigen and other antigens were analysed by ELISA to assess antibody levels produced. Histological examinations were used to measure lengths of villi and crypts, as well as to enumerate the number of mucosal MCs accumulated in the gut. Results indicated that microbiome enhanced MCs immune responses, which hastened expulsion of parasitic worms. Microbiome increased MCs hyperplasia in WT but failed in W-sh/-sh mice. As expected, higher total IgE observed in WT C57, while extremely reduced in W-sh/-sh mice. However, microbiome had no effect on pathological aspects of crypt hyperplasia, or villus atrophy. Simultaneously, MC hyperplasia, increased T. Ag-specific IgG1, and total IgE reaching their peaks at 14 (d.p.i) along with expulsion of worms. In protective response, microbiome influenced MC responses by boosting MLNs hyperplasia, but not on T cell proliferation. T. spiralis infection stimulated Th2 immune responses with higher levels of IgG1 and IgE instead of Th1 since minimal IgG2a produced. In immunodiagnostics, sensitivity and specificity of ELISA were assessed from a pool of T. spiralis own antigen with other unrelated (Ag)s on immune sera. Results showed that T. spiralis infection sensitised high production of T. Ag-specific IgG1, and moderately stimulated production of IgG2a and IgM, with no detectable IgA and IgE. The assay proved high specificity on T. spiralis since it only picked up relevant T. Ag of its own species from a pool of unrelated (Ag)s in T. spiralis immune sera. In the same way, only H. polygyrus Ag was selected in H. polygyrus immune sera. Moreover, stability of T. spiralis was analysed in different processing conditions of heat, salt, and acid to mimic processing of pork in diagnosis of T. spiralis infection. The assay was stable to boiling temperatures for short time or treatment with low salt and acid contents. Furthermore, ELISA assay was unstable in the diagnosis of T. spiralis infection on T. spiralis Ag mixed with pork protein due to blocking effect of pork protein. In conclusion, microbiome enhances MCs protective and pathological immune responses, but Direct ELISA cannot be used in the detection of T. spiralis in pork. To increase reliability of the effect of microbiome on MCs immune responses, GF mouse model and Antibiotics Treatment method are recommended for future studies. Equally, to overcome the problems of instability of processed meat samples, and cross reactivity among Trichinella species or closely related parasite infections as well as the blocking effect of analyte protein to Direct ELISA assay, LF-RPA diagnostic strip assay and sandwich ELISA are recommended in diagnosis of Trichinella species in pork and domestic animals.
Advisor / supervisor
  • Wiese, Martin
  • Lawrence, Catherine
Resource Type
Date Created
  • 2022
Embargo Note
  • This thesis is restricted to Strathclyde users only.