Characterisation of the G.
mellonella cellular innate
immune response and a
comparison with the
PhD thesis, National University of Ireland Maynooth.
The use of insects as alternative model organisms in areas of research such
as pathogen virulence studies, the development of novel therapeutics and the
screening of microorganism strains are increasing. Some of the reasons for this are
the lower cost of insects, results are often acquired very quickly with insect
experiments and there are relatively few ethical issues involved with the use of
insects compared to the ethical issues that are involved when using the mammalians.
Larvae of the Lepidopteran Greater Wax Moth, Galleria mellonella are used
extensively in biological and chemical research. G. mellonella larvae possess an
immune cell, the haemocyte, which is capable of participating in many of the
processes that the human innate immune cell, the neutrophil participates in. The
haemocyte and the neutrophil are compared to each other throughout this project in
a bid to further elucidate similarities between the human innate immune system and
the insect immune system.
Experimental standardizations are studied and optimized in this work in
order to characterize ideal conditions for G. mellonella larvae to be used in the
laboratory and to study the effect that the nutritional status of the insect has on it’s
ability to fight fungal infections. This was carried out by employing bioassays,
proteomic studies and by employing the molecular biology technique, Real Time
This project also studied a number of similarities between the two immune
cells, such as phagocytosis, a crucial component of the immune system’s first line of
defense. Proteomic similarities between the haemocyte and the neutrophil were
studied extensively throughout this work, different techniques were utilised
throughout, to identify proteins of interest in the haemocyte. These techniques
included SDS-PAGE, mass spectrometry, Western blotting, confocal microscopy
and phospho-proteomic staining techniques.
The cytoskeletal properties of the haemocyte were also studied and
compared to the neutrophil cytoskeleton due to it’s importance in killing processes
such as reactive oxygen species production, phagocytosis and pseudopodia
production. Work in this Thesis documents the separation of the G. mellonella
larvae haemocyte population into sub-populations that differ to each other in size
and granularity by employing Flow cytometry cell sorting techniques. It is possible
that one of these sub-populations is more similar to the human neutrophil than the
others. The presence of granules in the haemocyte was also studied, particularly the
presence of MPO-like and lactoferrin-like material.
This work outlines many parallels between the human innate immune system
and the immune system of G. mellonella larvae and the results demonstrated
throughout this Thesis further justify the use of insects as alternative model
||G. mellonella cellular; innate immune response; human neutrophil;
||Science & Engineering > Biology
||06 Jun 2012 09:45
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