Development of model systems to study the function of excretory-secretory proteins from the parasitic nematode 'Trichinella spiralis'
Invasion of host muscle by the larvae of the nematode parasite Trichinella spiralis is associated with a series of ultrastructural, biochemical and molecular changes to the host muscle fibre that amalgamates in the formation of a unique host-parasite complex. It is hypothesised that proteins that are secreted or excreted (ES proteins) by the muscle larva are responsible for triggering some or all of the changes to the host cell. No such effector molecules have yet been identified although a number of candidate molecules are now emerging. There is therefore a need for an experimental system (or systems) that will enable the study of function of candidate ES proteins as they arise. In this investigation I describe the development of three model systems that allow the characterisation of different aspects of putative protein function with the aim of determining whether a candidate protein could contribute to the formation of the muscle host parasite complex. These models included: firstly, a cell culture model to investigate the effect of T. spiralis ES proteins of the differentiation of the myogenic cell line C2C 12; secondly, two in vivo heterologous expression systems to investigate the secretion and localisation of T. spiralis ES proteins; and thirdly, a cell-free in vitro translation system to investigate the secretion and potential processing and post-translation modifications of candidate T. spiralis ES proteins. The model systems described have enabled conclusions to be drawn on the potential role that a candidate ES protein, TsJ5, may play in both the biology of the muscle larvae and within the parasitised host cell.