Tug-of-war between host immunity and microbial pathogenesis using Caenorhabditis elegans as a model system

Globally, bacterial infections have been recognized as a predominant issue associated with significant morbidity and mortality. This global burden could be overcome by understanding the mechanism of both microbial virulence and host immune response. One approach to identify novel virulence strategies adopted by pathogens and host immune defense is to study the host-pathogen interaction using suitable model system which could be an analogue for human. Testing pathogenesis and immune defense in rodent is generally not feasible due to its expensive maintenance. Therefore, the invertebrate nematode model Caenorhabditis elegans could represent a valuable alternative. The era of post-genomics has set a milestone in research by identifying and validating an appropriate potential human “diseases causing” or “disease associated” genes by using host model system. Consequently, investigation of host-pathogen interaction has always been spotlighted area to the scientific community that decodes the mechanism of bacterial virulence including the conserved system of host defense and antimicrobial factors like c-type lectins, lysozymes, neuropeptide-like protein, etc. In this review, we present the host-pathogen interaction using C. elegans as an appropriate model to decipher the alteration happened at the context of both host and pathogen. Infection in C. elegans by microbes induces a number of defensive mechanisms which are evolutionary conserved to mammalian innate immunity. Additionally, it has also been exhibited that several microbial virulence factors required for complete pathogenicity in mammals are indeed required for causing infection in nematodes. Based on these facts, a number of novel virulence strategies adopted by pathogens as well as conserved hosts’ immune defense against respective infections have been screened using C. elegans which opens new avenue to develop novel alternate therapeutics.