[
International Worm Meeting,
2005]
Human imunodeficiency is caused by AIDS, aging, and so on. In such immunodeficient individuals, opportunistic infections are often caused by pathogens which are incapable of causing infection in immunocompetent individuals. We are attempting to screen immunodeficinet mutants using C. elegans as a model for opportunistic infection. Escherichia coli BL21(DE3) expressing EGFP is almost nonpathogenic for C. elegans on NGM agar plates. Wild-type worms grow and proliferate without any obvious disorders under the existence of BL21(DE3). However, this bacterium was detected in the intestine of app. 2% of adult worms 4 days after hatch, and the ratio of bacteria-detected worms increased with aging [1]. Dying worms were often filled with bacteria. In rare cases, a small number of bacteria was detected also in younger worms. These observations are identical to the symptom of opportunistic infection, i.e., BL21(DE3) is nonpathogenic to immunocompetent worms but parasitic/pathogenic to immunodeficient worms caused by aging or accidental debilitation. Thus, disorders which are not seen in wild type animals are expected to arise if immunodeficient mutants are cultured with this bacterium. In some EMS-induced mutant, EGFP-expressing BL21(DE3) was accumulated in the uterus. Such phenotype was never observed in wild-type worms. Those mutants can grow up to be adult since no significant disorder affects development before vulva formation, but are sterile. Further characterization of those mutants is presently progressing. [1] Garigan et al., (2002) Genetics 1616, 1101.