bakeri appears to serve the interests of both the host and

the parasite by allowing the development of adult worms, but limiting egg production and spread of the parasite into the environment. To date, few data are available investigating the impact of antibodies on parasite chronicity, although lines of Biozzi mice bred selectively for either high or low antibody responses to a wide range of antigens showed no difference in the pattern and extent of faecal egg counts over Rucaparib a 4-week period following primary infection [76]. However, consistent with the crucial role of antibodies in acquired resistance, faecal egg output differed learn more markedly in secondary and tertiary infections with complete suppression of faecal egg counts in the lines bred for high antibody responses and in excess of 90% loss of worms [76].

Inbred strains of mice that show poor antibody responses also harbour longer infections than those that respond more vigorously [65, 77], but clearly, the role of antibodies needs to be investigated more thoroughly through the kinetics of worm rejection in wild-type or genetically modified antibody-deficient mice as has been done for challenge infections. This would be an important and exciting task for the near future given that antibodies might be expected to neutralize parasite products important in the modulation of the host immune response. H. p. bakeri will continue to be an important model organism

for understanding immunity to helminth infections of humans and of domestic animals. One growing area where this nematode will play a key role is in elucidating the mechanisms underlying the hygiene hypothesis, whereby a lack of early exposure to worms increases susceptibility to autoimmune and allergic disease ([78, 79] and see also ref [80] for diagrammatic explanations of the relationships between the component parts). H. p. bakeri is the preferred species for modelling in rodent chronic infections and immunoregulation in humans [81]. Infection with H. p. bakeri has been shown to inhibit allergy GBA3 [82, 83], diabetes [84, 85], experimental autoimmune encephalomyelitis [83] and colitis [86]. This makes H. p. bakeri a convenient and interesting model for the development of novel therapies to treat autoimmune disease, whose public health importance is accelerating most rapidly in developing countries [87] and which are also a significant cause of morbidity in economically challenged African American and Hispanic American communities in the U.S.A. But are antibodies involved? A recent in-depth analysis of the evidence would suggest that they are [80].