Genetic Background Affects the Mucosal Secretory IgA Levels, Parasite Burden, Lung Inflammation, and Mouse Susceptibility to Infection.

Ascariasis is a neglected tropical disease that is widespread in the world and has important socioeconomic impacts. The presence of various stages of worm development in the pulmonary and intestinal mucosae induces a humoral and cellular immune response. However, although there is much evidence of the protective role of mucosal immunity against various pathogens, including helminths, there is still a gap in the knowledge about the immune response and the mechanisms of action that are involved in protection against diseases, especially in the initial phase of ascariasis. Thus, the aim of this study was to evaluate the kinetic aspects of the immune parasitological parameters in intestinal and pulmonary mucosae in male mice with early ascariasis. Therefore, two mouse strains that showed different susceptibilities to ascariasis (BALB/c and C57BL/6J) when experimentally infected with 2,500 infective eggs of Ascaris suum from time point 0 were examined: the immune parasitological parameters were evaluated each 2 days after infection over a period of 12 days. The results were suggestive of a synergetic action of intestinal and pulmonary secretory IgA (S-IgA) contributing to protection against early ascariasis by reducing the amount of migrating larvae as well as the influx of leukocytes in the lung and the consequent impairment of pulmonary capacity.