Extracts of Ascaris suum egg and adult worm share similar immunosuppressive properties

Abstract

Adult Ascaris suum body extract (Asc) prepared from male and female worms (with stored eggs) down-regulates the specific immune response of DBA/2 mice to ovalbumin (OA) and preferentially stimulates a Th2 response to its own components, which is responsible for the suppression of the OA-specific Th1 response. Here, we investigated the participation of soluble extracts prepared from male or female worms or from eggs (E-Asc) in these immunological events. Extracts from either sex (1 mg/animal) or E-Asc (0.35 or 1 mg protein/ animal) suppressed the delayed-type hypersensitivity (DTH) reaction (60-85%), proliferative response (50-70%), IL-2 and IFN-g secretion (below detection threshold) and IgG1 antibody production (70-90%) of DBA/2 mice to OA. A dose of 0.1 mg E-Asc/animal did not change DTH or proliferation, but was as effective as 0.35 mg in suppressing IL-2 and IFN-g, and OA-specific IgG1 antibodies. Lymph node cells from DBA/2 mice injected with Asc (1 mg/animal) or a high dose of E-Asc (1 mg protein/animal) secreted IL-4 upon in vitro stimulation with concanavalin A. As previously demonstrated for Asc, the cytokine profile obtained with the E-Asc was dose dependent and changed towards Th1 when a low dose (0.1 mg protein/animal) was used. Taken together, these results suggest that adult worms of either sex and eggs induce the same type of T cell response and share similar immunosuppressive properties.

Ascaris suum-Derived Products Suppress Mucosal Allergic Inflammation in an Interleukin-10-Independent Manner via Interference with Dendritic Cell Function

“…The expression of products by A. suum could potentially limit local allergic reactions that contribute to a reduced host response to infection, since migrating larvae express antigens found in PCF (13,28). We are currently conducting a number of experiments to verify these concepts and to better define the mechanisms of PCF-induced regulation of APCs, influence on T-regulatory cells, and suppression of allergic inflammation.…”

“…Souza et al (28) compared Ascaris extracts from adult worms and eggs and found similar inhibitory profiles for allergic inflammation, suggesting that allergic inhibition is not parasite stage specific and likely involves numerous parasite antigens. In agreement with our chronic A. suum infection model (27), Paterson et al found that an extract of Ascaris body fluid mixed with ovalbumin (OVA) (25) increased IL-10 production and the development T-regulatory cells.…”

Influence of maternal schistosomiasis on the immunity of adult offspring mice

“…The mice were mated during the egg deposition period (on day 60 post-infection), when the immunomodulation to schistosomiasis occurs (Pearce et al 1991). All offspring were submitted to immunization with OA emulsified in an adjuvant, s.c., which has always been an appropriate protocol to evaluate the modulation induced by helminths (Ferreira et al 1995;Souza et al 2002).…”

Protective Effect of an Extract fromAscaris suumin Experimental Arthritis Models

“…The amount of extract to be administered was based on protein content, using the Bradford method. It has been shown that injection of 1 mg of A. suum extract was able to suppress immune responses in mice (30). After obtaining a dose-response curve in rats, the concentration of 1 mg of protein was chosen to use for both rats and mice.…”