Rat IgE directed against schistosomula‐released products is cytotoxic for Schistosoma mansoni schistosomula in vitro

Abstract

The immunogenicity of molecules shed by schistosomula into culture medium (antigens present in schistosomula-released products, SRP-A) has been studied. The results obtained show that SRP-A preferentially induce an IgE response when injected into rats, without the need for adjuvants. Moreover, anti-SRP-A IgE is cytotoxic in vitro for the larvae in the presence of macrophages, eosinophils or platelets, which have previously been demonstrated as being the three efficient killer cells for schistosomula in the presence of specific IgE. Immunofluorescence analysis locates the target antigens at the schistosomulum surface. Among the antigens recognized by anti-SRP-A IgE, two molecules of 26 and 22 kDa have been identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by western blotting.

Immunogenicity of the Hookworm Na-ASP-2 Vaccine Candidate: Characterization of Humoral and Cellular Responses after Vaccination in the Sprague Dawley Rat

“…Laboratory rats have been a model extensively employed to test immune responses to helminth antigens [16][17][18][19][20][21] and they also constitute an excellent model to evaluate vaccine safety and toxicity. However, there are no reports to date characterizing the immune response elicited by hookworm antigens in laboratory rats.…”

Induction of a Protective Immune IgE Response in Rats by Injection of Defined Antigens of Schistosomulum-Released Products: Immunochemical Properties of the Target Antigens

“…In rat experimental schistosomiasis, the use of IgG2a monoclonal antibodies, inducing a significant degree of protection by passive transfer experiments, has allowed the characterization of a 38-kilodalton (kDa) glycoprotein at the surface of the schistosomula [8]. Recent studies confirmed that apart from the 38-kDa antigens the IgE target antigens involved in the ADCC mechanisms could induce such a protec tive immunity [9]. The previously reported protection of rats (up to 83%) against S. mansoni infection was achieved by immunization with schistosomulumreleased products (SRP-A) without adjuvant [10].…”

“…Among the SRP-A molecules, only two bands of 22 and 26 kDa have been clearly revealed after West ern blotting by the anti-SRP-A IgE [9], The 26-kDa band was also recognized by infected rat sera IgE. In this paper, we have investigated whether the 22-and 26-kDa molecules were able to induce the production of specific IgE responsible for the cytotoxic effect to wards the larvae.…”

“…Schistosomula were incubated for 4 h at 37°C in Hank's bal anced solution and then extensively washed in the same medium [9]. The parasites (20,000/ml) were then incubated for 16 h at 37 °C.…”

“…The previously reported protection of rats (up to 83%) against S. mansoni infection was achieved by immunization with schistosomulumreleased products (SRP-A) without adjuvant [10]. Anti-SRP-A IgE were cytotoxic in vitro for the lar vae in the presence of macrophages, eosinophils or platelets, which have been demonstrated as being effector cells for schistosomula in the presence of IgE [9]. Moreover, passive transfer experiments of anti-SRP-A sera or anti-SRP-A sera depleted in IgE into S. mansoni infected rats confirmed the predominant role of the anti-SRP-A IgE anti bodies in the protective immunity developed by the rat [10].…”