Profiles of Th1 and Th2 Cytokines after Primary and Secondary Infection bySchistosoma mansoniin the Semipermissive Rat Host

Abstract

In contrast to most mouse strains, rats eliminate the primary schistosome burden around 4 weeks postinfection and subsequently develop protective immunity to reinfection. In rat schistosomiasis, we have shown predominant expression of a Th2-type cytokine response at the mRNA level after primary infection. In the present study, we showed a significant increase in interleukin-4 (IL-4) mRNA expression in inguinal lymph nodes early after a secondary infection. IL-5 mRNA expression showed a significant increase at days 2 and 4 postreinfection in the spleen and lymph nodes, respectively. We did not detect any gamma interferon (IFN-γ) mRNA after a challenge infection. Analysis of cytokine secretion by stimulated spleen cells after a primary infection showed predominant expression of IL-4 with maximum production on day 21, accompanied by production of IL-5 from day 11 to day 67. A significant increase in IFN-γ secretion was detected at day 21. Analysis of immunoglobulin G2b (IgG2b) and IgG2c (Th1-related isotypes) showed undetectable levels of IgG2b, but detectable levels of specific IgG2c antibodies were observed from day 42. The analysis of Th2-related isotypes showed high specific IgG1 and IgG2a antibody titers from day 29. After a secondary infection, only IL-4 and IL-5 secretion was sustained. This is supported by the increased production of Th2-related isotypes. These findings showed that S. mansoni infection can drive Th2 responses in rats in the absence of egg production which is required to induce a Th2 response in mice and are in favor of the role of Th2-type cytokines in protective immunity against reinfection.

The time course of biological and immunochemical allergy states induced by anisakis simplex larvae in rats

“…Of the immunoglobulin isotypes measured, the production of the specific antibodies IgE, IgG1 and IgG2a was apparent. This observation indicates that the synthesis of Th2 cytokines was prevalent [26,27], a conclusion compatible with mRNA analyses (data not published). Although some rat sera produced IgG2b, the production of which is controlled by Th1 cytokines, the low OD levels and high SEs showed that Th1 cytokine synthesis was irregular and weak.…”

Susceptibility of experimental animals to reinfection with Clonorchis sinensis

“…Rats are also known to be resistant to reinfection with Fasciola hepatica and Schistosoma mansoni, with which acquired immunity is closely related (Doy et al, 1978;Cetre et al, 1999). The mechanism of resistance to reinfection with C. sinensis in rats is not clear, however, the immunity has been suggested to be related with resistance to reinfection (Chung et al, 2004).…”

The developing schistosome worms elicit distinct immune responses in different tissue regions

“…type 1/type 2). 19 In this study, significant differences in antibody isotypes were detected in the larvae-induced antibody samples of the different tissue regions. In particular, we found a high level of IgE contained in liver LN samples, indicating a strong type 2 immune response.…”

“…By culturing cells of the LNs draining the different sites of parasite migration after challenge with Schistosoma japonicum, marked differences in antibody specificity were revealed at different tissue regions. In addition isotype responses, which are indicative of immune bias, 19 were distinct at each tissue site, suggesting that different regional immune mechanisms may be operating against the migrating parasites.…”