Accelerated influx of dendritic cells into the lymph nodes draining skin sites exposed to attenuated cercariae of Schistosoma mansoni in guinea‐pigs

Abstract

We compared temporal changes in the cell composition of the skin-draining lymph nodes (SLN) in guinea-pigs exposed percutaneously to normal or attenuated cercariae of Schistosoma mansoni. Different populations were analysed by flow cytometry of double-stained cells by monoclonal antibodies to the major histocompatibility complex class II molecule and lymph node cells of guinea-pigs. Exposure to S. mansoni caused a marked increase in the proportion of B cells and dendritic cells (DC) on day 2, reaching a peak number on day 4. These changes were comparable in both infected and vaccinated animals exposed to normal or attenuated parasites, respectively. Total number of DC, however, showed different kinetics; in infected animals, the number peaked on day 2 and then gradually declined, whereas it reached a higher peak on day 4 in vaccinated animal. Daily injection of bromo-deoxyuridine after exposure to the parasite reduced the total number of DC in the SLN on day 4. A reduction in DC counts in the contralateral side SLN was also evident in vaccinated animals. Our results indicate that a significant number of newly formed DC are recruited to the skin by 4th day of vaccination, followed by increased efflux to the SLN. It is possible that retention of attenuated S. mansoni in the skin may cause accelerated recruitment of newly formed DC from the bone marrow, and facilitate transport and processing of antigens highly expressed on attenuated parasites.

Immune Events Associated with High Level Protection against Schistosoma japonicum Infection in Pigs Immunized with UV-Attenuated Cercariae

“…Our results showed that after attenuated cercariae immunization, granzyme b , nk-lysin , ifnγ , il12p40 , il4 and il10 genes expression levels, related with CD8 + T and CD4 + T, were higher than that after normal cercaria infection. In mouse and pig models, the T cell and DC proliferation in sdLN induced by irradiated cercariae is stronger than that induced by normal cercariae, and RA vaccination preferentially induces the accumulation of IFN-γ in the sdLN of mice [39], [40], [41]. Fragile bodies and slow migration in the RA could release a great amount of parasite antigens, or prolong the exposure to the host immune system, which may in turn favor the priming of protective responses [7].…”

Ultraviolet-attenuated cercariae of Schistosoma japonicum fail to effectively induce a Th1 response in spite of up-regulating expression of cytotoxicity-related genes in C57BL/6 mice

“…IL-12 was also a critical component of this Th1-mediated protection[21],[22]. In addition, the number of dendritic cells (DC) transfered into the sdLNs after vaccination with attenuated S. manosi cercariae was more than that induced by NC[23]. CD40/CD154 interactions were required for the optimal maturation of skin-derived antigen-presenting cells (APCs) and the induction of S. mansoni antigen-specific IFN-γ[24].…”

Role of the Parasite-Derived Prostaglandin D2 in the Inhibition of Epidermal Langerhans Cell Migration during Schistosomiasis Infection

“…During schistosomiasis, little is known about the immunological consequences of the interactions between schistosomes and cutaneous cells. Sato et al suggested that resident LCs may participate in the initiation of the primary immune response in S. mansoni-infected guinea pigs, but the major APCs involved are rather newly recruited blood-born skin LCs/DCs (39,40). In another study, Riengrojpitak et al hypothesized that infiltrating dermal APCs are important in the T cell priming in the SLNs (41).…”