Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human Schistosomiasis: I. Granuloma formation and modulation around polyacrylamide antigen-conjugated beads

Abstract

We have developed an in vitro model of granuloma formation for the purpose of studying the immunological components of delayed type hypersensitivity granuloma formation in patients infected with Schistosoma mansoni. Our data show that 1) granulomatous hypersensitivity can be studied by examining the cellular reactivity manifested as multiple cell layers surrounding the antigen conjugated beads; 2) this reactivity is a CD4 cell dependent, macrophage dependent, B cell independent response and 3) the in vitro granuloma response is antigenically specific for parasite egg antigens. Studies designed to investigate the immune regulation of granulomatous hypersensitivity using purified populations of either CD4 or CD8 T cells have demonstrated the complexity of cellular interactions in the suppression of granulomatous hypersensitivity. The anti-S. mansoni egg immune responses of individual patients with chronic intestinal schistosomiasis can be classified either as soluble egg antigen (SEA) hypersensitive with maximal granulomatous hypersensitivity or SEA suppressive with activation of the T cell suppressor pathway with effective SEA granuloma modulation. Our data suggest that T cell network interactions are active in the generation of effective granuloma modulation in chronic intestinal schistosomiasis patients.

Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

“…We believe that IC-induced suppression of cell proliferative response may function in a different way, since these systems work differently. Studies on in vitro granuloma reaction have shown that this reaction is dependent on CD4 + cells and macrophages, and independent of B cells (Doughty et al 1987). Otherwise, B cells are involved in processing and presentation of antigens in proliferative responses (Vidard et al 1996) and may have their processing capability changed by the binding of Igs that form part of IC (Watts & Lanzavecchia 1993).…”

“…Antigen-conjugated polyacrylamide beads, ressuspended in culture medium, were distributed at 200 beads/well in 96 well flat-bottomed tissue culture plates together with 3 x 10 5 PBMC. In vitro granuloma reaction was evaluated on day 5 of culture by quantitation of cellular reactivity around the beads using a phase contrast inverted tissue culture microscope, as previously described (Doughty et al 1987, Hirsch & Goes 1996. Three hundred separated determinations of cellular reactivity were made for each experimental group.…”

The Role of Protein Kinases in Antigen-activation of Peripheral Blood Mononuclear Cells of Schistosoma mansoni Infected Individuals

“…Cell preparations -PBMC were isolated from heparinized blood by Ficoll-diatrizoate density gradient centrifugation (LSM, Organon Teknika, Charleston, SC) as previously described (Goes et al 1991). These cells were cultured in RPMI medium containing 1.6% L-glutamine, 300 U/ml of penicillin, 0.3 mg/ml of streptomycin, 0.05 mg/ ml of gentamicin and 10% heat inactivated AB+ human serum (RPMI 10% AB) in 96 well flatbottomed tissue culture plate.…”

“…In vitro granuloma reaction -Two hundred S. mansoni-conjugated polyacrylamide beads were distributed in a volume of 50 ml/well in 96 well flat-bottomed culture plates (Doughty et al 1987). Cells at the concentration of 3 x 10 5 /well in a final volume of 200 ml RPMI 10% AB were cultured in the presence and absence of genistein or H-7.…”

“…This phenomenon, termed immunomodulation (Andrade & Warren 1964) has been the subject of numerous studies that have implicated the participation of cellular as well as subcellular mechanisms in regulation of granulomatous process (Ottensen & Poindexter 1980, Goes et al 1991, Cheever et al 1992.…”