Immunohistological localisation of two hydatid antigens (antigen 5 and antigen B) in the cyst wall, brood capsules and protoscoleces of Echinococcus granulosus (ovine and equine) and E. multilocularis using immunoperoxidase methods

Abstract

Cyst wall, brood capsules and evaginated protoscoleces of E. granulosus (ovine and equine) and E. multilocularis were fixed in 10% formol-saline embedded in paraffin and cut at 8 μm. Specific rabbit antisera to antigen 5 and antigen B of hydatid cyst fluid were used with immunoperoxidase methods to localise the antigens in the histological sections.Antigen 5 was found in all parasites and was associated with cells of the subtegumental area of the protoscolex, the brood capsule wall and the germinal membrane. The labelled antigen appeared as distinct granules in all areas. It is suggested that antigen 5 may be synthesised in all of these sites and that a source of the antigen in cyst fluid may be the germinal and brood capsule membranes. The laminated membranes of E. granulosus (ovine and equine) were, except for the superficial layers, free from antigen 5.Antigen B was present in all parasites. It was distributed diffusely throughout the laminated membrane, germinal membrane and brood capsule wall. There were areas of densely labelled antigen B on the surface of the distal cytoplasm of the protoscolex tegument and the surface of calcareous corpuscles. The distribution of antigen B in relation to PAS positive meterial and possible complement activating substances is discussed.The laminated membrane of E. granulosus was apparently more permeable to antigen B than to antigen 5. It is suggested that differences in the diffusion of these antigens through the laminated membranes of hydatid cysts in the same or different host species may account for variable serological responses during infection.

Immunochemical localization of major hydatid fluid antigens in protoscoleces and cysts of Echinococcus granulosus from human origin

“…Ag 5 was shown to be associated with the parenchymal cells of the protoscoleces, the brood capsule wall and the germinal membrane (Yarzabal et al 1976, Rickard et al 1977, Davies et al 1978, it is also present in the superficial layers of the laminated membrane (Rickard et al 1977). Ag B has been located on a variety of tissues, including the tegument of the protoscoleces (Yarzabal et al 1977, Rickard et al 1977, Davies et al 1978, the brood capsule wall (Rickard et al 1977, Davies ef al. 1978, the germinal membrane (Rickard et al 1977), the parenchyma cells (Rickard et al 1977, Davies et al 1978) and the cyst contents (Yarzabal et al 1977, Davies et al 1978.…”

“…The two antigens have been localized in equine and ovine E. granulosus protoscoleces and cyst membranes by means of immunofluorescence (Yarzabal et al 1976; and immunoperoxidase techniques (Rickard et al 1977), and a peroxidase-antiperoxidase technique (Davies et al 1978) has been used to study their ultrastructural localization in Correspondence: Fernando Sanchez brood capsules and protoscoleces. Ag 5 was shown to be associated with the parenchymal cells of the protoscoleces, the brood capsule wall and the germinal membrane (Yarzabal et al 1976, Rickard et al 1977, Davies et al 1978, it is also present in the superficial layers of the laminated membrane (Rickard et al 1977). Ag B has been located on a variety of tissues, including the tegument of the protoscoleces (Yarzabal et al 1977, Rickard et al 1977, Davies et al 1978, the brood capsule wall (Rickard et al 1977, Davies ef al.…”

“…Ag B has been located on a variety of tissues, including the tegument of the protoscoleces (Yarzabal et al 1977, Rickard et al 1977, Davies et al 1978, the brood capsule wall (Rickard et al 1977, Davies ef al. 1978, the germinal membrane (Rickard et al 1977), the parenchyma cells (Rickard et al 1977, Davies et al 1978) and the cyst contents (Yarzabal et al 1977, Davies et al 1978.…”

Modulation of Human Immune Response byEchinococcus granulosusAntigen B and Its Possible Role in Evading Host Defenses

“…Antigen B (AgB), which accounts for as much as 10% of the total content of hydatid fluid, is a 160-kDa thermostable lipoprotein that produces three subunits at 8 or 12, 16, and 20 or 24 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and nonreducing conditions (21,36). Immunohistological studies have shown that this antigen is located in the protoscolex tegument and germinal membrane of the metacestode and therefore secreted into the cyst fluid (29,35). Observing that the 12-kDa subunit of AgB is a protease inhibitor with the ability to inhibit neutrophil recruitment Shepherd et al first suggested the role of this antigen in escape mechanisms from the early natural immunity (37).…”

Identification of a differentially expressed Echinococcus multilocularis protein Em6 potentially related to antigen 5 of Echinococcus granulosus

“…By immunolocalization studies, antigen 5 was detected in the germinal membrane, brood capsules and protoscoleces of E. granulosus ( Sanchez et al . 1991 , 1993), and the presence of a immunologically related molecule in E. multilocularis fertile metacestodes displaying the same topographic distribution was described ( Rickard et al . 1977 , Davies et al .…”