Echinococcus multilocularis: the non‐specific binding of different species of immunoglobulins to alveolar hydatid cysts grown in vivo and in vitro

Abstract

Alveolar hydatid cysts (AHC) were isolated from C57BL/6J and BALB/c mice at 8 and 12 weeks post-infection from subcutaneous and intraperitoneal foci and cultured in vitro. Freshly isolated as well as in vitro-grown cysts were incubated with Fc or F(ab')2 fragments of human, rabbit, mouse, goat or sheep immunoglobulins, then washed and incubated with a fluorescein-conjugated rabbit or goat F(ab')2 fraction of antisera to each of the above primary sera. Significant fluorescence on the surface of AHC was detected when they were incubated with human, rabbit or mouse Fc fractions followed by the addition of goat or rabbit fluorescein-conjugated antiserum. No fluorescence was detected when the AHC were incubated with the F(ab')2 fragments and fluorescein-conjugated antiserum, except when the primary antiserum was mouse F(ab')2 fractions. Cysts grown in vitro retained their binding ability to human, rabbit or mouse Fc fractions. However, the intensity of fluorescence decreased proportionally with time. The maximum intensity of staining was observed with small cysts. Large cysts showed diminished fluorescence. The non-specific binding of human, mouse or rabbit immunoglobulins (Fc fractions) to AHC was also confirmed by rosetting with sheep erythrocytes (SRBC) which suggests that the larvae of Echinococcus multilocularis may utilize the presence of Fc receptors on their surface in order to elude immune destruction by the host.

Immunology and morphology studies on the proliferation of in vitro cultivatedEchinococcus multilocularis metacestodes

“…The morphology of metacetodes generated in vitro as well as in vivo (separated from the host in a micropore chamber; Nahhas et al 1991) was very similar to that of metacestodes isolated from the peritoneum of experimentally infected mice and gerbils (Delabre et al 1987;Mehlhorn et al 1983). The parasite tissue was surrounded by the acellular laminated layer, a structure that is known to play a decisive role in protecting the parasite from its host's immune reaction (Alkarmi et al 1988;Gottstein et al 1992Gottstein et al , 1994. That this laminated layer was always present during cultivation in vitro clearly indicated that this structure was synthesized by the parasite itself.…”

Molecular characterization of the surface and cyst fluid components of Taenia crassiceps

“…The presence of immunoglobulins on parasite surfaces has been well documented (see Alkarmi et al (1988) for references). For example, immunoglobulins of the IgG 2 b class were found attached to, and in the integument of adult Schistosoma mansoni and tetrathyridia of Mesocestoides corti (Sogandares-Bernal, 1976;Sogandares-Bernal & Voge, 1978).…”

“…Analysis of the tegumental surface of adults and metacestodes, limited to a restricted number of species, has generally revealed a complex array of macromolecules, some of which exhibit enzyme activity, with molecular weights ranging from < 10000 to > 200000 (Knowles & Oaks, 1979;McManus & Barrett, 1985;McManus et al 1987;Parkhouse & Harrison, 1987). Components of host origin, including immunoglobulins and serum albumin, have also been identified on the surfaces of several species (Befus, 1977;Craig, 1988;Shepherd & McManus, 1987;Alkarmi, Alshakarchi & Behbehani, 1988;Smyth & McManus, 1989). In addition, a number of surface-associated proteins have been found on the oncosphere stage (Harrison & Parkhouse, 1986; see Craig, 1988).…”

Fc‐binding molecules specific for human IgG1 and IgG3 are present in Echinococcus granulosus protoscoleces

“…1981), the cestodes Taenia solium (Flisser, Espinoza, Tovar et al . 1986), Taenia crassiceps (Kalinna & McManus 1993) and Taenia taeniaeformis (Kwa & Liew 1978), as well as within the genus Echinococcus on E. multilocularis (Alkarmi, Alshakarchi & Behbehani 1988). The results obtained in all those cases suggest that the immunoglobulins are adsorbed on the parasite surface through interactions with Fc‐receptors (Kemp et al .…”