Di. Pritchard et al., IMMUNOSUPPRESSIVE PROTEINS SECRETED BY THE GASTROINTESTINAL NEMATODE PARASITE HELIGMOSOMOIDES-POLYGYRUS, International journal for parasitology, 24(4), 1994, pp. 495-500
Experiments are described in which the conditions for the production,
assay and isolation of immunomodulatory factors from the excretory-sec
retory (ES) products of Heligmosomoides polygyrus have been standardiz
ed. For the inhibition of an in vitro antibody response to keyhole lim
pet haemocyanin, immunosuppressive activity was most reproducibly prod
uced by 10-20-day-old adult worms maintained in culture for 24 h. This
activity was relatively stable at room temperature, at 50-degrees-C a
nd pH 2, but was destroyed by boiling. Immunosuppressive activity was
eluted from Sephadex G-100 in fractions preceding those containing the
bulk of ES proteins, and resolved on sodium dodecyl sulphate-polyacry
lamide gel electrophoresis with molecular masses of 67, 54 and 20 kDa.
The relative purity of these factors was confirmed by iso-electric fo
cusing, where immunosuppressive activity was associated with proteins
of pI values of approximately 4.2 and 4.35.