The interaction between Heligmosomoides polygyrus
superantigen and human peripheral blood mononuclear cells (PBMC)
was evaluated. Parasite homogenate and excretory–secretory proteins
from both L4 larvae and adult worms were examined
for their ability to stimulate, and be presented by, human cells. Proliferation
assays using PBMC from 3 human volunteers
indicated that naïve cells were stimulated by H. polygyrus
superantigen. Antigen presenting cells (APC) from a number
of human donors were able to successfully present H. polygyrus
superantigen to mouse T cell hybridomas. However, this
ability varied according to the source of the superantigen, and human APC,
in contrast to APC from mice, could only
present the superantigen contained within parasite homogenate. Also, in
contrast to
the situation with mice, human APC
could present H. polygyrus superantigen to stimulate mouse T cells
expressing not only TCR Vβ8.1, but also TCR Vβ7.
Therefore, H. polygyrus superantigen can successfully stimulate,
and be
presented by, human PBMC of different MHC
haplotypes, although the cellular mechanisms appear to be different from
those
observed in the mouse.