Mri. Young et al., Human squamous cell carcinomas of the head and neck chemoattract immune suppressive CD34(+) progenitor cells, HUMAN IMMUN, 62(4), 2001, pp. 332-341
CD34(+) progenitor cells have previously been shown to be mobilized in pati
ents with squamous cell carcinoma of the head and neck (HNSCC). The present
study showed that these CD34(+) cells inhibit the capacity of intratumoral
lymphoid cells to become activated in response to stimulation through the
TCR/CD3 complex, The mechanisms that could lead to the accumulation of CD34
(+) cells within the tumor tissue were assessed. This was accomplished thro
ugh in vitro studies that determined if HNSCC produce soluble factors that
chemoattract CD34(+) cells. The migration of cord blood CD34(+) cells, whic
h were used as a readily available source of progenitor cells, was stimulat
ed by products derived from HNSCC explants and primary HNSCC cultures. This
stimulated migration was due to chemotaxis because it was dependent on an
increasing gradient of HNSCC-derived products. CD34(+) cells that were isol
ated from the peripheral blood of HNSCC patients were similarly chemoattrac
ted to the HNSCC-derived products. The majority of the chemotactic activity
produced by HNSCC could be attributed to vascular endothelial cell growth
factor (VEGF). These studies indicate that HNSCC can chemoattract immune in
hibitory CD34(+) progenitor cells through their production of VEGF. (C) Ame
rican Society for Histocompatibility and Immunogenetics, 2001. Published by
Elsevier Science Inc.