Soluble CD16 binds peripheral blood mononuclear cells and inhibits
pokeweed-mitogen-induced responses
C Teillaud, J Galon, MT Zilber, N Mazieres, R Spagnoli, R Kurrle, WH Fridman and C Sautes
Laboratoire d'Immunologie Cellulaire et Clinique, Unite INSERM 255,
Institut Curie, Paris, France.
Human neutrophils express two types of low affinity receptors for IgG, Fc
gamma RII or CD32 and Fc gamma RIIIB or CD16. Human serum contains soluble
CD16 (sCD16), which is produced by proteolysis of neutrophil Fc gamma
RIIIB, the cleavage site being located close to the cell surface. In order
to assess the functional roles of sCD16, we have produced, in eukaryotic
cells, a recombinant sCD16 containing the extracellular region of Fc gamma
RIIIB. Purified sCD16, of molecular mass of 48 kD, bound human IgG1 and
IgG3 but not IgG2, IgG4, or F(ab')2. It inhibited, in a time and
dose-dependent fashion, proliferation and IgM and IgG production of human
peripheral blood mononuclear cells (PBMC) stimulated by pokeweed mitogen
(PWM) in vitro. FACS analysis showed that biotinylated sCD16 bound
specifically to a fraction (35%) of PBMC, which corresponds to monocytes
and to subsets of B and T lymphocytes. Moreover, sCD16 did not modify the
staining of PBMC by FITC-coupled PWM. Thus, the biologic function(s) of
sCD16 on PWM-induced responses are exerted through direct and specific
interaction(s) with mononuclear blood cells and not with PWM. In
conclusion, neutrophils may play a regulatory role on immune responses via
the production of soluble forms of CD16 with cell-binding and
antiproliferative capacities.
Volume 82,
Issue 10,
pp. 3081-3090,
11/15/1993
Copyright © 1993 by The American Society of Hematology
