Null cell identification and characterization with OKT16: an anti-p40
monoclonal antibody
MA Talle, P Rao, M Makowski, C Boselli, N Allegar and G Goldstein
A murine monoclonal antibody, OKT16, specific for human lymphocytes of T
lineage, was isolated by standard immunization and hybridization
techniques. The distribution of the antigen defined by OKT16 was similar to
the antigen reactive with monoclonal antibodies 3A1 and WT1. This identity
of antigen targets was confirmed in an enzyme-linked immunosorbent assay
system and by sequential immunoprecipitation. Under reducing conditions,
OKT16 reacted with an antigen of 40K daltons; however, under nonreducing
conditions this antigen appeared as an 84K- dalton molecule, which suggests
that the p40 antigen exists as a disulfide-linked dimer. By indirect
immunofluorescence, OKT16 reacted with a greater fraction of nonrosetting,
non-B (null) lymphocytes than with antibodies to other T cell-specific
proteins. Two-color immunofluorescence demonstrated the coexpression of the
T16 antigen and the C3bi receptor on most null cells. The T10 antigen
(found on cortical thymocytes and activated peripheral T cells) was
restricted to most T16-bearing null cells and expression of the Fc receptor
for aggregated IgG (defined by monoclonal antibody 73.1) was restricted to
a major subset of T16-bearing null cells. The T cell-specific markers
defined by OKT8, OKT11, and OKT17, as well as the monocyte marker defined
by OKM5, were expressed by smaller subsets of OKT16-reactive null cells.
These studies support by phenotypic analysis the functional heterogeneity
ascribed to null cells. The 40K-dalton T16 antigen has the most extensive
null cell representation of all the T lineage markers described to date.
Volume 66,
Issue 5,
pp. 1124-1132,
11/01/1985
Copyright © 1985 by The American Society of Hematology
