Mechanism of target cell recognition by natural killer cells: characterization of a novel triggering molecule restricted to CD3- large granular lymphocytes.

Abstract

Sllmmal-yIn an attempt to identify a molecule in target recognition by CD3-large granular lymphocytes (LGL), we have generated a rabbit antiidiotypic (anti-ID) serum against a monoclonal antibody (mAb 36) that reacted with the cell membrane of K562. Flow cytometry analysis demonstrated that the anti-ID serum bound selectively to CD3-LGL and that F(ab')2 fragments of the anti-ID serum blocked both target cell binding and lysis by NK cells. Stimulation of CD3-LGL with F(ab')z fragments resulted in the release of serine esterases and the secretion of interferon % Furthermore, anti-ID F(ab')2 antibodies crosslinked to anti-DNP F(ab')2 mediated directed cytotoxicity of a non-natural killer (NK)-susceptible mouse target (YAC-1) via this surface ligand. These functional reactivities were only removed by adsorption with the specific idiotype. Protein analysis showed that the anti-ID serum immunoprecipitated 80-, 110-, and 150-kD proteins. Using this anti-ID, a partial cDNA was cloned and an antipeptide antiserum was made against the portion of the predicted amino acid sequence that corresponded to a portion of the ID binding region. This antipeptide serum exhibited similar functional and biochemical reactivities to those observed with the anti-ID serum. These data suggest that the cell surface moiety recognized by the anti-ID and anti-p104 is novel and is selectively involved in both recognition and triggering of NK-mediated lytic function.

A cyclophilin-related protein involved in the function of natural killer cells.

“…A synthetic peptide corresponding to a positively charged region of the predicted NK-2 fusion protein (peptide 104; residues 476-497 in Fig. 1) was injected into rabbits and produced the anti-p104 antiserum that reacted with the 150-kDa molecule (12). The antipeptide antiserum possessed properties similar to the original anti-ID antiserum.…”

“…The anti-ID antiserum was shown by immunofluorescence to bind specifically to CD3, CD16+ NK cells, and it blocked the binding of LGL to NK-susceptible targets, thereby preventing lysis (12). Two proteins of 80 and 150 kDa were immunoprecipitated from 125I surface-labeled NK cells but not from T cells or monocytes.…”

“…On the basis of this evidence, the anti-ID antiserum was proposed to identify a putative NK receptor (pNKR; ref. 12) complex on the surface of NK cells that is involved in the recognition of tumor targets and is coupled to the cytolytic pathway. Therefore, we have named the 150-kDa member of the complex described herein as a NK-tumor recognition molecule (NK-TR).…”

Evidence for a functional receptor for cyclosporin A on the surface of lymphocytes.

“…Most recently, CD3-large granular lymphocytes have been reported to have a cell surface molecule involved in both recognition and triggering natural killer cell-mediated lytic function (43), which, when cloned and sequenced, has 50%6 homology to cyclophilin (S. K. Anderson, S. Gallinger, J. Roder, J. Frey, H. Young, and J. Ortaldo, personal communication).…”

An Overview of Cyclophilins in Human Cancers

“…15,52 In natural-killer cells, CypNK was identified as a component of the putative tumour recognition complexes. 52,53 Although a direct role for CypNK in target-cell recognition has not been demonstrated, CypNK may be a useful tool in the molecular basis of tumourcell recognition. 15 Cyclophilin 20 (Cyp20) is a less abundant, mitochondrially located, cyclophilin.…”