Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human large granular lymphocytes (LGL) and T cells were separated from peripheral blood on discontinuous density gradients of Percoll. On a per cell basis, cultured LGL demonstrated higher levels of cytotoxicity against K562 cells than fresh LGL. Cultured T cells acquired cytotoxicity against K562 cells, although they were less cytotoxic than fresh or cultured LGL. During culture, these LGL retained the 3G8, NKH1, OKM1, and OKT10 antigens. Cultured T cells retained the T101 antigen and acquired the OKM1 and OKT10 antigens, but remained negative for the 3G8 or NKH1 antigens. A series of pharmacologic agents known to inhibit cytotoxicity of fresh LGL were also tested for their effects on cultured LGL and T cells. Ethylenediaminetetraacetic acid, known to inhibit the binding of effectors to target cells, inhibited the cytotoxicity of cultured LGL and T cells to the same degree that it inhibited the cytotoxicity of fresh LGL. In contrast, agents which primarily effect post-binding events in cytotoxicity (trypsin, D-mannose 6-P, dexamethasone, prostaglandin E2, anti-LGL granule antibody, and 9.1C3 monoclonal antibody) inhibited the cytotoxicity of cultured LGL and T cells to a much lesser extent than fresh LGL. In addition, on the basis of Michaelis-Menten's kinetic analysis, cultured LGL and T cells developed a higher binding affinity to K562 cells than fresh LGL.
 ...
PMID:Regulation of large granular lymphocytes and human T cell growth and function by recombinant interleukin 2. II. Acquisition of potent cytotoxic capabilities. 311 1

A monoclonal antibody, 9.1C3, was used to investigate the mechanism of natural killer (NK) cell-mediated lysis. In addition to blocking NK cell function, the antibody blocked antibody-dependent cellular cytotoxicity against the K562 target cell at the effector cell level. The stage at which 9.1C3 antibody inhibited cytolysis was established with a Ca++ pulse technique, whereby it was shown that the antibody inhibited killing at a discrete step after the Ca++-dependent programming for lysis. The 9.1C3 antigen appeared to be associated with the T200 glycoprotein complex. Thus the 66 and 77 Kd proteins detected by 9.1C3 were also precipitated with a monoclonal antibody to T200, and in sequential immunoprecipitations, 9.1C3 antibody removed these bands from immunoprecipitates with antibody to T200. Also, in co-modulation studies, it was found that antibody to T200 co-capped the 9.1C3 antigen but that capping with 9.1C3 antibody did not induce co-modulation of the T200 antigen. Expression of the 9.1C3 and T200 antigens on different cell types, however, was not identical, and the 9.1C3 antibody did not immunoprecipitate high m.w. proteins in the region of 200 Kd. Functionally, in NK cell killing studies, the antibody to T200 used alone did not block but was synergistic with the 9.1C3 antibody. The differential effect of the enzymes pronase and trypsin on the cell surface expression of the 9.1C3 and T200 antigens reflected the ability of these enzymes to inhibit NK cell killing. These data suggest that the 9.1C3 antigen participates in a late event in the cytolytic pathway.
 ...
PMID:A novel antigenic cell surface protein associated with T200 is involved in the post-activation stage of human NK cell-mediated lysis. 637 48