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Triggering of the proteinase dipeptidyl peptidase IV (CD26) amplifies human T lymphocyte proliferation
Author(s) -
Bednarczyk John L.,
Carroll Susan M.,
Marin Carmen,
McIntyre Bradley W.
Publication year - 1991
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240460304
Subject(s) - dipeptidyl peptidase , monoclonal antibody , microbiology and biotechnology , t cell , cell growth , biology , t lymphocyte , biochemistry , antigen , cell culture , enzyme , chemistry , antibody , immune system , in vitro , immunology , genetics
CD26 (Ta1, dipeptidyl peptidase IV) is a M r 105,000 protein expressed at high levels on activated T lymphocytes and is a potential marker of memory T cells. Reciprocal immunodepletion and solid phase double determinant binding studies showed that mAb AC7 and the CD26‐specific mAb anti‐Ta1 reacted with spatially distinct sites on the same molecule. The proteinase dipeptidyl peptidase IV (DPP IV) was immunoprecipitated with mAb AC7 and its enzymatic activity directly assayed using an enzyme overlay membrane system. High levels of DPP IV activity were detected on the T cell tumor line CCRF‐HSB‐2 and on PBMC stimulated by a variety of methods. By itself, soluble mAb AC7 was not mitogenic for T cells but enhanced T cell proliferation that resulted from treatment with phorbol myristic acetate (PMA) in the presence of accessory cells. T cell proliferation was also induced by co‐immobilized mAb AC7 and mAb OKT3 (anti‐CD3). Cultures of T cells growing in the presence of IL‐2 responded with accelerated growth when exposed to a combination of immobilized mAb AC7 and soluble mAb OKT3, a result not seen with freshly isolated T cells.