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Identification of dipeptidyl peptidase IV as the antigen of a monoclonal anti‐prostasome antibody
Author(s) -
Schrimpf Sabine P.,
Hellman Ulf,
Carlsson Lena,
Larsson Anders,
Ronquist Gunnar,
Nilsson B. Ove
Publication year - 1999
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/(sici)1097-0045(19990101)38:1<35::aid-pros4>3.0.co;2-j
Subject(s) - dipeptidyl peptidase , monoclonal antibody , antigen , identification (biology) , immunology , antibody , medicine , monoclonal , dipeptidyl peptidase 4 , biology , endocrinology , enzyme , biochemistry , diabetes mellitus , botany , type 2 diabetes
BACKGROUND Our purpose was to elucidate the identity of an antigen of a monoclonal antibody against prostasomes, which are prostate‐derived organelles occurring freely in human semen. METHODS Monoclonal antibodies against prostasomes were generated by intrasplenic immunization to allow better characterization of the prostasomes. One third of the resulting antibodies bound to a 110‐kDa prostasomal protein on Western blots. RESULTS The antigen was purified from seminal prostasomes by anion exchange chromatography and gel electrophoresis. After in‐gel digestion and amino‐acid sequence analysis of selected peptides, it was identified as dipeptidyl peptidase IV (DPP IV), EC 3.4.14.5, also known as T‐cell‐activating antigen CD26. No DPP IV could be detected in the supernatant obtained after preparative ultracentrifugation of the prostasomes. CONCLUSIONS DPP IV/CD26 is structurally bound to prostasomes rather than being free in seminal fluid. This enzyme may play a critical role in the promoting effect of prostasomes on forward motility of spermatozoa. Prostate 38:35–39, 1999. © 1999 Wiley‐Liss, Inc.