Identification of prolactin-like proteins synthesized by normal murine lymphocytes.
Cultured murine lymphoid cells release a PRL-like immunoreactive (IR) protein which may be important in immunity, as anti-PRL antisera inhibit lymphocyte proliferation in vitro. We examined culture supernatants (SNs) and cell lysates from concanavalin A (Con A) activated murine thymocytes to identify these proteins. Western blot analysis of cell lysates revealed three specifically-stained PRL-IRs. A doublet of bands at 35.6 and 33.6 kDa was associated with the particulate fraction of the cell. These PRL-IRs were present in lymphocytes independently of mitogen stimulation. In contrast, a 22 kDa PRL-IR was only produced in mitogen stimulated cells, and was specifically immunoprecipitated with anti-PRL antiserum. In addition, all three PRL-like IRs incorporated 35S-methionine in vitro, indicating that they are synthesized by these cells. Only the 22 kDa PRL-like protein was present in culture medium from stimulated cells, suggesting that this may be the PRL bioactivity previously demonstrated in SNs from murine lymphocytes.
Montgomery
D W
DW
Department of Pharmacology, University of Arizona College of Medicine, Tucson 85724.
LeFevre
J A
JA
Ulrich
E D
ED
Adamson
C R
CR
Zukoski
C F
CF
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D008214:Lymphocytes / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D011388:Prolactin / Q000096:biosynthesis*; D012016:Reference Values; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism
D011388:Prolactin