Related Experiment Video
Updated: Aug 8, 2026
Isolating And Immunostaining Lymphocytes and Dendritic Cells from Murine Peyer's Patches
Published on: March 17, 2013
Identification of prolactin-like proteins synthesized by normal murine lymphocytes
D W Montgomery1, J A LeFevre, E D Ulrich
1Department of Pharmacology, University of Arizona College of Medicine, Tucson 85724.
Insights
Murine lymphocytes produce prolactin-like proteins. A 22 kDa protein is secreted upon stimulation and may play a role in immune responses, as it
Area of Science:
- Immunology
- Endocrinology
- Cell Biology
Background:
- Lymphoid cells release prolactin (PRL)-like immunoreactive (IR) proteins.
- Anti-PRL antisera inhibit lymphocyte proliferation in vitro, suggesting a role in immunity.
Purpose of the Study:
- To identify PRL-like proteins released by cultured murine lymphoid cells.
- To characterize the PRL-like proteins in concanavalin A (Con A) activated murine thymocytes.
Main Methods:
- Western blot analysis of cell lysates and culture supernatants.
- Immunoprecipitation using anti-PRL antiserum.
- 35S-methionine incorporation to assess protein synthesis.
Main Results:
- Three PRL-IR proteins were detected in cell lysates: a doublet at 35.6 and 33.6 kDa (particulate fraction, present without stimulation) and a 22 kDa protein (produced only upon mitogen stimulation).
- All three PRL-IRs were synthesized by the lymphocytes, as shown by 35S-methionine incorporation.
- Only the 22 kDa PRL-like protein was secreted into the culture medium of stimulated cells.
Conclusions:
- Murine lymphocytes synthesize and release PRL-like proteins.
- A 22 kDa PRL-like protein is secreted by activated thymocytes and may represent the bioactive PRL previously found in lymphocyte culture supernatants.
- These findings suggest a potential role for PRL-like proteins in lymphocyte function and immunity.
Abstract:
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.
