Immunology: Evidence for the in-vitro de-novo synthesis of immunoglobulin and a previously undescribed 17 kDa protein (TEP-2) by the mucosa of the Fallopian tube

Abstract

De-novo synthesis and secretion of proteins by short-term explants of matched Fallopian tube mucosa and endometrium were studied using radiolabelled L-[35S]methionine and [3H]glucosamine. To compare directly each anatomical site of the Fallopian tube and endometrium from the same source, newly synthesized proteins were separated on one-dimensional polyacrylamide gel electrophoresis and examined by auto-radiography. De-novo synthesis of two protein bands provisionally designated as tubal epithelial protein 1 (TEP-1) and tubal epithelial protein 2 (TEP-2), was observed in explants of the Fallopian tube mucosa obtained from each anatomical site throughout the ovarian cycle (n = 20). TEP-2 was not apparent in tubal mucosa obtained from post-menopausal women (n = 5). De-novo synthesis of TEP-1 and TEP-2 was not apparent in autoradiographs of radiolabelled proteins from short-term explants of endometrium. From the autoradiographs the molecular mass of TEP-1 and TEP-2 was calculated to be 25 kDa and 17 kDa, respectively. Incorporation of glucosamine into newly synthesized protein occurred in TEP-2 but not TEP-1. TEP-1 was observed to be immunochemically identical to immunoglobulin kappa light chains.

Tubal transport of gametes and embryos: a review of physiology and pathophysiology

“…Another specific feature of tubal fluid is the presence of oviductspecific glycoproteins with their highest levels observed in the peri-ovulatory phase. Using radiolabelled L-[35S] methionine and [3H]glucosamine, investigators have been able to identify and isolate two proteins, named Tubal Epithelial Protein 1 and 2 (TEP-1 and TEP-2) that were exclusively produced by the tubal explants from premenopausal women and were absent in similar explants' secretions from postmenopausal women [75,76] . Although the biological role of these proteins is not well established, it has been suggested that their production and secretion is enhanced in response to estrogenic stimulation [77].…”

An update on hormonal regulation of early embryo-fallopian tube interactions: insights for improvements of assisted reproductive technology outcomes

“…Previously, using the proteomics approach, the FT luminal secretion was studied using in vitro primary epithelial cell culture due to the lack of ideal in vivo interventions to collect real-time secretions. The tubal secretome contains many bioactive compounds including glucose, lactate, pyruvate, various other metabolites, amino acids [116] , and certain FT-specific proteins such as TEP-1 and TEP-2 [117] . Moreover, the human FT expresses activin βA- and βB-subunits, activin type IIA and IIB receptors, and follistatin when the peak secretions can be found during the luteal phase that encompasses early embryo development and transit.…”