NCBI Summary:
The protein encoded by this gene is a cytokine that regulates T and natural killer cell activation and proliferation. This cytokine and interleukine 2 share many biological activities. They are found to bind common hematopoietin receptor subunits, and may compete for the same receptor, and thus negatively regulate each other's activity. The number of CD8+ memory cells is shown to be controlled by a balance between this cytokine and IL2. This cytokine induces the activation of JAK kinases, as well as the phosphorylation and activation of transcription activators STAT3, STAT5, and STAT6. Studies of the mouse counterpart suggested that this cytokine may increase the expression of apoptosis inhibitor BCL2L1/BCL-x(L), possibly through the transcription activation activity of STAT6, and thus prevent apoptosis. Alternatively spliced transcript variants of this gene have been reported. [provided by RefSeq, Feb 2011]
General function
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Cellular localization
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Ovarian function
Oocyte maturation
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Interleukin 15 concentrations in follicular fluid and their effect on oocyte maturation in subfertile women undergoing intracytoplasmic sperm injection. Spanou S et al. (2018) To calculate the concentrations of interleukin 15 (IL-15) in follicular fluid (FF) and evaluate their relation with oocyte maturation, follicle size, and patients' body mass index (BMI) and age. Follicular fluid specimens were obtained from 56 subfertile women undergoing intracytoplasmic sperm injection (ICSI) during oocyte retrieval for measurement of IL-15 concentrations with ELISA. Wilcoxon's test and Pearson's correlation coefficient were used to correlate FF concentrations of IL-15 with follicular size and stage of oocyte maturation, along with patients' BMI and age. IL-15 concentrations in FF of follicles with immature oocytes were significantly greater than those from follicles with mature ones (median 5.333 vs. 3.250 pg/ml, respectively, p < 0.001). There was a significant negative correlation between IL-15 concentrations and follicle size (r = - 0.333, p = 0.003). No significant correlation was observed between IL-15 concentrations and patients' BMI and age (p > 0.05). IL-15 concentrations in FF are adversely related with the size of the follicles and the maturity of the corresponding retrieved oocytes in a cohort of expected normal responders undergoing intracytoplasmic sperm injection (ICSI). Follicular fluid concentrations of IL-15 should be investigated as a possible predictive factor for oocyte maturity.//////////////////
Expression regulated by
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Ovarian localization
Granulosa, Theca, Luteal cells, Follicular Fluid
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Differential expression of interleukins IL-13 and IL-15 in normal ovarian tissue and ovarian carcinomas.
Ripley D, et al .
Objective. To determine the temporal and spatial expression of interleukins (IL)-13 and IL-15 in ovarian carcinoma compared to normal ovarian tissue. Methods. Quantitative RT-PCR, ELISA and immunohistochemistry. Results. Q-RT-PCR, ELISA and immunohistochemical analysis indicates that IL-13 and IL-15 mRNA and protein are expressed in normal ovary at various phases of the menstrual cycle with immunoreactive proteins detected in granulosa/theca and luteal cells and to a lesser extent in stromal cells and surface epithelial cells. Compared to normal ovary, ovarian carcinoma expresses elevated levels of IL-13 and IL-15 mRNA, with higher IL-13 expression in primary vs. metastatic tumors. IL-13 and IL-15 protein expression was also higher in the tumor tissues compared to ascites. In normal ovary, ovarian tumors and ascites, the ratio of IL-13/IL-15 favored IL-13. Immunoreactive IL-13 and IL-15 proteins were localized primarily in the tumor cells and infiltrated inflammatory cells with increased intensity with disease stage. Conclusion. Normal ovary and ovarian tumors express IL-13 and IL-15 and pattern of their expression in carcinomas suggests that these cytokines may function in various ovarian cellular activities including inflammatory/immune responses that are integrated cellular events taking place in normal ovary and ovarian tumors.
Ovarian follicular concentration of IL-12, IL-15, IL-18 and p40 subunit of IL-12 and IL-23. Vujisic S et al. BACKGROUND: The aim of the study was to determine the presence of interleukin (IL)-12, IL-15, IL-18 and p40 subunit of IL-12/IL-23 in follicular fluid from spontaneous cycles and the relation between the concentration of selected cytokines and IVF-embryo transfer outcome. METHODS: IVF-embryo transfer and enzyme immunoassay (EIA) (R&D Systems, Minneapolis, MN, USA and MBL, Nagoya, Japan) were used. RESULTS: Follicular fluid of women included in the IVF-embryo transfer procedure contained common p40 subunit of IL-12/IL-23 (median 70.1 pg/ml), IL-15 (median 1.3 pg/ml) and IL-18 (median 38.2 pg/ml). There was a significant negative correlation between follicular fluid concentrations of IL-15 and IL-18 (R = -0.392, P = 0.003). Significantly higher concentrations of common p40 subunit of IL-12/IL-23 (median 79.8 pg/ml) were found in the follicular fluid taken from follicles containing oocytes, when compared with those without an oocyte (median 44.5 pg/ml, P = 0.006). Patients who achieved clinical pregnancy had significantly decreased concentration of IL-15 (median 0.8 pg/ml) compared with patients without successful IVF-embryo transfer outcome (median 1.4 pg/ml, P = 0.047). CONCLUSION: Follicular fluid collected from spontaneous cycles contains detectable levels of p40 subunit of IL-12/IL-23, IL-15 and IL-18. Increased concentrations of p40 subunit of IL-12/IL-23 in follicles containing oocytes suggest an important role of this cytokine in reproduction. Possible negative value of IL-15 as a predictor of IVF-embryo transfer success remains to be determined.
Follicle stages
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Levels of follicular G-CSF and interleukin-15 appear as noninvasive biomarkers of subsequent successful birth in modified natural in vitro fertilization/intracytoplasmic sperm injection cycles. Lde N et al. OBJECTIVE: To explore oocyte competence for subsequent birth. The modified natural IVF/intracytoplasmic sperm injection (ICSI) cycle was used as an experimental model by measuring levels of cytokines, chemokines, and growth factors in individual follicular fluids (FF). DESIGN: A retrospective blinded study. SETTING: European network of research, Embryo Implantation Control (EMBIC). PATIENT(S): Single FF from 83 women were analyzed during a modified natural IVF/ICSI cycle, and reproducibility of follicular composition was evaluated over two cycles for 15 patients. INTERVENTION(S): Each FF sample was blindly tested to assess levels of 26 factors by bead-based immunoassays. MAIN OUTCOME MEASURE(S): Each mediator was evaluated as a potential biomarker of subsequent birth by multivariate regression analysis. RESULT(S): A combination of both FF G-CSF and IL-15 was the optimal model to predict birth (AUC(ROC), 0.85). Birth rates per cycle were 48.9% (16/33) if two good-prognosis criteria were present (FF G-CSF >12 pg/mL and IL-15 <7 pg/mL) and 8% (3/36) and 0% (0/14) if, respectively, one or none were present. FF G-CSF was significantly correlated over two cycles (r = .71), suggesting a possible prognostic value of its documentation. CONCLUSION(S): Combined follicular G-CSF and IL-15 quantification appears as an efficient and noninvasive method to define oocyte competence for subsequent successful conception in modified natural IVF/ICSI cycles.