The effect produced by IL-2 and IL-15 on the proliferation of T cells in vitro in patients diagnosed with breast cancer

National Medical Research Centre for Oncology, Rostov-on-Don, Russia

Introduction : Over the past decade, the use of adoptive immunotherapy has emerged as a promising approach to treatment of various malignancies, including breast cancer. Cytokines are involved in the development, differentiation and homeostasis of the T cells. Despite the similarities in signaling pathways, the γc cytokines shape the T cell responses differently: IL-2 plays a major role in the development and maintenance of the regulatory T cells, while IL-15 stimulates the proliferation and cytotoxic functions of the CD8+ T cells and NK- cells that leads to an enhanced antitumor response. It is of interest to study the combined effect of these cytokines in an experiment.

Aim : To evaluate the combined effects produced by cytokines IL-2 and IL-15 on the T cell proliferation in vitro in patients diagnosed with breast cancer.

Materials and methods : The material for the study covered 10 blood samples taken from patients with breast cancer, followed by isolation of mononuclear cells (MNC) in Ficoll-Urografin density gradient centrifugation. Cells were cultivated in equal seeding fractions of 500 thousand cells/ ml in 6-well plates for 15 days at 37°C with 5–10% CO2. Anti-biotin magnetic particles MACSiBead and antibodies to CD2, CD3 and CD28 (Miltenyi Biotec, Germany) were used to activate the T cells. An induction of lymphocyte proliferation was performed on the fourth, eighth and twelfth days by 32 | Cardiometry | Issue 29. November 2023

adding cytokines - IL-2, IL-15 and the combination of IL-2 / IL-15 (MiltenyiBiotec, Germany) with the use of a negative control. Cytokines were added at a concentration of 40 ng/ml. Daily counts of viable lymphocytes were completed using an analyzer (Eve, NanoEnTek Inc, Korea), and morphology was conducted using an inverted microscope (AxioIm-agerA.2 Zeiss, Germany). Statistical data processing was carried out using Microsoft Office Excel and Statistica 10.0. The statistical significance of differences in the data between groups was assessed utilizing the Student’s t-test. The number of cells on the first day of cultivation corresponded to the seeding dose and was taken as 100%.

Results : In samples with the addition of the IL-2/ IL-15 combination, an increased proliferative activity, as compared to the reference, and the formation of conglomerates were noted, which possibly indicates the influence of γc-cytokines on the processes of maturation and differentiation of T-lymphocytes during expansion under the in vitro cultivation conditions. After the expiration of the cultivation period, all experimental samples statistically significantly exceeded the reference, namely, the presence of IL-2 led to an increase in the number of viable cells by 2.25 times, due to the effect made by IL-15 there was the increase by 2.9 times recorded, and in case of the addition of the IL-2/IL-15 combination the increase by 2. 33 times was reported.

Conclusions : Thus, we can assume that IL-15 defi- Keywords : Expansion of lymphocytes, Breast can-ciency reduces the level of expansion of CD8+ T-lym- cer, Activation of human T-lymphocytes, IL-2, IL-15. phocytes, but is not critical for their formation in their culture.