????????????-?????????????????? ?????????????????????? ?????????????? NaPi2b ?????????????????? ?? ???????????????? ?????????????????????????????? ?????????????? ?? ?????????????????????? ???????????????????? ???????????????????? ?? ?????????????????? ????????????????. ?????????????? NaPi2b ???????????? ?????? ???????????? ???????? ?????????????? ????35. ???????????????????????????? ???????????????? (????????) ???????????? ???????????????????????? NaPi2b, ?????????????????? ????35, ?????????????????? ?????????????????????????????? ?????????????????????????? ?????? ?????????????? ?????????????? ?????????? ??????????????. ???????? ???????????? ???????????? ???????????????? ?? ?????????????????? ????????, ???????????? ???? ???????????????????? ???????? ????35 ?? NaPi2b ???? ?????? ?????????????? ???????????????????????????????? ???????? ?????????????????????????????? ?????????????? ?? ?????????????????? ??????????????. ????????????. ???????????? ?????????? ??????293, ?????????????????? ?????????????????????????????? ?????????? ?????? NaPi2b ?? ?????????????????? ?????????? NaPi2b_T330V, ???? ???????????????????????????? ???????????????????? ????35, ???????????????????????? ?? ???????????????????? ????35, ?????????? ???????? ?????????????????????????? ???????????????????? ???????????????? ???????????????????????? ?????????????????? ??????????????. ????????????????????. ?????????? ?????????????????? ?? ???????????????????? ????35 ?? ???????????????????????? 50 ??????/???? ???????????????? ???????????????????????? ???????????????????? ???????????????????? ?????????????? ????????????????, ???????????????????????????????? ?????????? ?????? NaPi2b. ?????? ????????????, ?????????????????????????????? ?????????????????? ?????????? ???????????????????????? NaPi2b_T330V, ???? ???????????????? ???????????????????????? ?????????????????? ?? ???????????????????? ?????????????? ?????? ?????????????????????? ?????????????????????????????????? ????????????????. ????????????. ???????? ???????????????????? ?????????????????????????????? ?? 1,8-?????????????? ???????????????? NaPi2b-???????????????????? ???????????????????? ?????????????? ?? ???????????????????? ?????????????????? ?? ???????? ????35, ?????????????? ?????????? ?????????????????????????? ?????? ?????????????????????????? ?????????????????? ?????????????? NaPi2b. ???????????????? ??????????: NaPi2b, ???????????????????????????? ???????????????? ????35.

????????????-???????????????? ?????????????????????? ?????????????? NaPi2b ???????? ???????????? ?? ?????????????????????? ?????????????????????????? ?????????????? ???? ?????????????????????? ???????????????????? ???????????????????? ?? ?????????????????? ????????????. ?????????????????? NaPi2b ?????????????? ???? ???????????? ???????? ?????????????? ????35. ?????????????????????????? ???????????????? (????????) ?????????? ???????????????????????? NaPi2b, ?????? ???????????????? ?????????? ????35, ?????????????????? ???????????????????????? ???????????????????????? ?????? ?????????????????? ???????????? ???? ?????? ??????????????. ???????? ?????????? ???????????? ???????????????? ?? ????????, ?????? ???????????????????, ???? ?????????????? ??????????????????????? ???????? ????35 ?? NaPi2b ???? ???????? ?????????????? ???????????????????????????? ???????? ?????????????????????????? ?????????????? ?? ?????????????????? ??????????????. ????????????. ?????????????? ?????????? ??????293, ???? ?????????????????? ?????????????????????? ?????????? ?????? NaPi2b ???? ???????????????? ?????????? NaPi2b_T330V, ?????? ???? ?????????????????????????? ???????????????????? ????35, ???????????????????? ?? ???????????????????? ????35, ?????????? ???????? ?????????????????????? ???????????????????? ?????????????????? ???????????????????????? ???????????????? ??????????????. ????????????????????. ?????????? ?????????????????? ?? ???????????????????? ????35 ?? ???????????????????????? 50 ??????/???? ?????????????????? ???????????? ?????????????????? ???????????????????? ?????????????? ??????????????????, ?????? ?????????????????????? ?????????? ?????? NaPi2b. ?????? ????????????, ???? ?????????????????????? ???????????????? ?????????? NaPi2b_T330V, ???? ?????????????????????? ?????????????????????????????????? ???????? ?????????????? ???????? ?? ???????????????????? ?????????????? ???? ????????????????. ????????????????. ???????? ???????? ???????????????? ?????? 1,8-???????????? ???????????????? NaPi2b-?????????????????? ???????????????????? ?????????????? ?? ???????????????????? ?????????????????? ?? ???????? ????35, ?????? ???????????? ?????????????????? ?????????????????????? ?????????????????????? ?????????????? NaPi2b. ?????????????? ??????????: NaPi2b, ?????????????????????????? ???????????????? ????35.

Sodium-dependent phosphate transporter NaPi2b is involved in transport of inorganic phosphate and the maintenance of phosphate homeostasisin human body. NaPi2b wasrecently identified as a marker of ovarian cancer, termed MX35. Monoclonal antibody (mAb) against transporter NaPi2b, called MX35, demonstrated therapeutic efficacy in radioimmunotherapy of patients with ovarian cancer. Aim. The present experiments explored whether MX35 antibody can affect function of NaPi2b to transport inorganic phosphate ions in cellular models. Methods. HEK293 cells stably expressing wild type NaPi2b and mutant NaPi2b_T330V, which could not be recognized by MX35 antibody, were incubated with MX35 antibody and analyzed by phosphate uptake assay. Results. Cells expressing wild type NaPi2b showed reduced phosphate uptake after incubation with MX35 antibody at concentration 50 ??g/ml. No significant changes in phosphate transport were detected for cells expressing NaPi2b_T330V at the same experimental conditions. Conclusions. Our results demonstrate 1,8-fold decrease of NaPi2b-mediated phosphate transport in HEK293 cells stably expressing wild type NaPi2b after MX35 antibody application, which can be considered as a specific inhibitor of NaPi2b function. Keywords: NaPi2b, MX35 antibody.