[Dynamics of T-Cell receptor gene rearrangement and T-lymphocytes migration from thymus during post-radiation regeneration].

Recovery and migration of T-cells from the thymus to the secondary lymphoid organs in mice after sublethal gamma irradiation were investigated by measuring T-cell receptor excision circles (TRECs). The TRECs level practically represents the cellularity of thymus, in particular it correlates with the quantity of T-cells which have rearranged TCR genes and express the receptor complex CD3-TCR. So, TRECs can be considered as one of the markers of these cells. TREC-containing cells form a subset of recent thymic emigrants in the secondary lymphoid organs. After a significant TREC decrease in the lymph nodes within the early phase (4 days) after irradiation, we registered the increase of their number during urgent organ recovery due to T-cell migration from the thymus (the maximum is on the 10th day). The secondary thymic atrophy is accompanied by a weakening migration of the T-cells containing TRECs to lymph nodes. A significant TREC increase in the spleen was registered on the 4th day after irradiation. The rest of the recovery period. (up to 60 days) is characterized by the low TREC level. Thus, determination of TREC level allows obtaining additional information about recovery and migratory processes in lymphoid organs during post-radiation regeneration.

[Analysis of cellular bases of secondary thymic atrophy in irradiated mice by flow cytometry].

Using flow cytometry we looked for a thymocyte subpopulation responsible for the development of thymus urgent recovery and secondary atrophy in sublethally irradiated mice (4 Gy). It was expected that the number of these cells would grow before the urgent recovery peak and would drop during secondary atrophy. It was found out that DN3 thymocytes were the best for these criteria. The DN3 stage of thymocytes development is characterized by the rearrangement of the major portion of T-cell receptor genes. On the basis of this finding we have discussed the possibility of secondary atrophy correction using IL-7.

[Acanthamoeba isolated from child thymus: Acanthamoeba growth during cocultivation with human and murine eukaryotic cells and induction of cytopathogenic effect on these cells]. / Nekotorye osobennosti povedeniia in vitro kletok ameby roda Acanthamoeba, vydelennykh iz timusa rebenka: zavisimost' razmnozheniia ot prisutstviia v kul'ture iadrosoderzhashchikh kletok cheloveka i myshi i tsitopatogennoe deistvie na éti kletki.

A cell line of the ameba assigned to the genus Acanthamoeba by morphological and cariotypic signs and by the specific features of its life cycle was isolated from the thymus of a child operated on for heart disease. The line received the name CDHT (Cells Derived from Human Thymus). Actively proliferating mammalian cells maintain the multiplication of Acanthamoeba cells in vitro. Using thymocytes as an example, it was shown that death of these cells occurred through the mechanism of apoptosis. The human thymocytes preincubated with the supernatant obtained through the cocultivation of CDHT and thymocytes may also undergo apoptosis.