膀帯血リンパ球Subpopulation及び男児臍帯血中の母体リンパ球に関する研究

Abstract

At first, lymphocyte subpopulations were examined in the cord blood by using various technics, which were the E-rosette forming cell, EN-rosette forming cell, early-EN-rosette forming cell, EAC-rosette forming cell, IgG-Fc-receptor binding T cell (double rosette forming cell), and immunofluorescent staining assays, and the results were compared with t hose of adults.In the second study, the possibility of maternofetal transfer of lymphocytes was investigated in the cord blood. Cord lymphocytes were obtained from 15 healthy male newborns and cultured for chromosome analysis. The culture was carried out in many combinations of pH, mitogens, cell numbers and culture time as follows: (1)pH of culture media were 7.2 and 6.8, (2) Mitogens were phytohemagglutinin (PHA), pokeweed mitogen (PWM), and concan avalin A (Con-A),(3) Added cell concentrations (per 5 ml of culture media) were 3×106,2.5×106,5×105, and 1 x 105, (4) Culture time were 72 hours and 96 hours.These four groups of conditions were combined each other and all cultures were done at 37°C in environment of 5 % CO2. Then the cultured cells were prepared for chromosome analysis and karyotyped. (One of them were performed whole blood cultures. )The following results were obtaind.1) In the cord blood, E-, EN-, and early-EN-rosette forming cells (T lymphocytes) decreased in percentage as compared with those of adults.2) The absolute numbers of EN-rosett e forming cells increased in the cord blood compared with those of adults.3) In the cord blood, neuraminidase-treated E rosette forming cells (EN- and early-EN-rosette forming cells) increased in percentage and its standard deviation was smaller than that of the results obtained from neuraminidase-untreated E rosette forming cells (E-rosette forming cells)4) In the cord blood, there was no difference in percentage between EN-rosette forming cells and early-EN-rosette forming cells, which suggests that these two populations were the same lymphocyte-subset (of T cells).5) EAC-rosette forming cells sho wed no difference in percentage between the cord lymphocytes and the peripheral blood lymphocytes of adults, but the absolute numbers of EAC-rosette forming cells increased in the cord blood compared to those of adults.6) The percentage of surface immunoglobulin (SmIg) bearin g lymphocytes (B lymphocytes)were higher in the cord blood than those of adults.7) Surface IgD bearing lymphocytes in the cord blood showed an increased percentage as compared with those of adults.8) In the cord blo od, it is likely that “null cells” (lymphocytes which have no surface marker) increased in percentage compared with those of adults.9) IgG-Fc-receptor binding T lymphocytes examined by double rosette formation showed no significant difference in percentage between cord lymphocytes and adults.10) Chromosome analysis were performed on 1320 metaphases in PWM culture,196 metaphases in PHA culture, and 126 metaphases in Con-A culture, altogether 1642 metaphases from 15 healthy male cord blood. Among these experiments, only 1 XX-karyotype was found among the PWM-stimulated metaphases, which was cultured for 96 hours in culture media of pH 7.2. The results obtained so far suggest that maternal lymphocytes do not pass across the placental barrier in normal pregnancy.