Search

The CD8+ natural killer (NK) subpopulation has recently been identified as a fast and reliable biodosimetric indicator within human peripheral blood mononuclear cells (PBMC) in vitro. In irradiated and subsequently cultivated PBMC, a decrease of the relative number of intact CD3-CD8+ lymphocytes 16 and 48 h after treatment has allowed for estimating the received dose in the range of 0 - 10 Gy and lethal/sublethal dose discrimination, respectively. Here we show that suitable biodosimeters can also be found in the peripheral blood B-cell compartment. Multiparameter flow cytometric analysis of irradiated and subsequently cultivated human PBMC revealed that both the CD27+ and CD21 B-cell subpopulations can be used as biodosimeters and the CD19+CD27+ lymphocytes have proved useful for retrospective determination of the received dose in the range of 0 - 6 Gy. In addition, several CD19+ lymphocyte subsets characterized by co-expression of CD21, CD27+ and CD38 have been shown to bear biodosimetric potential, too. However, when important parameters like the original size within the CD19+ compartment, its radiation-induced changes and data variation had been taken into account, the CD27+ subpopulation proved superior to the other B-cell subpopulations and subsets. It appears that, in the dose range of 0 - 6 Gy, the relative decrease of CD27+ B lymphocytes provides more sensitive and reliable data than that of CD8+ NK-cells due mainly to lower data variation. In contrast to CD27+ B-cells, the proportions of CD27+ subpopulations of T-cells were not affected by irradiation. We have also proposed a simple experimental protocol based on full blood cultivation and three-color CD27/C03/CD19 immunophenotyping as a time-saving and inexpensive approach for practical biodosimetric evaluations on simple, three-to-four color flow cytometers. [ABSTRACT FROM AUTHOR]

The aim of our work was to evaluate peripheral blood lymphocyte subsets as in vitro indicators of the received dose of ionizing radiation (biodosimetric markers) in the range of 3-20 Gy and to determine the appropriate time interval, during which a dose-dependent induction of apoptosis occurs upon γ irradiation. In lymphocyte subsets characterized by double color surface immunophenotyping, four-color flow cytometry was used for visualizing cell death-associated increase in superficial phosphatidylserine exposure and cytoplasmic membrane permeability by fluorinated Annexin V and propidium iodide, respectively. No differences between sham-treated and lethal dose (7 Gy)-irradiated samples were observed upon 6 h cultivation in vitro. Ten and 18 h later, about 50 % of lymphocytes were apoptotic, but only the minority of them was in the late apoptotic phase. The only difference in radioresistance of the CD4+CD8- and CD4- CD8+ lymphocyte subsets was seen upon 2-day cultivation when huge depletion of intact cells and prevalence of the late apoptotic population became obvious. A dose-dependence study in 16 and 48 h cultures confirmed the effectiveness of major T cell subsets as biodosimetric indicators. On the other hand, the minor CD8+ subset of natural killer (NK) cells has been identified as a radiosensitive lymphocyte population the disappearance of which correlated with the received dose. We demonstrated that the CD3-CD8+ NK subset can be used as a lethal/sublethal dose discriminator to 16 h cultivation. In addition, our data indicate that two-day cultivation followed by CD3/CD8 expression analysis in an intact lymphocyte population may provide a clue for low dosage biodosimetry. [ABSTRACT FROM AUTHOR]

Pig fetuses, colostrum-deprived newborns and germ-free (GF) piglets, animals in which B-cell development is not influenced by maternal regulatory factors, were employed to study the occurrence and specificity of natural antibodies (NAb). Serum immunoglobulins of all isotypes were found in 44-day-old fetuses (the gestation period in pigs lasts 114 days) and their level, with predominating IgM, was increased during fetal ontogeny. In sera of fetuses at the end of embryonic life as well as of newborns and older GF piglets, antibody activity against autoantigens (thyroglobulin, hormones, ssDNA), phylogenetically conserved proteins (myosin), haptens (trinitrophenyl; TNP) and bacterial components (Escherichia coli 086, tetanic anatoxin) was detected by enzyme-linked immunosorbent assay. The antigen-binding activity of IgM NAb increased after isolation of the serum immunoglobulins on a Staphylococcus Protein A (SPA)-Sepharose column. IgM reactivity similar to that detected in serum was found in supernatants from polyclonally stimulated cultures of spleen of 8- and 12-day-old GF piglets. Pig fetal liver IgM+ B cells, which were able to produce IgM after polyclonal stimulation, did not express the CD5 molecule. Our results indicate that pig preimmune repertoire is comparable to that described in humans and mice, although in contrast to these species pig B-1 cells do not express CD5. [ABSTRACT FROM AUTHOR]

3-day-old miniature piglets were stimulated in vivo with Bacillus firmus by the intraperitoneal or intragastric route for 1 d. Cells containing IgA and IgG2 were detected in the ileum in all stimulated but not in control animals. The frequency of blood CD3+ cells increased after intraperitoneal administration of B. firmus, the ratio of polymorphonuclears to lymphocytes increased in all stimulated piglets. B. firmus induced antitumor immunity in rats with transplanted Yoshida sarcoma cells. Granular lymphocytes and dead tumor cells were found in peritoneal exudate of stimulated animals. B. firmus induced IFN-γ synthesis in human blood lymphocytes stimulated in vitro for 1 d. The amount of TNF-α produced by these stimulated human peripheral blood mononuclears (PBMC) was lower than that of PBMC stimulated with some other bacterial immunomodulators. Cells containing TGF-β or IL-8 were not found in human PBMC stimulated with B. firmus. [ABSTRACT FROM AUTHOR]