Lymphocyte migration in internally irradiated animals. Effect of internal beta radiation on the migration of spleen lymphocytes in CBA mice

The syngeneic transfer system was used to study migration of 51Cr-labelled spleen lymphocytes in mice after incorporation of beta-emitter, 35S-methionine. Migration of 51Cr-labelled lymphocytes to lymph nodes was stably decreased, and to liver, kidneys and lungs increased. The lymphocyte migration impairment was associated with the influence of beta-radiation on both the migratory properties of cells and the factors of their microenvironment responsible for the lymphocyte migration within the mouse body. No distinctions were observed in the character and manifestation of disturbances of the lymphocyte migration after the injection of 35S-methionine and gamma-emitter, 75Se-selenomethionine.     

Effect of gamma radiation on the immunobiological and immunochemical properties of cholera exotoxin. IV. The biological and immunochemical properties of purified irradiated choleragen

The results of investigations carried out to study the effect of gamma radiation on the properties of the purified preparations of cholera exotoxin are presented. Irradiation has been shown to decrease the anterotoxicity of purified choleragen and the activity of its permeability factor, depending on the radiation dose. The investigations have revealed that in purified toxin enterotoxicity is completely inactivated with a lover radiation dose than in crude toxin filtrate (25 kGy). In immunochemical reactions the increase of the electrophoretic mobility of the choleragen components, correlated with the increase of the radiation dose, and the reduced number of protein zones have been observed. The irradiated preparations of purified choleragen have been found to retain their immunogenic properties and serological activity.     

Effect of gamma radiation on the immunobiological and immunochemical properties of cholera exotoxin. III. The serological activity and immunochemical properties of irradiated unpurified toxin

The immunochemical properties and serological activity of irradiated preparations of crude cholera exotoxin have been studied. This study has revealed that with the increase of the dose of ionizing radiation changes occur in the physico-chemical properties of the preparations of the toxin, which leads to an increase in the electrophoretic motility of the protein components of the toxin, to the aggregation and polymerization of individual fragments. The preparations of antigen exotoxins have been shown to retain their serological activity within the range of radiation doses under study (10-350 kGy).     

Effect of gamma radiation on resting B lymphocytes. II. Functional characterization of the antigen-presentation defect

The effect of radiation on three discrete Ag-presentation functions in resting B cells was examined: 1) Ag uptake and processing, 2) expression of processed Ag in the context of functional class II molecules, and 3) provision of necessary co-stimulatory, or "second," signals. Analysis of radiation's effect on B cell presentation of intact vs fragmented Ag or its effect on presentation by Ag-pulsed B cells indicated that damage to Ag uptake and processing could not account for the bulk of the radiation-induced Ag-presentation defect. Experiments with phosphatidylinositol hydrolysis as an indirect measure of TCR occupancy suggested that irradiation caused a fairly rapid (within 1 to 2 h) decrease in the ability of the B cell APC to display a stimulatory combination of Ag and class II molecule. Ag dose-response analyses demonstrated that when presenting a fragment of the Ag pigeon cytochrome c to a T cell clone, 3000 rad-treated B cell APC were able to stimulate approximately 50% as much phosphatidylinositol turnover as unirradiated B cells. It was also found that, in contrast to their inability to initiate T cell proliferation, and similarly to chemically cross-linked splenocytes, heavily irradiated resting B cells plus Ag induced a state of Ag hyporesponsiveness in T cell clones. This effect on T cells had the same Ag- and MHC-specificity as did receptor occupancy required for proliferation, indicating that heavily irradiated resting B cells bear functional class II molecules. Co-culture of T cells with allogeneic B cells and syngeneic heavily irradiated B cells or chemically cross-linked splenic APC plus Ag resulted in T cell proliferation and interfered with the induction of the hyporesponsive state. This co-stimulatory function was radiosensitive in resting allogeneic B cells. Together, these data support the hypothesis that the major functional consequences of radiation to resting B cell APC are a reduction in the effective display of Ag plus class II molecules and, probably what is more important, a loss in the ability to provide APC-derived co-stimulatory signals.     

Effect of cAMP on the migration and proliferation of CFUs and the survival of irradiated animals

The exogenous administration of cAMP to nonirradiated mice slightly stimulates the haemopoietic stem cell migration, does not promote colony-formation in the spleen, in conditions of the endotest, and has no therapeutic effect on the irradiated rats and hamsters.     

Sizes of isotopically labeled molecules released during lysis of tumor cells labeled with 51Cr and [14C]nicotinamide.

Previous studies of mechanisms of immune lysis have utilized the release of isotopically labeled molecules from cells labeled with Na₂⁵¹Cr0₄ and [¹⁴C]nicotinamide, among others. The interpretation of specific isotope release from such cells was hampered by the lack of knowledge about the molecular sizes of the released radioactive molecules. In the present study, P815 tumor cells were labeled with the above two isotopic compounds. The cells were then lysed by freezing and thawing, antibody and complement, or immune T-lymphocyte-mediated killing. Soluble supernatants from the lysates were chromatographed in the cold on Sephadex G-10, G-25, and G-200 using several elution media. No differences were detected due to different kinds of lysis or different eluting media. Eighty-five percent of ¹⁴C-labeled molecules released from the cells were indistinguishable from nicotinamide and clearly distinct from nicotinamide adenine dinucleotide. The results suggest that [¹⁴C]nicotinamide taken up by the tumor cells during overnight culture is released unaltered during lysis. Ninety percent of ⁵¹Cr-labeled lysate molecules had an apparent molecular weight less than 4000. Most of this material was distinct from inorganic chromate, but its chemical form is not known.     

Effect of gamma radiation on retroviral recombination.

To elucidate the mechanism(s) of retroviral recombination, we exposed virions to gamma radiation prior to infecting target cells. By using previously described spleen necrosis virus-based vectors containing multiple markers, recombinant proviruses were studied after a single round of retrovirus replication. The current models of retroviral recombination predict that breaking virion RNA should promote minus-strand recombination (forced copy-choice model), decrease or not affect plus-strand recombination (strand displacement/assimilation model), and shift plus-strand recombination towards the 3' end of the genome. However, we found that while gamma irradiation of virions reduced the amount of recoverable viral RNA, it did not primarily cause breaks. Thus, the frequency of selected recombinants was not significantly altered with greater doses of radiation. In spite of this, the irradiation did decrease the number of recombinants with only one internal template switch. As a result, the average number of additional internal template switches in the recombinant proviruses increased from 0.7 to 1.4 as infectivity decreased to 6%. The unselected internal template switches tended to be 5' of the selected crossover even in the recombinants from irradiated viruses, inconsistent with a plus-strand recombination mechanism.     

Effect of sodium humate on animals irradiated with lethal doses

A therapeutic effect of natrium humate given to experimental mongrel rats exposed to 60Co-gamma-radiation of lethal doses has been studied. A single administration of natrium humate, 5-10 min following irradiation with a dose of 193.5 mC/kg (LD100/30) leads to a 43.3 per cent survival of animals after 60 days; with a dose of 232.2 mC/kg (LD100/8) there is a trend toward the increase in the life span of exposed rats.     

Migratory patterns of B lymphocytes. IV. Effect of anti-Ig on follicular localization of radioactively labeled murine spleen and bone marrow cells.

A study was made of the localization of nylon-wool-adherent (AD) and nonadherent (NA) murine spleen cells in lymphoid tissue of irradiated syngeneic recipients. Cells were labeled in vitro with [³H]uridine or ⁵¹Cr and injected intravenously. Localization in recipient tissues was expressed as percent of injected radioactivity. NA and AD [³H]uridine labeled cells gave spleen to lymph node (S:LN) ratios of 1.0 and 2.7, respectively. After treatment of AD cells with rabbit anti-mouse Fab + C at 37 °C, localization in S decreased markedly.NA cells primarily localized in LN paracortex and splenic periarteriolar sheaths. Untreated and NRS-treated AD cells localized in lymphoid follicles, whereas anti-Fab-treated AD cells did not. When ⁵¹Cr-labeled AD cells were treated with anti-Fab at 4 °C without C, there was a transient decrease in splenic localization at 24 hr followed by a recovery to the normal pattern at 48 hr after transfer. [³H]uridine-labeled bone marrow (BM) cells showed less localization in lymphoid tissue than did S cells. Some BM cells were seen in LN follicles, particularly at 48 hr after transfer, but this localization was not affected by prior treatment with anti-Fab + C. The possible role of surface Ig in the determination of follicular localization of B lymphocytes is discussed.     

Changes in the spontaneous DNA-synthesizing activity in the peripheral blood lymphocytes of irradiated animals

In lymphocytes of sheep exposed to 52 and 103 mC/kg radiation revealed was an increase in spontaneous incorporation of 3H-thymidine into DNA. A change in spontaneous DNA-synthesizing activity in lymphocytes of exposed animals was accompanied by the increase in the total protein content of the peripheral blood lymphocytes.     

Impairment of antibody formation in the spleen of irradiated animals subjected to additional thermal injury

It was shown that the 3d degree thermal burn of 10% of CBA mouse body aggravates disturbances of antibodygenesis in the spleen of irradiated (4 Gy) animals. The aggravating effects of the thermal trauma manifests itself at the time of complete recovery of the postirradiation immunoreactivity and is not associated with the dynamics of injury and repopulation of T- and B-lymphocytes.