Plaque-forming Cells In Spleen Research Articles

Activation of host-defense mechanism induced by exposure to a low dose of radiation: an approach to accumulate evidence on the interaction between the whole body and radiation

We found that the effect of a small dose of irradiation on the whole body exists at certain dose level windows which induce delayed radio-protective effects on an animal after a fixed time span depending on its dose levels. The striking increase of survivals against the second mid-lethal irradiation was observed in mice pre-irradiated with 5 cGy eight weeks before, or pre-irradiated with 50 cGy two weeks before. Thymocyte apoptosis was increased six hours after 5 or 50 cGy pre-irradiation. While in spleen plaqueforming cell counts with SRBC immunisation increased at the very time when mice manifested the optimal increase in survival, namely two weeks after 50 cGy pre-irradiation or eight weeks after 5 cGy pre-irradiation. Stress inducing treatment (e.g. administration of a heavy metal salt or irradiation at higher dose etc.) seems to act within a few days stimulating more events at the biochemical level. However, the low-dose irradiation seems to act more at the immune level influencing the cooperation between immune system components in the whole body.

Effect of the period of treatment with a single dose of propylthiouracil on the antibody response in rats

Propylthiouracil (PTU) was employed in a fixed quantity to evaluate the effect of the period of treatment with this drug on the antibody response to sheep red blood cells in Wistar rats. Animals were treated for 8, 16, 30 and 90 days by intragastric route with 5 mg/day, and immunized 24 h following the end of treatment; other groups were treated for 21 days, and immunized on the 17th day of treatment. Animals were sacrificed 5 or 6 days following immunization; the primary response was evaluated by the number of plaque-forming spleen cells and in some cases also by enzyme-linked immunosorbent assay (ELISA). Secondary response of PTU-treated rats, immunized and boostered after 15 days, was evaluated by ELISA 3 days following the booster. RIA performed the measurement of T3 in animals treated for 16 days, immunized, and sacrificed after 1, 2, 3, 4 and 5 days following immunization. Results showed that treatment for 8 and 16 days increased production of antibodies, and for 30 and 90 days decreased this response. Thus, according to the period of treatment, the same dose of PTU stimulates or suppresses the antibody response. This biphasic effect of a single dose of PTU was independent of alterations of serum levels of T3 during the buildup of the immune response. These results contributes towards the understanding of the literature controversy regarding the effects of this drug on the immune response, and could be of interest for studies involving autoimmune processes in thyroid.

Effect of hot water extract from Agaricus blazei Murill on antibody-producing cells in mice

We investigated the immunopotentiating activities of boiled water-soluble extracts from desiccated Agaricus blazei Murill (ABM). Effect of ABM extract on antibody production was investigated by method of hemolytic plaque-forming cells (PFC) against sheep red blood cells (SRBC) antigen. ABM extracts significantly ( p<0.01) increased the number of PFC in spleen with intraperitoneal administration at doses of 25 mg/kg as compared with control group. The populations of Mac-1- or CD25-positive cells significantly ( p<0.01, p<0.001) increased, but in CD19-positive cells, there were no differences in ABM-treated mice as compared with control mice. The expressions of IL-6 and IL-1β mRNA were augmented by ABM extract in both peritoneal macrophages and spleen cells. These results suggested that ABM extract might be an effective stimulator for T cell and macrophage to IL-1β and IL-6 release, resulting in augmentation of antibody production against SRBC antigen.

Immune effects of low-dose radiation: short-term induction of thymocyte apoptosis and long-term augmentation of T-cell-dependent immune responses.

We and others have shown that low-dose X or gamma irradiation of mice leads to an increase in their survival after a subsequent lethal high-dose irradiation. The greatest increase in radioresistance appears at a fixed window of dose and time, e.g. 8 weeks after 5-10 cGy or 2 weeks after 50 cGy preirradiation. We show that low-dose irradiation induces thymocyte apoptosis with a maximal level at 6 h postirradiation that returns to background levels after 24 h. At the same time, we observed no morphological alteration of splenocytes and no early modification of the intensity of T-cell-dependent immune responses as measured by plaque-forming cell (PFC) counts. Nevertheless, we found that PFCs were increased 2 weeks after 50 cGy irradiation, which is the same time at which mice expressed the optimal increase in survival after a second lethal irradiation. We also examined thymocyte apoptosis and spleen PFCs in mice subjected to other stress-inducing pretreatments. Our results emphasize the existence of a lag time between the time of low-dose irradiation in vivo and the appearance of radioresistance. A mechanism that interconnects an environmental stimulus with the response of the animal is proposed based on the evidence presented here and reported in the literature.

Effects of phenytoin administration on murine immune function

The results obtained in these series of experiments indicate that oral administration of phenytoin (100, 50, or 25 mg/kg) to mice significantly depressed both humoral and cellular immune responses, evaluated by the techniques of enumeration of direct and indirect spleen plaque-forming cells (PFC) and the delayed-type hypersensitivity reaction (DTH) against sheep red blood cells (SR BC), when compared with those observed in normal control animals. Furthermore, spleen cells, purified splenic T lymphocytes or Ly 2 + T cells obtained from 100 mg/kg phenytoin-treated donor mice were capable of diminishing both PFC and DTH responses of normal cells transferred into lethally irradiated mice. The immunodepressor effect of phenytoin was observed despite the fact that administration of this drug induced a rise in spleen cellularity.

Effects of carbamazepine on murine humoral and cellular immune responses.

Oral administration of carbamazepine (CBZ) (15, 10, or 5 mg/kg) to mice significantly decreased both humoral and cellular immune responses evaluated by enumeration of direct and indirect plaque-forming spleen cells (PFC) and delayed-type hypersensitivity reaction (DTH) against sheep red blood cells (SRBC) as compared with those observed in normal control animals. Moreover, spleen T cells obtained from CBZ-treated donor mice were capable of decreasing both PFC and DTH responses of normal spleen cells transferred into lethally irradiated recipient animals. The immunodepressor effect of CBZ was observed even though administration of CBZ induced augmentation of spleen cellularity.

Genetic control of the radiosensitivity of lymphoid cells for antibody formation ability in mice.

To analyze the genetic basis of the relationship between the radiosensitivity of the immune response and radiation lymphomagenesis, we examined the radiosensitivity of lymphoid cells for antibody formation in BALB/cHeA, STS/A, F1 hybrids, and their recombinant inbred mouse strains. The decrease in the number of plaque-forming spleen cells in BALB/cHeA mice exposed to 3 Gy X-irradiation was more than tenfold that in STS/A mice. The phenotype of radioresistance was dominant over sensitivity. The coincidence between the strain distribution patterns of the genetic markers and radiosensitivities of antibody formation in the various recombinant inbred strains was in the region with the Igh locus on chromosome 12. There was obvious difference between the patterns in the region containing the Ifa locus on chromosome 4 which has been shown to be related to the incidence of radiation-induced lymphomas. These results indicate that the region on chromosome 12 may contain major gene(s) related to radiosensitivity for antibody formation.

Effects of Acupuncture On Immune Response in Mice

The effect of acupuncture points stimulation on the induction of plaque-forming cells (PFC) in spleen cells of BALB/c mice was investigated in vivo and in vitro tests. In in vivo experiment, mice were immunized with 2 x 10(8) sheep red blood cells (SRBC) and the PFC was markedly increased by daily (once a day for 4 days) acupuncture stimulation. The enhancement of PFC by acupuncture was completely blocked by preadministration of procain, hexamethonium, naloxone, propranolol, but not by phentolamine. The enhancement of PFC by acupuncture was also observed in spleen cells of non-immunoized mice when spleen cells of the acupunctured mice were cultured with SRB in vitro. The enhancement of PFC in spleen was observed after stimulation with acupuncture, and a similar effect was also found in bone marrow cells of normal mice, but not in thymic cells. The spleen cells of mice given acupuncture showed no enhancement of PFC after treatment with anti-Thy 1.2 antibody and complement. Furthermore, these helper T cells were found to be not restricted by the H-2 gene complex. These data demonstrate that the helper T cells induced by acupuncture lack the H-2 restriction, and thus suggest that they may be drived from the bone marrow, but not from the thymus. It is therefore concluded that the helper T cells derived from the bone marrow were activated via the sympathetic nervous system stimulated by acupuncture.

EFFECTS OF LEAD SHOT INGESTION ON SELECTED CELLS OF THE MALLARD IMMUNE SYSTEM

The immunologic effects of lead were measured in game-farm mallards (Anas platyrhynchos) that ingested lead shot while foraging naturally, mallards intubated with lead shot, and unexposed controls. Circulating white blood cells (WBC) declined significantly in male mallards exposed to lead by either natural ingestion or intubation, but not females. Spleen plaque-forming cell (SPFC) counts were significantly lower in mallards intubated with lead pellets compared to controls. Declines in WBC and SPFC means with increasing tissue lead concentrations provide further evidence that lead exposure reduced immunologic cell numbers. Hormonal activity and diet may have influenced the immunologic effects of lead exposure in this study.

Humoral immune activity in CBA/Ca mice during late pregnancy and the post-partum period

Syngeneically mated CBA/Ca mice were used to measure “spontaneous” immunoglobulin (Ig) secretion in the Peyer's patches (PP), spleen and the para-aortic lymph nodes (PALN), employing a protein A plaque assay, during the latter part of pregnancy and in the post-partum period. The lactating and non-lactating females were compared with respect to humoral immune activity (plaque-forming cells) and serum Ig levels (ELISA technique). The pregnancy-induced weight changes in some lymphoid organs and the elevation in the number of plaque-forming cells in spleen (IgG and IgM PFC), PALN (IgG and IgM PFC) and the PP (IgA PFC) lasted longer in the lactating than in the non-lactating mice (owing to hormonal differences). A very strong decrease in serum IgG was observed during pregnancy and after parturition IgG levels remained depressed longer in lactating than in non-lactating mice. Interest has been focused on IgA in the study and this has been discussed as well as the possible reasons for the increased turnover of maternal serum Ig (especially IgG).

In vivo effects of cyclosporin A on murine B-cells responding to type III pneumococcal polysaccharide

The effect of cyclosporin A (CSA) on the antibody response to pneumococcal polysaccharide type III (a T-independent class 2 antigen) was investigated in mice. A single oral CSA administration (50 mg/kg) was able to depress (40%) the primary antibody response evaluated as spleen plaque-forming cells. Repeated treatments (12–50 mg/kg × 5) resulted in a higher degree of inhibition (80%) of anti-SIII response. Both single and repeated CSA treatments were active only when administered concomitantly with or after immunization, whereas no effects were seen with drug pretreatment. Comparable inhibitions of anti-SIII response were observed in control and nude mice suggesting a direct effect of CSA on B-cells.

Immunomodulating Activity of Ginsenoside Rg1 from Panax Ginseng

The immunomodulatory activity of ginsenoside Rg1 from Panax ginseng was studied in mice using sheep red cells as the antigen. It was found that ginsenoside Rg1 at a dose of 10 mg/kg administered for three consecutive days before immunization increased the number of spleen plaque-forming cells, the titers of sera hemagglutinins as well as the number of antigen-reactive T-cells. Ginsenoside Rg1 also increased the number of T-helper cells with respect to the whole T-cell number and the splenocyte natural killer activity. Ginsenoside Rg1 induced an augmentation of the production of IL-1 by macrophages and exerted a direct mitogenic effect on microcultured thymus cells. Ginsenoside Rg1 also partly restored the impaired immune reactivity by cyclophosphamide treatment.

Synovial fluid from rheumatoid arthritis patients induces polyclonal antibody formation in vivo.

Our previous studies demonstrated the presence of a T-cell replacing factor in the synovial fluid (SF) of patients with rheumatoid arthritis (RA) and that RA-SF can activate, selectively, the induction of IgG2b antibody secreting cells in lipopolysaccharide (LPS)-pretreated mouse spleen cell cultures. In the present study the effect of RA-SF was tested in vivo in mice. Injection of the polyclonal activator LPS induced the production of IgM and IgG3 secreting cells in normal mice. However, the addition of RA-SF led to a selective increase in the production of IgG2b with a peak response on day 5 and IgG1 plaque-forming cells (PFC) with a peak on day 7. Neither the IgG2b nor IgG1 responses were caused by specific immunity against heterologous proteins present in RA-SF, as injection of in vitro inactive RA-SF samples did not induce PFC. The effect on B cells of RA-SF was further evaluated by injection of RA-SF in combination with LPS to the Xid B-cell deficient CBA/N mice. RA-SF had identical effects in CBA/N as in normal mice. The biological implication of these findings is discussed. Our earlier results support the idea that B cells are endogenously activated in RA patients. We have speculated that this activation is caused by the B-cell differentiation factor which is present in SF. Therefore, we also tested whether RA-SF could influence antibody-forming cells in mice that spontaneously develop autoimmunity. We found that injection of RA-SF alone, in the absence of any other activating substance, induced a very marked increase of IgG producing cells in (NZW x NZB) F1 hybrid mice. From a relatively high background level the RA-SF could still induce an up to 100-fold increase in the numbers of PFC in spleens of such mice.

Humoral immunodepression following acute NO2 exposure in normal and adrenalectomized mice.

The effects following 20 ppm NO2 exposure on humoral immunity were investigated in C57Bl/6 mice after 48, 72, and 96 h exposure. Both spleen plaque-forming cell (PFC) responses and serum hemagglutinins (HA) using sheep red blood cells (SRBC) as antigen were studied. Splenic and thymic weight and cellularity decreased on acute exposure to NO2. PFC were markedly depressed after 48 h exposure and continued to decrease as exposure time was lengthened. HA titers were also depressed. The same significant suppression of PFC and HA titers was observed in adrenalectomized mice after 96 h NO2 exposure. The depression of humoral immunity in NO2-exposed mice was independent of stress-induced endogenous steroids.

Effect of Maternal Antigenic Stimulation on the Active Immune Responses of Their Offspring

Pregnant mice were stimulated by heterologous erythrocyte and protein antigen, and the active immune responses of their offspring as measured by plaque-forming cells (PFC) were investigated. In offspring derived from mothers immunized by a suitable amount of T-dependent antigen, clear-cut suppression of development of specific PFC in spleen was observed over a significant period after delivery. The mechanism of this suppression was investigated, and the following results were obtained. When the heterologous erythrocyte was used as antigen, the more the specific PFC developed in the mother spleen, the stronger the suppression of PFC observed in their offspring. However, it is worthy of note that passive administration of antibody to pregnant mice did not induce suppression in their young. In case of the protein antigen ovalbumin (OVA), pregnant mice had to be injected with a suitable amount of antigen, along with aluminium hydroxide, for either primary or secondary stimulus to induce the suppression of specific PFC in their offspring. Soluble OVA administered to pregnant mice was not effective for inducing suppression in the offspring. Based on these results, some possible mechanisms are discussed concerning specific PFC suppression in the offspring when pregnant mice are stimulated.

Sensitization of T and B cells by a normally tolerogenic macromolecule: the induction of unresponsiveness and of sensitization is polymorphic

Changes induced in B and T cells by tolerogen were experimentally defined in animals which resist down-regulation. Female A/J, C57BL/6J, MLR/MpJ-lpr/lpr, MLR/MpJ-+/+ and NZB/B1NJ mice were injected at various ages with a tolerogenic form of rabbit gamma globulin (sRGG) or were left uninjected, and all were then immunized with dinitrophenylated RGG (DNP-RGG) on alum. The degree of tolerance was estimated by measuring anti-DNP and anti-RGG spleen plaque-forming cell (PFC) numbers. In some cases, the state of T or B cells deduced from these experiments was further examined by cell transfer experiments. Four types of responsiveness to the tolerogenic form of RGG (sRGG) were distinguished: 1) persistent tolerance inducibility of T and B cells to tolerance induction (A/J); 2) T cells retaining tolerance-inducibility after initiation of age-dependent sensitization of B cells by the tolerogenic form of RGG (C57BL/6J, NZB/B1NJ); 3) age-dependent resistance of T cells to tolerance-induction and age-dependent sensitization of B cells by tolerogen, with the sensitization only manifesting itself in reactivity with T cells from immunized donors (SJL/J); and 4) sensitization of T cells by a usually tolerogenic form of RGG (MLR/MpJ-lpr-lpr). Thus, the development of resistance against tolerance induction is highly polymorphic, not only with respect to the age of onset, but also with respect to the cellular site of its first manifestation and the effect. Possible mechanisms of B-cell sensitization in sRGG-treated C57BL/6 and NZB mice are discussed in relation to the age-dependent emergence of a B-cell subpopulation and of non-specific helper T-cell factors.

Chronic zinc deficiency in rats: Its influence on some parameters of humoral and cell-mediated immunity

The effect of dietary zinc deficiency on immune function was studied in specific pathogen-free rats. The spleen cell response to sheep red blood cells (srbc) and serum hemolysins were measured in rats maintained on the depleted or normal diet for periods of time ranging from 3 to 10 weeks and immunized with srbc six days prior to sacrifice. The in vitro response of splenic lymphocytes to the polyclonal T-cell mitogen, phytohemagglutinin (PHA), was also investigated. There was no significant effect of the diet on spleen plaque-forming cells, although values for zinc-deficient rats tended to vary widely as the time on the diet increased. Hemolysin titers were unaffected by diet at all intervals. A significant reduction in lymphocyte blastogenesis was observed in the zinc-deficient rats after 5 weeks on the diet. Control animals responded with four times the stimulation observed in the low zinc group. Thymus weight and serum zinc levels were significantly reduced by the zinc-deficient diet. Chronic, moderate zinc deficiency appears to have a differential effect on humoral and cell-mediated lymphocyte functions in this model. The normal plaque-forming cell and hemolytic antibody response to srbc suggests that helper T-cell and B-cell functions are intact. In contrast, the impaired mitogenesis in response to PHA stimulation indicates that zinc deficiency is affecting other T-cell subset(s).

T and B lymphocyte function in response to a protein-free diet.

Groups of female adult rats were fed either isocaloric protein-free or 18% protein diets for various intervals. Four days before sacrifice, the animals were immunized either with sheep erythrocytes or with a trinitrophenyl-lipopolysaccharide (TNP-LPS) conjugate. Spleen lymphoid cell populations, spleen plaque-forming cells, and serum hemolysins were measured. A persistent diminution, proportional to the duration of protein deprivation, was observed in all parameters studied after immunization with the T-dependent antigen, sheep erythrocytes. The immune dysfunction was more pronounced for hemolysin titers, which became undetectable after 15 days of protein-free diet. The response of the protein-free group to the T-independent antigen (TNP-LPS) after 15 days of diet was only 34% of the control. When a T-cell lymphokine, macrophage migration inhibitory factor, was measured, a normal response was observed in the protein-free group. Feeding a normal diet rapidly restored the spleen plaque-forming cell populations to 60% of normal after 4 days and to 100% after 6 days. Protein starvation influenced the production of antibodies more than it did the number of antibody-forming cells. The nutritional impairment of immunoglobulin synthesis appears to be reversible.

Use of a solid-phase 3H-radioimmunoassay for the measurement of immunoglobulin produced in short-term cultures of antibody-secreting cells

A slid-phase radioimmunoassay (RIA) for assaying immunoglobulin produced from antibody-secreting myeloma, hybridoma and immune spleen cells is described. Specific antibody is detected by culturing antibody-producing cells on antigen-coated flexible polyvinylchloride microtiter wells, washing away the cells, and measuring the bound specific antibody with tritiated affinity-purified anti-isotype reagents. Antibody produced from 10 3 myeloma cells can be detected with as little as 4 h of incubation. With 24–48 h of incubation, antibody from as few as approximately 3–15 myeloma, hybridoma or immune spleen plaque-forming cells (PFC) can be detected. This culture-well RIA has certain distinct advantages over the hemolytic PFC assay and RIA assays in which antibody in culture supernatants is measured.

Cells involved in the immune response. XXX. An evaluation of the different assays to demonstrate rabbit spleen plaque-forming cells. Enhancement of the assay by anti-target cell antibodies

Four different procedures for the detection of rabbit spleen plaque-forming cells (PFC) directed toward the sheep erythrocyte (SRBC) antigen were evaluated in terms of their sensitivity. These included the conventional localized hemolysis in gel (LHG) assay, the thin-layer LHG assay, the LH assay using a monolayer of the target SRBC erythrocytes and the localized hemolysis in liquid phase (Cunningham) assay. The latter assay consistently proved to be the most sensitive assay. The sensitivity of this latter assay was further improved by incorporating preformed IgG or IgM antibodies directed toward the target erythrocytes, in subhemolytic concentrations, into the assay. This antibody-enhanced plaque assay in liquid medium is 20–50 times more sensitive than the conventional LHG assay.