Modulation of the human in vitro antibody response by human leukocyte interferon preparations

The ability of human leukocyte Interferon to modulate the plaque-forming-cell response of human peripheral blood leukocytes to horse red blood cells was examined. Human peripheral blood mononuclear cells were cultured in vitro with the addition of varying doses of human leukocyte interferon 24 hr prior to, simultaneously with, and 24 hr after sensitization of the cultures with horse red blood cells. Plaque-forming-cell responses were measured 5 days after sensitization with antigen using poly-L-lysine-coupled horse red blood cell monolayers. When human leukocyte interferon preparations were added 24 hr prior to sensitization with antigen, a significant enhancement of the plaque-forming-cell response was observed. When the interferon was added simultaneously with antigen, the plaque-forming-cell response was significantly suppressed. Therefore, human leukocyte interferon appears to have a time-dependent immunomodulatory activity. The kinetics of immunomodulation appear to be different from those of previously described mouse models.     

Bacteria-derived human leukocyte interferons alter in vitro humoral and cellular immune responses

Cultures of gradient-purified human peripheral blood mononuclear cells (PBMC) have been employed to examine the effects of three bacteria-derived human leukocyte interferon subtypes on certain aspects of in vitro immune responses. The addition of highly purified IFN-alpha 1, -alpha 2, -alpha 2/alpha 1 to PMBC cultures stimulated with phytohemagglutinin (PHA) or pokeweed mitogen resulted in a significant suppression of the mitogenic response. This suppression required the presence of interferon in the cultures because pretreatment of cells and removal of interferon had no effect on their response to PHA. The presence of these interferons at 200 U/ml also caused a substantial reduction of human mixed-lymphocyte reactions (MLR) as measured by [3H]thymidine incorporation by responder cells. Interestingly, pretreatment of stimulator cells was sufficient for this reduction to occur whereas pretreatment of responder cells had no effect on their ability to respond to allogenic stimulation. In contrast to these suppressive effects, the three interferons enhanced human in vitro primary immune response to sheep red blood cells (SRBC). These data demonstrate that both purified interferon subtypes and genetic hybrids of human interferons produced by recombinant DNA technology have effects on in vitro immune responses.     

Time and dosage dependence of immunoenhancement by murine type II interferon preparations.

Preparations of Type II immune induced Interferon enhanced the plaque forming cell response of mice to sheep red blood cells both in vivo and in vitro. The enhancement of the antibody response was dependent on the dosage of interferon used and the time of administration of interferon. The expression of the antiviral and immuno-enhancing activities of Type II interferon preparations shared several physical-chemical properties, including pH 2 lability and heat stability. The plaque forming cell response to lipopolysaccharide, a T-independent antigen, could not be enhanced by treatment with Type II interferon. In addition, treatment of spleen cell cultures of nude thymic deficient mice with Type II interferon could not cause an enhancement of the plaque forming cell response to lipopolysaccharide. These data suggest that the immunoenhancing effect of Type II interferon on antibody responses is produced by an effect on T lymphocytes in contrast with the immunosuppressive effect which appears to be mediated through an effect on B lymphocytes.     

Mechanism of the suppressive effect of interferon on antibody synthesis in vivo.

Mouse interferon preparations significantly suppress the in vivo antibody response to sheep red blood cells (SRBC), a thymus-dependent antigen, and to Salmonella typhimurium lipopolysaccharide (LPS), a thymus-independent antigen. It is also possible to effect the late responses of antigen sensitive "memory" cells observed during secondary immunization by administration of interferon prior to primary immunization. The immunosuppressive activity of interferon was time- and dose-dependent. Maximum suppression was produced when animals were given 1.5 times 10-5 units of interferon between 4 and 48 hr before antigenic stimulation. These findings suggested that interferon affects some early event(s) in the process of antibody synthesis which might be related to the general inhibitory effect of interferon on rapidly dividing cells and viral m-RNA translation. In addition, the use of nonadherent spleen cell cultures from interferon-treated mice, immunized in vitro with a thymus-independent antigen, indicated that in this situation the inhibitory effect of interferon was due to an action on B lymphocytes. A variety of soluble "suppressive" factors are secreted by T cells as a consequence of activation by mitogens or specific antigens in vitro. Since T cells are recognized as one of the sources of interferon, it is suggested that interferon should be investigated as a suppressor T cell-produced lymphokine which can regulate B cell expression.     

Differentiation of the immunosuppressive and antiviral effects of interferon.

Virus-induced (virus-type) interferon suppression of the in vitro antibody response of mouse (C57B1/6) spleen cells to sheep red blood cells was blocked by 5 × 10^?5M 2-mercaptoethanol (2-ME). The blockade was not due to a direct effect on interferon since 2-ME was capable of blocking the suppression when added to cultures up to 48 hr after interferon. 2-ME blockade of virus-type interferon immunosuppression was not due to the immunoenhancing property of 2-ME. Similar protective effects of 2-ME were observed during immunosuppression by virus-type interferon inducers, but not T-cell mitogen inducers of interferon (immune interferon). The data suggest that the immunosuppressive properties of virus-type and immune interferon preparations involve different mechanisms. Virus-type interferon inhibited DNA synthesis in unstimulated spleen cell cultures and in 2-ME stimulated cultures, and the degree of inhibition of DNA synthesis appeared to be related to the immunosuppressive property of interferon in the absence or presence of 2-ME. 2-ME did not affect the antiviral properties of either virus-type or immune interferon in nonlymphoid cells. Further, the induction of virustype interferon in spleen cells was neither inhibited nor enhanced by 2-ME, while the induction of immune interferon was enhanced. This enhancement is consistent with 2-ME enhancement of the immunosuppressive effects of immune interferon inducers.There are two possibilities for 2-ME blockade of the immunosuppressive effect of virus-type interferon, while not affecting the antiviral property. Firstly, the immunosuppressive and antiviral properties of virus-type interferon may involve different mechanisms at the subcellular level. Secondly, the selectivity of the blockade by 2-ME could be due to the fact that spleen cells are the target cells in immunosuppression, while L cells are the target cells in inhibition of virus replication. Thus, virus-type interferon may suppress the immune response at the level of the macrophage and 2-ME may reverse this effect by replacing a blocked macrophage function.     

Interferon-induced 2-5A synthetase activity in human peripheral blood mononuclear cells after immunization with influenza virus and rubella virus vaccines.

The interferon-induced enzyme 2-5A synthetase can be a sensitive indicator of activation of the human interferon system during viral infection or interferon therapy. To determine the response of the human interferon system to viral antigens, the level of 2-5A synthetase activity was monitored in peripheral blood mononuclear cells of healthy adults before and after immunization with influenza or rubella virus vaccine. The influenza virus-vaccinated individuals demonstrated increases in enzyme activity on days 1 and 11 in vivo, whereas those vaccinated with rubella virus vaccine showed an increase only on day 11. The difference in the day 1 in vivo 2-5A synthetase response in the two vaccinated groups could be demonstrated by in vitro incubations of peripheral blood mononuclear cells isolated approximately 90 days postvaccination with the two vaccines. The day 11 increase of enzyme activity in the rubella virus group showed a positive correlation with an increase in serum antibody titer, suggesting activation of the interferon system during antibody production in vivo after human exposure to virus antigens. The demonstration of increased 2-5A synthetase activity at specific times postimmunization in this investigation indicates that the interferon system is involved in the human in vivo response to virus vaccination.     

Inhibition of the immune response by membrane-bound antibody.

Cells from the spleens of "normal" swine, which were pretreated with pronase to remove surface membrane-bound immunoglobulin, gave an enhanced hemolytic plaque-forming cell response to sheep red blood cells in vitro in comparison with untreated controls. The enhancement could be abrogated by preincubating pronase-treated spleeen cells in preparations containing antibody to sheep red blood cells. This effect was demonstrated by autologous sera, immune sera, and all three known classes of porcine serum immunoglobulins, including IgM, IgA, and IgG and could be removed by absorption with sheep red blood cells. Surface membrane-bound antibody exerted its effect by binding to the nonadherent cell population. The response of normal spleen cells was unaffected by antibody treatment. Pronase-treatment was not mitogenic, did not function as a polyclonal B cell activator, and did not selectively eliminate T or B cells. The results indicate that removal of antibody from the surface of lymphoid cells enhanced the humoral immune response invitro and confirm that membrane-bound antibody can inhibit response to antigen.     

Suppression of in vitro antibody response by ribosome-associated factor(s) from interferon-treated cells.

Initiation factor preparation (eIF-IF) from mouse L cells treated with virus-type interferon suppressed the in vitro plaque-forming cell (PFC) response to sheep red blood cells. The eIF-IF preparation had previously been shown to block formation of the ternary complex Met-tRNA_f-eIF-GTP. The formation of this complex is a necessary step in initiation of protein synthesis. Initiation factor preparation (eIF) from untreated L cells affected neither the PFC response nor the participation of eIF in the formation of ternary complex. The induced factor was shown not to be Interferon by antibody neutralization experiments with anti-interferon. The factor must be present in the PFC cultures during the early stages of antigen induction in order to suppress the immune response. Speculatively, eIF-IF may act at the level of the macrophage, perhaps entering the cell by pinocytosis. This may account for its inability to inhibit virus replication in L cells. The production of the inhibitory factor is blocked or partially blocked by actinomycin D. It is possible that this factor is a mediator of the immunosuppressive effects of virus-type interferon. This is the first report of biological activity on cells, which is associated with a ribosome-associated factor induced by interferon.     

Establishment of T-cell hybridoma constitutively producing macrophage-dependent T-cell replacing factor

A T-cell hybridoma was established by the fusion of concanavalin A-stimulated splenic T cells with BW 5147. The hybridoma cells secrete a factor constitutively to support antibody formation of spleen cells depleted of T cells against TNP-Ficoll but not against horse red blood cells. The activity was indicated not to be due to interleukin 2, B-cell growth factor I, B-cell growth factor II, or interferon. The factor-mediated antibody response to TNP-Ficoll required the presence of adherent cells. The adherent cell function could be replaced by the macrophage culture supernatant containing interleukin 1. B cells responding to TNP-Ficoll in the culture with hybridoma factor were indicated to be Lyb 5+ and to bear receptors for third component of complement.     

Lipid antigens derived from erythrocytes infected with Plasmodium berghei

Lipids were extracted from red blood cells infected with Plasmodium berghei, from the membranes of infected red cells and from free parasites. A radioimmunoassay was used to detect antibodies to these lipids in sera from convalescent and immune rats. Most of the antigenic activity could be attributed to the parasite although some activity was found in lipids isolated from the membranes of infected red blood cells. Absorption studies showed that the binding was specific for malarial lipid antigens. Immune sera showed no cross-reactivity with lipids from red blood cells of non-infected rats. However, sera from non-infected control rats showed low levels of cross-reactivity with the parasitized red cell-derived lipids. Levels of anti-lipid antibodies were directly correlated with the progress of the infection. The highest antibody level occurred when the parasitaemia reached zero. The malarial lipids had no effect on lymphoblast transformation of immune splenocytes in vitro. However, liposomes prepared from either malarial or non-specific lipids caused an increased response to antigen by the blast cells.     

Different metabolizing ability of thiol reactants in human and rat blood: biochemical and pharmacological implications

The effect of oxidants, electrophiles, and NO donors in rat or human erythrocytes was analyzed to investigate the influence of protein sulfhydryl groups on the metabolism of these thiol reactants. Oxidant-evoked alterations in thiolic homeostasis were significantly different in the two models; large amounts of glutathione protein mixed disulfides were produced in rat but not in human erythrocytes by treatment with hydroperoxides or diamide. The disappearance of all forms of glutathione (reduced, disulfide, protein mixed disulfide) was induced by menadione only in human erythrocytes. The treatment of rat red blood cells with electrophiles produced glutathione S-conjugates to a much lower extent than in human red blood cells; GSH was only minimally depleted in rat red blood cells. The NO donor S-nitrosocysteine induced a rapid transnitrosation reaction with hemoglobin in rat erythrocytes producing high levels of S-nitrosohemoglobin; this reaction in human red blood cells was negligible. All drugs were cleared more rapidly in rat than in human erythrocytes. Unlike human Hb, rat hemoglobin contains three families of protein SH groups; one of these located at position beta125 is directly implicated in the metabolism of thiol reactants. This is thought to influence significantly the biochemical, pharmacological, and toxicological effects of some drugs.     

Immunomodulating properties of interferon inducers

Data on the immunomodulating activity of interferon inductors are presented. It was revealed that the inductors increased the animal vaccinal response. Schemes for combined use of the interferon inductors and immunomodulators were developed. The immunomodulators were shown to increase the host interferon response evident from synergistic increasing of the interferon titers or prolongation of interferon circulation in blood of the animals. The efficiency of the schemes for combined use of the interferon inductors and immunomodulators was obvious from stimulation of the antibody production. As a result the time of the antibody circulation in blood increased. The effect of the combined use of the immunomodulators and interferon inductors was studied. The combined use of the preparations significantly increased the average life-span of the animals and the rate of their survival.     

Interferon action: effects of mouse alpha and beta interferons on rosette formation, phagocytosis, and surface-antigen expression of cells of the macrophage-type line RAW 309Cr.1

Treatment with an essentially pure mouse α or β interferon boosts the binding and phagocytosis of opsonized sheep red blood cells by cells of the murine macrophage-like cell line RAW 309Cr.l. The kinetics and the dose dependence of the effects of the two interferons are very similar. The effects depend on continued RNA and protein synthesis, and they diminish after the removal of interferon from the medium. Studies with agents specifically binding FcRI receptors (i.e., IgG2a) and FcRII receptors (i.e., the Fab fragment of the antireceptor monoclonal antibody 2.4G2) revealed a three- to fivefold increase in the level of FcRI receptors per cell and an about twofold increase in that of FcRII receptors per cell after treatment with interferon. The enhanced binding and phagocytosis of opsonized sheep red blood cells by interferon treatment are apparently a consequence of the increased number of Fc receptors. As revealed by studies involving the binding to the cells of labeled monoclonal antibodies to several cell surface antigens, the level of the H-2D^d surface antigen is also selectively increased three- to fourfold in the cells after exposure to interferon.     

The primary immune response of brown trout (Salmo trutta) to injection with cellular antigens

The primary immune response of brown trout ( Salmo trutta L.) was studied after injections of two cellular antigens– Salmonella typhi H, flagellar antigen d, and human group 'O'Rh+ red blood cells. Both intraperitoneal and intramuscular injections were employed. Agglutinins and complement–fixing antibodies were produced to S. typhi and haem–agglutinins to human 'O' red blood cells. Maximum titres to S. typhi were reached after 49 days in the case of both agglutinins and complement-fixing antibody. Haem-agglutinins reached a maximum value of 1 : 512 between 35 and 42 days. Haemagglutinins to human 'O' red blood cells were detected as early as 7 days after injection. Antibodies against S. typhi were found after 14 days. Natural haemolysins were present against horse, sheep and human groups 'A', 'B' and 'AB' but not with group 'O'. No natural haemagglutinins were present to the six types of red blood cells tested. No precipitins were detected to either S. typhi or human 'O' red blood cells by immunodiffusion.     

Pinocytotic response of circulating erythrocytes to specific blood grouping antibodies

Human blood samples from adults and newborns of blood groups O, A, and B were treated with either anti-A blood grouping serum, ferritin-conjugated anti-A serum, free ferritin, or saline and then prepared for electron microscopy. Morphological differences were observed between the untreated erythrocytes of infants and adults. Circulating red cells of newborns were frequently vesiculated (25.5%), whereas those of adults only occasionally showed vesicles (5.5%). On the basis of morphology and incidence, the majority of these vesiculated cells seemed to be mature erythrocytes. The introduction of anti-A serum to group A erythrocytes of infants appeared to stimulate vesicle formation, but anti-A serum did not have a similar effect on group O or B cells of infants or on group A cells of adults. Vesicles which formed in response to antiserum treatment appeared to be the result of pinocytosis. In contrast to the well dispersed ferritin along the membrane of agglutinated adult cells, the ferritin particles on the infants' cells were frequently clustered at irregular intervals. These accumulations seemed to lead to invaginations of the cell membrane, resulting in ferritin-lined intracytoplasmic vesicles. The addition of free ferritin or ferritin-conjugated antibodies of the wrong specificity to red cells did not increase vesicle formation.     

南方鲇血型的初步鉴定

本研究旨在通过观察南方鲇血清与其红细胞的交叉反应以鉴定南方鲇的血型.实验结果表明:南方鲇的血清与同种其他个体的红细胞进行交叉反应时均未出现凝集现象,这表明南方鲇可能不存在血型或南方鲇具备血型但血清中相应的凝集素含量不足.以南方鲇的红细胞为抗原免疫日本种大耳白兔制备的抗血清与南方鲇的红细胞进行交叉反应,出现了不同程度的凝集反应,这表明南方鲇存在血型.据上述两个实验结果可以推断,南方鲇可能存在4种血型,分别命名为NA、NB、NAB和NO型;同时也证实,在鉴定南方鲇血型的研究中,通过制备抗血清与红细胞进行交叉反应的方法更为可靠.     

The nature of the suppressive effect of interferon and interferon inducers on the in vitro immune response

Viral-induced interferon inhibition of the primary in vitro plaque-formong cell (PFC) response in the mouse (C57B1/6) involves a dynamic relationship between the nature of the antigen, the concentration of interferon added to antigen-stimulated cultures, and the time of addition of interferon relative to antigen addition. The PFC response to a thymus-dependent antigen (sheep red blood cells) was more easily suppressed by viral-induced interferon than was that to a thymus-independent antigen (E. coli 0127 LPS), both in terms of inhibitory concentrations of interferon and the time at which the interferon could be added to cultures after antigen and still inhibit the PFC response. These differential effects of interferon could be related to the difference in cellular requirements (B and T lymphocytes) of the two antigens. Interferon was effective in inhibiting the in vitro PFC response of antigen-primed spleen cells, indicating that it can block the response of memory lymphocytes. By using interferon inducers as inhibitors of the in vitro PFC response, it was possible to show that at least two antigenically distinct interferons may be involved in suppressing the immune response. It is known that one type of interferon is induced by virus and synthetic double-stranded polyribonucleotides. The other type is stimulated by antigen and T cell mitogens. A model is proposed to explain the nature of these interferon inhibitory effects in terms of mediation of immune suppressor cell effects.     

Effect of phenylalanine- or tryptophan-loaded liposomes on the rheological properties of AA and SS erythrocytes

Phenylalanine or tryptophan was incorporated into AA and SS red blood cells by a liposomal transport system which was previously shown by Kumpati to inhibit and reverse sickling of intact SS red blood cells in vitro. In the present study, the effect of phenylalanine or tryptophan incorporation on the rheological properties was evaluated. The incorporation of phenylalanine or tryptophan into red blood cells decreased the viscosity of deoxy SS red blood cells which reached a level close to that for normal red blood cells due to the antisickling effect. These results demonstrate that this liposomal transport system which transferred phenylalanine or tryptophan into intact red cells and did not have any adverse effect on red cell metabolism or function did correct the viscosity of deoxy SS red cells by its antisickling effect. This method may have significant therapeutic implications in the treatment of sickle cell disease.     

Oxidative Stress-Induced DNA Damage and Repair in Human Peripheral Blood Mononuclear Cells: Protective Role of Hemoglobin

Background

DNA repair is a cellular defence mechanism responding to DNA damage caused in large part by oxidative stress. There is a controversy with regard to the effect of red blood cells on DNA damage and cellular response.

Aim

To investigate the effect of red blood cells on H₂O₂-induced DNA damage and repair in human peripheral blood mononuclear cells.

Methods

DNA breaks were induced in peripheral blood mononuclear cells by H₂O₂ in the absence or presence of red blood cells, red blood cells hemolysate or hemoglobin. DNA repair was measured by ³H-thymidine uptake, % double-stranded DNA was measured by fluorometric assay of DNA unwinding. DNA damage was measured by the comet assay and by the detection of histone H2AX phosphorylation.

Results

Red blood cells and red blood cells hemolysate reduced DNA repair in a dose-dependent manner. Red blood cells hemolysate reduced % double-stranded DNA, DNA damage and phosphorylation of histone H2AX. Hemoglobin had the same effect as red blood cells hemolysate on % double-stranded DNA.

Conclusion

Red blood cells, via red blood cells hemolysate and hemoglobin, reduced the effect of oxidative stress on peripheral blood mononuclear cell DNA damage and phosphorylation of histone H2AX. Consequently, recruitment of DNA repair proteins diminished with reduction of DNA repair. This suggests that anemia predisposes to increased oxidative stress induced DNA damage, while a higher hemoglobin level provides protection against oxidative-stress-induced DNA damage.     

乙型肝炎病毒4种基因型与干扰素治疗应答的关系

目的:在细胞水平上比较乙型肝炎病毒(HBV)基因型A,B,C,D对干扰素治疗的不同应答反应,进而探讨基因型对干扰素治疗效果的影响。方法:利用脂质体法将前期构建好的HBV基因型A,B,C,D质粒分别转染入Hep G2细胞系中,并在转染细胞上清中加入干扰素-α2a(IFN-α2a)。ELISA方法用来检测上清中HBV抗原,荧光定量PCR方法检测上清中HBV DNA,通过比较加药前后上清中HBV抗原和DNA水平的变化,反应HBV基因型对IFN-α2a的治疗反应。结果:HBV 4种基因型对IFN-α2a治疗的应答反应存在差异,其中A和B基因型对IFN-α2a的应答明显高于C和D基因型;而基因型A和B之间、以及基因型C和D之间对IFN-α2a的反应无统计学差异。结论:HBV基因型能影响干扰素的治疗效果,其中A和B基因型对IFN-α2a的治疗反应优于C和D基因型,在临床上应开展HBV基因分型检测,用以指导临床用药的选择。