Effect of trypsin on suppressor cell formation and function in localized staphylococcal infection

The present study has been made on (CBA X C57BL)F1 mice immunized with sheep red blood cells (SRBC) and inoculated with staphylococci (M-SRBC-S). The injection of splenic lymphocytes from syngeneic M-SRBC-S into intact mice has been found to suppress immune response to SRBC in these mice. The injection of trypsin into M-SRBC-S decreases the suppressive action of their lymphocytes on SRBC-induced immune response in syngeneic recipients. The injection of trypsin into the recipients has been found to produce no effect on the immunosuppressive action of transplanted lymphocytes obtained from M-SRBC-S. The injection of trypsin into M-SRBC-S induces the release of the factor, inhibiting the formation and function of suppressor cells, by their splenocytes. Previously formed suppressor cells block the release of the immunostimulating factor by the splenocytes of the animals receiving the injections of trypsin.     

Mechanism of the intensification of the immune response to Staphylococcus in mice after the transplantation of primed donor splenocytes

Experiments on CBA, C57Bl/6 mice and (CBA X X C57Bl/6)F1 hybrids were made to study the mechanism of stimulation of the immune response to staphylococci after injection of primed splenocytes. The stimulating action of immune splenocytes was reversed after their in-vitro treatment with anti-immunoglobulin serum and complement. The stimulant effect was also seen in a semi-allogeneic system (adoptive transfer of CBA mice immune cells to (CBA X C57Bl/6)F1 recipients). Preincubation of splenocytes with CBA-anti-C57Bl/6-serum and complement prior to demonstration of antibody-forming cells did not influence their number in the spleen of hybrid recipients injected with immune cells carrying parent genotype but decreased this indicator of the immune response in control mice. It is concluded that stimulation of the immune response to staphylococci after transplantation of primed splenocytes is due to the anamnestic response of donor's cells repeatedly stimulated by antigen in the recipient's host.     

Effect of interferon type I on staphylococcal persistence and indices of body immunoreactivity

After the subcutaneous injection of type I (alpha) interferon into mice their survival rate in staphylococcal infection greatly increased. At the same time duration of staphylococcal persistence in these animals and the number of persisting staphylococci were found to decrease. After the injection of interferon the splenocytes of the treated animals showed a higher capacity for interferon production. During the whole experiment the characteristics of delayed hypersensitivity in these animals showed a tendency towards normalization in comparison with those in infected mice receiving no interferon.     

The methods for correcting with specific and nonspecific immunomodulators the immunopathological processes arising from the administration of a staphylococcal vaccine]

In mice immunized with staphylococcal vaccine the arresting of graft-versus-host reaction under the influence of small doses of staphylococcal vaccine, hyperimmune antistaphylococcal serum, cyclophosphamide, antilymphocytic serum has been demonstrated. Small doses of staphylococcal vaccine stimulated the production of antibodies to staphylococci and dermal extract in the animals, previously immunized with this vaccine, with the simultaneous suppression of cell-mediated immune reactions to both antigens. Immunosuppressing agents have been found to inhibit humoral and cell-mediated immune response to microbial antigen and dermal extract. No influence of vermox and levamisole on the outcome of the graft-versus-host reaction has been registered; the latter preparation has been found to intensify cell-mediated immune reactions to microbial and tissue antigens.     

Roles of I-E molecule and CD28 costimulation in induction of suppression by staphylococcal enterotoxin B in vivo.

Exposure to bacterial superantigens leads to the induction of a subsequent state of immune hyporesponsiveness. Using a transwell coculture system, a previous report demonstrated that splenocytes from staphylococcal enterotoxin B (SEB)-injected BALB/c mice secreted soluble mediators to suppress the proliferative response of naive syngeneic splenocytes to SEB stimulation. We show in the present study that, in contrast to the suppressive effect induced by SEB in BALB/c (H-2(d) haplotype), MRL(+/+), and MRL-lpr/lpr (H-2(k)) mice, SEB-primed splenocytes from I-E(-) strains such as B6, B10, A.BY (H-2(b)), and A.SW (H-2(s)) mice failed to inhibit the CD25 expression and the proliferative activity of their syngeneic naive responder splenocytes. Further results revealed that the SEB-primed cells from BALB/c, but not B6, mice inhibited the CD25 expression and proliferation of naive responder cells from either BALB/c or B6 mice, indicating the critical regulatory role of the effector cells. Unlike SEB, staphylococcal enterotoxin A induced profound suppression in both BALB/c and B6 mice. Moreover, the suppressive competence of SEB-primed splenocytes was diminished in CD28-deficient BALB/c mice. Taken together, our results indicate that when SEB is used as a stimulator in vivo, both the I-E molecule and CD28 costimulation are required for the induction of regulatory cells bearing suppressive activity.     

Patterns in the antigen-nonspecific modulation of the B-cell activity in mice under the influence of a purified staphylococcal anatoxin

Purified staphylococcal toxoid (PST) has been shown to be an antigen-nonspecific immunomodulator, capable of inducing changes in the immune response of B-cells to unrelated antigens, such as sheep red blood cells (SRBC), in a wide range of doses (from 15 to 0.15 binding units per mouse). The manifestation of the immunomodulating effect depends on the conditions of the experiment: the doses of PST and SRBC, the age of mice, the sequence of the injections of the antigens and the intervals between the injections. The simultaneous injection of PST and SRBC induces, as a rule, an increase in immune response to the test antigen, while their separate injection induces mainly immunosuppression.     

Inoculation of plasmids encoding Japanese encephalitis virus PrM-E proteins with colloidal gold elicits a protective immune response in BALB/c mice

We established a simple and effective method for DNA immunization against Japanese encephalitis virus (JEV) infection with plasmids encoding the viral PrM and E proteins and colloidal gold. Inoculation of plasmids mixed with colloidal gold induced the production of specific anti-JEV antibodies and a protective response against JEV challenge in BALB/c mice. When we compared the efficacy of different inoculation routes, the intravenous and intradermal inoculation routes were found to elicit stronger and more sustained neutralizing immune responses than intramuscular or intraperitoneal injection. After being inoculated twice, mice were found to resist challenge with 100,000 times the 50% lethal dose (LD(50)) of JEV (Beijing-1 strain) even when immunized with a relatively small dose of 0.5 micro g of plasmid DNA. Protective passive immunity was also observed in SCID mice following transfer of splenocytes or serum from plasmid DNA- and colloidal gold-immunized BALB/c mice. The SCID mice resisted challenge with 100 times the LD(50) of JEV. Analysis of histological sections detected expression of proteins encoded by plasmid DNA in the tissues of intravenously, intradermally, and intramuscularly inoculated mice 3 days after inoculation. DNA immunization with colloidal gold elicited encoded protein expression in splenocytes and might enhance immune responses in intravenously inoculated mice. This approach could be exploited to develop a novel DNA vaccine.     

Schistosoma mansoni and alpha-galactosylceramide: prophylactic effect of Th1 Immune suppression in a mouse model of Graves' hyperthyroidism

Graves' hyperthyroidism, an organ-specific autoimmune disease mediated by stimulatory thyrotropin receptor (TSHR) autoantibodies, has been considered a Th2-dominant disease. However, recent data with mouse Graves' models are conflicting. For example, we recently demonstrated that injection of BALB/c mice with adenovirus coding the TSHR induced Graves' hyperthyroidism characterized by mixed Th1 and Th2 immune responses against the TSHR, and that transient coexpression of the Th2 cytokine IL-4 by adenovirus skewed Ag-specific immune response toward Th2 and suppressed disease induction. To gain further insight into the relationship between immune polarization and Graves' disease, we evaluated the effect of Th2 immune polarization by helminth Schistosoma mansoni infection and alpha-galactosylceramide (alpha-GalCer), both known to bias the systemic immune response to Th2, on Graves' disease. S. mansoni infection first induced mixed Th1 and Th2 immune responses to soluble worm Ags, followed by a Th2 response to soluble egg Ags. Prior infection with S. mansoni suppressed the Th1-type anti-TSHR immune response, as demonstrated by impaired Ag-specific IFN-gamma secretion of splenocytes and decreased titers of IgG2a subclass anti-TSHR Abs, and also prevented disease development. Similarly, alpha-GalCer suppressed Ag-specific splenocyte secretion of IFN-gamma and prevented disease induction. However, once the anti-TSHR immune response was fully induced, S. mansoni or alpha-GalCer was ineffective in curing disease. These data support the Th1 theory in Graves' disease and indicate that suppression of the Th1-type immune response at the time of Ag priming may be crucial for inhibiting the pathogenic anti-TSHR immune response.     

T cell antiviral effector function is not dependent on CXCL10 following murine coronavirus infection

The chemokine CXCL10 is expressed within the CNS in response to intracerebral infection with mouse hepatitis virus (MHV). Blocking CXCL10 signaling results in increased mortality accompanied by reduced T cell infiltration and increased viral titers within the brain suggesting that CXCL10 functions in host defense by attracting T cells into the CNS. The present study was undertaken to extend our understanding of the functional role of CXCL10 in response to MHV infection given that CXCL10 signaling has been implicated in coordinating both effector T cell generation and trafficking. We show that MHV infection of CXCL10(+/+) or CXCL10(-/-) mice results in comparable levels of T cell activation and similar numbers of virus-specific CD4+ and CD8+ T cells. Subsequent analysis revealed no differences in T cell proliferation, IFN-gamma secretion by virus-specific T cells, or CD8+ T cell cytolytic activity. Analysis of chemokine receptor expression on CD4+ and CD8+ T cells obtained from MHV-immunized CXCL10(+/+) and CXCL10(-/-) mice revealed comparable levels of CXCR3 and CCR5, which are capable of responding to ligands CXCL10 and CCL5, respectively. Adoptive transfer of splenocytes acquired from MHV-immunized CXCL10(-/-) mice into MHV-infected RAG1(-/-) mice resulted in T cell infiltration into the CNS, reduced viral burden, and demyelination comparable to RAG1(-/-) recipients of immune CXCL10(+/+) splenocytes. Collectively, these data imply that CXCL10 functions primarily as a T cell chemoattractant and does not significantly influence T cell effector response following MHV infection.     

Effect of E-64, thiol protease inhibitor, on the secondary anti-SRBC response in vitro

E-64, L-trans-epoxysuccinyl- leucylamido (4-guanidino) butane, a specific inhibitor of thiol proteases originally isolated from the culture of a fungus, was examined in connection with the immune responses to the splenocytes of mice. In cultures of C3H/He mouse splenocytes, E-64 and its analogues showed mitogenic activity, and some of them enhanced the lymphocyte blast transformation induced by a suboptimal concentration of concanavalin A. E-64 caused a significant suppressive effect on the secondary anti-SRBC responses when 7- or 14-day-primed BDF1 mouse splenocytes were cultured with SRBC, while it induced no effect on cultured splenocytes either from mice treated with cyclophosphamide, from mice sensitized with dinitrophenyl-Ficoll. The results with E-64 and its close analogues revealed that their effects on the immune response roughly correlated with their inhibitory activity against thiol protease. These results suggest that a thiol protease might be involved in the process of secondary immune response in mouse splenocytes.     

The effect of aging on the induction of experimental autoimmune thyroiditis

The effect of age on the ability to elicit the various immune functions comprising experimental autoimmune thyroiditis in mice has been examined. Compared with young mice (2 to 3 mo), CBA/CaJ and A/J aged mice (20 to 30 mo) show a drastic reduction in their ability to develop circulating antibody after injection of mouse thyroglobulin (MTg) or mouse thyroid extract (MTE) in complete Freund's adjuvant (CFA). Delayed-type hypersensitivity responses were also depressed, as well as the ability of aged lymph node cells to proliferate in vitro to antigen and the ability of aged splenic T cells to function as helper cells for in vitro antibody production. However, after injection of these thyroid antigens in CFA, aged mice developed thyroid lesions either comparable to or only slightly less intense than those observed in young mice. The disparity between the levels of immune responses and thyroid lesions observed in aged mice can be explained by the greater susceptibility of aged thyroids to tissue damage, since transfer of identical numbers of Con A-activated MTE-primed young splenocytes to young and aged recipients results in a more severe thyroiditis in the aged recipients. Priming mice to MTE in CFA at 9 mo of age, at which time mice are responsive to MTE, did not enhance either T or B cell responsiveness to injection of MTE in CFA at 24 mo of age. Lymphocytes from MTE-injected aged mice also failed to transfer thyroiditis to young recipients after in vitro activation of the lymphocytes with Con A.     

Secondary immune response of mice immunized with a protein-cellulose complex

It has been previously established that an intravenous injection of a protein antigen solution into mice primed with the same antigen in the form of a protein-cellulose complex induces an intensive antibody production (up to 10,000 antibody-forming cells/10(6) splenocytes and up to 3 mg of antibodies/ml of serum). The present study has shown that secondary immune response can be considerably enhanced if large amounts of the antigen are administered intraperitoneally in a protein-cellulose complex during secondary immunization. In these experiments the mean number of antibody-forming cells was 50.000/10(6) splenocytes and the antibody serum level averaged 10 to 12 mg/ml. The effect persisted for a long time: as late as on day 80 the antibody concentration was 2 mg/ml of serum.     

Differential effects of nicotine and aging on splenocyte proliferation and the production of Th1- versus Th2-type cytokines

Nicotine has a multitude of biological actions in the central and peripheral nervous systems where nicotinic acetylcholine receptors are found. Nicotinic acetylcholine receptors have also been identified on immune cells, but the effects of nicotine on immune responses are not well characterized. These studies tested the hypotheses that nicotine has an effect on both T-lymphocyte proliferation and the production of cytokines by activated T cells, processes that are necessary for effective T-cell-mediated immune responses. In addition, the effects of nicotine on these immune responses in aging animals and the effects of nicotine exposure prior to immunostimulation were investigated. Murine splenocytes were exposed to nicotine and stimulated with concanavalin A (ConA). The highest concentration of nicotine (128 microg/ml) significantly depressed proliferation of T cells both when nicotine and ConA were added concurrently and when nicotine was added 3 hr prior to ConA. Nicotine, added concurrently with ConA at concentrations between 0. 25 and 64 microg/ml, significantly inhibited the production of IL-10 by splenocytes from young adult mice, whereas the inhibition of production of IL-10 by splenocytes from old mice was significantly inhibited, but the response was more variable, depending on the nicotine concentration. In contrast, the production of IFN-gamma by splenocytes from either young adult or old mice was not affected when nicotine (0.016-64 microg/ml) was added concurrently with ConA. Pre-exposure to 1 microg/ml of nicotine for 3 hr significantly enhanced the production of IFN-gamma by splenocytes from young adult mice, whereas pre-exposure to 0.016 microg/ml of nicotine tended to but did not significantly enhance IFN-gamma production. Nicotine is now being used as an over-the-counter drug by people who differ in age and general immunocompetence. Therefore, the effects of nicotine on immune responses, independent from the effects of the other chemicals found in tobacco, need to be investigated.     

The role of humoral and cellular mediators in enhanced mammary inflammatory reactions to staphylococcal infection in systemically immunized ewes

Prior systemic immunization with live Staphylococcus aureus vaccine enhances the early recruitment of neutrophils into nonlactating mammary glands infected with staphylococci. The study investigates the role of humoral and cellular mediators in this phenomenon. Intramammary infusion of bacteria suspended in immune sheep serum did not enhance the inflammatory response to infection in nonimmunized ewes despite the presence of complement in the infused serum. Infusion of complement activated by incubation with zymosan evoked a massive neutrophil influx into mammary secretions by 4 hr after infusion. Hemolytic complement activity was not detected in mammary secretions of immunized or nonimmunized ewes. These findings indicate that, despite the inflammatory effect of complement activation, humoral immune factors did not promote neutrophil migration into infected glands. Mammary glands of systemically immunized ewes stimulated 5 days previously with staphylococcal soluble antigens (SSA) supported larger neutrophil influxes during staphylococcal infection than contralateral glands stimulated with endotoxin 5 days prior to infection. Exudates of SSA-stimulated glands had significantly higher cell concentrations, prior to infection, than endotoxin-stimulated glands; however elevated cell concentrations in endotoxin-stimulated glands of nonimmune ewes did not support enhanced inflammatory responses. These findings suggest that qualitative but not quantitative characteristics of mammary leucocytes influence the inflammatory response to infection in systemically immunized ewes.     

The spider acylpolyamine Mygalin is a potent modulator of innate immune responses

Mygalin is an antibacterial molecule isolated from the hemocytes of the spider Acanthoscurria gomesiana. It was identified as bis-acylpolyamine spermidine. We evaluated the modulator effects of synthetic Mygalin in the innate immune response. We demonstrate that Mygalin induces IFN-γ synthesis by splenocytes increasing the nitrite secretion by splenocytes and macrophages. A specific inhibitor of iNOS abrogated Mygalin-induced nitrite production in macrophages independent of IFN-γ activation. In addition, Mygalin-activated macrophages produced TNF-α but not IL-1β, demonstrating that Mygalin does not act directly on the inflammasome. Furthermore, this compound did not affect spontaneous or Concanavalin A-induced proliferative responses by murine splenocytes and did not induce IL-5 or apoptosis of splenocytes or bone marrow-derived macrophages. These data provide evidence that Mygalin modulates the innate immune response by inducing IFN-γ and NO synthesis. The combined immune regulatory and antibacterial qualities of Mygalin should be explored as a strategy to enhance immune responses in infection.     

Effect of an autovaccine on the course of an experimental staphylococcal infection]

The effect of autovaccine on the state of cellular immunity in mice with staphylococcal infection was studied. The maximum decrease of staphylococcal dissemination in internal organs, espeically in the lungs, as well as an increase in the intensity of phagocytosis by peritoneal macrophages were observed after the administration of the vaccine by the method of inhalation. The intranasal administration of the vaccine also proved to be more effective than subcutaneous injection. The cumulation of immune response was more pronounced after the aerosol administration of autovaccine, especially in cases of pathological processes in the respiratory organs.     

A role for CD44 in the production of IFN-gamma and immunopathology during infection with Toxoplasma gondii

The interaction of activated CD44 with its ligand, low m.w. hyaluronan, is involved in inflammation, but no role has been identified for this interaction in the regulation of an immune response to infection. In these studies, infection of C57BL/6 mice with Toxoplasma gondii resulted in increased expression of CD44 on T cells, B cells, NK cells, and macrophages, and a small percentage of CD4(+) T cells express an activated form of CD44. Administration of anti-CD44 to infected mice prevented the development of a CD4(+) T cell-dependent, infection-induced inflammatory response in the small intestine characterized by the overproduction of IFN-gamma. The protective effect of anti-CD44 treatment was associated with reduced production of IFN-gamma, but not IL-12, in vivo and in vitro. Furthermore, the addition of low m.w. hyaluronan to cultures of splenocytes or purified CD4(+) T cells from infected mice resulted in the production of high levels of IFN-gamma, which was dependent on IL-12 and TCR stimulation. Together, these results identify a novel role for CD44 in the regulation of IFN-gamma production by CD4(+) T cells during infection and demonstrate a role for CD44 in the regulation of infection-induced immune pathology.     

Interferon in the modulation of the immune response in pyelonephritis caused by Staphylococci and Pseudomonas aeruginosa

In experiments on mice the influence of mouse serum interferon, type I, on immune response in pyelonephritis caused by staphylococci and P. aeruginosa has been studied. The immunomodulating action of interferon and its therapeutic effectiveness have been shown to depend on the etiology of the disease. When injected intraperitoneally in a dose of 1,000 ED, interferon produces a pronounced therapeutic effect in pyelonephritis caused by P. aeruginosa and no effect in pyelonephritis of staphylococcal etiology. Type I interferon introduced in the dose used in this investigation has no influence on the killer activity of spleen lymphocytes, enhances the activity of the complement and the production of antibodies, produces a leukopenic effect and, depending on the etiology of pyelonephritis, exerts influence on the activity of dehydrogenases, the number of EAC- and E-rosette-forming cells, the oxidation metabolism of neutrophils and their phagocytic activity.     

Influence of staphylococcal enterotoxin B (SEB) on the course of murine listeriosis

Abstract Confrontation of the immune system with bacterial superantigens leads to an initial activation of the immune system followed by a state of profound immunosuppression. To investigate the role of a superantigen in an acute infection with a facultatively intracellular bacterium, we have studied the effect of staphylococcal enterotoxin B on the course of murine listeriosis. Intraperitoneal injection of SEB led to a statistically significant growth restriction of Listeria monocytogenes in the organs of mice infected intravenously or intraperitoneally when treatment with SEB and infection with L. monocytogenes were given simultaneously or when the mice were treated two days before infection. No effect of SEB on murine listeriosis was found when SEB was given more than two days before infection or one or more days after infection. We conclude that initial immunostimulation by SEB which is indicated by a massive liberation of all interleukins measured (IL1α, IL6, TNFα, IL2, IFNγ, IL4) is responsible for the growth restriction of L. monocytogenes in the organs of treated mice. Apoptosis of Vβ8 positive T cells which was accompanied by a 30% reduction of these cells at day 7 after treatment seems to be totally compensated.     

Induction of protective immunity against Schistosoma mansoni by a nonliving vaccine. III. Correlation of resistance with induction of activated larvacidal macrophages

Mice protected against Schistosoma mansoni infection by intradermal (i.d.) immunization with nonliving larval or adult worm antigens plus bacterial adjuvant developed 24-hr skin test responsiveness to schistosome antigens with the histologic features of delayed hypersensitivity. Intraperitoneal antigen injection elicited a mononuclear cell-enriched exudative population containing macrophages activated for direct cytotoxicity against schistosomula and tumor cell targets. This was likely to be due to in vivo exposure to macrophage-activating lymphokines, since these cells were unresponsive to further lymphokine stimulation in vitro and splenocytes from immunized mice reacted to specific in vitro antigen challenge by production of lymphokines capable of conferring larvacidal activity upon control macrophages. In contrast, mice treated with schistosome antigens by i.v. injection, which were not protected against challenge infection, failed to develop delayed hypersensitivity or activated macrophages in response to specific antigen challenge in vivo, and the titers of macrophage-activating lymphokine produced by in vitro antigen-stimulated splenocytes from these mice were threefold to fourfold lower than those produced by cells from animals immunized by the i.d. route. Thus, sensitization for cell-mediated immune responses including lymphokine production and macrophage activation correlated with induction of resistance to S. mansoni in this model of vaccination.