Enhancement Of Cellular Immune Responses Research Articles

Hijacking Factor H for Complement Immune Evasion.

The complement system is an essential player in innate and adaptive immunity. It consists of three pathways (alternative, classical, and lectin) that initiate either spontaneously (alternative) or in response to danger (all pathways). Complement leads to numerous outcomes detrimental to invaders, including direct killing by formation of the pore-forming membrane attack complex, recruitment of immune cells to sites of invasion, facilitation of phagocytosis, and enhancement of cellular immune responses. Pathogens must overcome the complement system to survive in the host. A common strategy used by pathogens to evade complement is hijacking host complement regulators. Complement regulators prevent attack of host cells and include a collection of membrane-bound and fluid phase proteins. Factor H (FH), a fluid phase complement regulatory protein, controls the alternative pathway (AP) both in the fluid phase of the human body and on cell surfaces. In order to prevent complement activation and amplification on host cells and tissues, FH recognizes host cell-specific polyanionic markers in combination with complement C3 fragments. FH suppresses AP complement-mediated attack by accelerating decay of convertases and by helping to inactivate C3 fragments on host cells. Pathogens, most of which do not have polyanionic markers, are not recognized by FH. Numerous pathogens, including certain bacteria, viruses, protozoa, helminths, and fungi, can recruit FH to protect themselves against host-mediated complement attack, using either specific receptors and/or molecular mimicry to appear more like a host cell. This review will explore pathogen complement evasion mechanisms involving FH recruitment with an emphasis on: (a) characterizing the structural properties and expression patterns of pathogen FH binding proteins, as well as other strategies used by pathogens to capture FH; (b) classifying domains of FH important in pathogen interaction; and (c) discussing existing and potential treatment strategies that target FH interactions with pathogens. Overall, many pathogens use FH to avoid complement attack and appreciating the commonalities across these diverse microorganisms deepens the understanding of complement in microbiology.

Immune responses elicited by the recombinant Erp, HspR, LppX, MmaA4, and OmpA proteins from Mycobacterium tuberculosis in mice.

Immunogenic potency of the recombinant Erp, HspR, LppX, MmaA4, and OmpA proteins from Mycobacterium tuberculosis (MTB), formulated with Montanide ISA 720 VG adjuvant, was evaluated in BALB/c mice for the first time in this study. The five vaccine formulations, adjuvant, and BCG vaccine were subcutaneously injected into mice, and the sera were collected at days 0, 15, 30, 41, and 66. The humoral and cellular immune responses against vaccine formulations were determined by measuring serum IgG and serum interferon-gamma (IFN-γ) and interleukin-12 (IL-12) levels, respectively. All formulations significantly increased IgG levels post-vaccination. The highest increase in IFN-γ level was provided by MmaA4 formulation. The Erp, HspR, and LppX formulations were as effective as BCG in enhancement of IFN-γ level. The most efficient vaccine boosting the IL-12 level was HspR formulation, especially at day 66. Erp formulation also increased the IL-12 level more than BCG at days 15 and 30. The IL-12 level boosted by MmaA4 formulation was found to be similar to that by BCG. OmpA formulation was inefficient in enhancement of cellular immune responses. This study showed that MmaA4, HspR, and Erp proteins from MTB are successful in eliciting both humoral and cellular immune responses in mice.

A long-term subacute sclerosing panencephalitis survivor treated with intraventricular interferon-alpha for 13 years

Subacute sclerosing panencephalitis (SSPE) is a rare, progressive, and fatal central nervous system disorder resulting from persistent measles virus infection. Long-term data are scarce, with a maximum follow-up period of 10 years. Interferon-alpha (IFN-α) is a protein that exerts its antiviral activity via enhancement of cellular immune response and is reported to be an effective drug for the treatment of SSPE. However, there is currently no consensus regarding the optimal duration of IFN-α therapy. Here, we present a case report of a patient with SSPE treated with long-term intraventricular IFN-α therapy, which facilitated clinical improvement and neurological stabilization without causing serious adverse effects. To the best of our knowledge, this is one of the longest follow-up studies investigating a patient with SSPE receiving intraventricular INF-α treatment. Further studies are necessary to validate the benefits and safety of long-term intraventricular IFN-α treatment in patients with SSPE.

Acute metabolic response of Portunus trituberculatus to Vibrio alginolyticus infection

Vibrio alginolyticus is a common pathogen that causes vibrio disease in swimming crab, Portunus trituberculatus. An understanding of the metabolic response mechanism of swimming crab to V. alginolyticus is essential for further control of this disease. In the present study, we analyzed the metabolic responses of gill, hepatopancreas, and muscle of swimming crab to an acute V. alginolyticus infection using 1H NMR spectroscopy coupled with multivariate data analysis. Our results showed that V. alginolyticus infection induced significant metabolomic alterations in crab muscle and gill within 24h. These alterations showed tissue-specific in the infected swimming crabs. V. alginolyticus infection resulted in depression of gluconeogenesis from amino acids, improvement of energy accumulation, and enhancement of cellular immune response of muscle. These metabolic alterations were highlighted in the depletion of amino acids and inosine monophosphate as well as in the accumulation of ATP and betaine in muscle. Vibrio infection also caused energy disturbance in gill, which manifested in the depletion of glucose and in the accumulation of lactate and adenosine monophosphate. These findings provided details of acute metabolomic alterations of swimming crab after V. alginolyticus infection and demonstrated the potentiality of altered metabolites as biomarker in vibrio infection. Statement of relevanceProvide potential metabolite biomarkers for vibrio infection of crab.

Synergistic enhancement of cellular immune responses by the novel Toll receptor 7/8 agonist 3M-007 and interferon-γ: implications for therapy of cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is responsive at all stages to immunotherapy. We determined whether a novel agonist for Toll-like receptor (TLR) 7/8 (3M-007) combined with either interferon-γ (IFN-γ) or interleukin-15 (IL-15) would enhance patients’ immune responses in vitro. Our data demonstrate that IFN-γ or IL-15 in combination with 007 significantly increases patients’ natural killer (NK) cytolytic activity against CTCL tumor cell lines and synergistically induces dendritic cell cytokines, compared to 007 alone. Microarray studies of gene expression of patients’ peripheral blood mononuclear cells (PBMCs) primed with IFN-γ followed by stimulation with 007 identified significant up-regulation of the expression of IL-12 p35 (α-chain), IL-12 p40 (β-chain), and nine IFN-α genes. Importantly, the underlying mechanism of increased levels of IFN-α and IL-12 from combined treatment appears to involve IFN regulatory factor 8 (IRF-8). These results further support our hypothesis that combinations of biological modifiers activating different arms of the immune system may provide significant therapeutic benefits for patients with advanced CTCL.

Immune Responses to a Dicistronic Plasmid Expressing HBsAg of Hepatitis B Virus and Interferon-γ

DNA vaccines encoding a viral protein have been shown to induce antiviral immune responses and provide protection against subsequent viral challenge. The present article deals with the efficacy of a DNA vaccine greatly improved by the simultaneous expression of HBsAg and interferon-γ gene. We constructed a dual expression vector pHIN encoding the HBsAg of Hepatitis B virus and murine IFN-γ which are connected with Internal Ribosome Entry Site (IRES). Mice immunized with this dual expression DNA vaccine exhibited the enhancement of cellular immune response and increased the production of anti-HBV surface antibody, compared with the mice of single gene expression control. Taken together, these results demonstrate that the application of a cytokine gene in a DNA vaccine formulation as an adjuvant can improve its immunigenicity.

Enhancement of cellular immune response to a prostate cancer DNA vaccine by intradermal electroporation

Recently it has become clear that more potent methods for DNA vaccine delivery need to be developed to enhance the efficacy of DNA vaccines. In vivo electroporation has emerged as a potent method for DNA vaccine delivery. In a mouse model, we evaluated the CD8+ T lymphocyte response to a prostate cancer DNA vaccine encoding prostate-specific antigen (PSA) after intradermal electroporation. A significantly increased gene expression (100- to 1000-fold) and higher levels of PSA-specific T cells, compared to DNA delivery without electroporation, was demonstrated. Interestingly, investigation of a panel of different electroporation conditions showed that only some conditions that induce high levels of gene expression additionally induced cellular immunity. This suggests that electroporation parameters should be carefully optimized, not only to enhance transfection efficiency, but also to enhance the immune response to the vaccine. This study demonstrates the applicability of intradermal electroporation as a delivery method for genetic cancer vaccines and other DNA vaccines relying on antigen-specific T cell induction.

Molecular and immunological significance of chimpanzee major histocompatibility complex haplotypes for hepatitis C virus immune response and vaccination studies.

The chimpanzee is a critical animal model for studying cellular immune responses to infectious pathogens such as hepatitis B and C viruses, human immunodeficiency virus, and malaria. Several candidate vaccines and immunotherapies for these infections aim at the induction or enhancement of cellular immune responses against viral epitopes presented by common human major histocompatibility complex (MHC) alleles. To identify and characterize chimpanzee MHC class I molecules that are functionally related to human alleles, we sequenced 18 different Pan troglodytes (Patr) alleles of 14 chimpanzees, 2 of them previously unknown and 3 with only partially reported sequences. Comparative analysis of Patr binding pockets and binding assays with biotinylated peptides demonstrated a molecular homology between the binding grooves of individual Patr alleles and the common human alleles HLA-A1, -A2, -A3, and -B7. Using cytotoxic T cells isolated from the blood of hepatitis C virus (HCV)-infected chimpanzees, we then mapped the Patr restriction of these HCV peptides and demonstrated functional homology between the Patr-HLA orthologues in cytotoxicity and gamma interferon (IFN-gamma) release assays. Based on these results, 21 HCV epitopes were selected to characterize the chimpanzees' cellular immune response to HCV. In each case, IFN-gamma-producing T cells were detectable in the blood after but not prior to HCV infection and were specifically targeted against those HCV peptides predicted by Patr-HLA homology. This study demonstrates a close functional homology between individual Patr and HLA alleles and shows that HCV infection generates HCV peptides that are recognized by both chimpanzees and humans with Patr and HLA orthologues. These results are relevant for the design and evaluation of vaccines in chimpanzees that can now be selected according to the most frequent human MHC haplotypes.

In vivo engineering of a cellular immune response by co-administration of IL-12 expression vector with a DNA immunogen

Recent studies support the importance of investigating a DNA vaccination approach for the immunologic control of HIV-1. In this regard, it may be important to specifically engineer immune responses in order to improve on first generation vaccine attempts. Especially for HIV, induction of cell-mediated immunity may be an important feature for any candidate vaccine. In an attempt to engineer in vivo the enhancement of cellular immune response and to direct Ag-dependent immune response from Th2 to Th1 type, we investigated the role of codelivery of genes for IL-12 and granulocyte-macrophage-CSF along with DNA vaccine formulations for HIV-1 Ag. We found that codelivery of IL-12 expression cassettes with DNA vaccines for HIV-1 in mice resulted in splenomegaly as well as a shift in the specific immune responses induced. The codelivery of IL-12 genes resulted in the reduction of specific Ab response, while the coinjection of granulocyte-macrophage-CSF genes resulted in the enhancement of specific Ab response. In addition, we observed a significant Ag-specific stimulation of T cells with codelivery of both cytokines. Most importantly, we observed a dramatic increase in specific CTL response from the group coimmunized with the HIV-1 DNA vaccine and IL-12 genes. This work demonstrates the power of DNA delivery in vivo for both the production of a new generation of more effective and targeted vaccines or immunotherapies as well as an analytic tool for the molecular dissection of the mechanisms of immune function.

In vivo engineering of a cellular immune response by coadministration of IL-12 expression vector with a DNA immunogen.

Recent studies support the importance of investigating a DNA vaccination approach for the immunologic control of HIV-1. In this regard, it may be important to specifically engineer immune responses in order to improve on first generation vaccine attempts. Especially for HIV, induction of cell-mediated immunity may be an important feature for any candidate vaccine. In an attempt to engineer in vivo the enhancement of cellular immune response and to direct Ag-dependent immune response from Th2 to Th1 type, we investigated the role of codelivery of genes for IL-12 and granulocyte-macrophage-CSF along with DNA vaccine formulations for HIV-1 Ag. We found that codelivery of IL-12 expression cassettes with DNA vaccines for HIV-1 in mice resulted in splenomegaly as well as a shift in the specific immune responses induced. The codelivery of IL-12 genes resulted in the reduction of specific Ab response, while the coinjection of granulocyte-macrophage-CSF genes resulted in the enhancement of specific Ab response. In addition, we observed a significant Ag-specific stimulation of T cells with codelivery of both cytokines. Most importantly, we observed a dramatic increase in specific CTL response from the group coimmunized with the HIV-1 DNA vaccine and IL-12 genes. This work demonstrates the power of DNA delivery in vivo for both the production of a new generation of more effective and targeted vaccines or immunotherapies as well as an analytic tool for the molecular dissection of the mechanisms of immune function.

Widespread activation and consequences of interleukin-1 in the brain.

The results described herein indicate that elevation of IL-1 in rat brain, either by infusion of IL-1 into the brain or by stimulation of release of endogenous IL-1 in the brain by LPS, rapidly suppresses a variety of immune responses measured in peripheral lymphocytes. This effect can be blocked by infusion of alpha-MSH into brain, an attribute that was used to indicate that the effects of LPS infusion occurred by stimulation of endogenous IL-1 and not some other influence of LPS. That suppression of cellular immune responses indeed describes the consequences of elevating IL-1 in brain was shown by determining the time course of effects and thereby demonstrating that rebound enhancement of cellular immune responses did not occur after either IL-1 or LPS. Studies that examined the mechanisms by which brain IL-1 affects immune responses indicated that IL-1 influences peripheral lymphocytes by stimulation of CRF in the central nervous system and that CRF in turn causes suppression of cellular immune responses through activation of both the pituitary-adrenal axis and the autonomic nervous system. These findings have also been observed in another laboratory. Moreover, Brown et al. have shown that IL-1 in brain suppresses macrophage function in addition to the suppression of lymphocyte functions described herein. The physiologic significance of IL-1 actions in the brain on immune responses remains to be determined, but the demonstration that this cytokine influences immune processes by acting in brain opens for study another means by which brain and immune system interact.

Development of a new type of influenza subunit vaccine made by muramyldipeptide-liposome: enhancement of humoral and cellular immune responses

The muramyldipeptide (MDP), [6- O-(2-tetradecyl-hexa-decanoyl)-N-acetylmuramyl-l-isoglutamine] can be incorporated into liposomes with haemagglutinin and neuraminidase molecules of influenza virus. Electron microscopic examination revealed that haemagglutinin and neuraminidase subunits were attached to the inner and outer surfaces of lamellar structures of the liposomes, probably through their hydrophobic ends. The addition of cholesterol resulted in much more stable liposomes, which were similar in size and shape to native influenza virus particles. These liposomes enhanced the immunogenicity of haemagglutinin in mice, such that the levels of antibody induced were about 16-fold higher than those of subunit haemagglutinin vaccine alone. Results of proliferation tests with spleen cells from mice and guinea-pigs were consistent with the immunopotentiation of haemagglutinin by liposomes. In addition, the higher antibody levels produced in mice, immunized with the haemagglutinin and MDP-containing liposomes (MDP-virosomes), were maintained for at least 6 months. Enhancement of the cellular immune response, measured by delayed type hypersensitivity reactions, was also observed in the guinea-pigs immunized with MDP-virosome vaccine. Preliminary tests with splenocytes from mice immunized with different vaccines also indicated that the MDP-virosome vaccine induced cytotoxic T-cell activity in these mice. This study revealed that the formation of liposomes with muramyldipeptide enhanced the level and persistence of circulating antibody, and enhanced cellular immunity in guinea-pigs and mice.

Local immunotherapy of stomach and intestinal carcinoma by Propionibacterium granulosum.

The effect of cell suspension of Propionibacterium granulosum strain KP-45 injected intratumorally was estimated in patients with advanced malignant neoplastic disease of the upper and lower part of the digestive tract. These patients received no other anticancer treatment, and results of therapy with P. granulosum were compared with a control group of nontreated patients. In the course of immunotherapy, general clinical state, dynamics of tumor growth as judged by endoscopy and morphologic, biochemical and immunologic parameters of the peripheral blood, were evaluated. Treatment with KP-45 preparation usually resulted in partial regression of tumor growth, accompanied by improvement of the clinical state of these patients, as well as reappearance of normal values of blood picture and biochemical parameters. Enhancement of cellular immune response, evaluated by increased number of peripheral blood T lymphocytes and increased skin reactivity to PHA and PPD, was observed. No serious side effects or complications of local immunotherapy were noted. No patients who had immunotherapy suffered from bacterial infection; this was not the case in the control group.