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At least 973 records · Page 54Linked to original sources
PubMed2006

Neural-immune interactions: an integrative view of the bidirectional relationship between the brain and immune systems.

This review briefly summarizes a part of the relevant knowledge base of neuroimmunology, with particular emphasis on bidirectional neural-immune interactions. These complex systems interact at multiple levels. Both neuroendocrine (the primary hormonal pathway is hypothalamic-pituitary-adrenal axis) and neuronal (direct sympathetic innervation of the lymphoid organs) pathways are involved in the control of the humoral and cellular immune responses. Although, the recent evidence has been made on immunosuppressive effect of acetylcholine-secreting neurons of the parasympathetic nervous system. The immune system, in turn, influences the central nervous system primarily through cytokines. At the molecular level, neuro- and immune signal molecules (hormones, neurotransmitters, neuropeptides, cytokines) or their receptors are member of the same superfamily which enable the mutual neuroimmune communication. Most extensively studied are cytokine-neuropeptide/neurotransmitter interactions and the subcellular and molecular mechanisms of these interactions. At the system (neuroanatomical) level, advances in neural-immune communication have been made in the role of discrete brain areas related to emotionality. The immunoenhancement, including the antiviral and antitumor cytotoxic activity, related to the "brain reward system", limbic structures and neocortex, offers a new directions for therapy in immune disorders.

Animals↗
PubMed2006

Changes in immune gene expression and resistance to bacterial infection in lobster (Homarus gammarus) post-larval stage VI following acute or chronic exposure to immune stimulating compounds.

Real-time PCR was used to measure changes in transcript abundance of genes encoding important immune proteins, namely prophenoloxidase (proPO gene), beta-1,3-glucan binding protein (betaGBP gene) and a 12.2 kDa antimicrobial peptide (amp gene) in post-larval stage VI (PLVI) juveniles of the European lobster, Homarus gammarus. Gene expression was studied in both healthy PLVI and following single or repeat exposure to a range of compounds claimed to induce immune reactivity. A single acute (3-h) exposure to any of the tested stimulants did not produce a significant increase in expression of either the proPO or betaGBP genes, measured 6h after stimulation. However, there were a small sub-group of positive responders, identified mainly from betaGBP expression, within the experimental groups stimulated with either a beta-1,3-glucan or an alginate. There was also no significant increase in the expression of any of the three genes tested 24 h after repeated weekly (3-h) exposures to a either the beta-1,3-glucan or the alginate over the longer (36-day) period. The results do show that amp is expressed at an extremely high level compared to proPO or betaGBP in healthy animals and a significant correlation was found between the expression of proPO and both betaGBP and amp, irrespective of whether or not the larvae were stimulated. None of the immune stimulated compounds improved survival of PLVI challenged with the opportunistic pathogen, Listonella anguillarum, or the lobster pathogen, Aerococcus viridans var. homari. Thus, we found no evidence to support recent claims that immunity and disease resistance can be primed or promoted within a given population of crustaceans or that these animals exhibit functional immune memory to some soluble immune elicitors.

Animals↗
PubMed2006

Estrogen regulation of nitric oxide and inducible nitric oxide synthase (iNOS) in immune cells: implications for immunity, autoimmune diseases, and apoptosis.

Nitric oxide plays a central role in the physiology and pathology of diverse tissues including the immune system. It is clear that the levels of nitric oxide must be carefully regulated to maintain homeostasis. Appropriate levels of nitric oxide derived from iNOS assist in mounting an effective defense against invading microbes. Conversely, inability to generate nitric oxide results in serious, even fatal, susceptibility to infections. Further, dysregulation or overproduction of nitric oxide has been implicated in the pathogenesis of many disorders, including atherosclerosis, neurodegenerative diseases, inflammatory autoimmune diseases, and cancer. Therefore, depending upon the levels of nitric oxide generated, the potential exists for nitric oxide to behave like a "double-edged" biological sword. Taking these issues into consideration, it is thus pivotal to understand the regulation of nitric oxide. Nitric oxide is regulated by many endogenous factors including hormones such as estrogens. While the effects of estrogen on the generation of nitric oxide in non-immune tissues are relatively well documented, the effect of estrogen on iNOS/nitric oxide in immune cells is only now becoming apparent. Our laboratory has recently shown that estrogen treatment of mice markedly upregulates the levels of iNOS mRNA, iNOS protein, and nitric oxide in activated splenocytes. This upregulation of nitric oxide is in part mediated through interferon-gamma (IFN-gamma), a pro-inflammatory cytokine that is enhanced by estrogen. These findings are important considering that estrogens are not only involved in regulation of normal immune responses, but also are implicated in many autoimmune and inflammatory diseases. To date, there are no reviews on the effects of estrogen on immune tissue-derived nitric oxide and therefore this review will address this critical gap in the literature. Given the increasing importance of immune-tissue-derived iNOS in health and disease, studies on estrogen-induced regulation of iNOS may offer a better understanding of diseases and aid in devising new therapeutic interventions.

Animals↗
PubMed2004

Intranasal immunization with outer membrane protein P6 and cholera toxin induces specific sinus mucosal immunity and enhances sinus clearance of nontypeable Haemophilus influenzae.

Nontypeable Haemophilus influenzae (NTHi) is one of the leading pathogens in sinusitis. One of the outer membrane proteins of NTHi, P6, is a common antigen to all strains and is an attractive candidate for a subunit bacterial vaccine. In this study, we characterized normal sinus mucosa (SM) and investigated the potential of intranasal immunization with P6 and cholera toxin (CT) for induction of mucosal protective immunity against NTHi in the maxillary sinuses of rats. Intranasal immunization induced P6-specific sinus mucosal and systemic immunological responses, mainly of the IgA and IgG isotype. The protective effect of intranasal immunization was demonstrated by enhancement of sinus clearance of NTHi. The present study showed that unilateral intranasal immunization has a capacity to induce protective immunity against NTHi in the bilateral maxillary sinuses. Systemic administration of the vaccine did not affect sinus clearance of NTHi. These findings suggest that a nasal vaccine might be useful for preventing sinusitis.

Administration, Intranasal↗
PubMed2006

Poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) is a potent enhancer of mixed Th1/Th2 immune responses in mice immunized with influenza virus antigens.

We investigated the ability of a novel polyphosphazene polyelectrolyte, poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) to enhance antigen-specific immune responses. BALB/c mice were immunized once subcutaneously with either bovine serum albumin (BSA) or influenza virus X:31 antigen alone, or in combination with PCEP, or either of the adjuvants poly[di(sodium carboxylatophenoxy)phosphazene] (PCPP) and alum. Both PCEP and PCPP significantly enhanced serum antigen-specific total IgG, IgG1 and IgG2a antibody titers, and these responses were highest in PCEP-immunized mice. Alum induced only a modest enhancement of antibody responses. Reducing the dose of X:31 antigen by 25-fold had no effect on antibody responses in mice immunized with PCPP and PCEP, but resulted in reduced titers in those immunized with alum. Analysis of X:31 antigen-specific cytokines revealed that alum and PCPP were associated with a predominantly IL-4 response. In contrast, PCEP was associated with production of both IFNgamma and IL-4. We conclude that PCEP is a potent enhancer of antigen-specific Th1 and Th2 immune responses and is a promising adjuvant for vaccine applications.

Adjuvants, Immunologic↗
PubMed2004

Oral immunization induces local and distant mucosal immunity in swine.

Transmission of porcine reproductive and respiratory syndrome virus (PRRSV) in semen and reproductive disease in pregnant swine might be reduced by vaccines that induce mucosal immunity in the reproductive tract. Cholera toxin (CT), when delivered orally, is a potent mucosal adjuvant and immunogen in swine. To determine if oral immunization additionally elicits immunity at distant mucosal surfaces, we examined antibody responses to CT-B subunit in the reproductive tract and oral cavity. Orally administered CT induced distant mucosal immunity, as measured by antibodies to CT-B subunit in saliva and vaginal secretions. Presentation of PRRSV nucleocapsid as a genetic fusion with CT resulted in local mucosal antibody production, but no response was observed in vaginal secretions. The results demonstrate the feasibility of using orally administered CT for the induction of immunity to reproductive pathogens in swine. However, effective induction of PRRSV-specific immune responses in the reproductive tract requires a better understanding of the mechanisms of antigenicity and adjuvanticity at distant mucosal sites.

Administration, Oral↗
PubMed2003

The effectiveness and limitations of immune memory: understanding protective immune responses.

Immune memory is the foundation of the practise of vaccination. Research on the molecular and cellular events leading to generation and development of memory T and B lymphocytes explain why there are heightened secondary immune responses after an initial encounter with antigen. In this review, we discuss how clonal expansion, targeted tissue localisation, more efficient antigen recognition and more proficient effector functions contribute to the improved effectiveness of memory cells. Despite the enhanced efficacy of memory cells and the recall immune response, there are numerous experimental and empirical examples in which protection provided by vaccines are short-lived, particularly against pathogens that replicate and cause pathology at their site of entry. In the absence of active immune effector activities, the ability of memory cells to respond quickly enough to control this type of infection is limited. The protective efficacy of bovine herpes virus-1 vaccines in experimental and field challenge conditions are used to illustrate the concept that full protection from disease conferred by vaccination requires the presence of active immune effector mechanisms. Thus, regardless of the many successful technological advances in vaccine design and better understanding of mechanisms underlining induction of memory responses by vaccination, we should recognise that vaccine immunoprophylaxis has limitations. Expectations for vaccines should be realistic and linked to the understanding of host immune responses and knowledge regarding the pathogen and disease pathogenesis.

Animals↗
PubMed1998

Intranasal immunization with a plant virus expressing a peptide from HIV-1 gp41 stimulates better mucosal and systemic HIV-1-specific IgA and IgG than oral immunization.

Control of pandemic human immunodeficiency virus type 1 (HIV-1) infection ideally requires specific mucosal immunity to protect the genital regions through which transmission more often occurs. Thus a vaccine that stimulates a disseminated mucosal and systemic protective immune response would be extremely useful. Here we have investigated the ability of a chimeric plant virus, cowpea mosaic virus (CPMV), expressing a 22 amino acid peptide (residues 731-752) of the transmembrane gp41 protein of HIV-1 IIIB (CPMV-HIV/1), to stimulate HIV-1-specific and CPMV-specific mucosal and serum antibody following intranasal or oral immunization together with the widely used mucosal adjuvant, cholera toxin. CPMV-HIV/1 has been shown previously to stimulate HIV-1-specific serum antibody in mice by parenteral immunization. All mice immunized intranasally with two doses of 10 microg of CPMV-HIV/1 produced both HIV-1-specific IgA in faeces as well as higher levels of specific, predominantly IgG2a, serum antibody. Thus there was a predominantly T helper 1 cell response. All mice also responded strongly to CPMV epitopes. Oral immunization of the chimeric cowpea mosaic virus was less effective, even at doses of 500 microg or greater, and stimulated HIV-1-specific serum antibody in only a minority of mice, and no faecal HIV-1 specific IgA.

AIDS Vaccines↗
PubMed1984

Enhanced immune response in the urinary tract of the rat following vaginal immunization.

The immune response in the rat urinary tract was assessed by an enzyme-linked immunosorbent assay for immunoglobulins following vaginal immunization and subsequent intravesical challenge with live E. coli 06. Vaginally immunized rats showed a strong and rapid bladder immune response following intravesical challenge, in contrast to nonimmunized control rats. The immune response was localized to the urinary tract in that antibody to E. coli 06 was not detected in serum, saliva and vaginal washes from immunized rats.

Animals↗
PubMed1976

Immune cytolysis of human renal carcinoma mediated by xenogeneic immune ribonucleic acid.

With a microcytotoxicity assay it was shown that normal, non-immune human lymphocytes were converted to effector cells specifically cytotoxic to human renal carcinoma cells after incubation with xenogeneic immune ribonucleic acids. The ribonucleic acid was extracted from the lymphoid tissues of sheep that had been immunized with human renal carcinoma tissue. Lymphocytes incubated without ribonucleic acid from or with ribonucleic acid sheep immunized with Freund's adjuvant alone did not increase cytotoxicity. Immunotherapy with immune ribonucleic acid increased cytotoxic activity of lymphocytes from a patient with metastatic renal carcinoma. The microcytotoxicity assay may be a useful method to assessing the cellular immune response in patients receiving immunotherapy and seems to correlate with their clinical course.

Adenocarcinoma↗
PubMed2003

Immunization with a dicistronic plasmid expressing a truncated form of bovine herpesvirus-1 glycoprotein D and the amino-terminal subunit of glycoprotein B results in reduced gB-specific immune responses.

As an approach to create a divalent DNA vaccine, a truncated secreted version of bovine herpesvirus-1 (BHV-1) glycoprotein D (tgD) and the amino-terminal subunit of glycoprotein B (gBb) were expressed from a dicistronic plasmid, designated pSLIAtgD-IRES-gBb. Intradermal immunization of mice with pSLIAtgD-IRES-gBb or a mixture of plasmids encoding tgD (pSLIAtgD) and gBb (pSLIAgBb) by needle injection or gene gun elicited strong tgD-specific immune responses. However, a significant reduction in gBb-specific immune responses was observed upon immunization of mice with pSLIAtgD-IRES-gBb or a mixture of pSLIAtgD and pSLIAgBb in comparison to immunization with pSLIAgBb alone. This reduction in gBb-specific immune responses induced by pSLIAtgD-IRES-gBb was due to production of low amounts of gBb from pSLIAtgD-IRES-gBb, inefficient processing and transport of gBb, and possibly competition for antigen-presenting cells by tgD and gBb. These results indicate that, although divalent plasmids may be used to express different antigens, the efficacy of vaccination with such plasmids may be influenced by the plasmid design and the characteristics of the expressed antigens.

Animals↗
PubMedDate not supplied

Are state immunization programs effective? Implications for the children's immunization initiative.

Several states operate universal vaccine purchase (UVP) programs aimed at ensuring adequate immunization of children. Some of these programs have been in operation for many decades. Recently, there has been a great deal of interest in implementing a federal UVP program. It is not clear, however, that such programs can significantly increase immunization levels; many nonfinancial barriers to full immunization exist and would have to be addressed. This paper uses cross-sectional data at the state level to estimate the effect of state UVP programs on the immunization levels of preschool children. The results indicate that states with UVP programs do not have significantly higher immunization rates than do other states. Therefore, it is not likely that a federal UVP program would significantly affect immunization rates.

Child↗
PubMedDate not supplied

Elaboration of systemic immunity following inner ear immunization.

The development of systemic humoral and cellular immunity following antigen presentation in the inner ear was compared with that seen following middle ear and peritoneal inoculation routes. Antibody developing against keyhole limpet hemocyanin was measured by a sensitive enzyme-linked immunofiltration assay, and cell-mediated immunity was measured by in vitro lymphocyte blastogenesis. The inner ear and peritoneal routes of antigen presentation resulted in a parallel rise in antibody over a 3-week period. In contrast, the middle ear route resulted in a weak, transient antibody response by 2 weeks. The acquisition of cell-mediated immunity occurred earliest (day 14) in the group receiving antigen intraperitoneally. A significant but smaller proliferative response was also seen in the group receiving antigen via the inner ear route on days 14 and 21. In contrast, the middle ear route failed to result in cell-mediated immunity. These studies indicate that the inner ear is an effective route of antigen processing which results in the acquisition of systemic humoral and cellular immunity. The development of systemic immunity, in turn, has been found to be protective of the inner ear.

Animals↗
PubMed2000

Protection and humoral immune responses against Bordetella pertussis infection in mice immunized with acellular or cellular pertussis immunogens.

In the present study, protection against Bordetella pertussis infection and humoral immunological responses in mice has been assessed upon immunization with custom-made acellular pertussis vaccines (ACVs) and whole-cell pertussis vaccine (WCV). Mice were immunized, next intranasally infected with B. pertussis and during 14 days the number of bacteria in the trachea and lungs and the level of serum antibodies were determined. ACV contained five immunogens, filamentous hemagglutinin, pertactin, fimbriae serotypes 2 and 3, and chemically detoxified pertussis toxin (PMC-5), or three immunogens, filamentous hemagglutinin, pertactin, and genetically detoxified (BC-3) or chemically detoxified pertussis toxin (SKB-3). Immunization with a high or low dose of ACV or WCV resulted in significant protection against B. pertussis, with differences in the degree of protection between the vaccines. The lowest protection was found with a low dose of SKB-3 and WCV. The pattern of cytokine production by spleen cells of immunized, non-infected, mice indicated that T-helper 1 cells are activated by vaccination with WCV, and T-helper 1 and T-helper 2 cells are involved in the immune response upon vaccination with ACVs. Each vaccine stimulated the production of IgG, but not IgA, antibodies. In mice immunized with ACV, elimination of B. pertussis from trachea and lungs correlated significantly with the titre of IgG1, but not IgG2a, antibodies.

Animals↗
PubMed2003

Mucosal immunization with a replication-deficient adenovirus vector expressing murine cytomegalovirus glycoprotein B induces mucosal and systemic immunity.

The murine cytomegalovirus (MCMV) glycoprotein B (gB) gene was expressed in an adenovirus replication-deficient vector. This virus, designated Ad-gB, was used to immunize BALB/c and B6 mice by the intranasal (i.n.) route to induce an immune response. Following primary immunization, antibody was detected in serum of 100% of vaccinees, as well as the bronchoalveolar lavage, fecal suspensions and vaginal washings. The viral titer of lung and salivary gland of vaccinees 10 days after intranasal challenge with MCMV at 10(5) or 10(3)plaque forming units (PFU) were significantly reduced compared to controls. Re-exposure of vaccinees to Ad-gB 30 days after primary immunization induced a remarkable boost of serum and mucosal antibody responses and further reduction of MCMV titers in the lung and salivary glands. The ability to induce both a systemic and mucosal immune response to a specific gene product may be important in reducing horizontal transmission of CMV infections across mucosal surfaces and in altering host immunity to CMV.

Animals↗
PubMed1996

DNA immunization confers protective immunity on mice challenged intravaginally with herpes simplex virus type 2.

The immunogenicity and protective efficacy of a nucleic acid vaccine encoding the herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) gene under the control of the CMV immediate early gene promoter was examined. Mice immunized three times by intramuscular injection with the vaccine developed an HSV specific IgG but not IgA antibody response detectable in both serum and vaginal secretions. In addition, antigen-specific cellular immune responses were detected in splenic lymphocytes isolated from DNA immunized animals. Immunization reduced virus replication in the genital tract following a lethal intravaginal HSV-2 challenge. Furthermore, symptomatic genital HSV disease was reduced in immunized mice and the animals were completely protected from death. We conclude that a nucleic acid vaccine expressing HSV-1 gD induced both humoral and cell mediated immune responses in mice which proved highly protective against disease following virus challenge.

Animals↗
PubMed1997

Mucosal immunization with a DNA vaccine induces immune responses against HIV-1 at a mucosal site.

Mucosal immunity is the first defense system in protection against mucosal infection by sexually transmitted diseases and subsequent systemic dissemination of infection. Development of vaccines which can induce protective mucosal immunity would have great promise for preventing sexually transmitted diseases including AIDS. DNA vaccines have recently shown certain advantages over other types of vaccines in safety and elicitation of specific immune responses. We have hypothesized that direct delivery of a DNA plasmid coding the HIV-1 envelope (pcMN160) via mucosal routes will stimulate mucosal immunity against HIV-1. The expression of DNA plasmid inoculated intravaginally was detected in various tissues. Intravaginal inoculation of pcMN160 elicits production of vaginal immunoglobulins which specifically bind to the HIV-1 envelope and neutralize HIV-1 infectivity in vitro. These results indicate the feasibility of inducing mucosal immunity following mucosal inoculation of DNA vaccines. When coupled with systemic inoculation of appropriate DNA constructs, effective mucosal and systemic immunity may be generated.

AIDS Vaccines↗
PubMed1999

Characterization of the humoral and cellular immune responses against hepatitis C virus core induced by DNA-based immunization.

Hepatitis C Virus (HCV) causes most cases of posttransfusion hepatitis. Chronic HCV infection is highly related to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Current therapies are only minimally effective and no vaccine has been developed. DNA-based immunization could be of prophylactic and therapeutic value for HCV infection. By intramuscular inoculation in BALB/c mice with an HCV recombinant plasmid pCI-HCV-C, we found significant levels of IgM antibody, but no significant IgG rise. After boost the immunized mice with recombinant HCV-core protein (cp1-10; 1-164aa), the anticore IgG, verified by Western-blotting, rose rapidly, which was two weeks earlier than that with control plasmid. Spleen cells from pCI-HCV-C immunized mice gave higher proliferation index (PI) than control (P < 0.05). The PI of cp1-10 boosted mice was even higher. Proliferation blocking assay with mAb proved the responding cell to be of CD4+ CD8- phenotype, supporting specific priming of T helper cells. A 51Cr-releasing CTL assay specific for HCV-core was developed, and a specific CTL response against HCV-core was demonstrated in both pCI-HCV-C immunized mice and mice boosted with cp1-10. Strong cytotoxic activity against peptide-pulsed p815 cells (H-2d), but not EL-4 cells (H-2b), suggested MHC class I restriction of the CTL activity. Blocking of CTL with mAb proved the effector cells to be of CD4- CD8+. Three CTL epitopes in HCV-core protein were demonstrated. We failed to detect CTL when immunized only with core protein. The results suggested that vaccination with HCV-core derived DNA sequences could be an effective method to induce humoral and cellular immune responses to HCV.

Animals↗