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Protection against influenza virus infection by intranasal administration of C3d-fused hemagglutinin.

For the induction of mucosal immune responses by intranasal vaccination, cholera toxin B subunits (CTB) and Escherichia coli heat-labile toxin (LT) are often administered as mucosal adjuvants in order to enhance immune responses to mucosally co-administered bystander antigens. However, these toxin also are the causative agents of diarrhea. There is a demand for the establishment of an effective and safer adjuvant or vaccine that elicits mucosal immunity, but does not require the use of CTB or LT adjuvants. In order to induce protective mucosal immune responses in the nasal area against influenza virus infection, we have examined the recombinant protein composed of the complement component, C3d, which is fused to the secreted form of hemagglutinin (sHA-mC3d3) in the influenza-BALB/c mouse model. The fusion protein sHA-mC3d3, the secretory form of hemagglutinin, and the transmembrane form of HA (tmHA) from the influenza virus were intranasally administered to the mice with or without CTB containing a trace amount of holotoxin (CTB*) as an adjuvant. After intranasal administration of these proteins with CTB*, all mice produced nasal IgA and serum IgG antibodies (Abs) against the viral HA. In addition, viral infection was completely inhibited in these mice. In contrast, in the absence of the adjuvant, only sHA-mC3d3-induced locally secreted IgA and serum IgG Abs and provided complete protection against the influenza virus challenge. Thus, C3d fused to the influenza HA antigen is an effective and safe tool for mucosal vaccination.

Adjuvants, Immunologic↗

Intranasal administration of a synthetic peptide vaccine encapsulated in liposome together with an anti-CD40 antibody induces protective immunity against influenza A virus in mice.

Mucosal immunity is critical for protection from viral infections. We attempted to activate mucosal cytotoxic T lymphocytes (CTLs) specific for influenza A virus nucleoprotein (NP) which play an important role in protective immunity. It has been shown that dendritic cells (DCs) activated by signaling via CD40-CD40 ligand (CD40L) interaction are required for the differentiation of naive CD8(+) T cells into antigen-specific CTLs in a non-mucosal environment. We herein inoculated mice intranasally with an anti-CD40 monoclonal antibody (anti-CD40 mAb) and NP366-374 peptide, corresponding to a CTL epitope on NP, encapsulated in liposome (liposomal NP366-374) to induce protective CTL responses against influenza A virus. Intranasal but not subcutaneous immunization with liposomal NP366-374 effectively induced mucosal immunity to reduce virus replication in the lung, suggesting that anti-CD40 mAb also functioned as a mucosal adjuvant. Interestingly, neither MHC class I- nor class II-deficient mice immunized intranasally with these materials were resistant to the infection. Since anti-CD40 mAb was considered to help replace CD4(+) T cells, another help of CD4(+) T cells are presumably required for the induction of CTL activity in the lung. This approach may prove promising for developing vaccines to induce mucosal CTL responses, and seems to highlight differences between mucosal and non-mucosal immunity.

Adjuvants, Immunologic↗

Mucosal adjuvants and anti-infection and anti-immunopathology vaccines based on cholera toxin, cholera toxin B subunit and CpG DNA.

The mucosal immune system consists of an integrated network of lymphoid cells that work in concert with innate host factors to promote host defence. Mucosal immunization can be used both to protect the mucosal surfaces against colonization and invasion by microbial pathogens and to provide a means for immunological treatment of selected autoimmune, allergic or infectious-immunopathological disorders through the induction of antigen-specific tolerance. The development of mucosal vaccines, whether for prevention of infectious diseases or for oral tolerance immunotherapy, requires efficient antigen delivery and adjuvant systems. Significant progress has recently been made to generate partly or wholly detoxified derivatives of cholera toxin (including the completely nontoxic cholera toxin B subunit) and the closely related Escherichia coli heat-labile enterotoxin, with retained adjuvant activity. Cholera toxin B subunit is a protective component of a widely registered oral vaccine against cholera, and has proven to be a promising vector for either giving rise to anti-infective immunity or for inducing peripheral anti-inflammatory tolerance to chemically or genetically linked foreign antigens administered mucosally. Promising advances have also recently been made in the design of efficient mucosal adjuvants based on bacterial DNA that contains CpG-motifs and various imidazoquinoline compounds binding to different Toll-like receptors on mucosal antigen-presenting cells.

Adjuvants, Immunologic↗

Oral route as method for immunizing against mucosal pathogens.

In the past three decades significant strides have been made in attempts at nonparenteral immunization. Appreciation of the importance of secretory immunity led to attempts to stimulate antibody production locally. The vaccines developed against respiratory pathogens as a result of this new knowledge have many practical limitations, such as the need for highly trained personnel, expensive equipment, very cooperative recipients for intranasal or aerosol administration, and a vaccine that is both adequately attenuated, immunogenic, and stable during storage. With recognition of the presence of a common mucosal defense system, new approaches to vaccine development have become possible. Oral immunization, by stimulating GALT, presents a promising approach for protecting many secretory surfaces against a variety of infectious agents. Recently, emphasis has been placed on developing an oral vaccine against S. mutans. McGhee et al. have demonstrated antibody to S. mutans in saliva and tears following oral ingestion of that antigen, without a rise in serum antibody, in both humans and rats. The rats were afforded protection from caries after rechallenge with both the original and cross-reacting serotypes of S. mutans. Similar results have recently been seen with viral antigens. Mice have been shown to have significant protection against influenza infection following oral immunization. And in a pilot study with human volunteers, the secretory antibody response in nasal washes was similar following either oral or parenteral vaccination. Oral immunization may prove to be far superior to parenteral vaccination against a variety of pathogens, because of fewer side effects and greater ease in vaccine preparation and administration.

Administration, Oral↗

Genital CD8+ T cell response to HIV-1 gag in mice immunized by mucosal routes with a recombinant simian adenovirus.

AdC6gag37, an E1-deleted adenovirus recombinant derived from the chimpanzee adenovirus serotype 6 expressing a codon-optimized truncated form of gag of HIV-1, was tested for induction of transgene-specific CD8+ T cell responses upon intranasal or intravaginal immunization of mice. Administration of AdC6gag37 induced gag-specific CD8+ T cells at systemic and mucosal sites. Frequencies of gag-specific CD8+ T cells elicited in the genital tract by intravaginal or intranasal immunizations were substantially increased by intranasal priming followed by intravaginal boosting with the same vector. Additionally, intravaginal immunization with AdC6gag37 increased the amount of gammadelta T cells that could be detected in genital tract.

AIDS Vaccines↗

Salivary lysozyme: a noninvasive marker for the study of the effects of stress of natural immunity.

Salivary lysozyme levels were measured to determine the effect of stress on innate mucosal immunity. In the first study perceived stress levels of 39 participants were using a stress/arousal checklist questionnaire. Salivary lysozyme levels were found to show a negative correlation (r = -.477, p < .01) with the perceived stress level. In a second study, salivary lysozyme concentrations were measured during periods of high and low stress in the form of an actual stressor--final year examinations. The concentration of lysozyme was found to be significantly (p < .05) lower in the sample taken before the examination when the students were awaiting entry into the examination hall compared to the levels after completion of all examinations. These results indicate that salivary lysozyme concentrations are sensitive to psychological stress and could be utilized as a potential marker in studies looking at the effects of stress on immunity. Because the usefulness of sIgA as a marker has been questioned, the use of salivary lysozyme as a noninvasive index of mucosal immunity warrants further investigation.

Journal Article↗

[Progress on lactococcus lactis expressing heterologous antigens as live mucosal vaccines].

Lactic acid bacteria (LAB) are natural commensals of the gastro-intestinal tracts of humans and most animals. They are considered to be safe bacteria with a GRAS (generally regarded as safe) status. The studies on LAB as live vehicles for expression of heterologous proteins or antigens have gained great progress in the past decades. Lactococcus lactis, an important species of LAB, possesses many properties that make it an ideal candidate for expressing and delivering heterologous proteins. With the significant advances in the genetic study of LAB, a series of constitutive or inducible gene expression systems as well as protein targeting systems had developed in Lactococcus lactis. Several antigens of pathogenic microorganisms, such as C subunit of tetanus toxin (TTFC) and the Brucella abortus ribosomal protein L7/L12, were successfully expressed in Lactococcus lactis. And it was showed that the recombinant Lactococcus lactis were able to induce specific mucosal immune response. It will be a great challenge how to make the recombinant Lactococcus lactis present heterologous proteins to the mucosal immune system in an effective way and induce specific immune response. One of the important directions for the further scientific development in this field is exploring protein targeting system to express heterologous antigens in precise locations of Lactococcus lactis. Expressing the antigen and cytokine simultaneously in Lactococcus lactis is an attractive direction as well. Using recombinant Lactococcus lactis that present antigens as live mucosal vaccines provides an effective way to prevent microorganisms invading and shows a promising future.

Animals↗

Self perceived work related stress and the relation with salivary IgA and lysozyme among emergency department nurses.

AIMS: To assess and compare the self perceived work related stress among emergency department (ED) and general ward (GW) nurses, and to investigate its relation with salivary IgA and lysozyme. METHODS: One hundred and thirty two of 208 (63.5%) registered female ED and GW nurses participated in the study. A modified mental health professional stress scale (PSS) was used to measure self perceived stress. ELISA methods were used to determine the salivary IgA and lysozyme levels. RESULTS: On PSS, ED nurses had higher scores (mean 1.51) than GW nurses (1.30). The scores of PSS subscales such as organisational structure and processes (OS), lack of resources (RES), and conflict with other professionals (COF) were higher in ED than in GW nurses. ED nurses had lower secretion rates of IgA (geometric mean (GM) 49.1 micro g/min) and lysozyme (GM 20.0 micro g/min) than GW nurses (68.2 micro g/min, 30.5 micro g/min). Significant correlations were observed between PSS and log IgA and lysozyme secretion rates. OS, RES, and COF were correlated with log IgA and lysozyme levels. CONCLUSION: ED nurses, who reported a higher level of professional stress, showed significantly lower secretion rates of salivary IgA and lysozyme compared to GW nurses. Salivary IgA and lysozyme were inversely correlated with self perceived work related stress. As these salivary biomarkers are reflective of the mucosal immunity, results support the inverse relation between stress and mucosal immunity.

Adult↗

Morphologic characterization of conjunctiva-associated lymphoid tissue in chickens.

Conjunctiva-associated lymphoid tissue (CALT) in the eyelids of chickens was studied by gross, histologic, and electron microscopic techniques. Structural features were characterized at 1 day of age and at posthatching week (PHW) 1, 2, 3, 4, 6, 8, 12, and 16. Beginning at PHW 1, prominent lymphoid nodules containing a heterogenous population of lymphocytes, lymphoblasts, and macrophages were first observed within conjunctival folds and fissures of the lower eyelid. Nodules contained germinal centers by PHW 2 and plasma cells by PHW 4. The epithelium associated with these nodules was flat, had short, irregular microvilli, contained intraepithelial lymphocytes, and lacked goblet cells. High endothelial venules were located at the base of lymphoid nodules and contained lymphocytes within and below the cuboidal endothelium. In the upper eyelid, CALT was morphologically similar to lymphoid tissue in the lower eyelid, but nodules were smaller and more random, lacked association with epithelial folds and fissures, and were clustered around the opening of the nasolacrimal duct. By PHW 12, CALT was characterized by basal germinal centers outlined by collagenous stroma, suprafollicular plasma cells, columnar epithelium with goblet cells, and fewer intraepithelial lymphocytes. On the basis of these features, CALT in chickens has morphologic characteristics similar to other components of the mucosal immune system and, therefore, may have a role in mucosal immunity.

Animals↗

Heterotypic protection of mice against chlamydial salpingitis and colonization of the lower genital tract with a human serovar F isolate of Chlamydia trachomatis by prior immunization with recombinant serovar L1 major outer-membrane protein.

Intrauterine infection of mice with a human genital tract isolate of Chlamydia trachomatis (serovar F) resulted in salpingitis. In some cases, oviduct damage was sufficient to cause infertility due to lumenal blockage. Parenteral immunization with a purified, heterologous, recombinant major outer-membrane (rMOMP) preparation reduced the proportion of animals developing severe salpingitis by 77% compared with mock-immunized controls, but failed to reduce chlamydial colonization of the lower genital tract. In contrast, mice immunized with rMOMP directly into the Peyer's patches to stimulate mucosal immunity shed fewer chlamydiae from the vagina than controls, but showed little reduction in oviduct damage. No consistent correlation was observed between antibody levels to rMOMP in immunized mice and reduced lower genital tract colonization. Immunization with rMOMP via the presacral space, a route previously shown to stimulate mucosal immunity in the genital tract, produced high levels of circulating anti-rMOMP IgG but only traces of anti-rMOMP IgA in vaginal secretions. There was no difference in the severity of salpingitis in these animals compared with mock-immunized controls. Immunization with rMOMP conferred no protection against infertility resulting from direct inoculation of chlamydiae into the oviducts.

Animals↗

Immunization with DNA, adenovirus or both in biodegradable alginate microspheres: effect of route of inoculation on immune response.

To determine the potential for biodegradable alginate microspheres to be used as a delivery vehicle for DNA based vaccines, we constructed a plasmid, pMNe-gal-SV40, containing the bacterial beta-galactosidase (LacZ) gene under the control of the murine cytomegalovirus (MCMV) immediate-early promoter and the simian virus 40 (SV40) polyadenylation signal. The effect of the route of administration and co-administration of adenovirus on systemic and mucosal immune responses were investigated. Mice were inoculated orally, intranasally (i.n.), intramuscularly (i.m.), subcutaneously (s.c.) or intraperitoneally (i.p.) on days 0, 14 and 28 with microspheres containing plasmid DNA, bovine adenovirus type 3 (BAd3) or plasmid DNA + BAd3. Systemic routes of immunization (i.m., s.c. and i.p.) resulted in higher LacZ- or BAd3-specific IgG ELISA titers compared to those obtained by mucosal routes of inoculation (oral and i.n.). Mucosal immunization led to slightly higher titers of LacZ- or BAd3-specific IgA at mucosal sites compared to those obtained by the various systemic routes. All the routes of immunization induced LacZ-specific lymphoproliferation. Co-administration of BAd3 enhanced the LacZ-specific IgG response irrespective of the route of administration.

3T3 Cells↗

Immunologic studies of specific mucosal and systemic immune responses in Mexican school children after booster aerosol or subcutaneous immunization with measles vaccine.

The purpose of the present study was to compare serum and mucosal immune responses following either aerosol (Aer) or subcutaneous (SQ) measles immunization of Mexican school children. A cohort of 49 children from 6 to 7 years of age received either Aer ( n = 22) or SQ ( n = 27) Edmonston-Zagreb (EZ) measles vaccine. Serum and nasal secretions were collected prior to (Pre), 1 and 3 months (mos) intervals and analyzed for immunoglobulin (Ig) concentrations and measles specific Ig isotype-associated antibody by enzyme immunoassay (EIA). Serum and nasal IgG and IgA antibody responses were stimulated following immunization with live, attenuated EZ measles vaccine administered either by SQ or Aer routes but these responses were significantly greater by the Aer compared to the SQ route. These studies also suggest that the level of antibody in these secretions may serve as an important marker of immunity to measles and lend further support for aerosol immunization as an effective alternative vaccine delivery strategy for measles eradication.

Administration, Intranasal↗

[Intranasal application of inactivated influenza virus vaccines].

Recent concept on the common mucosal immune system gives new direction of influenza vaccine development-mucosal vaccine. Vaccines have to be administered over the mucosal surface (in case of influenza vaccine, intranasal route may be the most suited route) to assure mucosal immunity which is the first hand armament against influenza virus. This article reviews our work on intranasal administration of inactivated influenza virus HA vaccines. Since influenza vaccines are usually given to people who has some degree of immunity due to past infection or immunization, vaccines which have booster effect are preferable. In this context, intranasally administered inactivated influenza HA vaccine was more immunogenic than cold adapted reassortant live influenza virus vaccine, another candidate mucosal influenza virus vaccine, which is now under investigation in the United States.

Administration, Intranasal↗

Mucosal defence along the gastrointestinal tract of cats and dogs.

Diseases that are associated with infections or allergic reactions in the gastrointestinal and respiratory tracts are major causes of morbidity in both cats and dogs. Future strategies for the control of these conditions require a greater understanding of the cellular and molecular mechanisms involved in the induction and regulation of responses at the mucosal surfaces. Historically, the majority of the fundamental studies have been carried out in rodents or with tissues obtained from man, but the expanding range of reagents available for the study of farm and companion animals provides opportunities for study in a wider range of animals including cats and dogs. To date, these studies have tended to be focussed on characterising the cellular distributions in healthy animals and in groups of cats and dogs identified as having an increased risk of mucosal disturbance. Where species comparisons of mucosal immune systems have been made, the results have tended to be divided between monogastric and ruminant animals. It is then not surprising that the mucosal immune systems of both cats and dogs bear greatest similarity to that documented for man and pigs. For example, IgA is the dominant immunoglobulin in mucosal secretions of cats and dogs and oral tolerance can be induced following the introduction of novel antigens into the diet. Also like several other species, cats become transiently hypersensitive to the newly introduced dietary antigen prior to the establishment of tolerance. In contrast, there are a number of potentially important differences. In particular, there are significant differences between cats and dogs in the expression MHC class II molecules on gut epithelial cells. Similarly, it has been reported that cats have elevated numbers of intraepithelial lymphocytes (IEL) and that a proportion of these express surface IgM. It remains to be determined if these differences reflect the way in which the animals are maintained and if they may have greater biological significance.

Animals↗

Induction of intestinal IgA and IgG antibodies preventing adhesion of verotoxin-producing Escherichia coli to Caco-2 cells by oral immunization with liposomes.

AIMS: To examine the efficacy of liposome oral administration to induce systemic and mucosal immune responses against verotoxin-producing Escherichia coli (VTEC) and the effect of the induced antibodies on the binding of the bacteria to Caco-2 cells. METHODS AND RESULTS: Mice were immunized orally with VTEC antigen and monophosphoryl lipid A (MPL)-containing liposomes composed of dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylserine and cholesterol (1 : 1 : 2, molar ratio) (PS-liposome). After immunization, significant IgA and IgG responses to VTEC were induced in both serum and the intestinal lavage fluid in all mice tested. Furthermore, anti-VTEC IgA and IgG antibodies in the lavage fluid effectively inhibited the adhesion of VTEC to Caco-2 cells. CONCLUSIONS: Oral immunization with liposome-associated E. coli O157:H7 antigen can induce significant systemic and mucosal antibody responses against the bacterial antigen and antibodies produced in the intestinal tract, thus functioning as inhibitors for preventing VTEC infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Oral PS-liposome vaccines containing MPL have the potential usefulness for the induction of a protective mucosal immune response against intestinal diseases.

Administration, Oral↗

Oral immunization with chlamydial major outer membrane protein (MOMP).

The effect of vaccination to stimulate mucosal immunity with a purified subunit vaccine of chlamydial major outer membrane protein (MOMP) on subsequent ocular challenge with Chlamydia trachomatis was studied in cynomolgus monkeys. Monkeys were immunized with MOMP by intraperitoneal priming plus oral boosting, with or without ocular boosting, or by ocular immunization alone. Cholera toxin was used as an adjuvant with the oral doses of MOMP vaccine. Animals were challenged with viable purified elementary bodies 35 days after the first immunization. The immunizing schedules used provided a transient decrease in the potentially deleterious inflammatory response in the eye but no reduction in duration of infection. Immunoblotting studies showed that anti-MOMP antibodies were induced by oral vaccination in some animals, but the antibody response following ocular challenge as determined by microimmunofluorescence (MicroIF) serology was similar in vaccinated and nonvaccinated animals. This study demonstrates that the stimulation of mucosal immunity by a vaccine of purified chlamydial MOMP was only partially effective in protecting against chlamydial eye infection. The lack of clear protection in these studies may be due to the failure of the various immunizing regimes to induce an antibody response prior to challenge.

Administration, Oral↗

Genetically detoxified mutants of heat-labile enterotoxin from Escherichia coli are effective adjuvants for induction of cytotoxic T-cell responses against HIV-1 gag-p55.

There is an urgent need for prophylactic and therapeutic vaccines against human immunodeficiency virus (HIV). Mucosal immunization strategies have great potential to elicit both mucosal and systemic cellular immunity required to protect against HIV-induced acquired immune deficiency syndrome (AIDS). However, mucosal immunizations with soluble protein antigens generally require adjuvants. In this study, we tested two mutants of the heat-labile enterotoxin (LT) from Escherichia coli, LTK63: with no measurable ADP-ribosyltransferase activity, and LTR72: with residual ADP-ribosyltransferase activity, as mucosal adjuvants for induction of cytotoxic T lymphocyte (CTL) responses to coadministered HIV gag p55 protein. We found that intranasal (i.n.) immunizations with HIV gag p55 protein coadministered with LTK63 or LTR72 induced systemic CTL responses comparable to that obtained following intramuscular (i. m.) immunizations with the same adjuvants. Moreover, oral coadministration of LTR72, but not LTK63, resulted in local as well as systemic p55-specific CTL responses in mesenteric lymph nodes (MLN) and spleens (SP) of the immunized mice. These data have important implications for current efforts to develop a safe vaccine against HIV.

AIDS Vaccines↗

Intranasal immunization confers protection against murine Pneumocystis carinii lung infection.

To evaluate the feasibility of mucosal immunization against Pneumocystis carinii (Pc) experimental infection, female BALB/c mice were intranasally immunized three times with soluble Pc antigens plus cholera toxin fraction B (Pc-CTB); control groups received either Pc antigen, CTB, or phosphate-buffered saline (PBS) alone. Two weeks after the last immunization, five animals from each group were sacrificed, and cellular and humoral immune responses were evaluated. The remaining five mice were CD4 depleted using a monoclonal antibody against mouse CD4 and inoculated with viable Pc. Significantly higher specific lymphoproliferative responses from tracheobronchial lymph node cells, immunoglobulin M (IgM) and IgG antibody levels in serum, and bronchoalveolar lavage (BAL)-derived IgA antibody concentrations were observed in the Pc-CTB group of mice relative to control groups (P < 0.01). Five weeks after challenge, no Pc organisms were observed in the lung smears of the Pc-CTB group, while the animals receiving antigen, adjuvant, or PBS had progressively higher numbers of Pc microorganisms. By Western blot analysis, a strongly reactive 55- to 60-kDa antigen was recognized by BAL IgA and by serum IgG. In summary, mucosal immunization elicited specific cellular and humoral immune responses and protected against Pc lung infection after immunosuppression.

Administration, Intranasal↗