Nasopharyngeal acute phase cytokines in viral upper respiratory infection: impact on acute otitis media in children

BACKGROUND

The role of acute phase cytokines generated in the nasopharynx during viral upper respiratory infection (URI) in subsequent development of acute otitis media (AOM) has not been examined.

METHODS

We studied 326 virus-positive URI episodes in 151 children aged 6-36 months. Nasopharyngeal secretions collected within 1 to 7 days of URI onset were studied for viruses by conventional and molecular techniques, and for concentrations of IL-1beta, IL-6, and TNFalpha by multiplex enzyme-linked immunosorbent assay. Children were followed up for 28 days to document AOM complication.

RESULTS

IL-1beta, IL-6, and TNFalpha concentrations correlated positively with each other (P<0.001). IL-6 and TNFalpha concentrations were higher in males than in females (P=0.01 and 0.02). IL-6 and TNFalpha concentrations were inversely correlated with age (P=0.02 and 0.05). IL-6 concentrations correlated positively with duration of fever (P=0.006) and correlated negatively with the number of days of URI symptoms (P=0.026). Furthermore, IL-6 concentrations were significantly higher during adenovirus and influenza virus URIs as compared with enterovirus and rhinovirus URIs (P<0.01). IL-1beta concentrations were higher during URI episodes with AOM than those without AOM (P<0.001).

CONCLUSIONS

We found IL-6 nasopharyngeal secretions concentrations to be higher with adenovirus and influenza infection, and in children with systemic febrile response during URI. However, IL-1beta was found to play a more important role in the development of AOM after URI. Additional studies are needed to further define the role of acute phase cytokines in virus-induced AOM.

Comparison of cytokine responses in nasopharyngeal aspirates from children with viral lower respiratory tract infections

Aim: To determine whether nasopharyngeal aspirates (NPAs) cytokine response is different according to the causative viruses in children with lower respiratory tract infections (LRTI).

Methods: NPAs from 277 children with LRTI caused by respiratory virus were evaluated. Based on the proven viral agents, LRTI patients were divided into four groups. Levels of IL‐4, IL‐5 and IFN‐γ were determined by ELISA.

Results: Patients with influenza virus infection demonstrated significantly lower IL‐4 and IL‐5 levels than those with other three groups. Patients with respiratory syncytial virus (RSV) infection showed an increase in production of IL‐4 and IL‐5, and a decrease in the IFN‐γ level when compared to patients with influenza virus infection. Interestingly, a similar Th2 response was seen in patients with parainfluenza virus or adenovirus infection.

Conclusion: These results demonstrate that respiratory viruses can induce different local cytokine responses. However, Th2 biased responses are not unique for RSV but seem to be predominant in respiratory viruses of young children.

[Association of INF-gamma/A+874T gene polymorphisms with respiratory syncytial virus bronchiolitis]

OBJECTIVE

A deficient interferon-gamma (IFN-gamma) response has been involved in the pathogenesis of severe respiratory syncytial virus (RSV) infection. Gene polymorphisms in IFN-gamma/A+874T have been associated with the susceptibility to asthma and might be related to disease severity of RSV infection. This study investigated the single nucleotide polymorphisms (SNPs) of IFN-gamma/A+874T in Han children in Wenzhou area and to explore the correlation between gene polymorphisms of IFN-gamma/A+874T and the susceptibility and disease severity of RSV bronchiolitis, as well as the effect of SNPs upon nasopharyngeal secretions (NPS) IFN-gamma and total serum IgE levels.

METHODS

One hundred and fourteen hospitalized children with RSV bronchiolitis and 90 healthy controls were recruited. Sequence analysis was used for detecting the SNPs of IFN-gamma/A+874T. NPS IFN-gamma levels were measured using ELISA. Total serum IgE levels were assayed using the chemiluminescence method.

RESULTS

IFN-gamma/A+874T gene polymorphisms were present in both the patient and the control groups. AA and AT genotypes were found in both groups, with a AA frequency of 82.5% vs 77.8% and a AT frequency of 17.5% vs 21.1% (p>0.05). The frequency of allele was 90.4% (A) and 9.6% (T) in the patient group, and 88.3% (A) and 11.7% (T) in the control group, respectively. There were no significant differences in the allele frequency between the two groups. Moreover, no difference was found both in NPS IFN-gamma and total serum IgE levels between AA and AT genotypes in the patient group. There were no significant differences in the variation of IFN-gamma/+874 between mild and moderate to severe cases.

CONCLUSIONS

IFN-gamma/A+874T gene polymorphisms were present in Han children in Wenzhou area. Gene variations were not associated with the susceptibility and disease severity of RSV bronchiolitis as well as IFN-gamma and total serum IgE levels.

A combination of Flt3 ligand cDNA and CpG ODN as nasal adjuvant elicits NALT dendritic cells for prolonged mucosal immunity

We explore cellular and molecular mechanisms of nasal adjuvant of a combination of a plasmid encoding the Flt3 ligand cDNA (pFL) and CpG oligodeoxynucleotides (CpG ODN). The double DNA adjuvant given with OVA maintained prolonged OVA-specific secretory IgA (S-IgA) Ab responses in external secretions for more than 25 weeks after the final immunization. Further, both Th1- and Th2-type cytokine responses were induced by this combined adjuvant regimen. The frequencies of plasmacytoid DCs (pDCs) and CD8(+) DCs were significantly increased in nasopharyngeal-associated lymphoreticular tissue (NALT) of mice given the combined adjuvant. Importantly, when we examined adjuvanticity of pFL plus CpG ODN in 2-year-old mice, significant levels of mucosal IgA Ab responses were also induced. These results demonstrate that nasal delivery of a combined DNA adjuvant offers an attractive possibility for the development of an effective mucosal vaccine for the elderly.

Predominance of Th2 cytokines, CXC chemokines and innate immunity mediators at the mucosal level during severe respiratory syncytial virus infection in children

Profiling of immune mediators in both nasal and plasma samples is a common approach to the study of pathogenesis in respiratory viral infections. Nevertheless, mucosal immunity functions essentially independently from peripheral immunity. In our study, 27 immune mediators were profiled in parallel, in nasopharyngeal aspirates (NPAs) and plasma from 22 < 2 year-old children with a severe respiratory syncytial virus infection involving the lower respiratory tract, using a multiplex assay. NPAs from 22 children with innocent heart murmurs were used as controls. Differences in mediator concentrations between NPAs from patients and controls were assessed using the Mann-Whitney test. Ratios of innate/adaptive-immunity mediators, Th2/Th1-cytokines and CXC/CC-chemokines were calculated for NPAs and plasmas and differences were assessed using the Wilcoxon test. Associations mediators, severity and leukocyte counts were studied using the Spearman-Karber test.

RESULTS

increased levels of Th1 cytokines (IL-1beta, IL-2, IL-12p70, IFNgamma, TNFalpha), Th2 cytokines (IL-13, IL-4, IL-6, IL-10), chemokines (IP-10, IL-8, MIP1alpha, MIP-1beta), growth factors (FGFb, PDGFbb, GCSF) and IL-1RA, IL-17 were observed in patient NPAs in comparison to controls. In the relative comparisons between patient NPAs and plasmas, a predominance of innate immunity mediators, Th2 cytokines and CXC chemokines was found at the mucosal level. No association between the level of each mediator in NPAs and plasma was found. In plasma, PDGFbb, VEGF, MIP-1alpha, IL-8 correlated with severity; RANTES and IL-6 correlated with leukocyte counts.

CONCLUSIONS

acute respiratory syncytial virus infection induces a relative predominance of innate-immunity mediators, Th2 cytokines and CXC chemokines in the mucosal compartment in infected children.

IL-10 and RANTES are elevated in nasopharyngeal secretions of children with respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) infection causes asthma-like symptoms in infants and young children. Although an increase in several mediators in the airway during RSV infection has been reported, the mechanisms involved in airway inflammation are not fully understood. The aim of this study was to investigate the immunological deviation associated with airway inflammation by measuring cytokine and chemokine levels in the airway during RSV infection.

METHODS

One hundred and ten children under 3 years of age with respiratory symptoms were enrolled in this study from November 2004 through January 2005. Nasopharyngeal secretions (NPAs) were gently aspirated and analyzed with RSV antigen, thereafter the concentrations of IL-4, IL-10, IFN-gamma, and RANTES were measured using an ELISA kit. We also investigated the prognosis of each child after 1 year by reference to clinical records or by interviews and re-evaluated the cytokine and chemokine levels.

RESULTS

Of the subjects, 70 children were RSV positive and 40 were negative. Only 4 children were given a diagnosis of asthma by the pediatrician when NPAs were collected. The levels of IL-4, IL-10, and RANTES were significantly higher in the RSV-positive patients than RSV-negative patients with P values at 0.0362, 0.0007, and 0.0047, respectively. In contrast, there was no significant difference in the levels of IFN-gamma. Furthermore, there was a significant positive correlation between IL-10 and RANTES.

CONCLUSIONS

The increased production of IL-4, IL-10, and RANTES in the airway may play an important role in the pathophysiological mechanisms of RSV infection.

[Uniqueness of the mucosal immune system for the development of prospective mucosal vaccine]

The mucosal immune system acts as the first line of defense against microbial infection through a dynamic immune network based on innate and acquired mucosal immunity. To prevent infectious diseases, it is pivotal to develop effective mucosal vaccines that can induce both mucosal and systemic immune responses, especially secretory IgA (S-IgA) and plasma IgG, against pathogens. Recent advances in medical and biomolecular engineering technology and progress in cellular and molecular immunology and infectious diseases have made it possible to develop versatile mucosal vaccine systems. In particular, mucosal vaccines have become more attractive due to recent development and adaptation of new types of drug delivery systems not only for the protection of antigens from the harsh conditions of the mucosal environment but also for effective antigen delivery to mucosa-associated lymphoid tissues such as Peyer's patches and nasopharynx-associated lymphoid tissue, the initiation site for the induction of the antigen-specific immune response. In this review, we shed light on the dynamics of the mucosal immune system and recent advances toward the development of prospective mucosal antigen delivery systems for vaccines.

[The implications of nasal associated lymphoid tissue in development of respiratory allergic diseases in children]

AIM

to asses the connection between the expression of costimulatory proteins associated with apoptosis of t lymphocytes of the adenoid in children with allergic rhinitis. To establish the usefulness of using the results of adenoid tissue immunohistochemical studies for prognosis in chronic respiratory allergic disease.

PATIENTS AND METHODS

prospective studies were carried out in 70 children with indications for adenectomy according to the European Pediatric ENT Association. These children had recurrent or chronic rhinitis. Two study groups were identified: Group I- 30 children with allergic rhinitis and group II- 40 children without specific IgE. Group II was subdivided according to family history of atopy: group IIa with positive family history and group IIb with negative family history. Children from group II were followed up for allergic symptoms during 36 months after adenectomy. Histopathologic and immunnohistochemical study of the adenoid tissue (from adectomy) was carried out. The expression of CD4, CD8, CD25, CD28, Cdl52 (CTLA4), Fas, FasL, bel-2 was investigated. The results were analysed statistically.

RESULTS

statistically significant differences between the studies group concerned the number of cells witch showed expression of CD28, CTLAL (CD152) and Fas-L (p<0.05). For CD25 expression statistically significant differences were evident between group I and IIb. No statistically evident differences were found in expression of Cd95 and bel-2 (p>0.05) - three years follow up of children after adenectomy and repeated investigations (every 6 months), allowed to identify specific IgE (for examined allergens) in 11 children from group IIa. These were not present before adenectomy. 3 year study results after adenectomy in children compared with immunnohistochemical investigations of adenoid tissue confirmed the correlation between CTLA4 and FasL expression in children with allergic rhinitis.

CONCLUSION

Intracellular expression of CTLA4 and FasL in T lymphocyts of the adenoid tissue may be a predictive factor in the development of respiratory allergy in children. Further studies are needed.

Eosinophil cationic protein and chemokines in nasopharyngeal secretions of infants with respiratory syncytial virus (RSV) bronchiolitis and non-RSV bronchiolitis

Bronchiolitis is a risk factor for the development of childhood asthma. Eosinophilic inflammation in airways plays an important role in the pathophysiology of both bronchiolitis and asthma. To investigate this inflammation, we measured the eosinophil cationic protein (ECP), regulated on activation normal T-cell expressed and secreted (RANTES) and eotaxin levels in nasopharyngeal secretions (NPS). Twenty-eight patients with RSV bronchiolitis (RSV group), 11 patients with non-RSV bronchiolitis (non-RSV group) and 7 controls were enrolled in this study. ECP, RANTES, and eotaxin levels were measured by enzyme immunoassays. The ECP level in the NPS of the RSV group was significantly higher than that in the NPS of the non-RSV group and controls. RANTES and eotaxin levels in infants with bronchiolitis were significantly higher than those in the controls, but there was no significant difference between the RSV and non-RSV groups. In conclusion, with regard to eosinophilic airway inflammation, as compared with non-RSV bronchiolitis, RSV bronchiolitis may be more similar to childhood asthma.

Increased susceptibility of human respiratory syncytial virus to neutralization by anti-fusion protein antibodies on adaptation to replication in cell culture

Subgroup A respiratory syncytial viruses present in respiratory secretions and low passage level cell culture isolates were found to be markedly less susceptible to neutralization with monoclonal antibodies (MAbs) to the F glycoprotein than the cell culture adapted A2 virus strain. Low passage virus isolates collected over a 20 year period and belonging to several sub-group A lineages were refractory to neutralization with antibodies recognizing two major neutralizing antigenic sites located sub-terminally at opposite ends of the F(1) glycoprotein sub-unit. On further passage in cell culture, virus isolates exhibited both increased infectivity titers and increased susceptibility to neutralization by antibodies to both antigenic sites. The consensus nucleotide sequence of the membrane associated proteins M and of the SH, G and F glycoprotein genes, and their intergenic regions were compared for neutralization resistant and susceptible stocks of one virus strain, R17532. No changes were observed in the known monoclonal antibody epitopes on the F glycoprotein. In line with this, the increase in susceptibility was not found to be associated with any increased binding of monoclonal antibody to isolated F glycoprotein in a BIAcore assay, thus excluding the possibility that passage in cell culture selected for viruses with mutations in the antibody binding sites. M and SH genes were conserved but a number of sites in the G and F glycoprotein genes were found to vary on adaptation to cell culture suggesting that change in susceptibility to neutralization was associated with a change in the prevalent quasispecies present in the virus population. The genetic basis of phenotypic change in susceptibility remains to be determined.

The blp bacteriocins of Streptococcus pneumoniae mediate intraspecies competition both in vitro and in vivo

The introduction of the conjugate seven-valent pneumococcal vaccine has led to the replacement of vaccine serotypes with nonvaccine serotypes of Streptococcus pneumoniae. This observation implies that intraspecies competition between pneumococci occurs during nasopharyngeal colonization, allowing one strain or set of strains to predominate over others. We investigated the contribution of the blp locus, encoding putative bacteriocins and cognate immunity peptides, to intraspecies competition. We sequenced the relevant regions of the blp locus of a type 6A strain able to inhibit the growth of the type 4 strain, TIGR4, in vitro. Using deletional analysis, we confirmed that inhibitory activity is regulated by the function of the response regulator, BlpR, and requires the two putative bacteriocin genes blpM and blpN. Comparison of the TIGR4 BlpM and -N amino acid sequences demonstrated that only five amino acid differences were sufficient to target the heterologous strain. Analysis of a number of clinical isolates suggested that the BlpMN bacteriocins divide into two families. A mutant in the blpMN operon created in the clinically relevant type 19A background was deficient in both bacteriocin activity and immunity. This strain was unable to compete with both its parent strain and a serotype 4 isolate during cocolonization in the mouse nasopharynx, suggesting that the locus is functional in vivo and confirming its role in promoting intraspecies competition.

Cutting edge: Uniqueness of lymphoid chemokine requirement for the initiation and maturation of nasopharynx-associated lymphoid tissue organogenesis

CD3(-)CD4(+)CD45(+) inducer cells are required for the initiation of mucosa-associated organogenesis of both nasopharynx-associated lymphoid tissues (NALT) and Peyer's patches (PP) in the aerodigestive tract. CXCL13(-/-) mice and mice carrying the paucity of lymph node T cell (plt) mutation and lacking expression of CCL19 and CCL21 accumulate CD3(-)CD4(+)CD45(+) cells at the site of NALT but not of PP genesis. Although NALT was observed to develop in adult CXCL13(-/-) and plt/plt mice, the formation of germinal centers in CXCL13(-/-) mice was affected, and their population of B cells was much lower than in the NALT of CXCL13(+/-) mice. Similarly, fewer T cells were observed in the NALT of plt/plt mice than in control mice. These findings indicate that the initiation of NALT organogenesis is independent of CXCL13, CCL19, and CCL21. However, the expression of these lymphoid chemokines is essential for the maturation of NALT microarchitecture.

Kinetics of mouse antibody and lymphocyte responses during intranasal vaccination with a lipooligosaccharide-based conjugate vaccine

We investigated the kinetics of humoral immunity and its related cellular immune responses to intranasal (IN) immunization with a detoxified lipooligosaccharide (dLOS)-tetanus toxoid (TT) conjugate against nontypeable Haemophilus influenzae (NTHi) in mice. IN vaccination with dLOS-TT elicited high titers of LOS-specific IgA in nasal washes and IgG in sera during a course of 4 inoculations while high titers of TT-specific IgA and IgG were found in sera. A significant increase of LOS-specific IgA antibody forming cells (AFCs) was observed in nasopharyngeal-associated lymphoid tissue (NALT) and nasal passages. However, TT induced broad responses with higher numbers of IgA and IgG AFCs found in NALT and nasal passages, less but significant IgA AFCs in cervical lymphoid nodes (CLN), spleen, and lungs. Phenotypic analysis revealed a significant rise of total B220+ B-lymphocytes in NALT and CLN, particularly a rise in IgA+/IgM+ cells in the NALT after the immunization. The latter result was complied with a significant rise of IL-4 but not IFN-gamma positive CD4+ T-lymphocytes in NALT. Analysis of IgG antibody subclasses showed that an IgG1 response to both LOS and TT epitopes dominated in serum when compared to IgG2a. These kinetic antibody patterns and cellular responses may provide useful information regarding to effective mucosal vaccines against NTHi infections.

Distribution of leucocyte subsets in the canine pharyngeal tonsil

This report describes the distribution and nature of lymphoid tissue in the nasopharyngeal mucosa of six puppies (mean age+/-SD, 0.3+/-0.25 years) and eight adult dogs (mean age+/-SD, 8.8+/-2.67 years) without respiratory disease. A non-encapsulated area of organized mucosa-associated lymphoid tissue was observed in the caudal part of the posterior wall of the nasopharynx, distal to the openings of the auditory tubes. This structure was consistent with the pharyngeal tonsil and was microscopically more extensive in puppies than in adult dogs. Histochemistry and immunohistochemistry were used to characterize and enumerate the leucocyte subsets in this part of the nasopharynx. Mast cells were found immediately beneath the respiratory epithelium but were also scattered in the glandular and muscular tissue. IgA(+) plasma cells outnumbered IgG(+) and IgM(+) plasma cells, especially in the glandular tissue. All classes of plasma cells were present in significantly greater numbers in adults than in puppies. MHC class II(+) cells were mainly observed in areas containing diffuse and follicular aggregates of lymphoid cells. Both MHC class II(+) cells and CD1c(+) cells with a dendritic morphology were predominantly found immediately beneath or within the epithelium, and cells expressing these markers were more abundant in puppies than in adult dogs. The anti-L1 marker labelled low numbers of cells with a neutrophilic morphology, which were significantly more abundant in puppies than in adult dogs. The majority of lymphoid cells were CD3(+) T lymphocytes and these were particularly abundant in areas containing aggregates of lymphoid cells; CD4(+), CD8(+) and TCR alphabeta(+) cells had the same distribution as the CD3(+) cells. CD4(+) cells were more numerous than CD8(+) cells. The quantitative and qualitative data obtained will enable comparisons to be made with similar studies in dogs suffering from nasopharyngeal diseases, or when the local immune system needs to be investigated.

Serum and mucosal antibody responses to pneumococcal protein antigens in children: relationships with carriage status

Streptococcus pneumoniae causes significant morbidity and mortality especially in children. Some pneumococcal protein antigens can protect mice against infection. Little information is available concerning the nature of naturally acquired protective immunity to pneumococci in humans induced by these antigens. This study investigates the relationships between systemic and local antibody production and carriage in children. Children undergoing adenoidectomy (n=112, ages 2-12 years) were studied. Nasopharyngeal swabs were collected for pneumococcal culture. Serum and saliva were assayed for antibodies to several pneumococcal proteins: choline binding protein A (CbpA), pneumolysin (Ply), pneumococcal surface adhesin A (PsaA) and pneumococcal surface protein A (PspA). Adenoidal mononuclear cells (MNC) were cultured with pneumococcal culture supernatants or recombinant proteins. Cell culture supernatants were analyzed for antigen-specific antibodies. Carriage rates fell with age and serum levels of anti-CbpA, Ply and PspA rose. Anti-CbpA and -Ply serum and salivary IgG antibody levels were higher in children who were culture negative than those who were colonized. Antigen stimulation increased respective antigen-specific IgG production by adenoidal MNC and these responses were greater in those who were colonized than in culture-negative children. Antibodies to CbpA and Ply may protect children aged 2 years and older against pneumococcal colonization. Adenoids may be important local induction and effector sites for both mucosal and systemic antibody production to pneumococcal proteins in children.

Mucosal immunity of nasopharynx: an experimental study in TCR-transgenic (OVA23-3) mice

The ideal vaccine therapy has been warranted for activation of the mucosal immune response in the upper respiratory tract against various types of microbial infection. However, the precise study in regard to the mucosal route of vaccine administration and its mechanism of action remains to be further investigated. Therefore, to better understand the exact mechanism of nasopharyngeal mucosal immunology, from T-cell aspects, the antigen-specific antibody response was investigated in T cell receptor transgenic (OVA23-3) mice (Tg-mice) and wild type BALB/c mice, in comparison, which were stimulated with repeated nasal antigen challenges of ovalbumin (OVA) together with cholera toxin (CT) or OVA alone. OVA-specific IgA and IgG antibodies were not detected in nasal washings of BALB/c mice when these mice were intranasally stimulated with OVA alone. But they were detected in those of BALB/c mice stimulated with OVA and CT, as we have already reported. Interestingly, OVA-specific IgA and IgG antibodies were significantly higher in nasal washings of Tg-mice stimulated with OVA and CT or OVA alone rather than those of BALB/c mice stimulated with OVA and CT. In line with data of the antibody response, OVA-specific IgA and IgG antibody-producing cells significantly increased in number in nasal passage (NP), nasopharyngeal-associated lymphoreticular tissue (NALT), cervical lymph node (CLN), and spleen (SP) of these mice. In nasal washings of Tg-mice, interferon (IFN)-gamma and interleukin (IL)-4 was detected even with a small amount of antigen. To see the cytokine profile of NALT, NP, CLN, and SP of these mice, various cytokine concentrations were measured in supernatants of these cells cultured in vitro with OVA. As a result, IFN-gamma was detected at significantly higher levels in culture supernatants of lymphocytes sampled from NP, CLN, SP as well as NALT of mice having increased antibody titers in nasal washings. On the other hand, Th2 type cytokines such as IL-4, IL-6 and IL-13 were efficiently detected in culture supernatants of NP, CLN, and SP cells from Tg-mice mice, but not in those from NALT cells of those mice. All these data taken together indicate that helper T cells recruited into nasal mucosa and locally activated in an antigen-specific fashion, as well as NALT T cells, are essential for mounting local antigen-specific antibody responses.

Nasal IL-12p70 DNA Prevents and Treats Intestinal Allergic Diarrhea

OVA-induced allergic diarrhea occurs as a consequence of over-expression of Th1 inhibitory IL-12p40 monomers and homodimers in the large intestine, establishing a dominant Th2-type environment. In this study, we demonstrate that intranasally administered murine IL-12p70 naked DNA expression plasmids resulted in the synthesis of corresponding cytokine in the large intestinal CD11c(+) dendritic cells, leading to the inhibition of Ag-specific Th2-type response for the prevention of allergic diarrhea and the suppression of clinical symptoms including OVA-specific IgE Ab synthesis. The nasal IL-12p70 DNA treatment proved effective even after the establishment of allergic diarrhea. These results suggest that the mucosal administration of naked IL-12p70 DNA plasmid should be considered as a possible preventive and therapeutic treatment for Th2 cell-mediated food allergic diseases in the intestinal tract.

Search for Herpesvirus 1 and 2 by in situ hybridization in tonsils and adenoids

OBJECTIVE

Herpes simplex virus (HSV) has been described as cause of acute tonsillitis. It has also been found in nasopharyngeal florid lymphoid infiltrate, mostly composed of CD4+, CD56+ T-cells, simulating lymphoma. In spite of its widespread prevalence in latent form, to the best of our knowledge no study is available on in situ detection of HSV in chronically hyperplastic nasopharyngeal lymphoid tissue. The purpose of the present study was to search for the presence of HSV 1 and 2 in 21 adenoids and 15 tonsils from children (2-12 years of age) in which these organs had been surgically removed due to hypertrophy.

METHODS

Paraffin wax-embedded sections from the 36 cases were submitted to the in situ hybridization technique, using the biotinilated probe to Herpes simplex virus 1 and 2 (Pan Path, Amsterdam) and the Rembrandt Universal DISH & HRP Detection Kit (Pan Path, Amsterdam). Positive control consisted of a previously tested Herpes infected lung.

RESULTS

In none of the 36 cases studied were positive nuclei detected in adenoid and tonsils, either in lymphoid, in stroma or in epithelial cells, as those seen in the positive control.

CONCLUSION

HSV does not seem to be implied in tonsil or adenoid chronic lymphoid hyperplasia. These organs do not seem to harbor the virus latently, or the amount of virus is too low to be detected without amplification methods.

Similar allergic inflammation in the middle ear and the upper airway: evidence linking otitis media with effusion to the united airways concept

BACKGROUND

Otitis media with effusion (OME) is a chronic inflammatory disease of the middle ear space characterized by the accumulation of fluid. Previous investigations have suggested that the immunopathologic mechanism underlying the development of middle ear effusion in patients with allergy is largely due to the effects of T(H)2 mediators. The composition of the inflammatory substrate in the effusions of allergic otitis media is similar to the late-phase allergic response seen elsewhere in the respiratory tract, such as in asthma and in allergic rhinitis.

OBJECTIVE

To determine whether the middle ear compartment may be a component of the united airways in allergic disease by comparing the inflammatory profiles of the middle ear to the upper airway.

METHODS

Middle ear effusions, torus tubaris (Eustachian tube mucosa at the nasopharyngeal orifice), and adenoidal tissue biopsies were obtained from 45 patients undergoing simultaneous tympanostomy tube placement for OME and adenoidectomy for adenoid hypertrophy. The cellular and cytokine profiles of each site were investigated by using immunocytochemistry (elastase, CD3, major basic protein) and in situ hybridization (IL-4, IL-5, IFN-gamma mRNA). Atopic status was determined for each patient by using skin prick testing.

RESULTS

Eleven of the 45 patients with OME (24%) were atopic. The middle ear effusions of atopic patients had significantly higher levels of eosinophils, T lymphocytes, and IL-4 mRNA + cells ( P < .01) and significantly lower levels of neutrophils and IFN-gamma mRNA + cells ( P < .01) compared with nonatopic patients. The nasopharyngeal tissue biopsies revealed similar cellular and cytokine profiles.

CONCLUSION

In atopic patients with OME, the allergic inflammation occurs on both sides of the Eustachian tube, both in the middle ear and in the nasopharynx. The results of this study support the concept that the middle ear may be part of the united airway in atopic individuals.

Immunogenicity, safety, and memory of different schedules of Neisseria meningitidis A/C-diphtheria toxoid conjugate vaccine in infants in Niger

We studied one to four doses of meningococcal polysaccharides A and C conjugated to diphtheria toxoid (Men D) versus A/C polysaccharide (Men PS) vaccine in 618 infants in Niger. Men PS at 24 months permitted evaluating memory. Two Men D doses (at 3 and 9 months) induced higher serum bactericidal activity (SBA) than other regimens. SBA titers after Men PS at 24 months were higher in those given Men D in infancy versus Men PS. While responses were lower for serogroup C, hyporesponsiveness was not evident. Men D was well-tolerated. A single Men D dose in infancy appeared to induce memory.

NALT- versus Peyer's-patch-mediated mucosal immunity

Recent studies indicate that the mechanism of nasopharynx-associated lymphoid tissue (NALT) organogenesis is different from that of other lymphoid tissues. NALT has an important role in the induction of mucosal immune responses, including the generation of T helper 1 and T helper 2 cells, and IgA-committed B cells. Moreover, intranasal immunization can lead to the induction of antigen-specific protective immunity in both the mucosal and systemic immune compartments. Therefore, a greater understanding of the differences between NALT and other organized lymphoid tissues, such as Peyer's patches, should facilitate the development of nasal vaccines.

Mucosal immunology of vaccines against pathogenic nasopharyngeal bacteria

The introduction of Haemophilus influenzae type b conjugate vaccines during the 1990s was followed by dramatic decreases both in the incidence of Haemophilus influenzae type b related invasive disease and in nasopharyngeal carriage of the organism. The extent of this effect has been influenced by the fact that Haemophilus influenzae type b conjugate vaccines reduce nasopharyngeal carriage and induce herd immunity. Based on the success of Haemophilus influenzae type b conjugate vaccines, chemical conjugation has been applied to the development of pneumococcal and meningococcal polysaccharide conjugate vaccines. Evidence has begun to accumulate that these new polysaccharide based conjugate vaccines can also reduce nasopharyngeal carriage and can induce immune responses at the local mucosal level, which may be responsible for these effects. This article reviews recent studies on mucosal immune responses induced by polysaccharide based vaccines and some protein vaccine antigens against several pathogenic nasopharyngeal bacteria, and discusses the mechanisms and functions of these immune responses that may help our understanding of mucosal immune responses to both immunisation and infection.

An Important Role for Polymeric Ig Receptor-Mediated Transport of IgA in Protection againstStreptococcus pneumoniaeNasopharyngeal Carriage

The importance of IgA for protection at mucosal surfaces remains unclear, and in fact, it has been reported that IgA-deficient mice have fully functional vaccine-induced immunity against several bacterial and viral pathogens. The role of respiratory Ab in preventing colonization by Streptococcus pneumoniae has now been examined using polymeric IgR knockout (pIgR(-/-)) mice, which lack the ability to actively secrete IgA into the mucosal lumen. Intranasal vaccination with a protein conjugate vaccine elicited serotype-specific anti-capsular polysaccharide Ab locally and systemically, and pIgR(-/-) mice produced levels of total serum Ab after vaccination that were similar to wild-type mice. However, pIgR(-/-) mice had approximately 5-fold more systemic IgA and 6-fold less nasal IgA Ab than wild-type mice due to defective transport into mucosal tissues. Wild-type, but not pIgR(-/-) mice were protected against infection with serotype 14 S. pneumoniae, which causes mucosal colonization but does not induce systemic inflammatory responses in mice. The relative importance of secretory IgA in host defense was further shown by the finding that intranasally vaccinated IgA gene-deficient mice were not protected from colonization. Although secretory IgA was found to be important for protection against nasal carriage, it does not appear to have a crucial role in immunity to systemic pneumococcus infection, because both vaccinated wild-type and pIgR(-/-) mice were fully protected from lethal systemic infection by serotype 3 pneumococci. The results demonstrate the critical role of secretory IgA in protection against pneumococcal nasal colonization and suggest that directed targeting to mucosal tissues will be needed for effective vaccination in humans.

IgA class switch occurs in the organized nasopharynx- and gut-associated lymphoid tissue, but not in the diffuse lamina propria of airways and gut

Secretory IgA plays a crucial role in the host immune response as a first line of defense. A recent demonstration of in situ IgA class switching in intestinal lamina propria provided an opportunity to reconsider the model for the homing of IgA-committed B cells characterized by distinctive trafficking patterns to effector sites. Those effector sites depend on the organized mucosa-associated lymphoid tissues as their site of induction. In this report we show the preferential presence of IgM(+)B220(+) and IgA(+)B220(+) cells belonging to pre- and post-IgA isotype class-switched cells in the organized mucosa-associated lymphoid tissues, such as nasopharynx-associated lymphoid tissues, isolated lymphoid follicles, and Peyer's patches, and the defect of those populations in the diffuse effector tissues, such as the nasal passage and intestinal lamina propria. Consistent with these findings, the expressions of a series of IgA isotype class switch recombination-related molecules, including activation-induced cytidine deaminase, Ialpha-C micro circle transcripts, and Ialpha-C micro circle transcripts, were selectively detected in these organized mucosa-associated lymphoid structures, but not in the diffuse mucosal effector sites. Taken together, these findings suggest that IgA isotype class switching occurs only in the organized mucosa-associated lymphoid organs (e.g., nasopharynx-associated lymphoid tissues, isolated lymphoid follicles, and Peyer's patches), but not in the diffuse effector tissues of the upper respiratory and gastrointestinal tracts.

Non-toxic Stx derivatives from Escherichia coli possess adjuvant activity for mucosal immunity

Both B subunit of Shiga toxin 1 (Stx1-B), which mediates the binding of toxin to the membrane, and mutant Stx1 (mStx1), which is a non-toxic double-mutated Stx1 harboring double amino acid substitutions in the A subunit, possess potent mucosal adjuvant activity. Nasal immunization of mice with ovalbumin (OVA) plus the Stx1-B or mStx1 induced OVA-specific serum IgG and mucosal IgA responses. IgG subclass analysis revealed that mStx1 and Stx1-B as mucosal adjuvants supported Ag-specific IgG1 followed by IgG2b Abs. The co-administration of either mStx1 or Stx1-B with OVA enhanced the production of IL-4, IL-5, IL-6 and IL-10 with low IFN-gamma, by OVA-specific CD4+ T cells. To better elucidate the mechanisms underlying mStx1's and Stx1-B's adjuvant activity, we next sought to examine whether or not dendritic cells (DC) residing in the nasopharyngeal-associated lymphoreticular tissue (NALT) were activated by nasal administration of Stx1-B or mStx1. We found that mice nasally administered with Stx1-B or mStx1 showed an up-regulation in the expression of CD80, CD86 and especially CD40 on NALT DCs. Taken together, these results suggest that non-toxic Stx derivatives could be effective mucosal adjuvants for the induction of Th2-type, CD4+ T cell mediated, antigen-specific mucosal IgA and systemic IgG Ab responses, and that they likely owe their adjuvant activity to the up-regulation of co-stimulatory molecules including CD80, CD86 and CD40 on NALT DCs.

[Detection of LOS-specific antibody-secreting cells by ELISPOT assay]

AIM

To detect dynamically the response of specific antibody-secreting cells elicited by a detoxified-lipooligosaccharide-cross-reactive mutant (dLOS-CRM) of diphtheria toxin conjugate vaccine for Moraxella catarrhalis (M.cat).

METHODS

BALB/c mice were intranasally immunized with dLOS-CRM conjugate vaccine. The specific antibody-secreting cells responding to LOS of M. cat in different inductive and effective sites, including nasally associated lymphoid tissues (NALT), spleen, cervical lymph nodes (CLN), nasal passages (NP), lungs and Peyer's patches (PP) were detected by an enzyme-linked immunospot assay (ELISPOT). The levels of LOS-specific antibodies IgA, IgG and IgM in serum, nasal flush fluid, alveolar douche fluid, saliva and fecal extract were also detected by ELISA.

RESULTS

Intranasal immunization with dLOS-CRM plus cholera toxin induced a significantly dose-dependent enhancement of immune response. LOS-specific antibody (IgA,IgG or IgM)-secreting cells were found in NALT, spleens, CLN, NP, lungs and PP with most LOS-specific IgA antibody-secreting cells located in nasal passages, and next, NALT and lungs. It was correlated well with the level of LOS-specific IgA, IgG or IgM antibody titers in nasal flush fluid, alveolar douche fluid, saliva, serum and fecal extract.

CONCLUSION

dLOS-CRM can induce specific mucosal and systemic humoral immune response through intranasal immunization. ELISPOT assay is quick, sensitive, specific, and would be a very useful tool to analyze dynamically the mechanism of single antibody-secreting cell response.

Evidence of Allergic Inflammation in the Middle Ear and Nasopharynx in Atopic Children with Otitis Media with Effusion

BACKGROUND

Otitis media with effusion (OME) occurs in the setting of eustachian tube (ET) dysfunction. Previous studies have demonstrated a predominance of T helper 2 (Th2) mediators in the middle ear effusions (MEEs) of atopic children, suggesting that allergy plays a role in the pathogenesis of OME. Given that the middle ear is contiguous with the upper airway, the allergic inflammation seen in the middle ear of atopic patients with OME may also have been observed in the nasopharynx.

OBJECTIVE

We hypothesize that atopic children have different cellular and cytokine profiles in MEE compared with nonatopic patients and that this allergic inflammation occurs in both the middle ear and the nasopharynx.

METHODS

Forty-five patients undergoing both ventilation tube placement for OME and adenoidectomy for adenoid hypertrophy were recruited. The atopic status was determined for each patient using standard skin testing. The cellular and cytokine profiles of the MEEs and the torus tubarius and adenoid tissues were investigated using immunocytochemistry and in situ hybridization.

RESULTS

Our results indicate that, within the atopic patient, there is a similar cellular and cytokine profile within the three regions sampled, with a predominant expression of interleukin-4 (a Th2 cytokine) and an increased infiltration of eosinophils compared with the nonatopic patient.

CONCLUSION

These findings confirm the association of allergy with MEE and support the hypothesis that the middle ear may be an integral part of the United Airway Concept.

RSV-induced bronchiolitis but not upper respiratory tract infection is accompanied by an increased nasal IL-18 response

The aim of this study was to investigate potential differences in the local nasal immune response between bronchiolitis and upper respiratory tract infection induced by respiratory syncytial virus (RSV). Nasal brush samples were obtained from 14 infants with RSV bronchiolitis and from 8 infants with RSV upper respiratory tract infection. The samples were taken during infection (acute phase) and 2-4 weeks later (convalescent phase). Cytospin preparations were stained immunohistochemically for T cells, macrophages, and eosinophils. Staining also took place for intercellular adhesion molecule-1 (ICAM-1), T-helper 1 (Th1)-like (interleukin-12 [IL-12], interferon-gamma [IFN-gamma]), Th2-like (IL-4, IL-10), and proinflammatory cytokines (IL-6, IL-8, IL-18). During both RSV-induced bronchiolitis and upper respiratory tract infection, cellular inflammation was observed. This was characterised by an increase in the numbers of nasal macrophages, which tended to be higher in bronchiolitis than in upper respiratory tract infection. Numbers of T lymphocytes and ICAM-1 positive cells increased during both bronchiolitis and upper respiratory tract infection. There were no differences between numbers in the groups. Interestingly, a distinct nasal proinflammatory cytokine response was observed in RSV-induced bronchiolitis. This is characterised by an increase in the number of IL-18 positive cells. This increase is specific for bronchiolitis, as a similar increase could not be detected in RSV-induced upper respiratory tract infection. Numbers of IL-6 and IL-12 positive cells were higher in both bronchiolitis and upper respiratory tract infection, and there were no differences between the groups. By contrast, the number of IL-8, IFN-gamma, IL-4, and IL-10-positive cells remained constant. In conclusion, clear differences were found in nasal immune responses of children with RSV-induced upper respiratory tract infection or bronchiolitis. The induction of a strong IL-18 response was typical for bronchiolitis, as this could not be observed in RSV-induced upper respiratory tract infection, and could explain the eosinophilia that is observed frequently during bronchiolitis.

Membranous cells in nasal-associated lymphoid tissue: a portal of entry for the respiratory mucosal pathogen group A streptococcus

Human tonsils are suspected to be an antibiotic-impervious human reservoir for group A streptococcus. An intranasal infection model in mice and a bioluminescent-tagged strain were used to investigate this possibility. Viable streptococci were predominantly found both intra- and extracellularly in nasal-associated lymphoid tissue (NALT), a human tonsil homologue. Ulex europaeus-1, a membranous (M) cell-specific lectin, identified cells harboring streptococci at the epithelial surface of NALT and blocked bacterial colonization of this tissue. These results suggest that M cells in NALT transport this Gram-positive pathogen across the epithelial layers in a manner similar to those in Peyer's patches, which permit enteric pathogens to invade deeper tissues from the gastrointestinal tract.

Cell proliferation in the endolymphatic sac in situ after the rat Waldeyer ring equivalent immunostimulation

OBJECTIVES/HYPOTHESIS

It has been recognized that immunological mechanisms could be involved in the pathogenesis of different inner ear disorders, such as progressive sensorineural hearing loss, Meniere's disease, and even sudden deafness. The endolymphatic sac acts as an immune control organ for the inner ear and has been considered as an effector site of the mucosa-associated lymphoid tissue. The purpose of the study was to determine the potentially immunological relationship between endolymphatic sac and Waldeyer ring equivalent, one of the most important affector organs in mucosa-associated lymphoid tissue.

STUDY DESIGN

Animal model.

METHODS

Thirty-six rats were employed. Two animals were killed for histological observation of Waldeyer ring equivalent, and another 34 animals were randomly divided into experimental and control groups and received bilateral intranasal immunizations with keyhole limpet hemocyanin or Freund adjuvant, respectively. The ears of immunized animals and control animals were examined for keyhole limpet hemocyanin-positive memory cells and immunoglobulin G-positive plasma cells with the technique of immunohistochemical analysis. The histopathological changes and cell proliferation in those ears were also assessed.

RESULTS

There were paired and organized lymphoid tissues in the lateral wall of the first choana in the rat. Keyhole limpet hemocyanin-positive lymphocytes appeared within the endolymphatic sac at 3 days after the first anti-genetic stimulus of the Waldeyer ring equivalent. Endolymphatic hydrops in the cochlea, elevated amounts of immunocompetent cells, and increased activity of cell proliferation within the endolymphatic sac were also considered after four intranasal injections of keyhole limpet hemocyanin.

CONCLUSION

Presumably, endolymphatic sac is supplied with immunocompetent cells from Waldeyer ring equivalent and has an ability of co-reaction with Waldeyer ring equivalent.

Efficacy of the 26-kilodalton outer membrane protein and two P5 fimbrin-derived immunogens to induce clearance of nontypeable Haemophilus influenzae from the rat middle ear and lungs as well as from the chinchilla middle ear and nasopharynx

The rat middle ear and lung clearance model has been used to show that the nontypeable Haemophilus influenzae 26-kDa outer membrane protein OMP26 is highly efficacious as a mucosal immunogen, inducing significantly enhanced clearance in immunized rats upon direct challenge of these two anatomic sites. Similarly, the chinchilla model of middle ear and nasopharyngeal clearance has been used to show that two P5 fimbrin adhesin-derived immunogens, LB1 and lipoprotein D (LPD)-LB1(f)(2,1,3), are highly efficacious as parenteral immunogens. Both induced significantly augmented clearance of nontypeable H. influenzae upon challenge of these sites. Here, these three nontypeable H. influenzae immunogens in addition to six bovine serum albumin and keyhole limpet hemocyanin conjugates of the synthetic peptide LB1(f) were assayed for relative efficacy in the reciprocal rodent model system. OMP26 was assayed in the chinchilla host by a parenteral immunization route, with clearance of the middle ear and nasopharynx used as outcome measures. Both LB1 and LPD-LB1(f)(2,1,3) were assayed in the rat host with a mucosal immunization route and clearance of nontypeable H. influenzae from the lungs and middle ears as outcome measures. Both of the immunogens were found to induce a high-titered and specific immune responses in the heterologous host system. Moreover, each was found to be highly efficacious in the reciprocal host system, providing strong support for the continued development and inclusion of both OMP26 and P5 fimbrin-derived peptides as candidate vaccine antigens directed at otitis media caused by nontypeable H. influenzae.

Effect of intranasal exposure to leukotoxin-deficient Mannheimia haemolytica at the time of arrival at the feedyard on subsequent isolation of M haemolytica from nasal secretions of calves

OBJECTIVE

To determine the effect of intranasal exposure to live leukotoxin (LktA)-deficient Mannheimia haemolytica (MH) at the time of feedyard arrival on nasopharyngeal colonization by wild-type MH in calves.

ANIMALS

200 calves.

PROCEDURE

Calves from Arkansas (AR calves; n = 100; mean body weight, 205 kg) were purchased from an order buyer barn. Calves from New Mexico (NM calves; n = 100; mean body weight, 188 kg) were obtained from a single ranch. Calves were transported to a feedyard, where half of each group was exposed intranasally with LktA-deficient MH at the time of arrival. Calves were observed daily for respiratory tract disease (RTD), and nasal swab specimens were collected periodically to determine nasopharyngeal colonization status with MH. Serum samples were assayed for antibodies to MH.

RESULTS

15 AR calves had nasopharyngeal colonization by wild-type MH at the order buyer barn, whereas none of the NM calves had nasopharyngeal colonization. Intranasal exposure to LktA-deficient MH elicited an increase in serum antibody titers against MH in NM calves, but titers were less in NM calves treated for RTD. Exposure of NM calves to LktA-deficient MH offered protection from nasopharyngeal colonization by wild-type MH.

CONCLUSIONS AND CLINICAL RELEVANCE

Exposure of calves to LktA-deficient MH elicited an increase in serum antibody titers against MH and decreased colonization of the nasopharynx by wild-type MH. Earlier exposure would likely allow an immune response to develop before transportation and offer protection from nasopharyngeal colonization and pneumonia caused by wild-type MH.

Single cell analysis of adenoid CD5+ B cells and their protective contributions to nasopharyngeal immunity

OBJECTIVES

CD5+ B cells are phenotypically and functionally distinct from the conventional (CD5-) B cells, and the function of CD5+ B cells in the upper respiratory tract remains unknown. A previous study showed that immunoglobulin A-producing cells in the adenoid play a protective role in the nasopharynx. In the present study, the contribution of adenoid CD5+ B cells to nasopharyngeal immunity at the single cell level was investigated.

STUDY DESIGN

In vitro laboratory study.

METHODS

Mononuclear cells were isolated from adenoids of children aged 1 to 12 years, and the frequency of CD5+ B cells was determined by flow cytometry. The numbers of cells producing immunoglobulin M, immunoglobulin G, and immunoglobulin A in sorted adenoid CD5+ B cells were determined by enzyme-linked immunospot assay. Further, to characterize adenoid CD5+ B cells, the expression of various surface molecules was analyzed by flow cytometry.

RESULTS

The results showed that adenoids of young children contain a relatively large number of CD5+ B cells, which have a greater capacity for antibody production than do CD5- B cells. CD5+ B cells also differed from CD5- B cells in the expression of interleukin receptors Il-4R, IL-5R, and IL-10R as well as CD27, B7-1, B7-2, Fas, and Bcl-2.

CONCLUSIONS

These findings suggest that adenoid CD5+ B cells contribute to protective immunity by forming a first line of defense in the upper respiratory tract of young children and that they are probably regulated in a manner that differs from that of CD5- B cells.

Mucosal immune response to specific outer membrane proteins of Moraxella catarrhalis in young children

BACKGROUND

Moraxella catarrhalis is an important cause of otitis media. A number of candidate antigens for a future infant otitis media vaccine have been identified, but their mucosal immunogenicity induced by nasopharyngeal M. catarrhalis colonization has not been characterized. The aim of this study was to determine the salivary IgA response to M. catarrhalis outer membrane proteins (OMP) in young children.

METHODS

Children ages 1 to 24 months evaluated for acute respiratory tract infection were prospectively enrolled. M. catarrhalis nasopharyngeal colonization was determined by (1) selective culture and (2) detection by reverse transcription-PCR of messenger RNA specific for the OMP UspA1 and UspA2. Salivary IgA responses were detected by immunoblot analysis of M. catarrhalis OMP. Isogenic knockout mutants for UspA1, UspA2, hemagglutinin (Hag), transferrin-binding protein B (TbpB) and CopB were constructed for identification of specific target OMP.

RESULTS

Sixty-six patients were studied. The rates of M. catarrhalis colonization by culture, reverse transcription-PCR for messenger RNA and mRNA were 40, 94 and 58%, respectively. Anti-M. catarrhalis salivary IgA was detected in 62 patients (94%). IgA directed against a >250-kDa antigen (assigned to UspA1/UspA2 by mutant analysis) and a 200-kDa antigen (Hag) were detected in 65 and 70% of patients, respectively. Bands at 80 to 85 kDa (82%) consisted of IgA directed against monomeric UspA2, TbpB and CopB.

CONCLUSIONS

colonization occurring in early infancy is associated with a consistent mucosal immune response directed against the UspA proteins, Hag and other OMP. The data suggest that several M. catarrhalis OMP are immunogens of the nasopharyngeal mucosal immune system of infants.

Cellular and humoral local immune responses in sheep experimentally infected with Oestrus ovis (Diptera: Oestridae)

Cellular and humoral local responses were investigated following repetitive artificial Oestrus ovis infections in lambs. The presence of larvae induced a huge local recruitment of either leucocytes (T and B lymphocytes, macrophages) or granulocytes (eosinophils, mast cells and globule leucocytes). This cellular response was more pronounced in the ethmoid and sinus (development sites of second and third instar larvae) than in the septum or turbinates where first instar larvae migrate. Infected lambs produced Oestrus ovis specific IgG and IgA antibodies in their mucus. This local humoral response was mainly directed against larval salivary gland antigens and not against larval digestive tract antigens. Compared to the control animals, the sinusal mucosa of infected animals was extremely thickened and the epithelium exhibited hyperplasia, metaplasia and eosinophilic exocytosis. The possible roles of these local immune responses in the regulation of O. ovis larvae populations in sheep are discussed.

Protective mucosal immunity in aging is associated with functional CD4+ T cells in nasopharyngeal-associated lymphoreticular tissue

Our previous studies showed that mucosal immunity was impaired in 1-year-old mice that had been orally immunized with OVA and native cholera toxin (nCT) as mucosal adjuvant. In this study, we queried whether similar immune dysregulation was also present in mucosal compartments of mice immunized by the nasal route. Both 1-year-old and young adult mice were immunized weekly with three nasal doses of OVA and nCT or with a nontoxic chimeric enterotoxin (mutant cholera toxin-A E112K/B subunit of native labile toxin) from Brevibacillus choshinensis. Elevated levels of OVA-specific IgG Abs in plasma and secretory IgA Abs in mucosal secretions (nasal washes, saliva, and fecal extracts) were noted in both young adult and 1-year-old mice given nCT or chimeric enterotoxin as mucosal adjuvants. Significant levels of OVA-specific CD4(+) T cell proliferative and OVA-induced Th1- and Th2-type cytokine responses were noted in cervical lymph nodes and spleen of 1-year-old mice. In this regard, CD4(+), CD45RB(+) T cells were detected in greater numbers in the nasopharyngeal-associated lymphoreticular tissues of 1-year-old mice than of young adult mice, but the same did not hold true for Peyer's patches or spleen. One-year-old mice given nasal tetanus toxoid plus the chimeric toxin as adjuvant were protected from lethal challenge with tetanus toxin. This result reinforced our findings that age-associated immune alterations occur first in gut-associated lymphoreticular tissues, and thus nasal delivery of vaccines for nasopharyngeal-associated lymphoreticular tissue-based mucosal immunity offers an attractive possibility to protect the elderly.

Intranasal immunization with a lipooligosaccharide-based conjugate vaccine from nontypeable Haemophilus influenzae enhances bacterial clearance in mouse nasopharynx

Nontypeable Haemophilus influenzae (NTHi) is a major cause of otitis media in children. We investigated whether intranasal immunization with a detoxified lipooligosaccharide-tetanus toxoid (dLOS-TT) conjugate vaccine would generate protective immunity against NTHi in a mouse model of nasopharyngeal clearance. The results demonstrated that intranasal immunization with dLOS-TT plus adjuvant cholera toxin (CT) significantly induced LOS-specific IgA antibodies in mouse external secretions, especially in nasal wash (90-fold), bronchoalveolar lavage fluid (25-fold), saliva (13-fold) and fecal extract (three-fold). LOS-specific IgA antibody-forming cells were also found in mucosal and lymphoid tissues with their highest numbers in the nasal passage (528 per 10(6) cells). In addition, the intranasal immunization elicited a significant rise in LOS-specific IgG (32-fold) and IgA (13-fold) in serum. For the immunized mice which had been challenged through the nose with 10(7) live NTHi strain 9274 cells, the vaccine group showed a significant reduction (74-77%) of NTHi, compared to that of control groups with CT alone or dLOS plus CT (P<0.05). Negative correlations were found between bacterial counts and the levels of nasal wash IgA or IgG, saliva IgA and serum IgG. The clearance of five heterologous strains was investigated and revealed a significant clearance of strains 3198, 5657 and 7502 but not of strains 1479 and 2019. These data suggest that intranasal immunization with dLOS-TT vaccine elicits both mucosal and systemic immunity against NTHi and enhances bacterial clearance from nasopharynx in mice. Such a vaccine and vaccination regime may be applicable to humans with an appropriate formulation.

Interferon-gamma levels in nasopharyngeal secretions of infants with respiratory syncytial virus and other respiratory viral infections

Respiratory syncytial virus (RSV) infection, one of the most common causes of hospitalization of children in developed countries, has been implicated as a cause of asthma. We aimed to characterize the cytokine profile in nasopharyngeal aspirates (NPAs) taken from infants during upper respiratory tract infection to investigate whether RSV induced a unique immune response as compared with other viruses. Additionally, we sought to determine whether this profile was influenced by the infants' atopic status. A prospective birth cohort of babies at high risk of atopy was recruited. Ratios of a T-helper 1 (Th1) cytokine, interferon gamma (IFN-gamma) and a T-helper 2 (Th2)-like cytokine, interleukin-10 (IL-10), in NPAs were determined during episodes of respiratory tract infections in the first year. The viral aetiology of the respiratory tract infections was determined using polymerase chain reaction (PCR), culture and immunofluorescence. Atopic status was ascertained at 1 year of age using skin prick tests. Participants were recruited antenatally and subsequently followed in the community. Sixty babies with one or both parents atopic were enrolled into the study. IFN-gamma : IL-10 ratios in NPAs during upper respiratory tract infections and their correlation with viral aetiology and atopic status were the main outcome measures. The mean IFN-gamma : IL-10 ratio was significantly lower (due to lower IFN-gamma) during RSV infections than during infections with other viruses (P = 0.035). The cytokine ratio, however, did not differ between infants with or without wheeze during URTIs (P = 0.44), or between infants who were atopic or non-atopic (P = 0.49). This study suggests that RSV is associated with lower IFN-gamma production in young babies, regardless of their atopic status, compared to upper respiratory tract infections where either another virus is detected or where no viral identification is made.

T cell cytokine responses to outer membrane proteins of Haemophilus influenzae and the house dust mite allergens Der p 1 in allergic and non-allergic subjects

BACKGROUND

Haemophilus influenzae are ubiquitous colonizers of the nasopharynx, Little is known about the T cell cytokine responses to the antigens of these bacteria and whether or not the responses may interact with responses to aeroallergen.

OBJECTIVE

To measure the T cell cytokine responses to conserved outer membrane protein antigens of Haemophilus influenzae and to house dust mite allergen of subjects allergic to the house dust mite and of subjects without allergic sensitization.

METHODS

T cell responses were measured by in vitro proliferation and cytokine release from peripheral blood monocytes (PBMC). The allergen used was Der p 1 and outer membrane proteins were recombinant polypeptides representing the OMP6 and D15 antigens.

RESULTS

The PBMC of most subjects had proliferative responses to OMP6 and D15, which were highly correlated. The pattern of cytokine release was Th1 biased with high levels of IFN-gamma and usually little IL-5 or IL-13 although PBMC from a few subjects did release IL-5 independent of allergic status. IL-10 release was readily detected. There was no difference in the anti-OMP cytokine response of PBMC from subjects without any known allergy and the responses of PBMC from subjects who were highly allergic to house dust mite. The responses to the Der p 1 allergen showed the expected Th2 cytokine release.

CONCLUSION

The outer membrane protein antigens of the ubiquitous colonizing bacteria Haemophilus influenzae induce Th1 cytokine responses which are similar for PBMC from non-allergic individuals and subjects with a high degree of allergy to the perennial house dust mite allergen and strong Th2 responses to Der p 1.

[7-valent conjugate Pneumococcal vaccine and nasopharyngeal cavity]

7-valent conjugate pneumococcal vaccine is effective for preventing invasive pneumococcal diseases in childhood. The present serotype formulation of the conjugate Pneumococcal Vaccine is effective for preventing 75-90% of the invasive pneumococcal disease cases, depending of the vaccine-serotypes distribution in the several countries. Recent studies, carried out in the north-american context, show that mass vaccination campaign by 7-valent conjugate Pneumococcal Vaccine in childhood, reduce, in vaccinated subjects, the nasopharyngeal colonization by vaccine-serotypes, that are much more joined to antibacterial resistance. This implies non only an active and specific protection for vaccinated, but also for family and community contacts, children and adults. This interesting results, need to be confirmed also in european countries, open a new view for a wider pharmacoeconomic evaluation of the 7-valent conjugate Pneumococcal Vaccine in childhood.

Immunization with Haemophilus influenzae Hap adhesin protects against nasopharyngeal colonization in experimental mice

Nontypeable Haemophilus influenzae is a common cause of respiratory tract disease and initiates infection by colonizing the nasopharynx. The H. influenzae Hap adhesin is an autotransporter protein that was discovered because it promotes intimate interaction with human epithelial cells. Hap contains an extracellular domain called Hap(s) that has adhesive and protease activity and an outer membrane domain called Hap(beta) that serves to present Hap(s) on the surface of the cell. Hap(s) purified from nontypeable H. influenzae strain P860295 was used to immunize BALB/c mice intranasally. Immunization stimulated significant mucosal and serum anti-Hap(s) antibody titers, which were augmented by the addition of mutant cholera toxin (CT-E29H) as an adjuvant. Immunization was associated with a marked reduction in the density of nasopharyngeal colonization when mice were challenged with a heterologous strain of nontypeable H. influenzae. These results suggest that intranasal immunization with Hap formulated with CT-E29H may be a valuable vaccine strategy for the prevention of nontypeable H. influenzae disease.

Initiation of NALT organogenesis is independent of the IL-7R, LTbetaR, and NIK signaling pathways but requires the Id2 gene and CD3(-)CD4(+)CD45(+) cells

Initiation of nasopharyngeal-associated lymphoid tissue (NALT) development is independent of the programmed cytokine cascade necessary for the formation of Peyer's patches (PP) and peripheral lymph nodes (PLN), a cytokine cascade which consists of IL-7R, LTalpha1beta2/LTbetaR, and NIK. However, the subsequent organization of NALT seems to be controlled by these cytokine signaling cascades since the maturation of NALT structure is generally incomplete in those cytokine cascade-deficient mice. NALT as well as PP and PLN are completely absent in Id2(-/-) mice. NALT organogenesis is initiated following the adoptive transfer of CD3(-)CD4(+)CD45(+) cells into Id2(-/-) mice, constituting direct evidence that CD3(-)CD4(+)CD45(+) inducer cells can provide an IL-7R-, LTalpha1beta2/LTbetaR-, and NIK-independent tissue organogenesis pathway for secondary lymphoid tissue development.

Characterization of ovine nasal-associated lymphoid tissue and identification of M cells in the overlying follicle-associated epithelium

The distribution of mucosal lymphoid nodules in the ovine nasopharyngeal tract was studied by an acetic acid fixation technique. Nodules, which were concentrated just posterior to the opening of the Eustachian tube, were excised and examined by light microscopy, and scanning and transmission electron microscopy. Immunohistochemical examination revealed that each lymphoid structure consisted of follicles containing discrete B- and T-cell areas, characteristic of a mucosal inductive site of the mucosa-associated lymphoid tissue (MALT). Electron microscopy revealed that specialized epithelial cells, displaying features characteristic of M cells, were present in the follicle-associated epithelium (FAE) that covered the lymphoid nodules. These cells had sparse irregular microvilli and were closely associated with lymphocytes in the underlying tissue. These findings suggest that targeting the nasopharyngeal region may provide a practical and effective route for the stimulation of protective mucosal immune responses.

Nasopharyngeal endoscopy adds to reliability of clinical diagnosis of infectious mononucleosis

Frequently, the clinical picture in the oropharynx alone does not lend itself to a reliable differentiation between acute pharyngotonsillitis in infectious mononucleosis and a streptococcal inflammation. Such a differentiation, however, is essential for the indication of antibiotic therapy. Therefore, it was the aim of the present study to investigate whether or not endoscopic verification of larger-than-normal lymphatic tissue with fibrinous membranes in the nasopharynx would enhance the reliability of diagnosis. Fifty hospitalized patients exhibiting the clinical picture of acute pharyngotonsillitis were examined for the following parameters: nasopharyngeal endoscopy, determination of glutamine-oxaloacetic transaminase (GOT), glutamine-pyruvic transaminase (GPT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), leucocytes and haemogram, antibodies to viral capsid antigen (VCA)-IgM, Epstein-Barr virus nuclear antigen (EBNA), and cytomegalovirus (CMV). In 24 patients with acute tonsillitis/peritonsillar abscess, and in 26 patients with infectious mononucleosis, the total leucocyte count in the blood and the blood/erythrocyte sedimentation rate were comparable. Atypical lymphocytes or absolute lymphocytosis were not seen in acute tonsillitis, but were found in 88.5 per cent of patients with infectious mononucleosis. Elevated transaminase levels were noted in 77 (GOT) and 88.5 per cent (GPT) of patients with infectious mononucleosis, and in acute tonsillitis in 4.2 (GOT) and 12.5 per cent (GPT) of patients. The CRP was higher than normal in 91.7 per cent of patients with acute tonsillitis, and in 57.7 of patients with infectious mononucleosis. In none of the patients with acute tonsillitis was lymphatic tissue with fibrinous membranes seen in the nasopharyngeal cavity. In contrast, nasopharyngeal endoscopy in infectious mononucleosis was positive in 24 out of 26 patients. Hence, the sensitivity was 92.3 per cent, the specificity 100 per cent, and the prediction value for a positive test turned out to be 1. Endoscopy of the nasopharngeal cavity employed as a simple and supplementary procedure adds to the reliability of diagnosis of infectious mononucleosis.

Passive immunization with Neisseria meningitidis PorA specific immune sera reduces nasopharyngeal colonization of group B meningococcus in an infant rat nasal challenge model

To examine the protective efficacy of specific immune sera generated by meningococcal vaccine candidates against nasopharyngeal colonization, we developed an infant rat nasal colonization model for group B meningococcus. In this model, Sprague-Dawley infant rats were challenged intranasally in with host adapted, piliated Neisseria meningitidis group B strains H355 or H44/76 administered concurrently with iron dextran. Colonization was assessed by quantitative culture of nasal homogenates and expressed as log(10) colony forming units (c.f.u.) per nose. Three to five log(10) c.f.u. of N. meningitidis were routinely recovered from the nasal tissue up to 4 days post-challenge. Passive immunization (i.p.) of the infant rats with either PorA or whole cell antisera 24 h prior to homologous challenge resulted in a significant reduction of N. meningitidis colonization in the nasal tissues of these animals. These results demonstrate that this model can be utilized to evaluate the role of antibody to prevent the initial nasopharyngeal colonization by group B meningococcus.

Macrophage inflammatory protein-1alpha (not T helper type 2 cytokines) is associated with severe forms of respiratory syncytial virus bronchiolitis

It has been suggested that the pathogenesis of respiratory syncytial virus (RSV) infection is related to the development of T helper (Th) type 2 cytokine responses. The presence of Th1 and Th2 cytokines and the chemokines macrophage inflammatory protein (MIP)-1alpha and monocyte chemotactic protein (MCP)-1 were assessed by ELISA in nasopharyngeal secretions of infants with RSV infection. Infants with mild bronchiolitis had increased Th1 cytokines and reduced Th2 cytokines, compared with infants with upper respiratory tract illness alone. Severe bronchiolitis was characterized by a more balanced Th1-Th2 response that did not differ from that of infants with upper respiratory tract illness alone. In contrast, MIP-1alpha was markedly increased in infants with severe bronchiolitis. MIP-1alpha and MCP-1 levels also were inversely related to oxygen saturation (P<.005). Thus, the severity of RSV bronchiolitis appears to be related more to chemokine release than to Th2 cytokine production.

Sendai virus fusion protein mediates simultaneous induction of MHC class I/II-dependent mucosal and systemic immune responses via the nasopharyngeal-associated lymphoreticular tissue immune system

Nasal administration of Ags using a novel hybrid Ag delivery vehicle composed of envelope glycoproteins of Sendai virus on the surface of liposome membranes (fusogenic liposome) efficiently delivered Ags to Ag-sampling M cells in nasopharyngeal-associated lymphoreticular tissue. Additionally, fusogenic liposomes also effectively delivered the Ags into epithelial cells and macrophages in nasopharyngeal-associated lymphoreticular tissue and nasal passages. In vitro Ag presentation assays clearly showed that fusogenic liposomes effectively presented encapsulated Ags via the MHC class II-dependent pathway of epithelial cells as well as macrophages. Fusogenic liposomes also have an adjuvant activity against mucosal epithelial cells to enhance MHC class II expression. According to these high delivery and adjuvant activities of fusogenic liposomes, nasal immunization with OVA-encapsulated fusogenic liposomes induced high levels of OVA-specific CD4(+) Th1 and Th2 cell responses. Furthermore, Ag-specific CTL responses and Ab productions were also elicited at both mucosal and systemic sites by nasal immunization with Ag-encapsulated fusogenic liposomes. These results indicate that fusogenic liposome is a versatile and effective system for the stimulation of Ag-specific immune responses at both mucosal and systemic compartments.