Immunogenicity and safety of seasonal and 2009 pandemic A/H1N1 influenza vaccines for patients with autoimmune diseases: a prospective, monocentre trial on 199 patients

The 2009 pandemic A/H1N1 influenza outbreak represented a theoretical risk for patients with autoimmune diseases (AID), especially those immunosuppressed. This study was undertaken to evaluate immunogenicity and tolerance of seasonal (SFV) and A/H1N1 flu vaccines (HFV) in AID patients.

Vaccination with a T-cell-priming Gag peptide of caprine arthritis encephalitis virus enhances virus replication transiently in vivo

CD4+ T cells are involved in several immune response pathways used to control viral infections. In this study, a group of genetically defined goats was immunized with a synthetic peptide known to encompass an immunodominant helper T-cell epitope of caprine arthritis encephalitis virus (CAEV). Fifty-five days after challenge with the molecularly cloned CAEV strain CO, the vaccinated animals had a higher proviral load than the controls. The measurement of gamma interferon and interleukin-4 gene expression showed that these cytokines were reliable markers of an ongoing immune response but their balance did not account for more or less efficient control of CAEV replication. In contrast, granulocyte-macrophage colony-stimulating factor appeared to be a key cytokine that might support virus replication in the early phase of infection. The observation of a potential T-cell-mediated enhancement of virus replication supports other recent findings showing that lentivirus-specific T cells can be detrimental to the host, suggesting caution in designing vaccine candidates.

Alternative vaccination against equine botulism (BoNT/C)

REASON FOR PERFORMING STUDY: In Europe the incidence of botulism in horses has increased in the last decade due to the growing popularity of haylage feeding. Recombinant vaccines are safer and less expensive to produce and are generally better tolerated than toxoids. OBJECTIVES: To investigate whether the recombinant C-terminal half of the heavy chain of the botulinum neurotoxin C (Hc BoNT/C) in combination with an immunstimulatory adjuvant is an appropriate vaccine candidate for horses by testing its efficacy to induce neutralising antibodies and by comparing its immunogenic properties and adverse reactions to a commercial toxoid vaccine. Formation of oedema and local pain reactions were assessed. ELISA and Western blot assay against Hc BoNT/C and testing of neutralising antibody induction in a mouse protection assay were used to evaluate the immune response. RESULTS: With the recombinant vaccine, only minor local swelling with full recovery after 5 days was noted after brisket injections. The toxoid vaccine produced local, painful reactions with longer recovery periods of up to 2 weeks. Horses vaccinated with either vaccine induced neutralising antibodies after the second booster vaccination, while seroconversion on ELISA and Western blot to Hc BoNT/C was apparent after the first recombinant vaccination, and at various time points in the vaccination schedule in horses that received commercial toxoid vaccine. CONCLUSION: The recombinant vaccine showed fewer adverse reactions compared to the only commercially available vaccine but induced similar concentrations of neutralising antibodies. There was no correlation between the serological response to Hc BoNT/C and the neutralising capacity of serum. POTENTIAL RELEVANCE: Recombinant Hc BoNT/C is an appropriate vaccine candidate to stimulate production of neutralising antibodies against botulinum neurotoxin C in horses and creates only minor local reactions at the injection site.

Vaccination with microneme protein NcMIC4 increases mortality in mice inoculated with Neospora caninum

NcMIC4 is a Neospora caninum microneme protein that has been isolated and purified on the basis of its unique lactose-binding properties. We have shown that this protein binds to galactosyl residues of lactose; antibodies directed against NcMIC4 inhibit host cell interactions in vitro, thus making it a vaccine candidate. Because of this feature, NcMIC4 was first purified on a larger scale in its native, functionally active form using lactose-agarose affinity chromatography. Second, NcMIC4 was expressed in Escherichia coli as a histidine-tagged recombinant protein (recNcMIC4) and purified through Ni-affinity chromatography. Third, NcMIC4 cDNA was cloned into the mammalian pcDNA3.1 DNA vector and expression was confirmed upon transfection of Vero cells in vitro. For vaccination studies, we employed the murine cerebral infection model based on C57Bl/6 mice, employing experimental groups of 10 mice each. Two groups were injected intraperitoneally with purified native NcMIC4 and recNcMIC4, respectively, employing RIBI adjuvant. The third group was vaccinated intramuscularly with pcDNA-NcMIC4. Control groups included an infection control, an adjuvant control, and a pcDNA3.1 control group. Following 3 injections at 4-wk intervals, mice were challenged by i.p. inoculation of 2 x 10(6) N. caninum tachyzoites (Nc-1 isolate). During the course of parasite challenge (3 wk), mice from the 3 different test groups showed varying degrees of symptoms bearing a semblance to neosporosis, i.e., walking disorder, rounded back, apathy, and paralysis of the hind limbs. Control groups showed no symptoms at all. Most notably, vaccination with pcDNA-MIC4 proved antiprotective, with 60% of mice succumbing to infection within 3 wk, and all mice lacking a measurable anti-NcMIC4 IgG response. NcMIC4 in its native form elicited a substantial humoral IgG1 immune response and a reduction in cerebral parasite load compared to the controls, but 20% of mice succumbed to infection. Vaccination with recNcMIC4 also resulted in 20% of mice dying; however, in this group, cerebral parasite load was similar to the controls, and recNcMIC4 vaccination elicited a mixed IgG1/IgG2 response. In conclusion, vaccines based on NcMIC4, especially pcDNA-NcMIC4, render mice more susceptible to cerebral disease upon challenge with N. caninum tachyzoites.

No temporal association between influenza outbreaks and invasive pneumococcal infections

OBJECTIVE: To assess whether the influenza peak in populations precedes the annual peak for invasive pneumococcal infections (IPI) in winter. DESIGN: Ecological study. Active surveillance data on influenza A and IPI in children up to 16 years of age collected from 1997 to 2003 were analysed. SETTING: Paediatric hospitals in Germany. Patients: Children under 16 years of age. RESULTS: In all years under study, the influenza A season did not appear to affect the IPI season (p = 0.49). Specifically, the influenza peak never preceded the IPI peak. CONCLUSION: On a population level there was no indication that the annual influenza epidemic triggered the winter increase in the IPI rate or the peak of the IPI distribution in children.

The influence of measles vaccination on the incidence of otosclerosis in Germany

The pathologic process of otosclerosis is characterized by an inflammatory lytic phase followed by an abnormal bone remodeling at very specific sites of predilection. There is a clear genetic predisposition with about half of all cases occurring in families with more than one affected member. Females are affected more frequently than males with an approximate 2:1 ratio. N, H, and F measles proteins as well as measles virus RNA have been demonstrated in osteoblasts, chondroblasts, and macrophages of the inflammatory phase of the disease. These observations merely show an association between measles viruses and otosclerosis. In the present study, we tried to prove that there is a causal relationship: voluntary measles vaccination has been available in Germany since 1974. In the absence of official data, we reconstructed the rate of vaccination coverage between 1974 and 2004 using information from the Robert Koch Institute (RKI, Berlin) and from the literature. From the German Federal Office of Statistics, we received the data of 64,112 patients who had been hospitalized between 1993 and 2004 and in whom otosclerosis (ICD-9: 387; ICD-10: H80) had been confirmed. We calculated the effect of measles vaccination on the incidence of hospital treatments for otosclerosis in the period from 1993 to 2004 in Germany. For this purpose, we divided the female and male otosclerosis patients treated as inpatients each year in the observation period into two age groups: those up to 25 years, who had in most cases been vaccinated (designated below as "vaccinated patients") and those over 25 years who mostly could not have been vaccinated (designated below as "unvaccinated patients"). We calculated the incidence of otosclerosis requiring inpatient treatment for the two age groups in each year in the period of observation. For external validation of the study results, the same analysis was carried out in all patients who received inpatient treatment for otitis media in the same period. Between 1993 and 2004 the incidence of hospital treatments for otosclerosis decreased to a significantly greater extent in the vaccinated patients than in the unvaccinated patients. The decline is much greater in men than in women. A comparable effect cannot be demonstrated in patients with otitis media. The results indicate that measles vaccination in Germany has resulted in a significant reduction in the number of hospital treatments for otosclerosis in the vaccinated age groups. We conclude that there is a causal relationship between measles viruses and the development of otosclerosis.

Oxidative stress in lungs of mice infected with influenza A virus

As oxidative stress has been implicated in the pathogenesis of certain viral diseases we determined antioxidant and prooxidant parameters in lungs and bronchoalveolar lavage fluid (BALF) of mice infected with a lethal dose of influenza A/PR8/34 virus. Viral infection was characterized by massive infiltration of leukocytes, mainly polymorphonuclear leukocytes, into the alveolar space. The total number of BALF cells increased up to 8-fold (day 3 post-infection) and these cells appeared activated as judged by their increased rates of superoxide anion radical (O2-.) generation upon stimulation. Maximal rates of radical generation by BALF cells during the early stages of infection were 15- or 70-fold higher than those of cells from control animals when expressed per cell or total BALF cells, respectively. At the terminal stages of infection the total capacity of BALF cells to release O2-. declined to approximately 35-fold the control values. Infection also resulted in increased in vivo formation of hydrogen peroxide (H2O2) within the lungs at a time that coincided with the maximal capacity of BALF cells to release O2-.. Whereas pulmonary activities of glutathione peroxidase and reductase remained unaltered, levels of ascorbate in the cell-free BALF decreased significantly during the early stages of the infection and then returned to normal levels and above, late in infection. The oxidation state of the dehydroascorbic acid/ascorbate couple increased concomitantly with the decrease in ascorbate concentrations early in infection and remained elevated throughout the infection. As assessed by the prevention of peroxyl radical-induced loss of phycoerythrin fluorescence, the total antioxidant capacity present in lung tissue homogenate from terminally ill animals was not diminished when compared to that prepared from lungs of control mice. We conclude that although early stages of influenza infection are associated with the presence of oxidative stress in the lung tissue and alveolar fluid lining the epithelial cells, this stress does not appear to overwhelm local antioxidant defenses. The results therefore do not support a direct causative role of oxidative tissue damage in the pathogenesis of influenza virus infection.

Human immunodeficiency virus type 1 and influenza virus exit via different membrane microdomains

Directed release of human immunodeficiency virus type 1 (HIV-1) into the cleft of the virological synapse that can form between infected and uninfected T cells, for example, in lymph nodes, is thought to contribute to the systemic spread of this virus. In contrast, influenza virus, which causes local infections, is shed into the airways of the respiratory tract from free surfaces of epithelial cells. We now demonstrate that such differential release of HIV-1 and influenza virus is paralleled, at the subcellular level, by viral assembly at different microsegments of the plasma membrane of HeLa cells. HIV-1, but not influenza virus, buds through microdomains containing the tetraspanins CD9 and CD63. Consequently, the anti-CD9 antibody K41, which redistributes its antigen and also other tetraspanins to cell-cell adhesion sites, interferes with HIV-1 but not with influenza virus release. Altogether, these data strongly suggest that the bimodal egress of these two pathogenic viruses, like their entry into target cells, is guided by specific sets of host cell proteins.

Lung epithelial apoptosis in influenza virus pneumonia: the role of macrophage-expressed TNF-related apoptosis-inducing ligand

Mononuclear phagocytes have been attributed a crucial role in the host defense toward influenza virus (IV), but their contribution to influenza-induced lung failure is incompletely understood. We demonstrate for the first time that lung-recruited "exudate" macrophages significantly contribute to alveolar epithelial cell (AEC) apoptosis by the release of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a murine model of influenza-induced pneumonia. Using CC-chemokine receptor 2-deficient (CCR2(-/-)) mice characterized by defective inflammatory macrophage recruitment, and blocking anti-CCR2 antibodies, we show that exudate macrophage accumulation in the lungs of influenza-infected mice is associated with pronounced AEC apoptosis and increased lung leakage and mortality. Among several proapoptotic mediators analyzed, TRAIL messenger RNA was found to be markedly up-regulated in alveolar exudate macrophages as compared with peripheral blood monocytes. Moreover, among the different alveolar-recruited leukocyte subsets, TRAIL protein was predominantly expressed on macrophages. Finally, abrogation of TRAIL signaling in exudate macrophages resulted in significantly reduced AEC apoptosis, attenuated lung leakage, and increased survival upon IV infection. Collectively, these findings demonstrate a key role for exudate macrophages in the induction of alveolar leakage and mortality in IV pneumonia. Epithelial cell apoptosis induced by TRAIL-expressing macrophages is identified as a major underlying mechanism.

Routine vaccination against pertussis and the risk of childhood asthma: a population-based cohort study

BACKGROUND: In industrialized countries vaccination coverage remains suboptimal, partly because of perception of an increased risk of asthma. Epidemiologic studies of the association between childhood vaccinations and asthma have provided conflicting results, possibly for methodologic reasons such as unreliable vaccination data, biased reporting, and reverse causation. A recent review stressed the need for additional, adequately controlled large-scale studies. OBJECTIVE: Our goal was to determine if routine childhood vaccination against pertussis was associated with subsequent development of childhood wheezing disorders and asthma in a large population-based cohort study. METHODS: In 6811 children from the general population born between 1993 and 1997 in Leicestershire, United Kingdom, respiratory symptom data from repeated questionnaire surveys up to 2003 were linked to independently collected vaccination data from the National Health Service database. We compared incident wheeze and asthma between children of different vaccination status (complete, partial, and no vaccination against pertussis) by computing hazard ratios. Analyses were based on 6048 children, 23 201 person-years of follow-up, and 2426 cases of new-onset wheeze. RESULTS: There was no evidence for an increased risk of wheeze or asthma in children vaccinated against pertussis compared with nonvaccinated children. Adjusted hazard ratios comparing fully and partially vaccinated with nonvaccinated children were close to one for both incident wheeze and asthma. CONCLUSION: This study provides no evidence of an association between vaccination against pertussis in infancy and an increased risk of later wheeze or asthma and does not support claims that vaccination against pertussis might significantly increase the risk of childhood asthma.

Economic evaluation of varicella vaccination in Swiss children and adolescents

This study explores the effects of three different 2-dose varicella zoster virus (VZV) vaccination strategies in Switzerland. The EVITA model was used to assess clinical benefits and costs of strategies (1) vaccination of 11-15 year old adolescents with a negative or uncertain history for chickenpox, (2) universal vaccination of toddlers at age 1 to 2 years, and (3) strategy 2 plus catch-up vaccination of 11-15 year old susceptible adolescents. The cost-effectiveness analysis compares strategies 2 and 3 versus strategy 1 (current vaccination policy in Switzerland). Probabilities for clinical outcomes and medical resource utilization were derived from a real-world survey among Swiss pediatricians and general practitioners including 236 individuals with VZV infection, published information on varicella complications, and expert opinion. Costs of medical resource utilization represent official Swiss medical tariffs. The model predicts both universal childhood vaccination strategies to be more effective in reducing varicella disease burden compared to strategy 1. Economically, both universal childhood vaccination strategies with or without catch-up result in net savings from the societal perspective reflected by a benefit cost ratio (BCR) of 1.22 or 1.29, respectively. In contrast, the model predicts net costs from the payer perspective (BCR of 0.27 and 0.30, respectively). These economic findings are comparable to those reported from other similar evaluations. However, due to the recent recommendation for using a 2-dose varicella vaccination schedule, our economic results for Switzerland are somewhat less favorable than those for other country analyses in which a less expensive 1-dose vaccination regimen for toddlers has been studied.

Vaccination of cystic fibrosis patients against Pseudomonas aeruginosa reduces the proportion of patients infected and delays time to infection

INTRODUCTION: Cystic fibrosis (CF) almost always leads to chronic airway infection with Pseudomonas aeruginosa. Despite advances in antibiotic therapy, after chronic infection rapid deterioration in lung function occurs, increasing morbidity and mortality. Prevention of infection by vaccination is desirable, but earlier trials produced disappointing results. The promising short term immunogenicity and safety of a new P. aeruginosa vaccine prompted us to evaluate its long term efficacy. We conducted a 10-year retrospective analysis of outcomes in a group of vaccinated patients. MATERIALS AND METHODS: In 1989-1990, 30 young children with CF, mean age 7 years, with no prior history of infection with P. aeruginosa, were vaccinated against P. aeruginosa with a polyvalent conjugate vaccine. We report the follow-up of 26 of these patients from 1989 to 2001. The patients were given yearly vaccine boosters. Comparisons were made with a CF patient control group matched for gender, age and, where possible, genetic mutation. Vaccinated patients and controls were attending a single CF clinic and received the same clinical management throughout the study period. Main outcomes were time to infection, proportion of patients infected, development of P. aeruginosa mucoid phenotype, lung function and body weight. RESULTS: The time to infection with P. aeruginosa was longer in the vaccination group than in the control group, and fewer vaccinated patients than controls became chronically infected (32% versus 72%; P < 0.001). The proportion of mucoid infections was higher in the control group (44%) than in the vaccinated group (25%). Patients >/=18 years of age at the end of the study had a lower mean forced expiratory volume at 1 s (FEV1) than did those 13-17 years of age, but this difference was small in the vaccinated group (73.6% versus 83.7%) compared with the controls (48.0% versus 78.7%). In the >/=18 year age category the mean FEV1% at 10 years was 73.6% (vaccinated) and 48.0% (controls) (P < 0.05). In the vaccinated group only 11 (44%) of 25 patients were underweight at the 10-year follow-up compared with 18 (72%) of 25 at the beginning of the study. In the control group 17 (68%) of 25 patients were underweight at 10-year follow-up compared with 16 (64%) of 25 at the beginning of the study. CONCLUSION: Regular vaccination of young CF patients for a period of 10 years with a polyvalent conjugate vaccine reduced the frequency of chronic infection with P. aeruginosa. This was associated with better preservation of lung function. Vaccinated patients gained more weight during the study period, a possible indication of an improved overall health status.

Antibody responses induced by long-term vaccination with an octovalent conjugate Pseudomonas aeruginosa vaccine in children with cystic fibrosis

We assessed the serological responses over 10 years to repeated immunization of cystic fibrosis (CF) patients with an O-polysaccharide (OPS)-toxin A conjugate vaccine against Pseudomonas aeruginosa. A retrospective analysis was performed with sera from 25 vaccinated and 25 unvaccinated children treated at the same CF centre and matched for clinical management, age and gender. Yearly immunization led to sustained elevations of serum immunoglobulin G (IgG) antibody levels to all vaccine components. Eighteen unvaccinated patients but only eight vaccinated ones developed chronic pseudomonal lung infections. Infection rapidly caused further marked elevations of polysaccharide- but not toxin A-specific serum IgG in both immunized and nonimmunized patients, indicating that protection did not depend on the quantity of IgG present. However, qualitative analyses revealed that the protective capacity of specific serum IgG antibodies was linked to high affinity and to specificity for OPS serotypes rather than for lipopolysaccharide core epitopes.