Early-life viral infections are associated with disadvantageous immune and microbiota profiles and recurrent respiratory infections.

The respiratory tract is populated by a specialized microbial ecosystem, which is seeded during and directly following birth. Perturbed development of the respiratory microbial community in early-life has been associated with higher susceptibility to respiratory tract infections (RTIs). Given a consistent gap in time between first signs of aberrant microbial maturation and the observation of the first RTIs, we hypothesized that early-life host-microbe cross-talk plays a role in this process. We therefore investigated viral presence, gene expression profiles and nasopharyngeal microbiota from birth until 12 months of age in 114 healthy infants. We show that the strongest dynamics in gene expression profiles occurred within the first days of life, mostly involving Toll-like receptor (TLR) and inflammasome signalling. These gene expression dynamics coincided with rapid microbial niche differentiation. Early asymptomatic viral infection co-occurred with stronger interferon activity, which was related to specific microbiota dynamics following, including early enrichment of Moraxella and Haemophilus spp. These microbial trajectories were in turn related to a higher number of subsequent (viral) RTIs over the first year of life. Using a multi-omic approach, we found evidence for species-specific host-microbe interactions related to consecutive susceptibility to RTIs. Although further work will be needed to confirm causality of our findings, together these data indicate that early-life viral encounters could impact subsequent host-microbe cross-talk, which is linked to later-life infections.

Bovine Immune Responses to Moraxella bovis and Moraxella bovoculi Following Vaccination and Natural or Experimental Infections.

Studies have sought to develop effective vaccines against infectious bovine keratoconjunctivitis (IBK). Most research has focused on parenterally administered vaccines against Moraxella bovis antigens; however, researchers have also included Moraxella bovoculi antigens in vaccines to prevent IBK. Critical knowledge gaps remain as to which Moraxella spp antigens might be completely protective, and whether systemic, mucosal, or both types of immune responses are required for protection against IBK associated with Moraxella spp. Immune responses to commensal Moraxella spp residing in the upper respiratory tract and eye have not been analyzed to determine if these responses control colonization or contribute to IBK.

Lymphocyte predominant cells of nodular lymphocyte predominant Hodgkin lymphoma interact with rosetting T cells in an immunological synapse.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a subtype of Hodgkin lymphoma with a preserved B-cell phenotype and follicular T helper (TFH ) cells rosetting around the tumor cells, the lymphocyte-predominant (LP) cells. As we recently described reactivity of the B-cell receptors of LP cells of some NLPHL cases with Moraxella spp. proteins, we hypothesized that LP cells could present peptides to rosetting T cells in a major histocompatibility complex class II (MHCII)-bound manner. Rosetting PD1+ T cells were present in the majority of NLPHL cases, both in typical (17/20) and variant patterns (16/19). In most cases, T-cell rosettes were CD69+ (typical NLPHL, 17/20; NLPHL variant, 14/19). Furthermore, both MHCII alpha and beta chains were expressed in the LP cells in 23/39 NLPHL. Proximity ligation assay and confocal laser imaging demonstrated interaction of the MHCII beta chain expressed by the LP cells and the T-cell receptor alpha chain expressed by rosetting T cells. We thus conclude that rosetting T cells in NLPHL express markers that are encountered after antigenic exposure, that MHCII is expressed by the LP cells, and that LP cells interact with rosetting T cells in an immunological synapse in a subset of cases. As they likely receive growth stimulatory signals in this way, blockade of this interaction, for example, by PD1-directed checkpoint inhibitors, could be a treatment option in a subset of cases in the future.

The upper-airway microbiota and loss of asthma control among asthmatic children.

The airway microbiome has an important role in asthma pathophysiology. However, little is known on the relationships between the airway microbiome of asthmatic children, loss of asthma control, and severe exacerbations. Here we report that the microbiota's dynamic patterns and compositions are related to asthma exacerbations. We collected nasal blow samples (n = 319) longitudinally during a clinical trial at 2 time-points within one year: randomization when asthma is under control, and at time of early loss of asthma control (yellow zone (YZ)). We report that participants whose microbiota was dominated by the commensal Corynebacterium + Dolosigranulum cluster at RD experience the lowest rates of YZs (p = 0.005) and have longer time to develop at least 2 episodes of YZ (p = 0.03). The airway microbiota have changed from randomization to YZ. A switch from the Corynebacterium + Dolosigranulum cluster at randomization to the Moraxella- cluster at YZ poses the highest risk of severe asthma exacerbation (p = 0.04). Corynebacterium's relative abundance at YZ is inversely associated with severe exacerbation (p = 0.002).

A 2-year randomized blinded controlled trial of a conditionally licensed Moraxella bovoculi vaccine to aid in prevention of infectious bovine keratoconjunctivitis in Angus beef calves.

BACKGROUND: Infectious bovine keratoconjunctivitis (IBK) in beef cattle has major welfare and production implications. Effective vaccination against IBK would also reduce antibiotic use in beef production. OBJECTIVE/HYPOTHESIS: To evaluate the efficacy of a conditionally licensed commercial IBK vaccine containing Moraxella bovoculi bacterin. Primary working hypothesis was that animals vaccinated with 2 doses of the commercial M. bovoculi vaccine would have a lower risk of disease. ANIMALS: Spring born calves at a university cow-calf herd. After excluding animals with ocular lesions, calves eligible for prevention assessment in 2017 and 2018 were 163 (81 vaccinated, 82 unvaccinated) and 207 (105 vaccinated, 102 unvaccinated). One hundred sixty two and two hundred and six calves completed the follow-up period in 2017 and 2018, respectively. METHODS: A randomized controlled trial. The trial design was a 2-arm parallel trial with a 1:1 allocation ratio. RESULTS: In both years, calves receiving the vaccine had more IBK. This effect was small. The pooled risk ratio was 1.30 (95% confidence interval 0.84-2.01). The pooled unadjusted difference in mean weight (kg) at weaning was -0.88 (95% confidence interval-7.2-5.43). CONCLUSIONS AND CLINICAL IMPORTANCE: We were unable to document that the M. bovoculi bacterin vaccine had a protective effect for the incidence of IBK in our single herd in a 2-year study.

Antigenic characterization of Moraxella bovis, Moraxella bovoculi and Moraxella ovis strains with potential use in vaccines.

Moraxella bovis is historically known as the primary agent of infectious bovine keratoconjunctivitis (IBK). However, Moraxella bovoculi and Moraxella ovis are also reported to be involved in the pathogenesis of IBK, therefore, these three species should be included in the development of a new vaccine with a broad-spectrum protection against the disease natural challenge. In this study we investigated the antigenic properties of clinical isolates and reference strains of M. bovis, M. bovoculi and M. ovis using a novel in vitro approach for vaccine evaluation based on two techniques, flow cytometry and western blotting (WB). Here, we demonstrated that rabbit antisera produced against reference M. bovis strain and commercial bacterin showed low number of IgG with capacity to recognize a panel of heterologous strains composed by M. bovoculi and M. ovis. On the other hand, the antisera generated against two clinical isolates of M. ovis (Mov2 and Mov3) presented high cross-reactivity levels against all M. ovis and M. bovis strains evaluated. Similarly, the antisera against Mbv3 (clinical isolate of M. bovoculi) had high levels of IgG associated on the surface of all M. bovoculi strains and most of the M. ovis strains analyzed. The WB analysis demonstrated that Moraxella spp. has multiple immunogenic antigens and most of them are shared between the three species. Based on the cross-reactivity analysis and considering the relative number of IgGs associated on the bacterial surface, we suggest that a multivalent vaccine including Mbv3, Mov2 and Mov3 strains may provide a strong and broad protection against all strains involved in IBK outbreaks.

A Pediatric Case of Bacteremia and Possible Cholecystitis Due to Moraxella osloensis.

We encountered a pediatric case of bacteremia and possible cholecystitis due to Moraxella osloensis that was treated successfully. We confirmed the diagnosis with the presence of a high serum titer of the antibody to the organism. Furthermore, 16S rRNA sequencing was performed to identify the bacteria.

Comparison of the prevalence of common bacterial pathogens in the oropharynx and nasopharynx of gambian infants.

BACKGROUND: CRM- based pneumococcal conjugate vaccines generally have little impact on the overall prevalence of pneumococcal carriage because of serotype replacement. In contrast, protein vaccines could substantially reduce the overall prevalence of pneumococcal carriage with potential microbiological and clinical consequences. Therefore, trials of pneumococcal protein vaccines need to evaluate their impact on carriage of other potentially pathogenic bacteria in addition to the pneumococcus. METHODS: As a prelude to a trial of an investigational pneumococcal vaccine containing pneumococcal polysaccharide conjugates and pneumococcal proteins, the prevalence of carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella species and Staphylococcus aureus in the nasopharynx of 1030 Gambian infants (median age 35 weeks) was determined. An oropharyngeal swab was obtained at the same time from the first 371 infants enrolled. Standard microbiological techniques were used to evaluate the bacterial flora of the pharynx and to compare that found in the oropharynx and in the nasopharynx. RESULTS: The overall pneumococcal carriage rate was high. Isolation rates of S. pneumoniae and Moraxella species were significantly higher using nasopharyngeal rather than oropharyngeal swabs (76.1% [95% CI 73.4%,78.7%] vs. 21.3% [95% CI 17.2%,25.8%] and 48.9% [95% CI 45.8%, 52.0%] vs. 20.5% % [95% CI 16.5%,25.0%] respectively). In contrast, S. aureus and H. influenzae were isolated more frequently from oropharyngeal than from nasopharyngeal swabs (65.0% [95% CI 59.9%, 69.8%] vs. 33.6% [95% CI 30.7%, 36.5%] and 31.8% [95% CI 16.5%, 25.0%] vs. 22.4% [95% CI 19.9%, 25.1%] respectively). No group A ß haemolytic streptococci were isolated. CONCLUSION: Collection of an oropharyngeal swab in addition to a nasopharyngeal swab will provide little additional information on the impact of a novel pneumococcal vaccine on pneumococcal carriage but it might provide additional, valuable information on the impact of the vaccine on the overall microbiota of the pharynx.

Randomized controlled field trial to assess efficacy of a Moraxella bovis pilin-cytotoxin-Moraxella bovoculi cytotoxin subunit vaccine to prevent naturally occurring infectious bovine keratoconjunctivitis.

OBJECTIVE: To evaluate efficacy of a recombinant Moraxella bovis pilin-cytotoxin-Moraxella bovoculi cytotoxin subunit vaccine to prevent naturally occurring infectious bovine keratoconjunctivitis (IBK). ANIMALS: 107 beef steers. PROCEDURES: 2 groups of calves were inoculated SC with an immunostimulating complex (ISCOM) matrix adjuvant (control group; n = 54) or a recombinant M bovis pilin-cytotoxin-M bovoculi cytotoxin subunit antigen with the ISCOM matrix adjuvant (vaccine group; 53); calves received booster injections 21 days later. Calves were examined once weekly for 16 weeks. Investigators and herd managers were not aware of the inoculum administered to each calf throughout the trial. Primary outcome of interest was the cumulative proportion of calves that developed IBK. Serum samples were obtained before inoculation (day 0) and on days 42 and 112. Serum hemolysin-neutralizing titers against native M bovis and M bovoculi cytotoxin were determined. RESULTS: No difference was detected between groups for the cumulative proportion of calves that developed IBK at weeks 8 and 16 after inoculation. Non-IBK-affected calves in the vaccine group had a significantly higher fold change in serum hemolysin-neutralizing titer against native M bovoculi cytotoxin from day 0 to 42 compared to control calves. CONCLUSIONS AND CLINICAL RELEVANCE: The M bovis pilin-cytotoxin-M bovoculi cytotoxin subunit vaccine with the ISCOM matrix adjuvant was not effective at preventing naturally occurring IBK. It is likely that the incorporation of additional protective antigens in a recombinant Moraxella spp subunit vaccine will be required to yield a product that can be used for effective immunization of cattle against IBK.

A randomized and blinded field trial to assess the efficacy of an autogenous vaccine to prevent naturally occurring infectious bovine keratoconjunctivis (IBK) in beef calves.

A randomized and blinded 2-arm parallel trial was conducted to assess the efficacy of an autogenous vaccine to prevent naturally occurring infectious bovine keratoconjunctivis (IBK) in beef calves. The trial was managed between May and November 2008 on university owned farms in Iowa and Wisconsin. The vaccine at Iowa contained Moraxella bovoculi (M. bovoculi) while the organism used in the Wisconsin herds vaccine was Branhemella ovis (B. ovis renamed M. ovis). Calves born between January and May 2008 without visible corneal lesions were randomized to receive an autogenous vaccine or placebo vaccine using a computer generated sequence. Two subcutaneous doses were administered 21-28 days apart. Allocation to treatment was concealed using bottles marked A or B. Staff were blind to the treatment allocation. The primary outcome was IBK cumulative incidence over the study period. The secondary outcome was weaning weight. Only the Iowa herd met the criteria for an "at-risk" herd i.e. >15% IBK in unvaccinated calves and M. bovoculi isolation from IBK cases. Analysis was "per-protocol". The cumulative incidence of IBK was 47/105 in vaccinated calves and 49/109 in unvaccinated calves (unadjusted odds ratio=0.99, 95% CI: 0.58-1.70). Weight at weaning did not differ between the vaccinated cohort 148kg (SD: +/-27) and unvaccinated cohort 146kg (SD: +/-26) (unadjusted beta=1.5 and 95% CI: -5.5 to 8.6). Results indicate that the autogenous vaccine was ineffective in this study population.

Infectious bovine keratoconjunctivitis vaccine development.

Infectious bovine keratoconjunctivitis is a common and highly contagious ocular disease affecting cattle worldwide. The tremendous economic losses attributable to this disease warrant continued investigation into methods of prevention. Multiple virulence factors have been linked to the primary aetiologic agent, Moraxella bovis. Efforts to develop an efficacious vaccine have primarily focused upon the use of surface pili or cytolysin to stimulate host immunity; however, M. bovis possesses other virulence determinants that include proteases, fibrinolysins, phospholipases and other cell surface components such as outer membrane proteins. These potentially conserved antigens provide additional possibilities for vaccine development. Examination of appropriate antigen presentation is necessary to attain an adequate immune response. Further, the potential for antigenic diversity as well as epitope conversion requires continuous epidemiological surveillance of isolates recovered from outbreaks. Current work targeting conserved immunogens provides hope for efficacious vaccines that when used in tandem with proper management may control, if not prevent, infectious bovine keratoconjunctivitis.

An epitope shared by enterobacterial and neisserial porin proteins.

A murine monoclonal antibody (MAb F9-16) raised against a porin protein epitope called Po I of an E. coli 055 strain showed broad cross-reactivity with bacteria within the Enterobacteriaceae, and also recognized neisseriae and moraxellae. In an immunodot assay, the antibody was bound by 32/33 strains of neisseriae and moraxellae after SDS treatment of the bacteria. Testing intact bacteria, 11/33 isolates showed definite MAb binding, including serogroup A and B meningococci. In Western blotting, the anti-Po I MAb targeted the gonococcal porin proteins PIA and PIB, and class 1, class 2, and class 3 porins of meningococci. The MAb showed no reactivity against decapeptides which corresponded to the whole length of a meningococcal class 1 porin protein of the subtype P1, 7, 16. These findings accord with the inference that enterobacterial, neisserial and moraxellae porin proteins share an epitope (Po I) which is determined by the three-dimensional rather than by the primary structure of the proteins and that this epitope is shielded in most isolates but surface-exposed in some isolates, including some strains of meningococci. Since Po I is broadly distributed among commensal and pathogenic bacteria and has demonstrated immunogenicity in humans, this epitope may play a role in elicitation of "normal" antibodies with immunoprotective activity.

Quantification of Moraxella bovis haemagglutinating adhesins with monoclonal antibodies.

Six monoclonal antibodies (MAbs) against Moraxella bovis GF 9 were used to quantify haemagglutinating adhesins of 16 strains of this organism. The amount of each MAb necessary to inhibit one haemagglutinating unit of each strain varied between 4 and 0.007 times that required by strain GF 9. Five strains reacted with six MAbs, one with five, two with four, one with three, two with two and three with none. The procedures used enabled to detect dominant strains candidates for vaccines.

Identity between polysaccharide antigens of Moraxella nonliquefaciens, group B Neisseria meningitidis, and Escherichia coli K1 (non-O acetylated).

A surface polysaccharide antigen of Moraxella nonliquefaciens, reported to be cross-reactive with the capsular polysaccharides of group B Neisseria meningitidis and Escherichia coli K1 (K. Blvre, K. Bryn, O. Closs, N. Hagen, and L. O. Froholm, NIPH Ann. 6:65-73, 1983), was isolated, purified, and characterized chemically, immunologically, and by nuclear magnetic resonance. This polysaccharide was shown to be a linear homopolymer of alpha (2----8)-linked N-acetylneuraminic acid, identical to the capsular polysaccharide of group B N. meningitidis and O-acetyl-negative variants of E. coli K1.

Effectiveness of two commercial infectious bovine keratoconjunctivitis vaccines.

Two commercially available infectious bovine keratoconjunctivitis (IBK) vaccines were evaluated for their effectiveness in protecting cattle from disease caused by experimental challenge exposure and natural transmission of Moraxella bovis infections. The study was conducted as 2 experiments, using a total of 81 cattle that were culture-negative for M bovis prior to vaccination. In each experiment, young adult cattle were randomly allotted to 4 groups. Each calf in groups 1 and 2 was vaccinated according to the vaccine manufacturer's directions. Groups 3 and 4 were unvaccinated controls. Three weeks after the last vaccination, each calf in groups 1 and 3 was experimentally challenge exposed by dropping a suspension of viable cells of a virulent strain of M bovis directly onto the corneal surface of each eye. Calves in all 4 groups were then commingled in open pastures so that calves in groups 2 and 4 could be naturally exposed to the calves with experimentally induced infections. Each calf was examined for signs of ocular disease on a regular basis by 2 experienced clinicians who scored each eye for severity of disease on the basis of a prearranged scale. Neither clinician was aware of the vaccination or exposure status of the calf nor to which experimental group they belonged. Lacrimal secretions were collected regularly to determine the number of eyes in which the virulent organism became established. Moraxella bovis with bacterial cultural characteristics similar to those of the virulent strain placed in the eyes of groups 1 and 3 was cultured from greater than or equal to 83% of the eyes of calves in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of the serologic properties of bacteria of the genus Moraxella]. / Kharakteristika serologicheskikh svoistv bakterii roda Moraxella.

Antigenic relationships between different Moraxella species and closely related bacteria were examined in agglutination (AT), indirect immunofluorescence (IIF), double gel immunodiffusion tests, and counter-current immunoelectrophoresis with experimentally obtained antisera. Specificities of commercial antibody reagents, manufactured by Abbott, USA, intended for enzyme immunoassay diagnosis of gonorrhea and urogenital chlamydia infections, were assessed. Results of donor blood serum examinations helped establish AT and IIF diagnostic titres to be used in serologic diagnosis of infections induced by various Moraxella species.

Identification of Moraxella bovis by using a monoclonal antibody to a lipopolysaccharide epitope.

A monoclonal antibody to the lipopolysaccharide of Moraxella bovis is described. In an indirect fluorescent-antibody test, this monoclonal antibody reacted with 39 of 39 strains of M. bovis tested and did not react with 26 nonfermenting gram-negative coccobacilli other than M. bovis. When used in an indirect fluorescent-antibody test, it proved useful for rapid and easy identification of M. bovis.

Attachment of Moraxella bovis to calf corneal cells and inhibition by antiserum.

An in vitro assay was developed using calf corneal cells to assess the importance of fimbriae in the colonisation of the bovine ocular surface by Moraxella bovis, and the role of fimbrial antibodies in the bovine immune response and resistance to infectious bovine keratoconjunctivitis (IBK). Fimbriae promoted adherence of M. bovis to calf corneal cells in culture; 15 fimbriate isolates, representative of 6 fimbrial serogroups of M. bovis, adhered to the cells whereas 4 non-fimbriate isolates failed to do so. Fimbrial antibodies in hyperimmune rabbit serum inhibited attachment of all fimbriate strains of the homologous fimbrial serogroup but not those of 5 heterologous serogroups. The relevance of these results to the use of a polyvalent fimbrial vaccine in the control of IBK is discussed.