Immune response to hepatitis B vaccination and factors associated with poor immune response among healthcare workers.

BACKGROUND: Hepatitis B virus (HBV) infection is a major global health problem, and healthcare workers (HCWs) are at high risk for HBV infection. Current guidelines strongly recommend immunization and screening for high-risk groups. AIMS: We evaluated immunization and screening for HBV vaccination, assessed post-vaccination immune status of HCW's and characterized potential risk factors associated with poor immune response. MATERIALS AND METHODS: From January 2010 to December 2018, we retrospectively analyzed comprehensive health checkup data for a total of 303 HCWs who received an HBV vaccination. After vaccination, HBV surface antibody (anti-HBs) titers were collected and the distribution of immune response types was determined. Risk factors for poor immune responses were identified using logistic regression. RESULTS: A total of 213 HCWs were analyzed after exclusion based on the exclusion criteria. In total, 28 (13.2%) HCWs had anti-HBs titers <100 mIU/mL (hyporesponsive/nonresponsive groups), and 185 (86.8%) had anti-HBs titers ≥100 mIU/mL (hyperresponsive group). Follow-up observations found that 75% (21/28) of the hyporesponsive/nonresponsive groups did not have increased anti-HBs titers or did not maintain an increased response. A multivariate analysis showed that HBV antibody titers at the time of employment were a significant risk factor (OR, 6.12; CI, 1.34-27.93; P = 0.019). CONCLUSIONS: More attention should be paid to groups that are hyporesponsive/nonresponsive after vaccination and to those with low anti-HBs titers at the beginning of employment. HCWs can be further protected from HBV if their results are discussed at postvaccination follow-ups.

Adult chronic myelomonocytic leukemia with trisomy 11: a case report.

Chronic myelomonocytic leukemia (cmml) is an indolent disease in the category of myelodysplastic and myeloproliferative neoplasms, which can often evolve into acute leukemic neoplasms. Although cytogenetic abnormalities such as trisomy 8 or absence of chromosome Y are well known, few reports about cmml with trisomy 11 have been published. Here, we report a case of cmml with trisomy 11 as the sole chromosomal abnormality, resulting in a very poor outcome. Based on a bone marrow specimen, cmml-1 with trisomy 11 was diagnosed in a 79-year-old man presenting with anemia and atypical peripheral blood cells. Because of the patient's age, he was followed without receiving anticancer treatment. Two months after his diagnosis, the patient's leucocytosis and anemia rapidly worsened, with increasing numbers of immature peripheral cells, which was strongly suggestive of leukemic transformation. Because of acute kidney injury superimposed on chronic kidney disease that led to poor performance status, cytotoxic chemotherapy was not considered feasible, and the patient was transferred to a hospice care facility.

Effects of ß-Glucan on the Release of Nitric Oxide by Macrophages Stimulated with Lipopolysaccharide.

This research analyzed the effect of ß-glucan that is expected to alleviate the production of the inflammatory mediator in macrophagocytes, which are processed by the lipopolysaccharide (LPS) of Escherichia. The incubated layer was used for a nitric oxide (NO) analysis. The DNA-binding activation of the small unit of nuclear factor-κB was measured using the enzyme-linked immunosorbent assay-based kit. In the RAW264.7 cells that were vitalized by Escherichia coli (E. coli) LPS, the ß-glucan inhibited both the combatant and rendering phases of the inducible NO synthase (iNOS)-derived NO. ß-Glucan increased the expression of the heme oxygenase-1 (HO-1) in the cells that were stimulated by E. coli LPS, and the HO-1 activation was inhibited by the tin protoporphyrin IX (SnPP). This shows that the NO production induced by LPS is related to the inhibition effect of ß-glucan. The phosphorylation of c-Jun N-terminal kinases (JNK) and the p38 induced by the LPS were not influenced by the ß-glucan, and the inhibitory κB-α (IκB-α) decomposition was not influenced either. Instead, ß-glucan remarkably inhibited the phosphorylation of the signal transducer and activator of transcription-1 (STAT1) that was induced by the E. coli LPS. Overall, the ß-glucan inhibited the production of NO in macrophagocytes that was vitalized by the E .coli LPS through the HO-1 induction and the STAT1 pathways inhibition in this research. As the host immune response control by ß-glucan weakens the progress of the inflammatory disease, ß-glucan can be used as an effective immunomodulator.

Effects of daidzein on alveolar bone loss and internal microstructures of bone in a rat model of experimental periodontitis: a study using micro-computed tomography.

BACKGROUND AND OBJECTIVE: Daidzein is an isoflavone abundant in soybeans, kudzu root and red clover, which have been widely studied for its therapeutic potential. The present study was designed to evaluate the effects of daidzein on alveolar bone loss and internal microstructures of bone in a rat model of experimental periodontitis by assessing morphological data obtained from micro-computed tomography (micro-CT). MATERIAL AND METHODS: Twenty-four male Sprague-Dawley rats were randomly assigned to the following three groups comprising eight animals each: the nonligation (NL) group; the ligation (L) group; and the ligation+daidzein (LD) group. To induce periodontitis, a 4-0 braided silk ligature was tied around the cervical area of the lower-right first molars of rats in groups L and LD. Rats in the LD group were given daily doses of daidzein (10 mg/kg of body weight) by intraperitoneal injection immediately after ligature placement. Two weeks after the placement of ligatures, mandibular block biopsies were scanned using a micro-CT system. RESULTS: Daily administration of daidzein strongly suppressed the ligature-induced loss of alveolar bone height. In addition, when rats were treated with daidzein, the ligature-induced decrease in the bone volume fraction was significantly recovered. Furthermore, daidzein significantly reversed ligature-induced deteriorations in the microarchitecture parameters of trabecular bone, such as trabecular thickness, bone mineral density, trabecular separation and structure model index. CONCLUSION: The study presented here demonstrates, for the first time, that daidzein effectively reduces alveolar bone destruction resulting from experimental periodontitis in rats. Further studies are necessary for the translation of this compound clinically to improve the outcomes of patients diagnosed with periodontitis.

Development of a genetic marker set to diagnose aspirin-exacerbated respiratory disease in a genome-wide association study.

We developed a genetic marker set of single nucleotide polymorphisms (SNPs) by summing risk scores of 14 SNPs showing a significant association with aspirin-exacerbated respiratory disease (AERD) from our previous 660 W genome-wide association data. The summed scores were higher in the AERD than in the aspirin-tolerant asthma (ATA) group (P=8.58 × 10(-37)), and were correlated with the percent decrease in forced expiratory volume in 1 s after aspirin challenge (r(2)=0.150, P=5.84 × 10(-30)). The area under the curve of the scores for AERD in the receiver operating characteristic curve was 0.821. The best cutoff value of the summed risk scores was 1.01328 (P=1.38 × 10(-32)). The sensitivity and specificity of the best scores were 64.7% and 85.0%, respectively, with 42.1% positive and 93.4% negative predictive values. The summed risk score may be used as a genetic marker with good discriminative power for distinguishing AERD from ATA.

Effect of caffeic acid phenethyl ester on Prevotella intermedia lipopolysaccharide-induced production of proinflammatory mediators in murine macrophages.

BACKGROUND AND OBJECTIVE: Caffeic acid phenethyl ester (CAPE) has numerous potentially beneficial properties, including antioxidant, immunomodulatory and anti-inflammatory activities. However, the effect of CAPE on periodontal disease has not been studied before. This study was designed to investigate the efficacy of CAPE in ameliorating the production of proinflammatory mediators in macrophages activated by lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease. MATERIAL AND METHODS: LPS from P. intermedia ATCC 25611 was isolated by using the standard hot phenol-water method. Culture supernatants were assayed for nitric oxide (NO), interleukin (IL)-1ß and IL-6. We used real-time polymerase chain reaction to quantify inducible NO synthase, IL-1ß, IL-6, heme oxygenase (HO)-1 and suppressors of cytokine signaling (SOCS) 1 mRNA expression. HO-1 protein expression and levels of signaling proteins were assessed by immunoblot analysis. DNA-binding activities of NF-κB subunits were analyzed by using the enzyme-linked immunosorbent assay-based kits. RESULTS: CAPE exerted significant inhibitory effects on P. intermedia LPS-induced production of NO, IL-1ß and IL-6 as well as their mRNA expression in RAW264.7 cells. CAPE-induced HO-1 expression in cells activated with P. intermedia LPS, and selective inhibition of HO-1 activity by tin protoporphyrin IX attenuated the inhibitory effect of CAPE on LPS-induced NO production. CAPE did not interfere with IκB-α degradation induced by P. intermedia LPS. Instead, CAPE decreased nuclear translocation of NF-κB p65 and p50 subunits induced with LPS, and lessened LPS-induced p50 binding activity. Further, CAPE showed strong inhibitory effects on LPS-induced signal transducer and activator of transcription 1 and 3 phosphorylation. Besides, CAPE significantly elevated SOCS1 mRNA expression in P. intermedia LPS-stimulated cells. CONCLUSION: Modulation of host response by CAPE may represent an attractive strategy towards the treatment of periodontal disease. In vivo studies are required to appraise the potential of CAPE further as an immunomodulator in the treatment of periodontal disease.

Combined surgical and endovascular management of a giant fusiform PCA aneurysm in a pediatric patient. A case report.

Treatment of intracranial giant aneurysms presents is challenging. In the case of pediatric giant aneurysm, more challenges arise. We describe our experience with a 17-year-old pediatric patient who presented with severe headache. She was diagnosed as having a giant fusiform aneurysm at the right P1-P2-Pcom junction. The aneurysm was treated with superficial temporal artery-posterior cerebral artery bypass and subsequent coil embolization of the aneurysm with parent artery occlusion. The patient had an excellent outcome at one-year follow-up. Our case suggests a combined approach of surgical and endovascular management may yield a better outcome than surgery or endovascular management alone in the treatment of pediatric giant aneurysm.

Isorhamnetin inhibits Prevotella intermedia lipopolysaccharide-induced production of interleukin-6 in murine macrophages via anti-inflammatory heme oxygenase-1 induction and inhibition of nuclear factor-κB and signal transducer and activator of transcription 1 activation.

BACKGROUND AND OBJECTIVE: Interleukin-6 (IL-6) is a key proinflammatory cytokine that has been considered to be important in the pathogenesis of periodontal disease. Therefore, host-modulatory agents directed at inhibiting IL-6 appear to be beneficial in terms of attenuating periodontal disease progression and potentially improving disease susceptibility. In the current study, we investigated the effect of the flavonoid isorhamnetin on the production of IL-6 in murine macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. MATERIAL AND METHODS: Lipopolysaccharide from P. intermedia ATCC 25611 was isolated using the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time PCR to quantify IL-6 and heme oxygenase-1 (HO-1) mRNA expression. The expression of HO-1 protein and the levels of signaling proteins were monitored using immunoblot analyses. The DNA-binding activity of nuclear factor-κB (NF-κB) was analyzed using ELISA-based assay kits. RESULTS: Isorhamnetin significantly down-regulated P. intermedia LPS-induced production of IL-6 as well as its mRNA expression in RAW264.7 cells. Isorhamnetin up-regulated the expression of HO-1 at both gene transcription and translation levels in cells stimulated with P. intermedia LPS. In addition, inhibition of HO-1 activity by tin protoporphyrin IX blocked the inhibitory effect of isorhamnetin on IL-6 production. Isorhamnetin failed to prevent LPS from activating either c-Jun N-terminal kinase or p38 pathways. Isorhamnetin did not inhibit NF-κB transcriptional activity at the level of inhibitory κB-α degradation. Isorhamnetin suppressed NF-κB signaling through inhibition of nuclear translocation and DNA binding activity of NF-κB p50 subunit and attenuated signal transducer and activator of transcription 1 signaling. CONCLUSION: Although further research is required to clarify the detailed mechanism of action, we propose that isorhamnetin may contribute to blockade of the host-destructive processes mediated by IL-6 and could be a highly efficient modulator of the host response in the treatment of inflammatory periodontal disease. Further research in animal models of periodontitis is required to better evaluate, the potential of isorhamnetin as a novel agent for treating periodontal disease.

SIGN-R1, a C-type lectin, enhances apoptotic cell clearance through the complement deposition pathway by interacting with C1q in the spleen.

Complements, such as C1q and C3, and macrophages in the splenic marginal zone (MZMs) play pivotal roles in the efficient uptake and processing of circulating apoptotic cells. SIGN-R1, a C-type lectin that is highly expressed in a subpopulation of MZMs, regulates the complement fixation pathway by interacting with C1q, to fight blood-borne Streptococcus pneumoniae. Therefore, we examined whether the SIGN-R1-mediated classical complement pathway plays a role in apoptotic cell clearance and immune tolerance. SIGN-R1 first-bound apoptotic cells and this binding was significantly enhanced in the presence of C1q. SIGN-R1-C1q complex then immediately mediated C3 deposition on circulating apoptotic cells in the MZ, leading to the efficient clearance of them. SIGN-R1-mediated C3 deposition was completely abolished in the spleen of SIGN-R1 knockout (KO) mice. Given that SIGN-R1 is not expressed in the liver, we were struck by the finding that C3-deposited apoptotic cells were still found in the liver of wild-type mice, and dramatically reduced in the SIGN-R1 KO liver. In particular, SIGN-R1 deficiency caused delayed clearance of apoptotic cells and aberrant secretion of cytokines, such as TNF-α, IL-6, and TGF-ß in the spleen as well as in the liver. In addition, anti-double- and single-stranded DNA antibody level was significantly increased in SIGN-R1-depleted mice compared with control mice. These findings suggest a novel mechanism of apoptotic cell clearance which is initiated by SIGN-R1 in the MZ and identify an integrated role of SIGN-R1 in the systemic clearance of apoptotic cells, linking the recognition of apoptotic cells, the opsonization of complements, and the induction of immune tolerance.

Characterization of low-pathogenicity H5 and H7 Korean avian influenza viruses in chickens.

To date, all isolated highly pathogenic avian influenza (HPAI) viruses that cause systemic infection with a high mortality rate in poultry species have been known to belong to either the H5 or H7 subtypes. The HPAI viruses may originate because of the insertion of multiple basic amino acids at the cleavage site of the hemagglutinin protein after the low-pathogenic H5 and H7 viruses have been introduced into poultry. In the present study, we investigated the phylogenetic characteristics of the H5 (n = 4) and H7 (n = 3) low-pathogenic avian influenza (LPAI) viruses isolated from wild birds in Korea by using nucleotide sequences of all 8 gene segments of the viral genome. Further, we evaluated the infectivity, transmissibility, and pathogenic potential of these viruses in chickens. Phylogenetic analysis showed that all viruses used in the study clustered in the Eurasian lineage and were similar to the viruses isolated in Asian countries that share the East Asian-Australasian migratory bird flyway. Our H5N2 isolates could not be replicated and transmitted in chickens, but the H7N8 isolates could efficiently be replicated and transmitted to contact-exposure chickens. In addition, because our H7N8 isolates caused watery diarrhea in chickens, these viruses cannot only serve as progenitors of novel HPAI strains but also potentially cause clinical disease in poultry. Although there have been no reports of LPAI mutation to HPAI in these regions, the wild bird surveillance effort should focus on monitoring the introduction and transmission of the HPAI H5N1 and LPAI H5 and H7 viruses.

Effect of intranasal administration of Lactobacillus fermentum CJL-112 on horizontal transmission of influenza virus in chickens.

The aim of this study was to determine whether intranasal administration of Lactobacillus sp. could prevent horizontal transmission of H9N2 avian influenza virus (AIV) in specific-pathogen-free chickens. Three-week-old chickens received 500 µL of 1.5 × 10(9) cfu of Lactobacillus fermentum CJL-112 strain (CJL) intranasally for 7 d before and 14 d after a challenge. Challenged chickens, each inoculated with H9N2 AIV, were kept in either direct or indirect contact with naive chickens, and morbidity and viral shedding were monitored. We demonstrated that the intranasal administration of CJL significantly decreased the number of chickens with viral shedding from the gastrointestinal tract in the indirect contact chickens (P < 0.001) and also significantly reduced viral shedding from the respiratory tract in the challenged (P < 0.05) and the direct contact chickens (P < 0.001) than those in the control group. Hence, the use of this lactobacilli strain may constitute a novel and effectively plausible alternative to prevent and control H9N2 AIV infection in chickens.

Prevalence and antimicrobial resistance of Salmonella species isolated from chicken meats produced by different integrated broiler operations in Korea.

Prevalence and antimicrobial resistance profiles of Salmonella serotypes isolated from 7 chicken meat brands produced by different integrated broiler operations in Korea were determined. In total, 210 samples were collected from retail supermarkets in Seoul, South Korea, and analyzed for the presence of Salmonella. Of 210 chicken meat samples, overall Salmonella prevalence was 22.4%. Salmonella Enteritidis was the dominant serovar, with an isolation rate of 57.4% from the Salmonella-positive chickens, followed by Salmonella Montevideo. Salmonella isolates frequently were resistant to various antibiotics, including 100% to erythromycin, 87% to cephalothin, 85% to nalidixic acid, and 70% to streptomycin. Of the 47 isolates, 41 (87.2%) isolates were resistant to 3 or more antibiotics. Moreover, the Salmonella profiles of each chicken meat brand were different by broiler operation. Brand A showed the highest prevalence of Salmonella (18 isolates, 60%), whereas brand G showed the lowest prevalence (one isolate, 3.3%). Eight among the 18 isolates of brand A were resistant to 11 antibiotics, whereas 5 of the 6 brand C isolates were resistant to only 2 antibiotics. This study demonstrates that a high proportion of chicken meat in Korea is contaminated with Salmonella and the prevalence and antimicrobial resistance patterns of Salmonella of chicken meat differ significantly according to the integrated broiler operation.

Lack of association between GTF2H4 genetic variants and AERD development and FEV1 decline by aspirin provocation.

Aspirin-exacerbated respiratory disease (AERD) is prevalent in about 10% of asthma patients and is characterized by a severe decline in forced expiratory volume in 1-s (FEV(1) ), an important phenotype for total lung capacity, upon ingestion of aspirin. The general transcription factor IIH subunit 4 (GTF2H4) is positioned at 6p21.33, a part of the major histocompatibility complex (MHC) class II region that contains a number of genes that play an important role in the immune system. In addition, genetic variants in another general transcription factor IIH gene have revealed significant association with lung disease. To investigate whether GTF2H4 genetic variants could be a causative factor for AERD development and FEV(1) decline by aspirin provocation, five common single-nucleotide polymorphisms (SNPs) were genotyped in 93 patients with AERD and 96 aspirin-tolerant asthma (ATA) controls. As a result, when adjusted for age, gender, smoking status and atopy as covariates, the rs1264307 variant and two haplotypes showed nominal signals in the association with AERD (P = 0.02-0.04), but the significances disappeared after corrections for multiple testing (corrected P > 0.05). In further multiple regression analysis, no genetic variants of GTF2H4 showed significant associations with FEV(1) decline by aspirin provocation in asthmatics (P > 0.05). Despite the need for replications in larger cohorts, our preliminary findings suggest that GTF2H4 variants may not be associated with susceptibility to AERD and obstructive symptoms in asthmatics.

5-HT(1B) receptors inhibit glutamate release from primary afferent terminals in rat medullary dorsal horn neurons.

BACKGROUND AND PURPOSE: Although 5-HT(1B) receptors are expressed in trigeminal sensory neurons, it is still not known whether these receptors can modulate nociceptive transmission from primary afferents onto medullary dorsal horn neurons. EXPERIMENTAL APPROACH: Primary afferent-evoked EPSCs were recorded from medullary dorsal horn neurons of rat horizontal brain stem slices using a conventional whole-cell patch clamp technique under a voltage-clamp condition. KEY RESULTS: CP93129, a selective 5-HT(1B) receptor agonist, reversibly and concentration-dependently decreased the amplitude of glutamatergic EPSCs and increased the paired-pulse ratio. In addition, CP93129 reduced the frequency of spontaneous miniature EPSCs without affecting the current amplitude. The CP93129-induced inhibition of EPSCs was significantly occluded by GR55562, a 5-HT(1B/1D) receptor antagonist, but not LY310762, a 5-HT(1D) receptor antagonist. Sumatriptan, an anti-migraine drug, also decreased EPSC amplitude, and this effect was partially blocked by either GR55562 or LY310762. On the other hand, primary afferent-evoked EPSCs were mediated by the Ca(2+) influx passing through both presynaptic N-type and P/Q-type Ca(2+) channels. The CP93129-induced inhibition of EPSCs was significantly occluded by ω-conotoxin GVIA, an N-type Ca(2+) channel blocker. CONCLUSIONS AND IMPLICATIONS: The present results suggest that the activation of presynaptic 5-HT(1B) receptors reduces glutamate release from primary afferent terminals onto medullary dorsal horn neurons, and that 5-HT(1B) receptors could be, at the very least, a potential target for the treatment of pain from orofacial tissues.

Outbreak of gizzard erosion associated with fowl adenovirus infection in Korea.

The pathogenicity of a fowl adenovirus serotype-1 (FAdV-1, K181 strain) isolated from a case of gizzard erosion in layer chickens was investigated in specific-pathogen-free (SPF) chicks. One-week-old SPF chicks were inoculated orally or intramuscularly with the isolate of FAdV-1 and euthanized for necropsy at 7, 14, and 21 d postinoculation. Although there were no clinical signs after inoculation, gizzard erosions were observed grossly and the virus was recovered from the gizzards in the inoculated chickens. Histologically, in the chickens that were infected orally, the lesions found in the gizzard consisted of severe degeneration and necrosis of glandular epitheliums and eosinophilic inclusion bodies. These results indicate that the Korean FAdV-1 isolate could induce gizzard lesions in chickens. Moreover, the present investigation reproduced an outbreak of gizzard erosion caused by FAdV-1 infection and, for the first time, described the isolation of FAdV-1 from chickens in Korea. These findings provide important information on the epidemiology and pathogenesis of FAdV-1 infection in chickens.

The effect of semiconditional dorsal penile nerve electrical stimulation on capacity and compliance of the bladder with deformity in spinal cord injury patients: a pilot study.

STUDY DESIGN: Bladder capacity, bladder compliance, the volume of the first overactive contraction, maximal volume during cystometry (CMG) and the vesicoureteral reflux, bladder wall deformity before and after semiconditional stimulation on DPN. OBJECTIVES: To evaluate the effect of the semiconditional electrical stimulation on dorsal penile nerve (DPN) to improve the complicated bladder function in male with spinal cord injury (SCI). SETTING: Semiconditional stimulation system and urodynamic laboratory in a university hospital. PARTICIPANTS: Six men (age, 33-59 years) with SCI incurred from 38 to 156 months before this study. INTERVENTION: semiconditional stimulation parameters were set during CMG and semiconditional stimulation on DPN by surface electrodes via Empi Focus stimulator was applied from 14 to 28 days, at home. Parameters about bladder function were measured before and after stimulation applied. RESULT: All parameters for bladder after semiconditional stimulation were increased. Also, the vesicoureteral reflux and bladder wall deformity was improved in five of six patients. CONCLUSION: Semiconditional electrical stimulation on DPN effectively suppresses neurogenic detrusor overactivity and distend the bladder physiologically in the SCI patient with a complicated bladder. The bladder capacity and compliance as well as the bladder wall deformity were improved as a result of this treatment.

Anti-influenza virus activity of green tea by-products in vitro and efficacy against influenza virus infection in chickens.

Polyphenolic compounds present in green tea, particularly catechins, are known to have strong anti-influenza activity. The goal of this study was to determine whether green tea by-products could function as an alternative to common antivirals in animals compared to original green tea. Inhibition of viral cytopathic effects ascertained by neutral red dye uptake was examined with 50% effective (virus-inhibitory) concentrations (EC50)determined. Against the H1N1 virus A/NWS/33, we found the anti-influenza activity of green tea by-products (EC50 = 6.36 µg/mL) to be equivalent to that of original green tea (EC50= 6.72 µg/mL). The anti-influenza activity of green tea by-products was further examined in mouse and chicken influenza infection models. In mice, oral administration of green tea by-products reduced viral titers in the lungs in the early phase of infection, but they could not protect these animals from disease and death. In contrast, therapeutic administration of green tea by-products via feed or water supplement resulted in a dose-dependent significant antiviral effect in chickens, with a dose of 10 g/kg of feed being the most effective (P < 0.001). We also demonstrated that unidentified hexane-soluble fractions of green tea by-products possessed strong anti-influenza activity, in addition to ethyl acetate-soluble fractions, including catechins. This study revealed green tea by-product extracts to be a promising novel antiviral resource for animals.

Live attenuated nephropathogenic infectious bronchitis virus vaccine provides broad cross protection against new variant strains.

Infectious bronchitis virus (IBV) infections cause great economic losses to the poultry industry worldwide, and the emergence of new variant strains complicates disease control. The present study investigated the genetic and protectotypic features of newly emerged Korean IBV strains. A phylogenetic analysis showed that several recent isolates formed 2 different clusters (new cluster 1 and 2), which were distinct from other preexisting clusters. New cluster 1 IBV strains represented recombinants between Korean nephropathogenic strain KM91 and the QXIBV strain. New cluster 2 IBV strains showed low amino acid homology (<58.7%) compared with previous isolates. We evaluated the protective efficacy of commercial IBV vaccines (H120 and K2 strain) against these new isolates. In cross-protection studies, the H120 strain did not provide sufficient protection against these variants. However, highly attenuated nephropathogenic IBV vaccine, K2 strain, provided significantly higher levels of protection against variants compared with chickens vaccinated with H120 (P < 0.05 or better). These results indicate that the K2 vaccine could be helpful for the reduction of economic losses caused by newly evolving IBV recombinants (new cluster 1) and variants (new cluster 2).