Innate-like Cytotoxic Function of Bystander-Activated CD8+ T Cells Is Associated with Liver Injury in Acute Hepatitis A.

Acute hepatitis A (AHA) involves severe CD8+ T cell-mediated liver injury. Here we showed during AHA, CD8+ T cells specific to unrelated viruses became activated. Hepatitis A virus (HAV)-infected cells produced IL-15 that induced T cell receptor (TCR)-independent activation of memory CD8+ T cells. TCR-independent activation of non-HAV-specific CD8+ T cells were detected in patients, as indicated by NKG2D upregulation, a marker of TCR-independent T cell activation by IL-15. CD8+ T cells derived from AHA patients exerted innate-like cytotoxicity triggered by activating receptors NKG2D and NKp30 without TCR engagement. We demonstrated that the severity of liver injury in AHA patients correlated with the activation of HAV-unrelated virus-specific CD8+ T cells and the innate-like cytolytic activity of CD8+ T cells, but not the activation of HAV-specific T cells. Thus, host injury in AHA is associated with innate-like cytotoxicity of bystander-activated CD8+ T cells, a result with implications for acute viral diseases.

High Housing Density-Induced Chronic Stress Diminishes Ovarian Reserve via Granulosa Cell Apoptosis by Angiotensin II Overexpression in Mice.

Repeated and prolonged stress causes hypothalamic-pituitary-adrenal (HPA) dysregulation. Excessive hypothalamic-pituitary-adrenal axis activity has been linked to inadequate activation of the hypothalamus-pituitary-ovarian axis, which controls the growth and development of ovarian follicles and oocytes. Therefore, we assessed the ovarian reserve under high-housing-density-induced prolonged stress, and investigated the mechanisms underlying diminished ovarian reserve in this study. Eight-week-old female C57BL/6 mice were housed for 10 weeks under different housing densities. We then assessed hormone levels, performed histology and immunohistochemistry analyses of ovarian follicles, evaluated ovarian mRNA expression, and measured angiotensin II-mediated apoptosis in vitro. More densely housed mice presented increased corticosterone levels and decreased follicle-stimulating and luteinizing hormone levels. Moreover, mice exposed to prolonged ordinary stress showed a reduced level of serum anti-Müllerian hormone and an increased number of atretic ovarian follicles. Stressed mice showed increased levels of angiotensinogen and angiotensin II in the ovaries and serum. Furthermore, our in vitro study confirmed that high-housing-density-related stress induced granulosa cell apoptosis, resulting in diminished ovarian reserves. Collectively, our findings highlight the importance of women managing everyday stress to maintain their reproductive health.

After cyclophosphamide exposure, granulosa cells recover their anti-müllerian hormone-producing ability but not their numbers.

Anti-müllerian hormone (AMH) produced by granulosa cells (GCs), reserves the ovarian follicle pool for future recruitment and ovulation. However, women who have undergone cyclophosphamide (Cy) treatment have decreased AMH levels due to damaged GCs. This study establishes flow cytometry protocols for identification of GCs and investigates the cause of the Cy-induced AMH decrease by analyzing the number of GCs and their AMH production at the single cell level. Over 2 weeks, C57BL/6 mice were intraperitoneally injected 6 times with 100 mg/kg Cy and sacrificed either immediately or 4 weeks after Cy treatment. Twenty-four hours post-Cy exposure, a decrease in serum AMH levels was seen due to a reduction in the number of follicle-stimulating hormone receptor (FSHR)+ AMH+ GCs and their ability to produce AMH. However, 4 weeks after Cy treatment, serum AMH levels were still decreased due to the decreased number of FSHR+ AMH+ GCs, however, their AMH-producing ability was unaltered. Consistently, in vitro, Cy-induced low AMH production in FSHR+ AMH+ hGL5 cells (immortalized human GCs) was restored 24 h after Cy treatment, although their numbers remained decreased. Thus, the surviving GCs after Cy exposure had intact AMH-producing ability. In future, an effort to minimize GC death by Cy treatment is required, while maintaining its therapeutic effects.

Anti-adipogenic effects of the traditional herbal formula Dohongsamul-tang in 3T3-L1 adipocytes.

BACKGROUND: Blood stasis syndrome (BSS) is a general pattern identification and refers to pathological stagnation of blood circulation, dysfunction of endothelial cells or metabolic disorder in traditional Korean medicine (TKM). Dohongsamul-Tang (DHSMT) is a well-known traditional herbal formula which used for treatment and prevention of BSS by promoting blood circulation in TKM. METHODS: Cytotoxicity of DHSMT was examined by cell counting kit-8 (CCK-8). We also investigated the anti-adipogenesis effect of DHSMT by using Oil Red O staining, intracellular triglyceride assay leptin ELISA and western blot analysis in 3T3-L1 adipocytes. In addition, the accumulation of adiponectin, resistin and plasminogen activator inhibitor-1 (PAI-1) were measured by magnetic bead panel kit. RESULTS: Oil Red O staining showed that DHSMT markedly reduced fat accumulation without affecting cell cytotoxicity. DHSMT also significantly decreased accumulation of triglyceride and adipokines such as leptin, adiponectin, resistin and PAI-1 compared with fully differentiated adipocytes. Furthermore, our results found that DHSMT significantly suppressed the adipocyte differentiation by downregulating adipogenic-specific transcriptional factors such as peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding proteins alpha (C/EBPα) and fatty acid binding protein 4 (FABP4) in adipocytes. CONCLUSIONS: Taken together, our findings provide that DHSMT has potential for treatment and prevention of obesity or MS related to BSS.

Antibody-secreting cells with a phenotype of Ki-67low, CD138high, CD31high, and CD38high secrete nonspecific IgM during primary hepatitis A virus infection.

Although studies investigating the nature of Ab-secreting cells (ASCs) during acute infection with influenza or dengue virus found that the ASC response was dominated by virus-specific IgG secretion, the Ag specificity and phenotype of ASCs during primary acute viral infection were not identified. To this end, we investigated the nature of ASCs in direct ex vivo assays from patients with acute hepatitis A caused by primary infection with hepatitis A virus (HAV). We found that the frequency of CD27(high)CD38(high) ASCs was markedly increased in the peripheral blood during the acute phase of HAV infection. Moreover, substantial numbers of ASCs were non-HAV-specific and dominantly secreted IgM. We detected HAV-specific ASCs by staining with fluorochrome-tagged HAV-VP1 protein. As compared with HAV-specific ASCs, non-HAV-specific ASCs were Ki-67(low)CD138(high)CD31(high)CD38(high), demonstrating that non-HAV-specific ASCs had a bone marrow plasma cell-like phenotype whereas HAV-specific ASCs had a phenotype typical of circulating plasmablasts. These data suggest that non-HAV-specific ASCs might be mobilized plasma cells from the bone marrow or the spleen, whereas HAV-specific ASCs were newly generated plasmablasts. In this study, we provide evidence that pre-existing plasma cells are released into the circulation and contribute to Ag-nonspecific secretion of IgM during primary HAV infection.

Perception of pattern identification in traditional medicine: a survey of Korean medical practitioners.

OBJECTIVE: To survey assesses the perception of pattern identification (PI) diagnosis of Traditional Medicine (TM) by Korean medical doctors (KMDs). METHODS: A total of 14,485 KMDs affiliated with the Association of Korean Medicine were sent surveys via email, and 1646 (11.1%) responded to the questionnaire on their perception of PI diagnosis. RESULTS: Of the 1646 respondents, more than ninety percent (1562, 94.9%) reported that they treated patients using PI. The most critical problem with PI diagnosis was the lack of objective diagnostic indicators (561, 34.1%). Ninety percent had issues diagnosing patients because of different diagnoses between KMDs (1491, 90.5% ). The majority of respondents thought herbal medicine was most related to PI (1528, 92.8%). Half of the respondents answered that PI of Ba Gang was the most commonly used PI system. Participants reported that it was most important to study standardisation of PI diagnosis and to develop standardised PI diagnoses using the classification system of the Korean Standard Classification of Diseases. The foremost PI type that physicians thought should be included in standardisation and objectification of PI ofTKM was the PI of Ba Gang. CONCLUSION: Our data suggest that we should focus on the standardisation of PI diagnosis and PI of Ba Gang in future research on PI diagnosis in TM. However, we cannot completely discount the possibility that a biased selection of subjects and a low response rate limit the generalisability of the findings.

Restoration of miR-223-3p expression in aged mouse uteri with Samul-tang administration.

BACKGROUND: During the secretory phase of the estrous cycle, endometrium senescence is accompanied by biological mechanisms such as metabolic dysfunction and epigenetic changes, leading to decreased embryo receptivity and implantation failure. Samul-tang has been reported to improve implantation potential in aged mice. METHODS: To uncover the age-related changes in the transcriptomes, we performed QuantSeq 3'mRNA sequencing to compare the mRNA expression patterns in the uteri between young and old mice. Young and old female BALB/c mice were administered distilled water or Samul-tang for 4 weeks, and the corresponding effects on the uteri of aged mice were investigated. RESULTS: We found 586 differentially expressed genes between the young and old mouse groups. Functional annotation analysis revealed 10 important pathways, including arachidonic acid metabolism and glutathione metabolism, involved in uterine cellular proliferation and decidualization. Using in silico analysis, we identified the three most abundantly interacting microRNAs-miR-223-3p, 155-5p, and 129-5p-with differentially expressed genes associated with important biological pathways. Samul-tang administration restored the expression of miR-223-3p, which could interact with important genes such as histamine ammonia-lyase (Hal) and acid phosphatase 5 (Acp5) for embryo implantation. CONCLUSION: Our study demonstrated that uterine aging changes the expression of genes involved in metabolic pathways that are crucial to uterine health, leading to cellular senescence. We postulate that the regulation of miR-223-3p via Samul-tang administration can be of therapeutic importance in cellular senescence.

Comprehensive analysis of miRNA-mRNA interactions in ovaries of aged mice.

Advanced maternal age and ovarian aging are deleterious to the quantity and quality of oocytes and epigenetic modifications, which can affect the health of offspring. However, relatively little is known about the regulation of microRNA-mediated transcription during ovarian aging. We therefore aimed to identify age-related mRNA and microRNA changes and their interactions in the ovaries of aged mice. We performed QuantSeq 3'mRNA and small RNA sequencing to compare their expression patterns in post-ovulation ovaries from young (12-week-old) and old (44-week-old) mice. Functional annotation and integrative analyses were performed to identify the potential functions of differentially expressed genes and identify binding sites for critical microRNAs. We found 343 differentially expressed genes and 9 microRNAs in our comparison of the two mouse groups, with fold changes >2.0 (P < 0.01). Furthermore, we identified possible direct interactions between 24 differentially expressed mRNAs and 8 microRNAs. The differentially expressed genes are involved in fat digestion and absorption, the PI3K-Akt signaling pathway, serotonergic synapse, and ovarian steroidogenesis, which are important for folliculogenesis and oocyte growth. During ovarian aging, changes in gene expression induce alterations in folliculogenesis, oocyte growth, and steroidogenesis, resulting in decreased oocyte quality and reproductive outcomes.

Dried Ginger Extract Restores the T Helper Type 1/T Helper Type 2 Balance and Antibody Production in Cyclophosphamide-Induced Immunocompromised Mice after Flu Vaccination.

Dried ginger (Zingiberis Processum Rhizoma (ZR)) is frequently used to prevent or treat common cold and flu. This study aimed to investigate the influence of ZR extracts on influenza-specific antibody production in cyclophosphamide (Cy)-induced immunocompromised mice. Female BALB/c mice were injected three times with saline or Cy. To investigate the effect of ZR, either distilled water or ZR was administered orally to mice daily for 10 days after Cy injection. After ZR administration, the mice were immunized with the 2017/2018 influenza vaccine. Pretreatment with ZR extracts enhanced influenza-specific antibody production in Cy-induced immunocompromised mice after flu vaccination and restored the influenza antigen-specific T helper (Th) type 1/Th2 balance to the normal state. Further, ZR suppressed the eosinophil enrichment caused by Cy injection in the spleen. We demonstrated that ZR can be used to increase antibody production in immunocompromised individuals before vaccination.

Extended adverse effects of cyclophosphamide on mouse ovarian function.

PURPOSE: Most patients with cancer undergo multiple administrations of anticancer drugs during treatment, resulting in chronic impairment of their reproductive health. As improved treatment options increase cancer survival, it has become increasingly important to address fertility issues in cancer survivors. In this study, we examined the pathophysiological effects of multiple exposures to cyclophosphamide (Cy) on the ovaries of mice and their underlying molecular mechanism. METHODS: Female C57BL/6 mice were intraperitoneally injected with 100 mg/kg Cy six times over 2 weeks; 4 weeks later, the mice were sacrificed and their ovaries, sera, and oocytes were collected for histological observation, measurement of anti-Müllerian hormone levels, and assessment of oocyte quantity and quality in response to hormonal stimulation. Gene expression changes in Cy-treated ovaries were examined by microarray and bioinformatics analyses. RESULTS: After repeated Cy exposure, the anti-Müllerian hormone level was decreased, and follicle loss and impairments in the quality of oocyte were irreversible. The expression levels of genes involved in folliculogenesis, oogenesis, and zona pellucida glycoprotein transcription displayed sustained alterations in Cy-exposed ovaries even after 4 weeks. CONCLUSION: The adverse effects of Cy on ovarian function and oocytes remained even after chemotherapy was complete. Therefore, strategies to prevent ovarian damage or restore ovarian function after treatment are required to safeguard the fertility of young cancer survivors.

Effect of samul-tang on female fertility via RAS signaling pathway in ovaries of aged mice.

Samul-tang (SM), a traditional herbal medicine, is used to treat age-related human conditions, such as infertility and menstrual irregularities. The mechanism underlying the role of SM in ovary function needs elucidation. In this study, the influence of SM administration on the ovarian reserve of aged mice was investigated. Female BALB/c mice (8 and 40 weeks-old) were administered with distilled water (young or old group) or SM for 4 weeks. SM administration prevented age-related ovarian follicle loss in mice. Quality of oocytes and blastocysts were enhanced in SM-administrated mice compared to those of non-treated old mice. Further, SM administration increased the pregnancy rate and number of litters. SM triggered changes in aging-related genes that are linked to the RAS-mediated pathway. Thus, we demonstrate that SM can be used to increase the oocyte yield in aged women, potentially improving age-related cognitive decline in the ovarian reserve.

Acupuncture for Poor Ovarian Response: A Randomized Controlled Trial.

Acupuncture is believed to improve ovarian reserve and reproductive outcomes in women undergoing in vitro fertilization (IVF). This study was conducted to evaluate the effect of network-optimized acupuncture followed by IVF on the oocyte yield in women showing a poor ovarian response. This study was an exploratory randomized controlled trial conducted from June 2017 to January 2020 at the Pusan National University Hospital. Women diagnosed with poor ovarian response were enrolled and randomly divided into two groups: IVF alone and Ac + IVF groups (16 acupuncture sessions before IVF treatment). Eight acupoints with high degree centrality and betweenness centrality were selected using network analysis. Among the participants, compared with the IVF treatment alone, the acupuncture + IVF treatment significantly increased the number of retrieved mature oocytes in women aged more than 37 years and in those undergoing more than one controlled ovarian hyperstimulation cycle. The negative correlation between the number of retrieved mature oocytes and consecutive controlled ovarian hyperstimulation cycles was not observed in the Ac + IVF group irrespective of the maternal age. These findings suggest that physicians can consider acupuncture for the treatment of women with poor ovarian response and aged > 37 years or undergoing multiple IVF cycles.

Samul-tang ameliorates oocyte damage due to cyclophosphamide-induced chronic ovarian dysfunction in mice.

Samul-tang (SM), a traditional herbal medicine, has been used to treat menstrual irregularities and infertility in women. However, the cellular and molecular mechanisms underlying the effects of SM remain elusive. We investigated the potential protective effect of SM against chronic ovarian dysfunction and used bioinformatics analysis to identify its underlying mechanism in a mouse model of cyclophosphamide (CP)-induced diminished ovarian reserve. Female C57BL/6 mice were intraperitoneally injected with CP three times a week, followed by oral administration of distilled water (CP group) or SM (CP + SM group) for 4 weeks. Four weeks later, the effect of SM was assessed by ovarian tissue histological analysis, steroid hormone measurement, oocyte quality, and mRNA and microRNA microarray analysis in the ovaries. Although SM administration did not prevent CP-induced follicle loss in mice, the quality of oocytes was better in CP + SM mice than in CP mice. Gene expression analysis revealed that the expression of fertilisation- and ovarian follicle development-related genes was altered by CP treatment but normalized after SM administration. Further bioinformatics analysis showed possible interactions between differentially expressed mRNAs and microRNAs. Therefore, we demonstrated the protective effects of SM on ovarian function and oocyte maturation against CP-induced damage via multiple epigenetic mechanisms.

Acupuncture for in vitro fertilization in women with poor ovarian response: a systematic review.

BACKGROUND: Poor ovarian response (POR) is one reason for infertility. In vitro fertilization (IVF) is frequently used to help achieve pregnancy, and performing acupuncture before IVF may promote ovulation and reduce egg retrieval pain. The purpose of this systematic review was to evaluate the effectiveness of acupuncture on clinical pregnancy rates (CPR) after IVF in women with POR. METHODS: Eight electronic databases were searched in January 2020, and reference lists of retrieved articles and previous review articles were hand-searched. Randomized controlled trials (RCTs) using any type of acupuncture for women with POR undergoing IVF were considered. Risk of bias was assessed using the Cochrane risk of bias standards. RESULTS: Three RCTs were included in this review. CPR and the number of retrieved oocytes were measured in two studies, while the values of anti-Mullerian hormone (AMH) and antral follicle count (AFC) were only reported in one study. In two studies, CPR was higher in the intervention group than the control group [37.8 % vs 24.3 %]. We did not conduct a meta-analysis, as there was a high level of heterogeneity in interventions among the included trials. CONCLUSIONS: This study suggests that acupuncture may improve CPR, AMH, AFC and the number of retrieved oocytes in women with POR undergoing IVF. However it is difficult to conclude that acupuncture is more effective than conventional treatment. Additionally, more clinical trials are needed to evaluate the effectiveness of acupuncture on CPR and other outcomes of POR. STUDY REGISTRATION: PROSPERO CRD42018087813; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018087813.

Carrot Pomace Polysaccharide (CPP) Improves Influenza Vaccine Efficacy in Immunosuppressed Mice via Dendritic Cell Activation.

Despite the advancements in vaccination research and practices, influenza viruses remain a global health concern. Inducing a robust immune response by vaccination is especially challenging in the elderly, the immunocompromised, and persons with chronic illnesses. Polysaccharides derived from food may act as a safe and readily accessible means to boost the immune system during vaccination. In this study, we investigated whether crude polysaccharides derived from carrot pomace (CPP) could stimulate innate immune cell function and promote influenza vaccine immunogenicity. In bone marrow-derived dendritic cells (BMDCs), CPP increased the fraction of CD11c+MHCII+ cells and the expression of co-stimulatory molecules CD40 and CD80, indicative of enhanced maturation and activation. Functionally, CPP-treated BMDCs promoted inflammatory cytokine production in splenic lymphocytes. In a mouse model of immunosuppression induced by cyclophosphamide, animals given CPP before and after an influenza vaccine challenge showed increased frequencies of dendritic cells and natural killer cells in the spleen, in addition to the recovery of vaccine-specific antibody titers. Moreover, innate myeloid cells in CPP-fed mice showed evidence of phenotypic modification via markedly enhanced interleukin(IL)-12 and interferon(IFN)-γ production in response to lipopolysaccharide(LPS) stimulation ex vivo. Our findings suggest that the administration of carrot pomace polysaccharides can significantly enhance the efficacy of influenza vaccination.

Current clinical practice status of Korean medicine for managing female infertility: A cross-sectional survey.

BACKGROUND: This survey aimed to investigate clinicians' perceptions and current practice patterns of Korean medicine (KM) treatment for female infertility. METHODS: A questionnaire on clinical practice patterns of KM treatment for female infertility was constructed and distributed to 703 KM doctors (KMDs). RESULTS: A total of 20.5% of physicians (n = 144/703) completed the survey and delivered integrative care for female infertility patients. Integrative care mainly consisted of acupuncture, herbal medicine, and moxibustion. The participants largely relied on radiological findings on ultrasonography and hormone tests for diagnosis. The most frequently prescribed herbal medication was Jogyeongjongok-tang (Tiaojing Zhongyu decoction), and the most frequently applied acupoints were SP6, CV4 and ST36. CONCLUSIONS: This study provides expert opinions and information on actual clinical practice patterns of KM for treating female infertility. However, we cannot completely discount the possibility that biased selection of subjects and the low response rate limit the interpretations of the study results.

A systematic review of herbal medicines for the treatment of cancer cachexia in animal models.

OBJECTIVE: The aim of this study is to summarize preclinical studies on herbal medicines used to treat cancer cachexia and its underlying mechanisms. METHODS: We searched four representing databases, including PubMed, EMBASE, the Allied and Complementary Medicine Database, and the Web of Science up to December 2016. Randomized animal studies were included if the effects of any herbal medicine were tested on cancer cachexia. The methodological quality was evaluated by the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADE) checklist. RESULTS: A total of fourteen herbal medicines and their compounds were identified, including Coptidis Rhizoma, berberine, Bing De Ling, curcumin, Qing-Shu-Yi-Qi-Tang, Scutellaria baicalensis, Hochuekkito, Rikkunshito, hesperidin, atractylodin, Sipjeondaebo-tang, Sosiho-tang, Anemarrhena Rhizoma, and Phellodendri Cortex. All the herbal medicines, except curcumin, have been shown to ameliorate the symptoms of cancer cachexia through anti-inflammation, regulation of the neuroendocrine pathway, and modulation of the ubiquitin proteasome system or protein synthesis. CONCLUSIONS: This study showed that herbal medicines might be a useful approach for treating cancer cachexia. However, more detailed experimental studies on the molecular mechanisms and active compounds are needed.

Korean medicines for poor ovarian reserve in infertility: A protocol for a multicenter observational study.

INTRODUCTION: Many infertile patients have used Korean medicines (KMs) as a primary or adjuvant therapeutic method to improve in vitro fertilization success rates. The aim of this multicenter observational study is to investigate the effects of KMs on poor ovarian reserve (POR) in infertile patients. METHODS AND ANALYSIS: We will perform a prospective multicenter observational study. This study will recruit 50 women between 25 and 44 years of age with infertility caused by POR from among patients who visit the KM clinic. All participants will visit the KM clinic on the 2nd or 3rd day of menstruation to receive the KMs. KM treatment will be delivered for 3 menstrual cycles (3 months) and will include herbal decoction, acupuncture, or moxibustion on demand. Every participant will be assessed based on KM clinical symptoms, a quality of life questionnaire, and ovarian reserve test results. ETHICS AND DISSEMINATION: The study was approved by Institutional Review Board of Semyung University (SMU-IM-190501). The results will be published in a peer-reviewed journal and will be disseminated electronically and in print. TRIAL REGISTRATION NUMBER: Clinical Research Information Service: KCT0004209.

Four Subgroups of Blood Stasis Syndrome Are Identified by Manifestation Cluster Analysis in Males.

Blood stasis syndrome (BSS) is an important pathological condition in traditional East Asian medicine and is associated with ischemic heart disease, cerebral vascular accident, diabetes mellitus, chronic renal failure, severe traumatic injury, and dysmenorrhea. However, previous studies have been unable to reveal the clinical and biological characteristics or biological markers of BSS. We hypothesized that the heterogeneity among the manifestations of BSS or non-BSS could interfere with an analysis to describe the characteristics of BSS. In this study, male participants based on the severity of BSS-associated symptoms and signs were clustered and classified into four subgroups: BSS subgroups (1), (2), (3), and (4). Non-BSS core subgroup was redefined using manifestation cluster analysis. Biological characteristics of subgroups BSS(1) and BSS(2) belong to the range of the non-BSS core subgroup (1), whereas that of subgroups BSS(3) and BSS(4) are characterized by different biological parameters such as systemic inflammatory conditions and elevated D-dimer level. Our results suggested that patients in subgroups of BSS(3) and BSS(4) are more likely to be exposed in an inflammatory state than other BSS subgroups. We found the heterogeneity among the manifestations which could mask the characteristics of BSS and identified the clinical and biological profiles of the four BSS subgroups through comparisons of the redefined non-BSS and BSS subgroups. This finding could provide accurate diagnostic criteria and new approaches for BSS treatments in different subgroups.

Immunodominance hierarchy of influenza subtype-specific neutralizing antibody response as a hurdle to effectiveness of polyvalent vaccine.

Strengthening of immunodominance hierarchy of influenza subtype-specific neutralizing antibody response by annual polyvalent vaccinations could increase the variation of vaccine effectiveness by subtype. Therefore, we suggest the assessment of neutralizing antibody titer prior to seasonal vaccination and recommend the inoculation of only strains lower than protective levels.