scholarly journals Dual role for B-1a cells in immunity to influenza virus infection

2008 ◽  
Vol 205 (13) ◽  
pp. 3053-3064 ◽  
Author(s):  
Youn Soo Choi ◽  
Nicole Baumgarth
Keyword(s):  
Influenza Virus ◽  
Steady State ◽  
Influenza Infection ◽  
Cell Subset ◽  
Influenza Virus Infection ◽  
Cell Receptor ◽  
Cell Responses ◽  
Specific Expansion ◽  
Local Accumulation ◽  
Draining Lymph Nodes

B-1 cells are known to contribute most of the “natural antibodies” that are secreted in the steady state, antibodies which are crucial for protection against many pathogens including influenza virus. Whether the CD5+ B-1a subset plays a role during an active immune response is incompletely understood. In contrast to recent data suggesting a passive role for B-1a cells, data provided here show strong highly localized activation of B-1 cells in the draining lymph nodes of the respiratory tract after influenza infection. B-1 cells are identified as a major source for both steady state and infection-induced local virus-neutralizing IgM. The CD5+ B-1a subset is the main B-1 cell subset generating this response. B-1a cell responses are generated by their increased local accumulation rather than by antigen-specific expansion. Our study reveals that during infection with influenza, CD5-expressing B-1a cells respond to and contribute to protection, presumably without the need for B cell receptor–mediated antigen-specific signals, which are known to induce the death of B-1a cells rather than activation. With that, our data reveal fundamental differences in the response regulation of B-1 and B-2 cells during an infection.

scholarly journals Contribution of  Virus-specific CD8+ Cytotoxic T Cells to Virus Clearance or Pathologic Manifestations of Influenza Virus Infection in a T Cell Receptor Transgenic Mouse Model

1998 ◽  
Vol 188 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Demetrius Moskophidis ◽  
Dimitris Kioussis
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Neutralizing Antibodies ◽  
Cytotoxic T Cells ◽  
Influenza Infection ◽  
Immune Surveillance ◽  
Influenza Virus Infection ◽  
Cell Receptor ◽  
Very High Frequency ◽  
Variable Surface

The ability of influenza virus to evade immune surveillance by neutralizing antibodies (Abs) directed against its variable surface antigens provides a challenge to the development of effective vaccines. CD8+ cytotoxic T lymphocytes (CTLs) restricted by class I major histocompatibility complex molecules are important in establishing immunity to influenza virus because they recognize internal viral proteins which are conserved between multiple viral strains. In contrast, protective Abs are strain-specific. However, the precise role of effector CD8+ CTLs in protection from influenza virus infection, critical for understanding disease pathogenesis, has not been well defined. In transgenic mice with a very high frequency of antiinfluenza CTL precursors, but without protective Abs, CD8+ CTLs conferred protection against low dose viral challenge, but exacerbated viral pathology and caused mortality at high viral dose. The data suggest a dual role for CD8+ CTLs against influenza, which may present a challenge to the development of effective CTL vaccines. Effector mechanisms used by CD8+ CTLs in orchestrating clearance of virus and recovery from experimental influenza infection, or potentiation of lethal pathology, are discussed.

scholarly journals Authors’ Response to Reply: Ketogenic diet activates protective γδ T cell responses against influenza virus infection

2020 ◽  
Author(s):  
Emily L Goldberg ◽  
Akiko Iwasaki ◽  
Vishwa Deep Dixit
Keyword(s):  
Influenza Virus ◽  
T Cell ◽  
Virus Infection ◽  
Ketogenic Diet ◽  
Influenza A ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
T Cell Responses ◽  
Γδ T Cell ◽  
Cell Responses

We are glad for the broad interest and readership our recent publication “Ketogenic diet activates protective γδ T cell responses against influenza virus infection” has received. The goal of our study was to understand how the immune system might be involved in mediating the surprising protection against lethal influenza A virus infection we observed when we fed mice a ketogenic diet (KD) for one week. What made our findings particularly intriguing is that robust protective changes were occurring in the lungs, the site of influenza infection and, importantly, not a tissue traditionally considered in manipulations of systemic metabolism, and that these protective changes were γδ T cell-dependent. Amidst this enthusiasm, Bass et al. have raised concern about the control diets used in our experiments, specifically with regards to the protein, fiber, and micronutrient content. We welcome critical feedback and appreciate the opportunity to respond to these criticisms.

scholarly journals Performance of case definitions and clinical predictors for influenza surveillance among patients followed in a rural cohort in Senegal

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mamadou Aliou Barry ◽  
Florent Arinal ◽  
Cheikh Talla ◽  
Boris Gildas Hedible ◽  
Fatoumata Diene Sarr ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Sore Throat ◽  
Predictive Value ◽  
Influenza Infection ◽  
Clinical Signs ◽  
Influenza Virus Infection ◽  
Nasal Discharge ◽  
Age Group ◽  
Case Definitions

Abstract Background Influenza is a major cause of morbidity and mortality in Africa. However, a lack of epidemiological data remains for this pathology, and the performances of the influenza-like illness (ILI) case definitions used for sentinel surveillance have never been evaluated in Senegal. This study aimed to i) assess the performance of three different ILI case definitions, adopted by the WHO, USA-CDC (CDC) and European-CDC (ECDC) and ii) identify clinical factors associated with a positive diagnosis for Influenza in order to develop an algorithm fitted for the Senegalese context. Methods All 657 patients with a febrile pathological episode (FPE) between January 2013 and December 2016 were followed in a cohort study in two rural villages in Senegal, accounting for 1653 FPE observations with nasopharyngeal sampling and influenza virus screening by rRT-PCR. For each FPE, general characteristics and clinical signs presented by patients were collected. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for the three ILI case definitions were assessed using PCR result as the reference test. Associations between clinical signs and influenza infection were analyzed using logistic regression with generalized estimating equations. Sore throat, arthralgia or myalgia were missing for children under 5 years. Results WHO, CDC and ECDC case definitions had similar sensitivity (81.0%; 95%CI: 77.0–85.0) and NPV (91.0%; 95%CI: 89.0–93.1) while the WHO and CDC ILI case definitions had the highest specificity (52.0%; 95%CI: 49.1–54.5) and PPV (32.0%; 95%CI: 30.0–35.0). These performances varied by age groups. In children < 5 years, the significant predictors of influenza virus infection were cough and nasal discharge. In patients from 5 years, cough, nasal discharge, sore throat and asthenia grade 3 best predicted influenza infection. The addition of “nasal discharge” as a symptom to the WHO case definition decreased sensitivity but increased specificity, particularly in the pediatric population. Conclusion In summary, all three definitions studies (WHO, ECDC & CDC) have similar performance, even by age group. The revised WHO ILI definition could be chosen for surveillance purposes for its simplicity. Symptomatic predictors of influenza virus infection vary according the age group.

scholarly journals Routine blood parameters are helpful for early identification of influenza infection in children

2020 ◽  
Author(s):  
Ronghe Zhu ◽  
Cuie Chen ◽  
Qiu Wang ◽  
Xixi Zhang ◽  
Chaosheng Lu ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Early Identification ◽  
Influenza A ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Cutoff Value ◽  
Routine Blood ◽  
Influenza A Virus Infection

Abstract Purpose Routine blood parameters, such as the lymphocyte (LYM) count, platelet (PLT) count, lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), LYM*PLT and mean platelet volume-to-platelet ratio (MPV/PLT), are widely used to predict the prognosis of infectious diseases. We aimed to explore the value of these parameters in the early identification of influenza virus infection in children.Methods We conducted a single-center, retrospective, observational study of fever with influenza-like symptoms in pediatric outpatients from different age groups and evaluated the predictive value of various routine blood parameters measured within 48 hours of the onset of fever for influenza virus infection.Results The LYM count, PLT count, LMR and LYM*PLT were lower, and the NLR and MPV/PLT were higher in children with an influenza infection (PCR-confirmed and symptomatic). The LYM count, LMR and LYM*PLT in the influenza infection group were lower in the 1- to 6-year-old subgroup, and the LMR and LYM*PLT in the influenza infection group were lower in the >6-year-old subgroup. In the 1- to 6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.75, the sensitivity was 81.87%, the specificity was 84.31%, and the area under the curve (AUC) was 0.886; the cutoff value of the LMR for predicting influenza B virus infection was 3.71, the sensitivity was 73.58%, the specificity was 84.31%, and the AUC was 0.843. In the >6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.05, the sensitivity was 89.27%, the specificity was 89.61%, and the AUC was 0.949; the cutoff value of the LMR for predicting influenza B virus infection was 2.88, the sensitivity was 83.19%, the specificity was 92.21%, and the AUC was 0.924.Conclusions Routine blood tests are simple, inexpensive and easy to perform, and they are useful for the early identification of influenza virus infection in children. The LMR had the strongest predictive value for influenza virus infection in children older than 1 year, particularly influenza A virus infection.

scholarly journals Brugada-Like Electrocardiographic Changes during Influenza Infection

2003 ◽  
Vol 31 (3) ◽  
pp. 244-246 ◽  
Author(s):  
K Kusaka ◽  
J Yamakawa ◽  
K Kawaura ◽  
T Itoh ◽  
T Takahashi ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Viral Infection ◽  
Brugada Syndrome ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Ecg Changes ◽  
Early Repolarization ◽  
Electrocardiographic Changes

We describe a 32-year-old man with electrocardiographic (ECG) changes consistent with Brugada syndrome and influenza virus infection. The ECG pattern changed after 1 week to one of early repolarization in V1 and V2. This case suggests an association between Brugada syndrome and viral infection.

scholarly journals Increased Plasma Matrix Metalloproteinase-9 Levels Contribute to Intracerebral Hemorrhage during Thrombolysis after Concomitant Stroke and Influenza Infection

2016 ◽  
Vol 6 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Sajjad Muhammad ◽  
Oliver Planz ◽  
Markus Schwaninger
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Matrix Metalloproteinase ◽  
Intracerebral Hemorrhage ◽  
Acute Stroke ◽  
Plasma Levels ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Concomitant Infection ◽  
Metalloproteinase 9

Background: Thrombolysis is the only approved therapy for acute stroke. However, life-threatening complications such as intracerebral hemorrhage (ICH) can develop after intravenous administration of tissue plasminogen activator (tPA). Both infection and thrombolysis during cerebral ischemia disrupt the blood-brain barrier (BBB). tPA can induce matrix metalloproteinase-9 (MMP-9), which is known to be involved in BBB disruption. However, it has still not been investigated whether preexisting influenza virus infection during thrombolysis after acute stroke affects systemic levels of MMP-9 and its inhibitor TIMP-1 and whether increased systemic MMP-9 levels affect ICH. This study aimed to investigate the influence of influenza virus infection on plasma levels of MMP-9 and TIMP-1 after thrombolysis in acute stroke, and to determine whether the infection correlates with intracerebral bleeding. Methods: C57BL/6 mice were infected by administering 1 × 105 plaque-forming units of human influenza (H1N1) virus intranasally. After 3 days of infection the middle cerebral artery was occluded for 45 min and then reperfused. Intravenous tPA (10 mg/kg) treatment was started 10 min after stroke onset. Twenty-four hours after stroke onset, mice were deeply anesthetized with ketamine, venous blood was drawn from the caval vein and centrifuged at 2,000 rpm, and the supernatant was collected and frozen at -80°C. Plasma levels of MMP-9 and TIMP-1 were quantified by using ELISA. Results: After stroke, plasma MMP-9 was significantly increased in mice with a concomitant influenza infection that were treated with tPA (9.99 ± 0.62 ng/ml, n = 7) as compared to noninfected control mice that were treated with tPA (4.74 ± 0.48 ng/ml, n = 8). Moreover, plasma levels of TIMP-1, an inhibitor of MMP-9, were also significantly increased in mice treated with tPA after concomitant infection and stroke (42.17 ± 7.02 ng/ml, n = 7) as compared to noninfected control mice that were treated with tPA after stroke (20.22 ± 2.12 ng/ml, n = 8). MMP-9 values significantly correlated with intracerebral hemoglobin levels in animals treated with tPA after stroke (p = 0.028, r = 0.76, n = 8) and after concomitant stroke and infection (p = 0.039, r = 0.78, n = 7). Conclusion: Preexisting influenza A virus infection led to increased plasma MMP-9 and TIMP-1 levels in mice undergoing thrombolysis after induced stroke. MMP-9 levels closely correlated with intracerebral bleeding after thrombolysis during concomitant infection and stroke. Thus, our data indicate that thrombolysis may be dangerous during influenza infection. MMP-9 inhibitors might be considered to reduce the side effects of thrombolysis during concomitant infection and stroke.

Vaccine development for protecting swine against influenza virus

2012 ◽  
Vol 13 (2) ◽  
pp. 181-195 ◽  
Author(s):  
Qi Chen ◽  
Darin Madson ◽  
Cathy L. Miller ◽  
D.L. Hank Harris
Keyword(s):  
Influenza Virus ◽  
Vaccine Development ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Cross Protection ◽  
Antigenic Drift ◽  
Financial Loss ◽  
Heterologous Challenge ◽  
Current Vaccine ◽  
Sea Mammals

AbstractInfluenza virus infects a wide variety of species including humans, pigs, horses, sea mammals and birds. Weight loss caused by influenza infection and/or co-infection with other infectious agents results in significant financial loss in swine herds. The emergence of pandemic H1N1 (A/CA/04/2009/H1N1) and H3N2 variant (H3N2v) viruses, which cause disease in both humans and livestock constitutes a concerning public health threat. Influenza virus contains eight single-stranded, negative-sense RNA genome segments. This genetic structure allows the virus to evolve rapidly by antigenic drift and shift. Antigen-specific antibodies induced by current vaccines provide limited cross protection to heterologous challenge. In pigs, this presents a major obstacle for vaccine development. Different strategies are under development to produce vaccines that provide better cross-protection for swine. Moreover, overriding interfering maternal antibodies is another goal for influenza vaccines in order to permit effective immunization of piglets at an early age. Herein, we present a review of influenza virus infection in swine, including a discussion of current vaccine approaches and techniques used for novel vaccine development.

scholarly journals Viral Replication Rate Regulates Clinical Outcome and CD8 T Cell Responses during Highly Pathogenic H5N1 Influenza Virus Infection in Mice

2010 ◽  
Vol 6 (10) ◽  
pp. e1001139 ◽  
Author(s):  
Yasuko Hatta ◽  
Karen Hershberger ◽  
Kyoko Shinya ◽  
Sean C. Proll ◽  
Richard R. Dubielzig ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza Virus Infection ◽  
Cd8 T Cell ◽  
H5n1 Influenza Virus ◽  
Replication Rate ◽  
Highly Pathogenic ◽  
Cell Responses ◽  
H5n1 Influenza ◽  
Pathogenic H5n1

scholarly journals Autoimmune neutropenia associated with influenza virus infection in childhood: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ignacio Callejas Caballero ◽  
Marta Illán Ramos ◽  
Arantxa Berzosa Sánchez ◽  
Eduardo Anguita ◽  
José Tomás Ramos Amador
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Viral Infections ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Rapid Test ◽  
Male Infant ◽  
Severe Neutropenia ◽  
Autoimmune Neutropenia ◽  
Benign Condition

Abstract Background Although neutropenia is relatively frequent in infants and children and is mostly a benign condition with a self-limited course, it can lead to life-threatening severe infections. Autoimmune neutropenia is a relatively uncommon hematological disorder characterized by the autoantibody-induced destruction of neutrophils. It is usually triggered by viral infections with very few documented cases after influenza virus. Case presentation An 8-month-old male infant presented at the emergency room with a 5-days history of fever up to 39.7 °C, cough and runny nose. In the blood test performed, severe neutropenia was diagnosed (neutrophils 109/μL). A nasopharyngeal aspirate revealed a positive rapid test for Influenza A. Serum antineutrophil antibodies were determined with positive results. Neutropenia targeted panel showed no mutations. Despite maintenance of severe neutropenia for 9 months the course was uneventful without treatment. Conclusions When severe neutropenia is diagnosed and confirmed, it is essential to rule out some potential etiologies and underlying conditions, since the appropriate subsequent management will depend on it. Although autoimmune neutropenia triggered by viral infections has been widely reported, it has seldom been reported after influenza infection. The benign course of the disease allows a conservative management in most cases.

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