Cell-Mediated Immunity against Francisella Tularensis after Natural Infection

1980 ◽  
Vol 12 (4) ◽  
pp. 281-287 ◽  
Author(s):  
Pentti Koskela ◽  
Elja Herva
Keyword(s):  
Francisella Tularensis ◽  
Natural Infection ◽  
Cell Mediated Immunity

Natural Infection of a European Red Squirrel (Sciurus vulgaris) with Francisella tularensis subsp. Holarctica

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
Simone R. R. Pisano ◽  
Sonja Kittl ◽  
Ulrike Eulenberger ◽  
Joerg Jores ◽  
Francesco C. Origgi
Keyword(s):  
Francisella Tularensis ◽  
Natural Infection ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
Tularensis Subsp

scholarly journals Murine model for study of cell-mediated immunity: protection against death from fully virulent Francisella tularensis infection.

1975 ◽  
Vol 12 (5) ◽  
pp. 999-1005 ◽  
Author(s):  
H T Eigelsbach ◽  
D H Hunter ◽  
W A Janssen ◽  
H G Dangerfield ◽  
S G Rabinowitz
Keyword(s):  
Francisella Tularensis ◽  
Murine Model ◽  
Cell Mediated Immunity

scholarly journals Long-lasting cell-mediated immunity induced by a live Francisella tularensis vaccine.

1985 ◽  
Vol 22 (4) ◽  
pp. 527-530 ◽  
Author(s):  
A Tärnvik ◽  
M L Löfgren ◽  
S Löfgren ◽  
G Sandström ◽  
H Wolf-Watz
Keyword(s):  
Francisella Tularensis ◽  
Cell Mediated Immunity

scholarly journals Development of Immunoassays for Detection of Francisella tularensis Lipopolysaccharide in Tularemia Patient Samples

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 924
Author(s):  
Emily E. Hannah ◽  
Sujata G. Pandit ◽  
Derrick Hau ◽  
Haley L. DeMers ◽  
Kayleigh Robichaux ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Point Of Care ◽  
Natural Infection ◽  
Lateral Flow ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Potential Threat ◽  
Infectious Dose ◽  
Antigen Capture ◽  
Wide Range

Francisella tularensis is the causative agent of tularemia, a zoonotic bacterial infection that is often fatal if not diagnosed and treated promptly. Natural infection in humans is relatively rare, yet persistence in animal reservoirs, arthropod vectors, and water sources combined with a low level of clinical recognition make tularemia a serious potential threat to public health in endemic areas. F. tularensis has also garnered attention as a potential bioterror threat, as widespread dissemination could have devastating consequences on a population. A low infectious dose combined with a wide range of symptoms and a short incubation period makes timely diagnosis of tularemia difficult. Current diagnostic techniques include bacterial culture of patient samples, PCR and serological assays; however, these techniques are time consuming and require technical expertise that may not be available at the point of care. In the event of an outbreak or exposure a more efficient diagnostic platform is needed. The lipopolysaccharide (LPS) component of the bacterial outer leaflet has been identified previously by our group as a potential diagnostic target. For this study, a library of ten monoclonal antibodies specific to F. tularensis LPS were produced and confirmed to be reactive with LPS from type A and type B strains. Antibody pairs were tested in an antigen-capture enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay format to select the most sensitive pairings. The antigen-capture ELISA was then used to detect and quantify LPS in serum samples from tularemia patients for the first time to determine the viability of this molecule as a diagnostic target. In parallel, prototype lateral flow immunoassays were developed, and reactivity was assessed, demonstrating the potential utility of this assay as a rapid point-of-care test for diagnosis of tularemia.

scholarly journals Persistence of immunity and impact of a third (booster) dose of an inactivated SARS-CoV-2 vaccine, BBV152; a phase 2, double-blind, randomised controlled trial

2022 ◽  
Author(s):  
Krishna Mohan Vadrevu ◽  
Brunda Ganneru ◽  
Siddharth Reddy ◽  
Harsh Jogdand ◽  
Raju Dugyala ◽  
...  
Keyword(s):  
Placebo Group ◽  
Booster Dose ◽  
Natural Infection ◽  
Geometric Mean ◽  
Booster Vaccination ◽  
Secondary Outcome ◽  
Effector Memory ◽  
Cell Mediated Immunity ◽  
Phase 2 ◽  
Neutralising Antibodies

Background: Neutralising antibody responses to SARS-CoV-2 vaccines have been reported to decline within 6 months of vaccination, particularly against Variants of Concern (VOC). We assessed the immunogenicity and safety of a booster dose of BBV152 administered 6 months after the second of a two-dose primary vaccination series. Methods: In an ongoing phase 2 trial (ClinicalTrials.gov: NCT04471519) the protocol was amended after six months to re-consent and randomise 184 previously vaccinated participants to receive a third dose of vaccine or placebo on Day 215. The primary outcome was to measure neutralising antibody titres by plaque-reduction neutralisation test (PRNT50) four weeks after the booster; safety as serious adverse events (SAE) was the key secondary outcome. Findings: Four weeks after a second BBV152 vaccination geometric mean titres (GMTs) of neutralising antibodies were 197.0 PRNT50 (95% CI: 155.6,249.4); this level declined to 23.9 PRNT50 (14.0,40.6) six months later, with a seroconversion rate of 75.4% (95% CI: 68.4,81.6). Four weeks after booster vaccination the GMT increased on Day 243 to 746.6 PRNT50 (514.9,1081) compared with 100.7 PRNT50 (43.6,232.6) in the placebo group. Corresponding seroconversion rates were 98.7% (92.8,99.9) and 79.8% (69.6,87.8). Increased titres in the placebo group were attributed to natural infection as the study was conducted during the second wave of COVID-19 in India. PRNT50 titres against the SARS-CoV-2 variants increased Alpha (32.6 fold), Beta (161.0 fold), Delta (264.7 fold), and Delta plus (174.2 fold) after the booster vaccination. We found that vaccine induces both memory B and T cells with a distinct AIM+ specific CD4+T central and effector memory phenotype, including CD8+ TEMRA phenotype. Reactogenicity after vaccine and placebo was minimal and comparable, and no SAEs were reported. Interpretation: Six months after a two dose BBV152 vaccination series cell mediated immunity and neutralising antibodies to both homologous (D614G) and heterologous strains (Alpha, Beta, Delta and Delta plus) persisted above baseline, although the magnitude of the responses had declined. Neutralising antibodies against homologous and heterologous SARS-CoV-2 variants increased 19 to 97 fold after a third vaccination. Booster BBV152 vaccination is safe and may be necessary to ensure persistent immunity to prevent breakthrough infections.

scholarly journals Variants of SARS Coronavirus-2 and Their Potential Impact on the Future of the COVID-19 Pandemic

Zoonoses ◽  
2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Xin Li ◽  
Kelvin Kai-Wang To ◽  
Kwok-Yung Yuen
Keyword(s):  
Mucosal Immunity ◽  
Health Management ◽  
Natural Infection ◽  
Severe Disease ◽  
Management Strategies ◽  
The Elderly ◽  
Cell Mediated Immunity ◽  
Viral Shedding ◽  
Global Eradication ◽  
Human Coronaviruses

The emergence of SARS-CoV-2 variants of concern (VOCs), especially the sweeping spread of the delta variant, and differing public health management strategies, have rendered global eradication of SARS-CoV-2 unlikely. The currently available COVID-19 vaccines, including the inactivated whole virus vaccines, mRNA vaccines, and adenovirus-vectored vaccines, are effective in protecting people from severe disease and death from COVID-19, but they may not confer good mucosal immunity to prevent the establishment of infection and subsequent viral shedding and transmission. Mucosal vaccines delivered via intranasal route may provide a promising direction, which, if given as a third dose after a two-dose series of intramuscular vaccination, likely promotes mucosal immunity in addition to boosting the systemic cell-mediated immunity and antibody response. However, immunity induced by vaccination, and natural infection as well, is likely to wane followed by re-infection as in the case of human coronaviruses OC43, 229E, NL63, and HKU1. It is a challenge to prevent and control COVID-19 worldwide with the increasing number of VOCs associated with increased transmissibility and changing antigenicity. Nevertheless, we may seek to end the current pandemic situation through mass vaccination and gradual relaxation of non-pharmaceutical measures, which would limit the incidence of severe COVID-19. Repeated doses of booster vaccine will likely be required, similar to influenza virus, especially for the elderly and the immunocompromised patients who are most vulnerable to infection.

scholarly journals Susceptibility to Secondary Francisella tularensis Live Vaccine Strain Infection in B-Cell-Deficient Mice Is Associated with Neutrophilia but Not with Defects in Specific T-Cell-Mediated Immunity

2001 ◽  
Vol 69 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Catharine M. Bosio ◽  
Karen L. Elkins
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Culture System ◽  
Live Vaccine ◽  
Cell Mediated Immunity ◽  
Live Vaccine Strain ◽  
Wild Type

ABSTRACT Previous studies have demonstrated a role for B cells, not associated with antibody production, in protection against lethal secondary infection of mice with Francisella tularensislive vaccine strain (LVS). However, the mechanism by which B cells contribute to this protection is not known. To study the specific role of B cells during secondary LVS infection, we developed an in vitro culture system that mimics many of the same characteristics of in vivo infection. Using this culture system, we showed that B cells do not directly control LVS infection but that control of LVS growth is mediated primarily by LVS-primed T cells. Importantly, B cells were not required for the generation of effective memory T cells since LVS-primed, B-cell-deficient (BKO) mice generated CD4+ and CD8+ T cells that controlled LVS infection similarly to LVS-primed CD4+ and CD8+ T cells from wild-type mice. The control of LVS growth appeared to depend primarily on gamma interferon and nitric oxide and was similar in wild-type and BKO mice. Rather, the inability of BKO mice to survive secondary LVS infection was associated with marked neutrophil influx into the spleen very early after challenge. The neutrophilia was directly associated with B cells, since BKO mice reconstituted with naive B cells prior to a secondary challenge with LVS had decreased bacterial loads and neutrophils in the spleen and survived.

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