ENHANCEMENT OF THE STABILITY OF CELLS TO THE DIPHTHERIA TOXIN UNDER THE INFLUENCE OF A LATENT VIRAL INFECTION

1969 ◽  
Author(s):  
A. A. Yabrov
2021 ◽  
Author(s):  
Isobel C. Mouat ◽  
Jessica R. Allanach ◽  
Vina Fan ◽  
Anna M. Girard ◽  
Iryna Shanina ◽  
...  

While age-associated B cells (ABCs) are known to expand and persist following viral infection and during autoimmunity, their interactions are yet to be studied together in these contexts. Epstein-Barr virus (EBV) infection has long been implicated in multiple sclerosis (MS), and it is not known whether ABCs could play a role in mediating viral contribution to autoimmunity. Here, we show that the circulating ABC population is expanded in people with MS and that EBV infection and MS status differentially impact the circulating ABC phenotype. We then directly compared ABCs during viral infection and autoimmunity using mouse models of EBV, gammaherpesvirus 68 (γHV68), and MS, experimental autoimmune encephalomyelitis (EAE). We observed that splenic ABCs are expanded in a sex-biased manner during both latent virus infection and EAE, and each event drives the ABC population to opposing phenotypes. We have previously shown that latent γHV68 infection exacerbates EAE and here we show that mice lacking ABCs fail to display γHV68-enhanced disease. Collectively, these findings indicate that latent viral infection and central nervous system autoimmunity differentially impact the ABC population and suggests that viral infections such as EBV prime ABCs to contribute pathogenically in MS.


2018 ◽  
Vol 11 (05) ◽  
pp. 1850071 ◽  
Author(s):  
Zhiting Xu ◽  
Youqing Xu

This paper is devoted to the study of the stability of a CD[Formula: see text] T cell viral infection model with diffusion. First, we discuss the well-posedness of the model and the existence of endemic equilibrium. Second, by analyzing the roots of the characteristic equation, we establish the local stability of the virus-free equilibrium. Furthermore, by constructing suitable Lyapunov functions, we show that the virus-free equilibrium is globally asymptotically stable if the threshold value [Formula: see text]; the endemic equilibrium is globally asymptotically stable if [Formula: see text] and [Formula: see text]. Finally, we give an application and numerical simulations to illustrate the main results.


2021 ◽  
Author(s):  
Tamara A. Shelabina ◽  
Dmitriy A. Danilov ◽  
Aleksandr I. Rodionenkov ◽  
Aleksey A. Kuznetsov

The creation of original seed grains of the Charoite variety, healed of pathogenic infections of various etiologies, was carried out through reproduction of the certified meristematic material of the microplants class. Mini tubers microplants were grown in 5.5 liter vessels on a “Agrobalt S” soil (control) mixed with peat and supplemented with 10% and 20% (of the volume) of the “ORVI” substrate. The use of the substrate “ORVI” mixed with peat and “Agrobalt S” soil positively influenced the growth, development and formation of tubers. The appliance of 10% of the “ORVI” substrate significantly increased the quantitative yield of mini tubers by 17% and the weight of tubers by 12.3%. The increase in the total number of mini tubers was due to the increase in tuber fraction from 10 to 30 mm. The appliance of a 20% “ORVI” substrate also led to an increase in the total number and mass of mini tubers. According to the EIA results, the mini tubers grown from microplants did not contain any latent viral infection. Tests on the seeds did not reveal symptoms of fungal diseases. Keywords: breed, potatoes, mini tubers, mass of tubers, peat fertilizer, substrate


2021 ◽  
Vol 22 (17) ◽  
pp. 9366
Author(s):  
Anna Lubkowska ◽  
Waldemar Pluta ◽  
Aleksandra Strońska ◽  
Alicja Lalko

Heat shock proteins (HSPs) are a large group of chaperones found in most eukaryotes and bacteria. They are responsible for the correct protein folding, protection of the cell against stressors, presenting immune and inflammatory cytokines; furthermore, they are important factors in regulating cell differentiation, survival and death. Although the biological function of HSPs is to maintain cell homeostasis, some of them can be used by viruses both to fold their proteins and increase the chances of survival in unfavorable host conditions. Folding viral proteins as well as replicating many different viruses are carried out by, among others, proteins from the HSP70 and HSP90 families. In some cases, the HSP70 family proteins directly interact with viral polymerase to enhance viral replication or they can facilitate the formation of a viral replication complex and/or maintain the stability of complex proteins. It is known that HSP90 is important for the expression of viral genes at both the transcriptional and the translational levels. Both of these HSPs can form a complex with HSP90 and, consequently, facilitate the entry of the virus into the cell. Current studies have shown the biological significance of HSPs in the course of infection SARS-CoV-2. A comprehensive understanding of chaperone use during viral infection will provide new insight into viral replication mechanisms and therapeutic potential. The aim of this study is to describe the molecular basis of HSP70 and HSP90 participation in some viral infections and the potential use of these proteins in antiviral therapy.


2016 ◽  
Vol 21 (2) ◽  
pp. 143-158
Author(s):  
Jia Liu ◽  
Qunying Zhang ◽  
Canrong Tian

This paper is concerned with the dynamics of a viral infection model with diffusion under the assumption that the immune response is retarded. A time delay is incorporated into the model described the delayed immune response after viral infection. Based upon a stability analysis, we demonstrate that the appearance, or the absence, of spatial patterns is determined by the delay under some conditions. Moreover, the spatial patterns occurs as a consequence of Hopf bifurcation. By applying the normal form and the center manifold theory, the direction as well as the stability of the Hopf bifurcation is explored. In addition, a series of numerical simulations are performed to illustrate our theoretical results.


2014 ◽  
Vol 22 (03) ◽  
pp. 449-462 ◽  
Author(s):  
CRUZ VARGAS-DE-LEÓN

We consider a mathematical model that describes a viral infection with lytic and non-lytic immune responses. One of the main features of the model is that it includes a rate of linear activation of cytotoxic T lymphocytes (CTLs) immune response, a constant production rate of CTLs export from thymus, and a nonlinear attack rate for each immune effector mechanism. Stability of the infection-free equilibrium, and existence, uniqueness and stability of an immune-controlled equilibrium, are investigated. The stability results are given in terms of the basic reproductive number. We use the method of Lyapunov functions to study the global stability of the infection-free equilibrium and the immune-controlled equilibrium. We give a sufficient condition on the non-lytic-immune attack rate for the global asymptotic stability of the immune-controlled equilibrium. By theoretical analysis and numerical simulations, we show that the lytic and non-lytic activities are required to combat a viral infection.


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