scholarly journals Host-pathogen coevolution and the emergence of broadly neutralizing antibodies in chronic infections

2015 ◽  
Author(s):  
Armita Nourmohammad ◽  
Jakub Otwinowski ◽  
Joshua B Plotkin

The vertebrate adaptive immune system provides a flexible and diverse set of molecules to neutralize pathogens. Yet, viruses such as HIV can cause chronic infections by evolving as quickly as the adaptive immune system, forming an evolutionary arms race. Here we introduce a mathematical framework to study the coevolutionary dynamics of antibodies with antigens within a host. We focus on changes in the binding interactions between the antibody and antigen populations, which result from the underlying stochastic evolution of genotype frequencies driven by mutation, selection, and drift. We identify the critical viral and immune parameters that determine the distribution of antibody-antigen binding affinities. We also identify definitive signatures of coevolution that measure the reciprocal response between antibodies and viruses, and we introduce experimentally measurable quantities that quantify the extent of adaptation during continual coevolution of the two opposing populations. Using this analytical framework, we infer rates of viral and immune adaptation based on time-shifted neutralization assays in two HIV-infected patients. Finally, we analyze competition between clonal lineages of antibodies and characterize the fate of a given lineage in terms of the state of the antibody and viral populations. In particular, we derive the conditions that favor the emergence of broadly neutralizing antibodies, which may be useful in designing a vaccine against HIV.

Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 372-378 ◽  
Author(s):  
Birgit M. Reipert

Abstract The development of neutralizing antibodies against factor VIII (FVIII inhibitors) and factor IX (FIX inhibitors) is the major complication in hemophilia care today. The antibodies neutralize the biological activity of FVIII and FIX and render replacement therapies ineffective. Antibodies are generated as a result of a cascade of tightly regulated interactions between different cells of the innate and the adaptive immune system located in distinct compartments. Any event that modulates the repertoire of specific B or T cells, the activation state of the innate and adaptive immune system, or the migration pattern of immune cells will therefore potentially influence the risk for patients to develop inhibitors. This chapter reviews our current understanding of different pathways of antibody development that result in different qualities of antibodies. Potential differences in differentiation pathways leading to high-affinity neutralizing or low-affinity non-neutralizing antibodies and the potential influence of gene polymorphisms such as HLA haplotype, FVIII haplotype, and polymorphisms of immunoregulatory genes are discussed.


2021 ◽  
Author(s):  
Kayla Sprenger ◽  
Simone Conti ◽  
Victor Ovchinnikov ◽  
Arup K Chakraborty ◽  
martin karplus

The design of vaccines against highly mutable pathogens, such as HIV and influenza, requires a detailed understanding of how the adaptive immune system responds to encountering multiple variant antigens (Ags). Here, we describe a multiscale model of B cell receptor (BCR) affinity maturation that employs actual BCR nucleotide sequences and treats BCR/Ag interactions in atomistic detail. We apply the model to simulate the maturation of a broadly neutralizing Ab (bnAb) against HIV. Starting from a germline precursor sequence of the VRC01 anti-HIV Ab, we simulate BCR evolution in response to different vaccination protocols and different Ags, which were previously designed by us. The simulation results provide qualitative guidelines for future vaccine design and reveal unique insights into bnAb evolution against the CD4 binding site of HIV. Our model makes possible direct comparisons of simulated BCR populations with results of deep sequencing data, which will be explored in future applications.


Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 372-378 ◽  
Author(s):  
Birgit M. Reipert

The development of neutralizing antibodies against factor VIII (FVIII inhibitors) and factor IX (FIX inhibitors) is the major complication in hemophilia care today. The antibodies neutralize the biological activity of FVIII and FIX and render replacement therapies ineffective. Antibodies are generated as a result of a cascade of tightly regulated interactions between different cells of the innate and the adaptive immune system located in distinct compartments. Any event that modulates the repertoire of specific B or T cells, the activation state of the innate and adaptive immune system, or the migration pattern of immune cells will therefore potentially influence the risk for patients to develop inhibitors. This chapter reviews our current understanding of different pathways of antibody development that result in different qualities of antibodies. Potential differences in differentiation pathways leading to high-affinity neutralizing or low-affinity non-neutralizing antibodies and the potential influence of gene polymorphisms such as HLA haplotype, FVIII haplotype, and polymorphisms of immunoregulatory genes are discussed.


2016 ◽  
Vol 75 (3) ◽  
pp. 74-84 ◽  
Author(s):  
A.E. Abaturov ◽  
◽  
E.A. Agafonova ◽  
N.I. Abaturova ◽  
V.L. Babich ◽  
...  

2021 ◽  
Vol 8 (8) ◽  
pp. 2004979
Author(s):  
Jun‐Young Park ◽  
Sung Jean Park ◽  
Jun Young Park ◽  
Sang‐Hyun Kim ◽  
Song Kwon ◽  
...  

2021 ◽  
pp. 1-19
Author(s):  
Sonia George ◽  
Trevor Tyson ◽  
Nolwen L. Rey ◽  
Rachael Sheridan ◽  
Wouter Peelaerts ◽  
...  

Background: α-Synuclein (α-syn) is the predominant protein in Lewy-body inclusions, which are pathological hallmarks of α- synucleinopathies, such as Parkinson’s disease (PD) and multiple system atrophy (MSA). Other hallmarks include activation of microglia, elevation of pro-inflammatory cytokines, as well as the activation of T and B cells. These immune changes point towards a dysregulation of both the innate and the adaptive immune system. T cells have been shown to recognize epitopes derived from α-syn and altered populations of T cells have been found in PD and MSA patients, providing evidence that these cells can be key to the pathogenesis of the disease. Objective To study the role of the adaptive immune system with respect to α-syn pathology. Methods: We injected human α-syn preformed fibrils (PFFs) into the striatum of immunocompromised mice (NSG) and assessed accumulation of phosphorylated α-syn pathology, proteinase K-resistant α-syn pathology and microgliosis in the striatum, substantia nigra and frontal cortex. We also assessed the impact of adoptive transfer of naïve T and B cells into PFF-injected immunocompromised mice. Results: Compared to wildtype mice, NSG mice had an 8-fold increase in phosphorylated α-syn pathology in the substantia nigra. Reconstituting the T cell population decreased the accumulation of phosphorylated α-syn pathology and resulted in persistent microgliosis in the striatum when compared to non-transplanted mice. Conclusion: Our work provides evidence that T cells play a role in the pathogenesis of experimental α-synucleinopathy.


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