Re-educating immunity in respiratory allergies: the potential for hematopoietic stem cell-mediated gene therapy

Brooks, Jeremy F.; Davies, Janet M.; Wells, James W.; Steptoe, Raymond J.

doi:10.1007/s00109-017-1611-8

Cited by 3 publications

(1 citation statement)

References 130 publications

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“…Clinically, engineered BMT is prescribed only for serious lifethreatening conditions [515]. Feasibility for autoimmunity [515] and allergy [637] rely on revisions that progress transduction efficiency and survival [638], stemness [639], and expansion [640], while minimising [515] or personalising [641] host conditioning. While not tested here, transfer of purified stem cell progenitors would more closely replicate current clinical practise, reduce the cell dose required for similar engraftment, and prevent the transfer of non-engrafting donor cells that may affect tolerance outcomes [515,526].…”

Section: Discussionmentioning

confidence: 99%

Defining B cell tolerance checkpoints and their modulation by immunotherapy

Brooks¹

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B cells that recognise self-antigens are thought to be deleted from the emerging repertoire and those which escape deletion are instead locked in an anergic state. Autoimmunity develops when this process breaks down. This paradigm was established almost three decades ago in mouse models where all B cells recognise a single model antigen. Since then, very little about B cell tolerance has been learned from polyclonal settings where mice express a normal endogenous repertoire. This is because we have lacked tools to dissect B cell tolerance within a physiological repertoire in fine detail. This thesis aimed to understand polyclonal B cell tolerance and ways to modulate it. To study B cell tolerance, I took advantage of mouse models that express membranebound ovalbumin (OVA) as a model self-antigen. Three models were used where OVA was expressed ubiquitously, by MHC class II-expressing cells, or by CD11c+ dendritic cells. I generated fluorescent OVA tetramers that could probe for OVA-specific B cells in a polyclonal repertoire in both naïve mice and following immunization. Surprisingly, at steady-state, self-reactive OVA-specific B cells populated OVA-expressing mice in a manner that suggested deletion during B cell development does not occur. Instead, the large number of self-reactive B cells in the peripheral repertoire are maintained as anergic cells. This anergic state largely prevented responses to self-antigen when mice were immunized with OVA in the presence of different immunogenic stimuli. Of the small number of self-reactive cells that became activated in OVA-expressing mice, these were rapidly deleted from germinal centres and OVA-specific antibody production was transient. Providing a source of T cell help, either cognate or from bystander T cells, failed to reverse anergy, indicating that anergy was B cell-intrinsic and not as a consequence of T cell tolerance. Collectively, these studies demonstrated checkpoints that maintain robust peripheral B cell tolerance in a polyclonal repertoire. As a way to modify an existing repertoire, I transplanted OVA-encoding bone marrow and tested whether OVA-specific responsiveness could be modulated following engraftment. OVA-specific B cells could be edited from the repertoire and rendered anergic by OVA expression as a neo-self-antigen, demonstrating an approach that could harness peripheral tolerance to control B cells. These studies refine our current understanding of B cell tolerance. Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, financial support and any other original research work used or reported in my th...

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Section: Discussionmentioning

confidence: 99%

Defining B cell tolerance checkpoints and their modulation by immunotherapy

Brooks¹

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Peripheral tolerance checkpoints imposed by ubiquitous antigen expression limit antigen-specific B-cell responses under strongly immunogenic conditions

Brooks

Murphy

Barber

et al. 2020

Preprint

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A series of layered peripheral checkpoints maintain self-reactive B cells in an unresponsive state. Autoantibody production occurs when these checkpoints are breached, however, when and how this occurs is largely unknown. In particular, how self-reactive B cells are restrained during bystander inflammation in otherwise healthy individuals is poorly understood. A weakness has been the unavailability of methods capable of dissecting physiologically-relevant B-cell responses, without the use of an engineered B-cell receptor. Resolving this will provide insights that decipher how this process goes awry during autoimmunity or could be exploited for therapy. Here we use a strong adjuvant to provide bystander innate and adaptive signals that promote B-cell responsiveness, in conjunction with newly developed B cell detection tools to study in detail the ways that peripheral tolerance mechanisms limit the expansion and function of self-reactive B cells activated under these conditions. We show that although autoreactive B cells are recruited into the germinal centre, their development does not proceed, possibly through rapid counter-selection. Consequently, differentiation of plasma cells is blunted, and autoantibody responses are transient and devoid of affinity maturation. We propose this approach and these tools can be more widely applied to track antigen-specific B cell responses to more disease relevant antigens, without the need for BCR transgenic mice, in settings where tolerance pathways are compromised or have been genetically manipulated to drive stronger insights into the biology underlying B cell-mediated autoimmunity.

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Peripheral Tolerance Checkpoints Imposed by Ubiquitous Antigen Expression Limit Antigen-Specific B Cell Responses under Strongly Immunogenic Conditions

Brooks

Murphy

Barber

et al. 2020

The Journal of Immunology

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A series of layered peripheral checkpoints maintain self-reactive B cells in an unresponsive state. Autoantibody production occurs when these checkpoints are breached; however, when and how this occurs is largely unknown. In particular, how self-reactive B cells are restrained during bystander inflammation in otherwise healthy individuals is poorly understood. A weakness has been the unavailability of methods capable of dissecting physiologically relevant B cell responses without the use of an engineered BCR. Resolving this will provide insights that decipher how this process goes awry during autoimmunity or could be exploited for therapy. In this study, we use a strong adjuvant to provide bystander innate and adaptive signals that promote B cell responsiveness in conjunction with newly developed B cell detection tools to study in detail the ways that peripheral tolerance mechanisms limit the expansion and function of self-reactive B cells activated under these conditions. We show that although self-reactive B cells are recruited into the germinal center, their development does not proceed, possibly because of rapid counterselection. Consequently, differentiation of plasma cells is blunted, and Ab responses are transient and devoid of affinity maturation. We propose this approach, and these tools can be more widely applied to track Ag-specific B cell responses to more disease-relevant Ags, without the need for BCR transgenic mice, in settings where tolerance pathways are compromised or have been genetically manipulated to drive stronger insights into the biology underlying B cell-mediated autoimmunity.

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Re-educating immunity in respiratory allergies: the potential for hematopoietic stem cell-mediated gene therapy

Cited by 3 publications

References 130 publications

Defining B cell tolerance checkpoints and their modulation by immunotherapy

Defining B cell tolerance checkpoints and their modulation by immunotherapy

Peripheral tolerance checkpoints imposed by ubiquitous antigen expression limit antigen-specific B-cell responses under strongly immunogenic conditions

Peripheral Tolerance Checkpoints Imposed by Ubiquitous Antigen Expression Limit Antigen-Specific B Cell Responses under Strongly Immunogenic Conditions

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