In the development of the immune response, the dendritic cell subset of leukocytes plays a key role in enhancing immunogenicity. Dendritic cells can pick up antigens in the tissues and move to lymphoid organs, through which T cells continually recirculate. It is proposed that dendritic cells at these sites express functions which have beenidentified in tissue culture models. These involve efficient binding to antigen‐specific T lymphocytes, as well as the induction of the lymphokines and growth factor receptors required for (...) immunity. The dendritic cell system, apparently under the control of cytokines, is a sentinel designed to signal T cells that a significant antigen burden is present, and to generate the activated T lymphoblasts that interact with many other cell types to bring about an immune response. (shrink)

Langerhans cells (LCs), residing in the epidermis, are able to induce potent immunogenic responses and also to mediate immune tolerance. We propose that tolerogenic and immunogenic responses of LCs are directed by signaling from the epidermis and involve counter‐acting gene circuits that are coupled to a core maturation gene module. We base our analysis on recent genetic and genomic findings facilitating the understanding of the molecular mechanisms controlling these divergent immune functions. Comparing gene regulatory network (GRN) analyses of various types (...) of dendritic cells (DCs) including LCs we integrate signaling‐dependent (TGFβ, EpCAM, β‐Catenin) and transcription factor (IRF4, IRF1, NFκB) regulated gene circuits that appear to orchestrate the distinctive LC functional states. Our model proposes, that while epidermal signaling in the steady‐state promotes LC tolerogenic function, the disruption of cell‐cell contacts coupled with inflammatory signaling induces LC immunogenic programing. The conceptual framework emphasizes the sensing of discrete epidermal and inflammatory cues by resident LCs in dictating their genomic programing and cell state dynamics. (shrink)

The main objective of immunology is to establish why and when an immune response occurs, that is, to determine a criterion of immunogenicity. According to the consensus view, the proper criterion of immunogenicity lies in the discrimination between self and nonself. Here we challenge this consensus by suggesting a simpler and more comprehensive criterion, the criterion of continuity. Moreover, we show that this criterion may be considered as an interpretation of the immune 'self'. We conclude that immunologists can (...) continue to speak of the self, provided that they admit that the self/nonself discrimination is not an adequate criterion of immunogenicity. (shrink)

I will offer a conceptual analysis of different notions of structure and function of viral immunogens and of different structure-function relationships. My focus will then be on the mechanisms by which the desired immune response is induced and why strategies based on three-dimensional molecular antigen structures and their rational design are limited in their ability to induce the desired immunogenicity. I will look at the mechanisms of action of adjuvants (thus the wordplay with Janeway's "immunologist's dirty little secret"). Strategies (...) involving adjuvants and other (more successful) vaccination strategies rely on taking into account activities and functions ("what is going on"), and not just the structures involved ("who is there"), in binding in a "lock and key" fashion. Functional patterns as well as other organizational and temporal patterns, I will argue, are crucial for inducing the desired immune response and immunogenicity. The 3D structural approach by itself has its benefitsand its limits, which I want to highlight by this philosophical analysis, pointing out the importance of structure-function relationships. Different functional aspects such as antigenicity, immunogenicity, and immunity need to be kept separate and cannot be reduced to three-dimensional structures of vaccines. Taking into account different notions of structure and function and their relationships might thus advance our understanding of the immune system and rational HIV vaccine design, to which end philosophy can provide useful tools. (shrink)

The vertebrate immune system uses an impressive arsenal of mechanisms to combat harmful cellular states such as infection. One way is via cells delivering real‐time snapshots of their protein content to the cell surface in the form of short peptides. Specialized immune cells (T cells) sample these peptides and assess whether they are foreign, warranting an action such as destruction of the infected cell. The delivery of peptides to the cell surface is termed antigen processing and presentation, and decades of (...) research have provided unprecedented understanding of this process. However, predicting the capacity for a given peptide to be immunogenic—to elicit a T cell response—has remained both enigmatic and a long sought‐after goal. In the era of big data, a point is being approached where the steps of antigen processing and presentation can be quantified and assessed against peptide immunogenicity in order to build predictive models. This review presents new findings in this area and contemplates challenges ahead. (shrink)

Multidrug-resistant Acinetobacter baumannii is recognized to be among the most difficult antimicrobial-resistant gram negative bacilli to control and treat. One of the major challenges that the pathogenic bacteria face in their host is the scarcity of freely available iron. To survive under such conditions, bacteria express new proteins on their outer membrane and also secrete iron chelators called siderophores. Antibodies directed against these proteins associated with iron uptake exert a bacteriostatic or bactericidal effect against A. baumanii in vitro, by blocking (...) siderophore mediated iron uptake pathways. Attempts should be made to discover peptides that could mimic protein epitopes and possess the same immunogenicity as the whole protein. Subsequently, theoretical methods for epitope prediction have been developed leading to synthesis of such peptides that are important for development of immunodiagnostic tests and vaccines. The present study was designed to in silico resolving the major obstacles in the control or in prevention of the diseases caused by A. baumannii. We exploited bioinformatic tools to better understand and characterize the Baumannii acinetobactin utilization structure of A. baumannii and select appropriate regions as effective B cell epitopes. In conclusion, amino acids 26–191 of cork domain and 321–635 of part of the barrel domain including L4–L9, were selected as vaccine candidates. These two regions contain functional exposed amino acids with higher score of B cell epitopes properties. Majority of amino acids are hydrophilic, flexible, accessible, and favorable for B cells from secondary structure point of view. (shrink)

Development of biopharmaceuticals is a challenging issue in bioethics. Unlike conventional, small molecular weight drugs, biopharmaceuticals are proteins derived from DNA technology and hybrid techniques with complex three dimensional structures. Immunogenicity of biopharmaceuticals should always be tested in clinical settings due to low predictive value of preclinical animal models. However, non-human primates and transgenic mice could be used to address certain aspects of immunogenicity. Substantial efforts have been made to reduce NHP use in biopharmaceutical drug development, e.g. study (...) design improvements and changes in regulatory policy. In addition, several expert groups are active in this field. Despite that, there is an increasing trend of use of NHP in preclinical safety testing of biopharmaceuticals, especially regarding monoclonal antibodies. Other potential bioethical issues related biopharmaceutical drug development are their cost/effectiveness ratio, clinical safety assessment, production of biosimilars, and comparison of their efficacy with placebo in countries without intention to market. Identification of the human genome has opened many new bioethical issues. Development of biopharmaceuticals is an important bioethical issue for several reasons. It connects all aspects of contemporary bioethics: bio?medicine, animal welfare and the most recent ad?vances in biotechnology. In particular, biopharmaceutical drug development is a challenging issue regarding treatment of rare diseases. Razvoj biofarmaceutika predstavlja izazov u bioetici. Za razliku od uobicajenih lekova male molekulske mase, biofarmaceutici su proteini kompleksne trodimenzionalne strukture koji se dobijaju tehnologijom rekombinantne DNK i tehnikom hibridoma. Imunogenost biofarmaceutika treba uvek proveriti u klinickim studijama zbog male prediktivne prednosti pretklinickih animalnih modela. Medjutim, primati i transgeni sojevi miseva mogu se upotrebiti da bi se naznacili neki aspekti imunogenosti. Znacajni napori su ucinjeni u cilju smanjenja upotrebe primata u razvoju biofarmaceutika, npr. poboljsanja dizajna istrazivanja i promene u zakonskoj regulativi. Osim toga, u ovoj oblasti su aktivne i pojedine ekspertske grupe. Uprkos tome, postoji rastuci trend upotrebe primata izuzev coveka u pretklinickom ispitivanju bezbednosti biofarmaceutika, posebno kada su u pitanju monoklonska antitela. Druga bioeticka pitanja koja se mogu dovesti u vezu sa razvojem biofarmaceutika su odnos njihove cene i efikasnosti, procena bezbednosti u klinickim uslovima, proizvodnja bioloski slicnih lekova i uporedjivanje njihove efikasnosti sa placebom u zemljama u kojima ne postoji namera o plasmanu. Upoznavanje humanog genoma otvorilo je mnoga bioeticka pitanja. Razvoj biofarmaceutika je vazno bioeticko pitanje iz vise razloga. Ono povezuje sve aspekte savremene bioetike: biomedicinu, dobrobit zivotinja i najnovija dostignuca u biotehnologiji. Posebno, razvoj biofarmaceutika je izazov kada je u pitanju lecenje retkih bolesti. (shrink)

Both concepts of the holobiont and the immune system are at the heart of an ongoing scientific and philosophical examination concerning questions of the organism’s individuality and identity as well as the relations between organisms and their environment. Examining the holobiont, the question of boundaries and individuality is challenging because it is both an assemblage of organisms with physiological cohesive aspects. I discuss the concept of immunity and the immune system function from the holobiont perspective. Because of the host-microbial close (...) relations of codependence and interdependence, the holobiont is more often than not confused with the host, as the host is the domain in which this entity exists. I discuss the holobiont unique ecological characteristics of microbial assemblages connected to a host in a network of interactions in which the host is one of the organisms in the community but also its landscape. Therefore, I suggest viewing the holobiont as a host-ecosystem and discuss the implication of such a view on the concept of immunity and the meaning of protection. Furthermore, I show that viewing the holobiont as a host ecosystem opens the possibility of using the same ecological definition of boundaries and immunity dealing with an ecological system. Thus, the holobiont’s boundaries and immunity are defined by the persistence of its complex system of interactions integrating existing and new interactions. This way of thinking presents a notion of immunity that materializes as the result of the complex interdependence relations between the different organisms composing the holobiont similar to that of an ecosystem. Taking this view further, I discuss the notion of immunogenicity that is ontologically heterogeneous with various causal explanations of the processes of tolerance and targeted immune response. Finally, I discuss the possible conceptualization of already existing and new biomedical practices. (shrink)

Strategies to support the psychosocial well-being of older adults living in aged-care are needed; and evidence points toward music listening as an effective, non-pharmacological tool with many benefits to quality of life and well-being. Yet, the everyday listening practices of older adults living in residential aged-care remain under-researched. The current study explored older adults’ experiences of music listening in their daily lives while living in residential aged-care and considered how music listening might support their well-being. Specifically, what might go into (...) autonomous listening activities? 32 Australian residents living in two Australian care facilities participated in semi-structured interviews. The results of a qualitative thematic analysis revealed three themes pertaining to “previous music experiences and interest,” “current music listening,” and “barriers to listening.” While an interest in and access to music did not necessarily result in everyday listening practices, of those participants who did listen to music, perceived benefits included outcomes such as entertainment, enjoyment, relaxation, and mood regulation. Drawing on Ruud’s notion of music as a “cultural immunogen” supporting well-being and Self-Determination Theory, theoretical implications of the findings are addressed, relating to how to create and support music activities in aged-care facilities so that they are engaging, meaningful, and promote emotional regulation, community, and well-being. (shrink)

BackgroundLittle is known about volunteers from Northern research settings who participate in vaccine trials of highly infectious diseases with no approved treatments. This article explores the motivations of HIV immunocompromised study participants in Canada who volunteered in a Phase II clinical trial that evaluated the safety and immunogenicity of an Ebola vaccine candidate.MethodsObservation at the clinical study site and semi-structured interviews employing situational and discursive analysis were conducted with clinical trial participants and staff over one year. Interviews were recorded, (...) transcribed and analysed using critical qualitative interpretivist thematic analytical techniques. Patterns were identified, clustered and sorted to generate distinct and comprehensive themes. We then reassembled events and contexts from the study participants’ stories to develop two ideal portraits based on "composite characters" based on study participants features. These provide ethnographically rich details of participants’ meaningful social worlds while protecting individual identities.ResultsTen of the 14 clinical trial participants, and 3 study staff were interviewed. Participant demographics and socio-economic profiles expressed limited contextual diversity. Half were men who have sex with men, half were former injection drug users experiencing homelessness, one was female, none were racialized minorities and there were no people from HIV endemic countries. Fully 90% had previous involvement in other clinical studies. Their stories point to particular socio-economic situations that motivated their participation as clinical labor through trial participation.ConclusionsOur findings support Fisher’s argument of “structural coercion” in clinical trial recruitment of vulnerable individuals experiencing precarious living conditions. Clinical trials should provide more detail of the structural socio-economic conditions and healthcare needs which lie “under consent” of study participants. Going well beyond an overly convenient narrative of altruism, ethical deliberation frameworks need to sufficiently address the structural conditions of clinical trials. We offer concrete possibilities for this and acknowledge that further research and clinical data should be made available underlying study participant contexts with regards to recruitment and participation in resource poor settings, in both the South and the North. (shrink)

Coordination of immune responses in the gut is a complex task. In order to fight pathogens and maintain a defined population of commensal microbes, the mucosal immune system has to coordinate information from the external (luminal) and internal (abluminal) environment and respond accordingly. Dendritic cells (DCs) are crucial cell types involved in this process as they integrate these signals and direct immunogenic or tolerogenic responses. Here, we review how various functions of DCs depend on microbial stimuli and how these stimuli (...) influence the course of immune activation. (shrink)

Cancer cells seem to exploit mechanisms that evolve as part of physiological tolerance, which is a complementary and often beneficial form of defense. The study of physiological systems of tolerance can therefore provide insights into the development of a state of host tolerance of cancer, and how to break it. Analysis of these models has the potential to improve our understanding of existing immunological therapeutic targets, and help to identify future targets and rational therapeutic combinations. The treatment of cancer with (...) immune checkpoint inhibitors aims to reverse the progression to tolerance of cancer, and achieve an immunogenic, rather than tolerogenic, homeostasis. Broadening the efficacy and durability of checkpoint inhibitors focuses on reversing tolerance and stimulating immunogenicity in the cancer, host, and environment. Two examples of important physiological states of tolerance that may inform tolerance of cancer are microbial infection and placental reproduction. These states of tolerance result from bilateral shaping of host and non‐self, akin to immunoediting in cancer, and offer reliable models to study the immune tolerance paradigm. (shrink)

The expression of products encoded by the major histocompatibility complex (MHC) on tumor cells has recently been studied extensively. It has been found that many malignant tumor cells have their MHC antigens ‘switched‐off’ but that these antigens are re‐expressed following DNA‐mediated gene transfer, with increased tumor immunogenicity as a result and the consequence that these ‘transformed’ tumor cells are rejected in vivo.: This review will discuss approaches that have been taken to induce strong tumor‐specific immunity by the manipulation of (...) MHC expression on tumor cells. (shrink)

Tremendous development in recent medical science and the consequent discoveries resulting in successful prevention and also cure of different diseases are shared by clinical research involving the human volunteers. Preceding the trials in the human subjects, and to ensure safety, the proposed drug and other interventions are either tested in animals (vivo) or in laboratory (vitro) to evaluate initial safe starting dose for the human beings and to key out the benchmarks for the clinical monitoring for the potential unfavorable effects. (...) These pre human trials might not necessarily protect against the untoward effects in the human beings as happened in the case of thalidomide tragedy, which caused disability and killed thousands of babies born to the mothers, those who took this medicine. Use of healthy human volunteers in the preliminary experiments or phase I clinical trials either reduces or excludes risks of subsequent undesirable effects in the future trails (1). Phase-1 trials are conducted in order to test the safety, reactions and immunogenicity of vaccines in volunteers. Novel treatments for the cancer are first tested in phase 1 trials enrolling the patients with advanced disease, who have exhausted the standard treatment options. Phase-1 oncology trials are the pivot point in the translation of new cancer therapies from bench to bedside. Nevertheless, these trials remain ethically controversial. The controversy stems from the fact that, classically, phase-1 oncology clinical trials involve first-in-human testing of experimental treatment candidates in patients with a terminal diagnosis, who typically have exhausted standard treatment options. Commentators on the ethics of phase-1 clinical trials make diametrically opposed claims about the prospect of direct medical benefit from participation in these trials-benefits that can be attributed to receiving the experimental treatment intervention. One camp of benefit skeptics, inhabited mainly by bioethicists, characterizes this form of research as lacking any reasonable prospect of direct medical benefit. They see an ethical cloud hovering over phase-1 trials, because the vast majority of patients volunteer for phase-1 trials out of a motivation to receive medical benefit. In the view of these skeptics, such patients therefore harbor a ‘therapeutic misconception’ about research participation. This misconception calls into question the validity of informed consent and thereby undercuts the ethical basis of these trials (2). In this paper, I will discuss the ethical justification of the participation of human volunteers in phase-1 trials. (shrink)

Biomedical ethics requires that clinical trial participants be accurately informed of the potential risks associated with investigational medical products. We found that the vaccine manufacturer Merck made false statements to the trial participants about the safety of Gardasil in its Future II HPV vaccine trial in Denmark. The clinical study protocol specified that safety testing was one of the trial’s primary objectives, but the recruitment brochure given to trial participants stated this was not the case, as allegedly the vaccine had (...) already been proven safe in previous trials. The advertising material for the trial and the informed consent forms stated that the comparator was saline or an inactive substance, when, in fact, it contained Merck’s proprietary aluminum adjuvant which is highly immunogenic. Several trial participants experienced long-term disabling symptoms during the trial, also some randomized to the adjuvant “placebo” control group. In all cases, their serious adverse events were dismissed as unrelated to the study treatment by Merck’s clinical investigators. We demonstrate that Merck’s published statements about the safety of their proprietary aluminum adjuvant is contradicted by the research evidence. The use of adjuvants as “placebos” in vaccine clinical trials is unethical as it makes it difficult to discover serious vaccine harms. (shrink)

Pregnant women and their interests have been underrepresented in health research. Little is known about issues relevant to women considering research participation during pregnancy. We performed in-depth interviews with 22 women enrolled in either one of two trials sponsored by the National Institutes of Health to assess the safety and immunogenicity of the H1N1 vaccine during pregnancy. Three themes characterized women’s decisions to participate in research: they valued early access to the vaccine, they perceived a safety advantage when participating (...) in research, and they wanted to help advance scientific knowledge. However, there were also some considerations that would disincline them to participate in research—for instance, a significant risk of maternal or fetal harm, the presence of a placebo arm in a study, or a requirement to significantly change planned therapy or behavior. Pregnant women who participated in the H1N1 vaccine trials viewed research favorably, citing its advantages over standard clinical care. These findings emphasize that access to benefit should guide policy for including pregnant women in research. (shrink)

Zonulin is a physiological modulator of intercellular tight junctions, which upregulation is involved in several diseases like celiac disease (CeD). The polyQ gliadin fragment binds to the CXCR3 chemokine receptor that activates zonulin upregulation, leading to increased intestinal permeability in humans. Here, we report a general hypothesis based on the structural connection between the polyQ sequence of the immunogenic CeD protein, gliadin, and enteric coccidian parasites proteins. Firstly, a novel interaction pathway between the parasites and the host is described based (...) on the structural similarities between polyQ gliadin fragments and the parasite proteins. Secondly, a potential connection between coccidial infections as a novel environmental trigger of CeD is hypothesized. Therefore, this report represents a promising breakthrough for coccidian research and points out the potential role of coccidian parasites as a novel trigger of CeD that might define a preventive strategy for gluten‐related disorders in general. Also see the video abstract here: https://youtu.be/oMaQasStcFI. (shrink)

Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the (...) forming of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology. (shrink)

Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the (...) forming of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology. -/- . (shrink)

The cyclic GMP‐AMP synthase–stimulator of interferon genes (cGAS‐STING) pathway is central for the initiation of anti‐tumoural immune responses. Enormous effort has been made to optimise the design and administration of STING agonists to stimulate tumour immunogenicity. However, in certain contexts the cGAS‐STING axis fuels tumourigenesis. Here, we review recent findings on the regulation of cGAS expression and activity. We particularly focus our attention on the DNA‐dependent protein kinase (DNA‐PK) complex, that recently emerged as an activator of inflammatory responses in (...) tumour cells. We propose that stratification analyses on cGAS and DNA‐PK expression/activation status should be carried out to predict treatment efficacy. We herein also provide insights into non‐canonical functions borne by cGAS and cGAMP, highlighting how they may influence tumourigenesis. All these parameters should be taken into consideration concertedly to choose strategies aiming to effectively boost tumour immunogenicity. (shrink)

Considerable progress has been made toward understanding the involvement of recoverin in a cancer-associated retinopathy (CAR) that results in blindness. We describe the expression of recoverin in tumors of individuals afflicted with CAR, characterize the immunological response towards recoverin in these patients, and demonstrate how the disease can be induced in rodents using recoverin as an immunogen.

Health regulators must carefully monitor the real-world safety and effectiveness of marketed vaccines through post-market monitoring in order to protect the public’s health and promote those vaccines that best achieve public health goals. Yet, despite the fact that vaccines used in collective immunization programmes should be assessed in the context of a public health response, post-market effectiveness monitoring is often limited to assessing immunogenicity or limited programmatic features, rather than assessing effectiveness across populations. We argue that post-market monitoring ought (...) to be expanded in two ways to reflect a ‘public health notion of post-market effectiveness’, which incorporates normative public health considerations: effectiveness monitoring should yield higher quality data and grant special attention to underrepresented and vulnerable populations; and the scope of effectiveness should be expanded to include a consideration of the various social factors that maximize a vaccine’s effectiveness at the population level, paying particular attention to how immunization programmes impact related health gradients. We use the case of the human papillomavirus vaccine in Canada to elucidate how expanding post-market effectiveness monitoring is necessary to close the gap between clinical practice and public health, and to ensure that vaccines are effective in a morally relevant sense. (shrink)

The demonstration that dendritic cell (DC)‐derived exosomes can be exploited for targeted RNAi delivery to the brain after systemic injection provides the first proof‐of‐concept for the potential of these naturally occurring vesicles as vehicles of drug delivery. As well as being amenable to existing in vivo targeting strategies already in use for viruses and liposomes, this novel approach offers the added advantages of in vivo safety and low immunogenicity. Fulfilment of the potential of exosome delivery methods warrants a better (...) understanding of their biology, as well as the development of novel production, characterisation, targeting and cargo‐loading nanotechnologies. Ultimately, exosome‐mediated drug delivery promises to overcome important challenges in the field of therapeutics, such as delivery of drugs across otherwise impermeable biological barriers, such as the blood brain barrier, and using patient‐derived tissue as a source of individualised and biocompatible therapeutic drug delivery vehicles. (shrink)

Developing a vaccine against HIV is one of the greatest challenges the scientific community faces today. Several vaccine candidates have undergone preliminary safety and immunogenicity studies in humans. Research teams are ready to test these vaccines in the field, yet the scientific community is divided as to whether efficacy trial should begin. This paper addresses the complex scientific and ethical issues raised by clinical trials. Considering the pressure to act rapidly to solve the crisis, scientists need to hold to (...) the fundamental principles that guide decisions in biomedical research: respect for persons, beneficence and justice. Because these studies need to enroll a large number of subjects, prospective vaccines will need to be tested in developing, as well as industrial countries. The international community needs to work to ensure that the populations that accept the risk of the research receive the full benefit of that research and, that the vaccine proven successful, be made accessible and affordable to people in less economically developed situation. (shrink)

The question as to why some hosts can eradicate their tumors while others succumb to tumor‐progression remains unanswered. Here, a provocative concept is proposed that intrinsic differences in the T cell receptor (TCR) repertoire of individuals may influence the outcome of anti‐tumor immunity by affecting the frequency and/or variety of tumor‐reactive CD8 and/or CD4 tumor‐infiltrating lymphocytes. This idea implicates that the TCR repertoire in a given patient might not provide sufficiently different TCR clones that can recognize tumor antigens, namely, “a (...) hole in the TCR repertoire” might exist. This idea may provide a novel perspective to further dissect the mechanisms underlying heterogeneous anti‐tumor immune responses in different hosts. Besides tumor‐intrinsic heterogeneity and host microbiome, the various factors that may constantly shape the dynamic TCR repertoire are also discussed. Elucidating mechanistic differences in different individuals’ immune systems will allow to better harness immune system to design new personalized cancer immunotherapy. (shrink)