The actin and tetraspanin networks organize receptor nanoclusters to regulate B cell receptor-mediated signaling.

A key role is emerging for the cytoskeleton in coordinating receptor signaling, although the underlying molecular requirements remain unclear. Here we show that cytoskeleton disruption triggered signaling requiring not only the B cell receptor (BCR), but also the coreceptor CD19 and tetraspanin CD81, thus providing a mechanism for signal amplification upon surface-bound antigen stimulation. By using superresolution microscopy, we demonstrated that endogenous IgM, IgD, and CD19 exhibited distinct nanoscale organization within the plasma membrane of primary B cells. Upon stimulation, we detect a local convergence of receptors, although their global organization was not dramatically altered. Thus, we postulate that cytoskeleton reorganization releases BCR nanoclusters, which can interact with CD19 held in place by the tetraspanin network. These results not only suggest that receptor compartmentalization regulates antigen-induced activation but also imply a potential role for CD19 in mediating ligand-independent "tonic" BCR signaling necessary for B cell survival.

Biomedical science postdocs: an end to the era of expansion.

After >3 decades of steady growth, the number of biological and medical science postdoctorates at doctoral degree-granting institutions recently began to decline. From 2010 through 2013, the most recent survey years, the postdoctoral population decreased from 40,970 to 38,719, a loss of 5.5%. This decline represents a notable departure from the previous long-standing increases in the number of postdoctorates in the biomedical workforce. The rate of contraction appears to be accelerating in the most recent survey years, and this has important implications for the biomedical workforce.

Family history of hematologic malignancies and risk of multiple myeloma: differences by race and clinical features.

PURPOSE: Multiple myeloma (MM) is the most common hematologic malignancy affecting Blacks in the USA, with standardized incidence rates that are twofold to threefold higher than Whites. The rationale for the disparity is unclear. METHODS: Using participants enrolled in the Molecular And Genetic Epidemiology study of myeloma (259 MM cases; 461 controls), we examined the risk of MM associated with family history of cancer, differences by race and among cases, defining clinical features. Risk estimates were calculated using odds ratios and corresponding 95% confidence intervals from logistic regression adjusted for confounders. RESULTS: Overall, MM risk in cases with relatives affected with any hematologic malignancy was significantly elevated compared to controls (OR 1.89, 95% CI 1.25-2.86). Myeloma risk associated with a family history of MM was higher than the risk associated with any hematologic malignancy (OR 3.75, 95% CI 1.75-8.05), and the effect was greater for Blacks (OR 20.9, 95% CI 2.59-168) than Whites (OR 2.04, 95% 0.83-5.04), among cases with early onset (≤60 years; OR 4.58, 95% CI 1.21-17.3) and with increasing numbers of affected relatives (p trend = 0.001). Overall, frequencies of end organ damage differed in cases with relatives affected with any hematologic malignancy and significantly more cases exhibited κ light chain restriction (OR 3.23, 95% CI 1.13-9.26). CONCLUSIONS: The excess risk of MM observed in Blacks and the variation in clinical features observed in MM patients according to family history of hematologic malignancy may be attributed to a shared germline and environmental susceptibility.

Lymphotoxin α1ß2 expression on B cells is required for follicular dendritic cell activation during the germinal center response.

CD19-deficient mice were used as a model to study follicular dendritic cell (FDC) activation because these mice have normal numbers of FDC-containing primary follicles, but lack the ability to activate FDCs or form GCs. It was hypothesized that CD19 expression is necessary for B-cell activation and upregulation of membrane lymphotoxin (mLT) expression, which promotes FDC activation. Using VCAM-1 and FcγRII/III as FDC activation markers, it was determined that the adoptive transfer of CD19(+) wild-type B cells into CD19-deficient hosts rescued GC formation and FDC activation, demonstrating that CD19 expression on B cells is required for FDC activation. In contrast, CD19(+) donor B cells lacking mLT were unable to induce VCAM-1 expression on FDCs, furthermore FcγRII/III upregulation was impaired in FDCs stimulated with mLT-deficient B cells. VCAM-1 expression on FDCs, but not FcγRII/III, was rescued when CD19-deficient B cells expressing transgenic mLT were cotransferred into recipient mice with CD19(+) , mLT-deficient B cells, suggesting that FDC activation requires the CD19-dependent upregulation of mLT on activated B cells. Collectively, these data demonstrate that activated B cells are responsible for the initiation of FDC activation resulting in a microenvironment supportive of GC development and maintenance.

Differential expression of the adaptor protein HSH2 controls the quantitative and qualitative nature of the humoral response.

Endogenous expression of the adaptor protein hematopoietic Src homology 2-containing adaptor protein (HSH2) is regulated in a dynamic manner during B cell maturation and differentiation. Developing B cells lack detectable HSH2, whereas transitional 1 and 2 B cells in the periphery exhibit increasing levels of expression. Mature follicular B cells exhibit decreased expression of HSH2 compared with transitional 2 B cells, and expression is further downregulated in germinal center B cells. In contrast, marginal zone B cells and B1a/b B cells exhibit high-level HSH2 expression. Regulation of HSH2 expression plays a critical role in determining the outcome of the humoral immune response as demonstrated using HSH2 transgenic (Tg) mice. Constitutive expression of HSH2 in the B lineage at levels comparable to B1a/b B cells results in decreased serum Ig titers for all subclasses with the exception of IgA. HSH2 Tg mice immunized with T-dependent or T-independent Ags exhibit a moderate decrease in the production of Ag-specific IgM, whereas class-switched isotypes are decreased by ∼80-90% compared with control mice. Analysis of HSH2 Tg B cell activation in vitro demonstrated that HSH2 selectively regulates the B cell response to TNF family receptors (i.e., CD40 and BAFF-R), but not BCR- or TLR-dependent signals. These data demonstrate that changes in HSH2 expression have profound effects on the humoral immune response.

TLT2 potentiates neutrophil antibacterial activity and chemotaxis in response to G protein-coupled receptor-mediated signaling.

Receptors encoded within the Trem locus have been shown to play an important role in modulating the cellular response to pattern recognition receptor signaling. TREM-like transcript 2 (TLT2) is a member of the Trem locus that is conserved in mouse and human. TLT2 exhibits a unique expression pattern in that it is expressed on cells of the myeloid and lymphoid lineage, suggesting that it plays a role in both innate and adaptive immunity. In this work, studies reveal that TLT2 plays an important role in potentiating neutrophil antibacterial activity and chemotaxis. TLT2 ligation enhances the neutrophil response to the formylated peptide FMLF, leading to increased reactive oxygen species production, degranulation, and chemotaxis. Moreover, TLT2 has the ability to specifically potentiate neutrophil activation and chemotaxis in response to a range of agonists that bind to G protein-coupled receptors, as it does not potentiate the response of cells to growth factor receptor-, Fc receptor-, or TLR-mediated signaling. Finally, TLT2 ligation potentiates the recruitment of neutrophils to sites of inflammation in vivo. These findings reveal a novel functional role for TLT2 that involves potentiation of neutrophil responses to G protein-coupled receptor signaling. Thus, TLT2 appears to play an important role in enhancing the innate immune response via a novel molecular mechanism.

Marginal zone B cells regulate antigen capture by marginal zone macrophages.

The marginal zone (MZ) of the mouse spleen contains macrophages that express receptors that trap pathogens, including the scavenger receptor macrophage receptor with a collagenous structure and the C-type lectin specific intracellular adhesion molecule-grabbing nonintegrin receptor 1 (SIGN-R1). We previously reported that expression of SIGN-R1 was decreased in CD19-deficient mice. In this study, we demonstrate that SIGN-R1 is expressed on a subset of macrophage receptor with a collagenous structure (MARCO)(+) macrophages. This subset is diminished when MZ B cells are absent due to either genetic developmental defects or following transient migration of B cells out of the MZ. When B cells return to the MZ, there is a delay in recovery of SIGN-R1-expressing macrophages. During this period, capture of Ficoll, which for the macrophages requires SIGN-R1, remains defective not only by the macrophages, but also by the B cells. Thus, MZ B cells regulate expression of molecules on macrophages that are important for trapping Ag, which, in turn, is required for Ag capture by the B cells.

Immune Literacy: a Call to Action for a System-Level Change.

Immune literacy-the ability to hear, learn, read, write, explain, and discuss immunological content with varied audiences-has become critically important in recent years. Yet, with its complex terminology and discipline-specific concepts, educating individuals about the immune system and its role in health and disease may seem daunting. Here, we reflect on how to demystify the discipline and increase its accessibility for a broader audience. To address this, a working group of immunology educators from diverse institutions associated with the research coordination network, ImmunoReach, convened virtually. As a result of these discussions, we request a call to action for a system-level change and present a set of practical recommendations that novice and experienced educators from diverse institutions, professional societies, and policymakers may adopt to foster immune literacy in their classrooms and communities.

Kindlin-3 puts the brakes on B cell activation and differentiation.

Discussion on the role of kindlin-3 in regulation of integrin function, B cell homing, cross-talk with the CXCR5:CXCL13 axis and B cell activation.

Antigen and Immunogen: An Investigation into the Heterogeneity of Immunology Terminology in Learning Resources.

The need to focus on immunology education has never been greater. The coronavirus disease 2019 pandemic has revealed that a significant proportion of our society is vaccine hesitant. Some of this hesitancy may stem from a general lack of understanding of how the immune system and immunological interventions work. In addition, social media platforms undercut public health efforts by quickly propagating a multitude of misconceptions and erroneous information surrounding the science behind these interventions. The responsibility to be advocates for science is well recognized by immunology researchers, educators, and public health professionals, as evidenced by the rich body of resources developed to communicate science to the lay audience. Scientific jargon, however, can be a barrier to effective communication and can negatively impact learning and comprehension. The field of immunology is especially laden with discipline-specific terminology, which can hamper educators' efforts to convey key concepts to learners. Furthermore, a lack of consistency in accepted definitions can complicate students' conceptual understanding. Learning resources, including textbooks, published in print or available online, and exclusively digital resources, continue to serve as the primary sources of information for both educators and students. In this article, we describe a vast heterogeneity in learning resource glossary descriptions of two key conceptual terms: antigen and immunogen We provide a perspective on pedagogical strategies to address these critical terms. Using current knowledge, we recommend an approach to standardize the definitions of the terms antigen and immunogen within the immunology educator community.

An Analysis of Factors That Influence Students to Pursue Immunology.

One considers many factors before choosing a career path, such as interest, accessibility of resources, academic ability, and social network support. As employment around the world in science, technology, engineering, and math (STEM) disciplines continues to increase, there is a need to understand why students select specific majors in an effort to increase overall enrollment and retention of STEM majors. The purpose of this study was to elucidate how undergraduate and graduate students were introduced to immunology, a STEM discipline, and how these experiences influenced their desire to pursue immunology as a major. The findings from this study show that a majority of both immunology and nonimmunology majors were initially exposed to immunology through an educational experience compared with a personal experience. Our data also indicate that the timing of the experience is critical, such that an educational experience at an advanced academic level, for example, in college, or a personal experience as a teen or young adult correlated with the decision to pursue an immunology degree. Moreover, graduate students studying immunology report that having research experiences and/or an experience with a mentor positively influenced their decision to pursue immunology. Overall, the findings from this research highlight the type and timing of exposures that influence individuals to major in the field of immunology, and these data can be used in the future to increase the number of immunology graduates.

Inside the Undergraduate Immunology Classroom: Current Practices that Provide a Framework for Curriculum Consensus.

Although immunological research has become increasingly important in recent decades for understanding infectious and immune-mediated diseases, immunological pedagogy at the undergraduate level has lagged behind in reports of evidence-based scholarship. To address the need for a renewed emphasis on immunology education and to describe the current status of undergraduate education in immunology, an online survey of instructors with experience in teaching immunology was conducted. The survey investigated the effects of instructors' level of teaching experience, target student population, and course components on the emphasis given to certain immunology subtopics in their courses. Instructor teaching experience and current role in teaching influenced the proportion of time allotted to lab techniques, clinical topics, and evolutionary aspects, but type of institution (undergraduate and graduate degree-granting institutions) did not affect course content or emphasis on subtopics. Topics that received the greatest emphasis were the adaptive immune system, the innate immune system, host-pathogen interactions, and molecular mechanisms. Vaccines, hypersensitivity, autoimmunity, and essential immunology techniques were ranked slightly lower, while topics such as evolution, metabolism and antibody purification received the least emphasis. Inclusion of a lab component increased time given to lab-related and clinical topics but did not affect the perceived importance of various scientific competencies. These data describe current curricular practices of instructors who have experience teaching immunology and inform curricular priorities and course design frameworks for undergraduate immunology education.

The Future of Undergraduate Immunology Education: Can a Comprehensive Four-Year Immunology Curriculum Answer Calls for Reform in Undergraduate Biology Education?

The field of immunology is rapidly evolving and has significant relevance to understanding human health, particularly in light of the threat from infectious diseases and the ability to harness the immune system to treat cancer, autoimmune diseases, and allergies. Providing opportunities to explore the field of immunology is relevant to undergraduate students interested in pursuing careers in health professions and biomedical research. There are calls for greater emphasis on interdisciplinary science education at the undergraduate level and the acquisition of transferrable competencies that will prepare undergraduates for success in a range of careers. The study of immunology provides an ideal platform to expose students to interdisciplinary science, both at the foundational and applied level. We describe the organization of an immunology curriculum, development of program learning objectives, selection and mapping of content objectives across courses, and programmatic assessment with the intent to meet calls for reform in undergraduate biology education.

Using real-world examples of the COVID-19 pandemic to increase student confidence in their scientific literacy skills.

Over the last few decades, there has been a shift in the classroom from lecture-based to active learning settings with the argument that students retain more information when they are involved in the learning process. This correlation is even stronger when the active learning setting incorporates a real-world or personal connection. Using active learning activities that develop students' ability to comprehend primary scientific literature is particularly important in the field of immunology, due to the rapid expansion of information in the field, which has been further accelerated due to the COVID-19 pandemic. By nature, immunology is interdisciplinary, requiring an integrated knowledge of concepts from several scientific disciplines to understand complex immune processes. Engaging undergraduate students through the use of primary literature can improve scientific literacy, develop critical thinking, and enhance understanding of complex topics. To explore this, we utilized a group learning activity in an introductory immunology course that incorporated both a coronavirus-related review and COVID-19 clinical research article. We found that this learning activity significantly enhanced student confidence in key scientific literacy skills: reading scientific literature, clearly explaining relevant points, and describing conclusions generated from the data. Moreover, all students reported that they enjoyed the activity and that it helped them understand more about the current COVID-19 pandemic in the context of the immune response.

Out of the Curricular Shadows: Revolutionizing Undergraduate Immunology Education.

Immunology has its developmental roots in understanding protection of the host from pathogens, leading to the development of vaccines and subsequently identification of soluble and cellular components of the immune system. Thus, immunology education has historically been tightly linked to infectious disease. Decades of research have demonstrated that the complexity and intricacies of the immune system are far greater than perhaps was once imagined. As a system that interfaces with all other organ systems in the body, it plays a key role in both maintaining health and causing life-threatening disease, thereby solidifying its importance in several clinical specialties beyond protective immunity. In the past decade, tremendous advances have taken place in which scientists and physicians have begun to harness the power of the immune system to create immunotherapies to fight cancer, inflammatory syndromes and autoimmune diseases. Thus, the argument can be made that training individuals in the field of immunology is becoming increasingly important. However, immunology is a highly conceptual discipline and understanding how the multiple cellular and soluble components of the immune system work in concert requires knowledge in a number of disciplines, including molecular biology, cell biology, genetics, and biochemistry. Time is needed for students to process, evaluate, and apply this information in meaningful ways. Concomitantly, knowledge in the field of immunology is expanding rapidly, bolstering the need for increased time in the curriculum to facilitate the ability of educators to convey information so that it can be effectively understood and applied. We propose that it is time for a renaissance in immunology education at the undergraduate level to better prepare individuals who will subsequently pursue careers in medicine, related health professions, and research. The purpose of this article is to discuss the current state of undergraduate immunology education with respect to its prevalence and how this compares to other biological disciplines, the need to develop robust immunology curricula at the undergraduate level and the importance of such programs in preparing students for pursuing postgraduate training in the health professions, and research-intensive careers.

TREM-like transcript 2 is stored in human neutrophil primary granules and is up-regulated in response to inflammatory mediators.

The triggering receptor expressed on myeloid cell locus encodes a family of receptors that is emerging as an important class of molecules involved in modulating the innate immune response and inflammation. Of the 4 conserved members, including triggering receptor expressed on myeloid cells 1 and 2 and triggering receptor expressed on myeloid cell-like transcripts 1 and 2, relatively little is known about triggering receptor expressed on myeloid cell-like transcript 2 expression and function, particularly in humans. In this study, experiments were performed to determine if triggering receptor expressed on myeloid cell-like transcript 2 expression is conserved between mouse and human, demonstrating that human triggering receptor expressed on myeloid cell-like transcript 2 is expressed on cells of the lymphoid, as well as myeloid/granuloid lineages, similar to murine triggering receptor expressed on myeloid cell-like transcript 2. Consistent with studies in the mouse, triggering receptor expressed on myeloid cell-like transcript 2 expression is up-regulated in response to inflammatory mediators on human neutrophils. Importantly, it was shown that triggering receptor expressed on myeloid cell-like transcript 2, in resting human neutrophils, is predominantly localized to intracellular vesicles, including secretory vesicles and primary granules; with the majority of triggering receptor expressed on myeloid cell-like transcript 2 stored in primary granules. In contrast to other primary granule proteins, triggering receptor expressed on myeloid cell-like transcript 2 is not expelled on neutrophil extracellular traps but is retained in the plasma membrane following primary granule exocytosis. In summary, these findings establish that triggering receptor expressed on myeloid cell-like transcript 2 expression is conserved between species and is likely to be important in regulating neutrophil antimicrobial function following primary granule exocytosis.

Evaluating function of transmembrane protein tyrosine phosphatase CD148 in lymphocyte biology.

The transmembrane protein tyrosine phosphatase CD148 is expressed on numerous cell types, including most cells of the hematopoietic lineage. CD148 has been shown to regulate density-dependent inhibition of cell growth as well as cellular differentiation in nonhematopoietic cells and has been shown to regulate signal transduction processes in several nonlymphoid hematopoietic cell types. Analysis of CD148 expression on lymphoid cells has demonstrated that CD148 is expressed at low levels on T cells and that it is upregulated in response to activation. Several groups have observed that CD148 negatively regulates T cell activation in response to crosslinking of the T cell antigen receptor, suggesting that it may play a role in feedback inhibition of the T cell immune response. In the B cell compartment, CD 148 expression appears to be restricted to the memory subpopulation, raising the possibility that it serves a unique function in these cells, which has yet to be determined. Recent studies have shown that CD148 interacts with the PDZ domain-containing protein syntenin, raising the possibility that its function or its localization with substrates in T and B cells may be controlled through this or a related interaction with another PDZ domain protein.

Putting PhDs to work: career planning for today's scientist.

Individual development plans (IDPs) have been promoted nationally as a tool to help research trainees explore career opportunities and set career goals. Despite the interest in IDPs from a policy perspective, there is little information about how they have been used. The authors examined IDP awareness and use, the benefits of creating an IDP, and ways to facilitate its use by administering a survey to current or former postdoctoral researchers via the National Postdoctoral Association (NPA) and University of Alabama at Birmingham email lists; individuals belonging to Federation of American Societies for Experimental Biology member societies who mentored postdocs; and postdoctoral administrators at member institutions of the Association of American Medical Colleges and the NPA. Although most postdoctoral administrators (>80%) were familiar with IDPs, less than 50% of postdocs and only 20% of mentors were aware of IDPs. For those postdocs and mentors who reported creating an IDP, the process helped postdocs to identify the skills and abilities necessary for career success and facilitated communication between postdocs and their mentors. Despite the fact that creating an IDP benefits postdocs and mentors, IDP use will likely remain low unless institutions and research mentors encourage trainees to engage in this process.

Murine marginal zone B cells play a role in Vibrio cholerae LPS antibody responses.

The emergence of Vibrio cholerae (Vc) lipopolysaccharide (LPS) as a lead protective antigen for a cholera subunit vaccine has increased the interest in what type of B cell is best suited to generate anti-Vc LPS antibodies. A related question is what form of LPS is the most immunogenic. C57Bl/6 (B6) neonatal mice (10 days old) whose marginal zone (MZ) B cell compartment is still maturing and two lines of knockout mice that either lack the signaling mechanism required for the maturation of MZ B cells or that lack a receptor required for MZ B cell retention in the MZ were used to determine the role of MZ B cells in anti-Vc LPS antibody responses. Data support the conclusion that MZ B cells play a significant role in the anti-Vc LPS antibody response. Serum and vibriocidal antibody titers also depend on whether the Vc LPS is purified or bacterial cell-associated.