Transcriptome dynamics of CD4+ T cells during malaria maps gradual transit from effector to memory.

The dynamics of CD4+ T cell memory development remain to be examined at genome scale. In malaria-endemic regions, antimalarial chemoprevention protects long after its cessation and associates with effects on CD4+ T cells. We applied single-cell RNA sequencing and computational modelling to track memory development during Plasmodium infection and treatment. In the absence of central memory precursors, two trajectories developed as T helper 1 (TH1) and follicular helper T (TFH) transcriptomes contracted and partially coalesced over three weeks. Progeny of single clones populated TH1 and TFH trajectories, and fate-mapping suggested that there was minimal lineage plasticity. Relationships between TFH and central memory were revealed, with antimalarials modulating these responses and boosting TH1 recall. Finally, single-cell epigenomics confirmed that heterogeneity among effectors was partially reset in memory. Thus, the effector-to-memory transition in CD4+ T cells is gradual during malaria and is modulated by antiparasitic drugs. Graphical user interfaces are presented for examining gene-expression dynamics and gene-gene correlations ( http://haquelab.mdhs.unimelb.edu.au/cd4_memory/ ).

The NK cell granule protein NKG7 regulates cytotoxic granule exocytosis and inflammation.

Immune-modulating therapies have revolutionized the treatment of chronic diseases, particularly cancer. However, their success is restricted and there is a need to identify new therapeutic targets. Here, we show that natural killer cell granule protein 7 (NKG7) is a regulator of lymphocyte granule exocytosis and downstream inflammation in a broad range of diseases. NKG7 expressed by CD4+ and CD8+ T cells played key roles in promoting inflammation during visceral leishmaniasis and malaria-two important parasitic diseases. Additionally, NKG7 expressed by natural killer cells was critical for controlling cancer initiation, growth and metastasis. NKG7 function in natural killer and CD8+ T cells was linked with their ability to regulate the translocation of CD107a to the cell surface and kill cellular targets, while NKG7 also had a major impact on CD4+ T cell activation following infection. Thus, we report a novel therapeutic target expressed on a range of immune cells with functions in different immune responses.

Plasmodium-specific antibodies block in vivo parasite growth without clearing infected red blood cells.

Plasmodium parasites invade and multiply inside red blood cells (RBC). Through a cycle of maturation, asexual replication, rupture and release of multiple infective merozoites, parasitised RBC (pRBC) can reach very high numbers in vivo, a process that correlates with disease severity in humans and experimental animals. Thus, controlling pRBC numbers can prevent or ameliorate malaria. In endemic regions, circulating parasite-specific antibodies associate with immunity to high parasitemia. Although in vitro assays reveal that protective antibodies could control pRBC via multiple mechanisms, in vivo assessment of antibody function remains challenging. Here, we employed two mouse models of antibody-mediated immunity to malaria, P. yoelii 17XNL and P. chabaudi chabaudi AS infection, to study infection-induced, parasite-specific antibody function in vivo. By tracking a single generation of pRBC, we tested the hypothesis that parasite-specific antibodies accelerate pRBC clearance. Though strongly protective against homologous re-challenge, parasite-specific IgG did not alter the rate of pRBC clearance, even in the presence of ongoing, systemic inflammation. Instead, antibodies prevented parasites progressing from one generation of RBC to the next. In vivo depletion studies using clodronate liposomes or cobra venom factor, suggested that optimal antibody function required splenic macrophages and dendritic cells, but not complement C3/C5-mediated killing. Finally, parasite-specific IgG bound poorly to the surface of pRBC, yet strongly to structures likely exposed by the rupture of mature schizonts. Thus, in our models of humoral immunity to malaria, infection-induced antibodies did not accelerate pRBC clearance, and instead co-operated with splenic phagocytes to block subsequent generations of pRBC.

Modified Docetaxel, Cisplatin, and Fluorouracil (mDCF) as a Neoadjuvant Chemotherapy for Non-metastatic Esophageal Cancer (nMEC).

Objective: Perioperative chemotherapy can potentially downstage esophageal cancer, reducing the risk of early systemic dissemination. One recommended neoadjuvant regimen for managing gastroesophageal junction and esophageal cancer is docetaxel, cisplatin, and 5-fluorouracil (DCF). To address the high toxicity profile of DCF, modifications in dosages and treatment intervals have been studied. We integrated a modified DCF regimen (mDCF) into a multimodal treatment approach for non-metastatic esophageal cancer (nMEC). Retrospectively, we sought to describe our community experience of administrating neoadjuvant mDCF to patients with nMEC.Design: Patients diagnosed with nMEC between August 2008 and November 2017 and prescribed mDCF were identified for retrospective review. Outcomes of interest included disease-free survival (DFS), overall survival (OS), and hematologic toxicities. Analyses were performed using SAS 9.4.Results: Thirty patients met inclusion criteria with a median age of 64.9 years; 90% were male. The 2-year and 5-year DFS was 60.8% and 41.7%, respectively, for adenocarcinoma and 71.4% and 71.4% for squamous cell carcinoma (SCC). The 2-year and 5-year OS was 64.9% and 44.5%, respectively, for adenocarcinoma and 71.4% and 71.4% for SCC. Both DFS and OS decreased with increasing disease stage, histology (adenocarcinoma versus squamous), esophageal compared to esophagogastric-junction involvement, and without surgical intervention. Frequent toxicity grades for leukopenia and thrombocytopenia were Grades I and II.Conclusion: Using an mDCF regimen in combination with chemoradiation +/- surgical resection in a community setting appears to have an acceptable toxicity profile as well as DFS and OS outcomes compared to chemotherapeutic regimens reported in other similar studies.

A new era of rational malaria vaccine development.

Holz et al. report a glycolipid-conjugate vaccine that provides sterile immunity in mice against Plasmodium berghei ANKA sporozoite challenge by inducing long-lasting tissue-resident memory (TRM) CD8+ T cells in the liver.

Development of circulating CD4+ T-cell memory.

The ability of circulating CD4+ T cells to retain memories of previous antigenic encounters is a cardinal feature of the adaptive immune system. Over the past two decades, since the first description of central and effector memory T cells, many studies have examined molecular mechanisms controlling CD8+ T-cell memory, with comparatively less research into CD4+ T-cell memory. Here, we review a number of seminal studies showing that circulating memory CD4+ T cells develop directly from effector cells; and in so doing, preserve features of their effector precursors. We examine mechanisms controlling the development and phenotypes of memory CD4+ T cells, and provide an updated model that accommodates both the central and effector memory paradigm and the diverse T helper cell classification system.

Development of a Novel CD4+ TCR Transgenic Line That Reveals a Dominant Role for CD8+ Dendritic Cells and CD40 Signaling in the Generation of Helper and CTL Responses to Blood-Stage Malaria.

We describe an MHC class II (I-Ab)-restricted TCR transgenic mouse line that produces CD4+ T cells specific for Plasmodium species. This line, termed PbT-II, was derived from a CD4+ T cell hybridoma generated to blood-stage Plasmodium berghei ANKA (PbA). PbT-II cells responded to all Plasmodium species and stages tested so far, including rodent (PbA, P. berghei NK65, Plasmodium chabaudi AS, and Plasmodium yoelii 17XNL) and human (Plasmodium falciparum) blood-stage parasites as well as irradiated PbA sporozoites. PbT-II cells can provide help for generation of Ab to P. chabaudi infection and can control this otherwise lethal infection in CD40L-deficient mice. PbT-II cells can also provide help for development of CD8+ T cell-mediated experimental cerebral malaria (ECM) during PbA infection. Using PbT-II CD4+ T cells and the previously described PbT-I CD8+ T cells, we determined the dendritic cell (DC) subsets responsible for immunity to PbA blood-stage infection. CD8+ DC (a subset of XCR1+ DC) were the major APC responsible for activation of both T cell subsets, although other DC also contributed to CD4+ T cell responses. Depletion of CD8+ DC at the beginning of infection prevented ECM development and impaired both Th1 and follicular Th cell responses; in contrast, late depletion did not affect ECM. This study describes a novel and versatile tool for examining CD4+ T cell immunity during malaria and provides evidence that CD4+ T cell help, acting via CD40L signaling, can promote immunity or pathology to blood-stage malaria largely through Ag presentation by CD8+ DC.

Proteomic analysis of Plasmodium falciparum histone deacetylase 1 complex proteins.

Plasmodium falciparum histone deacetylases (PfHDACs) are an important class of epigenetic regulators that alter protein lysine acetylation, contributing to regulation of gene expression and normal parasite growth and development. PfHDACs are therefore under investigation as drug targets for malaria. Despite this, our understanding of the biological roles of these enzymes is only just beginning to emerge. In higher eukaryotes, HDACs function as part of multi-protein complexes and act on both histone and non-histone substrates. Here, we present a proteomics analysis of PfHDAC1 immunoprecipitates, identifying 26 putative P. falciparum complex proteins in trophozoite-stage asexual intraerythrocytic parasites. The co-migration of two of these (P. falciparum heat shock proteins 70-1 and 90) with PfHDAC1 was validated using Blue Native PAGE combined with Western blot. These data provide a snapshot of possible PfHDAC1 interactions and a starting point for future studies focused on elucidating the broader function of PfHDACs in Plasmodium parasites.

Metastatic Prostate Cancer in a RAD51C Mutation Carrier.

A man, aged 61 years, with a history of hypogonadism and family history of cancer experienced persistent urinary difficulties with no visible prostate abnormalities. Laboratory testing and diagnostic imaging revealed a primary lesion in the prostate with lymph node involvement and multiple bone metastases. Treatment with androgen-deprivation therapy, 17,20-lyase inhibition, and bisphosphonates for 7 months was unsuccessful in preventing disease progression, but second-line chemotherapy and continued androgen-deprivation therapy improved prostate specific antigen levels. During the patient's second treatment regimen, his daughter received a diagnosis of breast cancer. The patient's daughter underwent genetic testing for oncogenic mutations, and it was discovered that she carried a mutation in RAD51C, a gene encoding a protein involved in DNA repair and genomic maintenance. Subsequent genetic testing of the patient revealed mutation in RAD51C as well. For patients with metastatic prostate cancer who are unresponsive to standard treatment and who have a positive family history of cancer, genetic testing may be warranted to develop alternative treatment regimens for the patient and guide family discussions regarding cancer risk. Targeted agents like poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors may be a consideration in prostate cancer patients with DNA repair mutations and with refractory disease.

Design and Synthesis of Novel Anti-Plasmodial Histone Deacetylase Inhibitors Containing an Alkoxyamide Connecting Unit.

Despite recent declines in mortality, malaria remains an important global health problem. New therapies are needed, including new drugs with novel modes of action compared to existing agents. Among new potential therapeutic targets for malaria, inhibition of parasitic histone deacetylases (HDACs) is a promising approach. Homology modeling of PfHDAC1, a known target of some anti-plasmodial HDAC inhibitors, revealed a unique threonine residue at the rim of the active site in close proximity to the location of the cap group of vorinostat-type HDAC inhibitors. Aiming to obtain HDAC inhibitors with potent and preferential anti-plasmodial activity, we synthesized a mini-library of alkoxyamide-based HDAC inhibitors containing hydrogen bond acceptors in the cap group. Using a 5-step synthetic route, 12 new inhibitors were synthesized and assayed against Plasmodium falciparum asexual blood stage parasites (clones 3D7 and Dd2) and human cells (HepG2). The most active compound 6h (Pf3D7 IC50 : 0.07 µM; PfDd2 IC50 : 0.07 µM) was 25-fold more toxic against the parasite versus human HepG2 cells. Selected compounds were shown to cause hyperacetylation of P. falciparum histone H4, indicating inhibition of one or more PfHDACs.

Adaptation of the [3H]Hypoxanthine Uptake Assay for In Vitro-Cultured Plasmodium knowlesi Malaria Parasites.

The zoonotic malaria parasite Plasmodium knowlesi has recently been established in continuous in vitro culture. Here, the Plasmodium falciparum [(3)H]hypoxanthine uptake assay was adapted for P. knowlesi and used to determine the sensitivity of this parasite to chloroquine, cycloguanil, and clindamycin. The data demonstrate that P. knowlesi is sensitive to all drugs, with 50% inhibitory concentrations (IC50s) consistent with those obtained with P. falciparum This assay provides a platform to use P. knowlesi in vitro for drug discovery.

The McGill Brisbane Symptom Score in relation to survival in pancreatic adenocarcinoma: a validation study.

PURPOSE: The McGill Brisbane Symptom Score (MBSS) is a clinical score for pancreatic cancer patients upon initial presentation that takes into account four variables (weight loss, abdominal pain, jaundice, and history of smoking) to stratify them into two MBSS intensity categories. Several studies have suggested that these categories are strongly associated with eventual survival in patients with resectable (rPCa) and unresectable (uPCa) pancreatic cancer. This study aimed to validate the MBSS in a cohort of patients with pancreatic cancer from a single institution. METHODS: Survival time by resection status and MBSS intensity category were analyzed among 633 patients from our institution between 2001 and 2010. Hazard ratios for death using Cox proportional hazards models, with age as the timescale, adjustment for sex and year of diagnosis, and stratified by adjuvant chemotherapy status were estimated. RESULTS: Median survival time was the longest in patients with low-intensity MBSS and rPCa (817 days), whereas the shortest survival time was found among patients with uPCa regardless of MBSS status (144-147 days). After consideration of age and chemotherapy status, high-intensity MBSS was associated with poorer survival for both rPCa (HR 1.64; 95 % CI 1.07-2.52) and uPCa (HR 1.35; 95 % CI 1.06-1.72). CONCLUSIONS: Preoperative MBSS intensity is a useful prognostic indicator of survival in resectable as well as unresectable pancreatic cancer.

Overview of recent trends in diagnosis and management of leptomeningeal multiple myeloma.

Neurological complications related to multiple myeloma (MM) are not uncommon; however, direct involvement of the central nervous system (CNS) is extremely rare and represents a diagnostic and therapeutic challenge. Significant survival difference has been noted with the introduction of novel therapy in patients with MM, but their effect on the incidence and their use for management of leptomeningeal myeloma (LMM) is uncertain. Analysis of published data demonstrates its recent increased incidence, median time to CNS presentation, and slight improvement in median survival after diagnosis of LMM. Less common MM isotypes have been overrepresented in LMM. CNS relapse occurred mostly in patients with Durie-Salmon stage III MM. Despite treatments, standard or experimental, the survival rates of LMM remain dismal. Monitoring high risk patients closely, even after achieving complete remission, may be useful in early detection of LMM. As we gain better understanding of LMM, we recommend that future research and clinical care focus on earlier diagnosis and development of more efficient CNS-directed therapy to improve survival in this patient population.

All-cause mortality is decreased in women undergoing annual mammography before breast cancer diagnosis.

OBJECTIVE: The value of annual mammography remains an area of debate because of concerns regarding risk versus benefit. The potential for harm due to overdiagnosis and treatment of clinically insignificant cancers may not be captured by breast cancer-specific mortality. Instead, we examined all-cause mortality as a function of missed annual mammography examinations before breast cancer diagnosis. MATERIALS AND METHODS: Primary breast cancer cases diagnosed in the Marsh-field Clinic Health System from 2002 through 2008 were identified for retrospective review, and whether annual mammography examinations had been performed in the 5 years before diagnosis was assessed. RESULTS: Analyses were performed on 1421 women with breast cancer. After adjustment of data for age, comorbidity status, a family history of breast cancer, insurance status, medical encounter frequency, and the calendar year, women who had missed any of the previous five annual mammography examinations had a 2.3-fold increased risk of all-cause mortality compared with subjects with no missed mammography examinations (hazard ratio=2.28; 95% CI, 1.58-3.30; p<0.0001). Additionally, an analysis by the number of missed annual mammography examinations showed a progressive increase in hazard as the number of missed mammography studies increased. CONCLUSION: These results suggest that annual mammography before breast cancer diagnosis is predictive of increased overall survival. A stepwise decline in overall survival was noted for each additional missed mammography examination. These results are similar to findings in the literature for breast cancer-specific mortality and illustrate the importance of recommending annual mammography to all eligible women.

Survival Comparisons for Breast Conserving Surgery and Mastectomy Revisited: Community Experience and the Role of Radiation Therapy.

OBJECTIVES: Evidence suggests superiority of breast conserving surgery (BCS) plus radiation over mastectomy alone for treatment of early stage breast cancer. Whether the superiority of BCS plus radiation is related to the surgical approach itself or to the addition of adjuvant radiation therapy following BCS remains unclear. MATERIALS AND METHODS: We conducted a retrospective cohort study of women with breast cancer diagnosed from 1994-2012. Data regarding patient and tumor characteristics and treatment specifics were captured electronically. Kaplan-Meier survival analyses were performed with inverse probability of treatment weighting to reduce selection bias effects in surgical assignment. RESULTS: Data from 5335 women were included, of which two-thirds had BCS and one-third had mastectomy. Surgical decision trends changed over time with more women undergoing mastectomy in recent years. Women who underwent BCS versus mastectomy differed significantly regarding age, cancer stage/grade, adjuvant radiation, chemotherapy, and endocrine treatment. Overall survival was similar for BCS and mastectomy. When BCS plus radiation was compared to mastectomy alone, 3-, 5-, and 10-year overall survival was 96.5% vs 93.4%, 92.9% vs 88.3% and 80.9% vs 67.2%, respectively. CONCLUSION: These analyses suggest that survival benefit is not related only to the surgery itself, but that the prognostic advantage of BCS plus radiation over mastectomy may also be related to the addition of adjuvant radiation therapy. This conclusion requires prospective confirmation in randomized trials.

A novel method for studying the temporal relationship between type 2 diabetes mellitus and cancer using the electronic medical record.

BACKGROUND: We developed an algorithm for the identification of patients with type 2 diabetes and ascertainment of the date of diabetes onset for examination of the temporal relationship between diabetes and cancer using data in the electronic medical record (EMR). METHODS: The Marshfield Clinic EMR was searched for patients who developed type 2 diabetes between January 1, 1995 and December 31, 2009 using a combination of diagnostic codes and laboratory data. Subjects without diabetes were also identified and matched to subjects with diabetes by age, gender, smoking history, residence, and date of diabetes onset/reference date. RESULTS: The final cohort consisted of 11,236 subjects with and 54,365 subjects without diabetes. Stringent requirements for laboratory values resulted in a decrease in the number of potential subjects by nearly 70%. Mean observation time in the EMR was similar for both groups with 13-14 years before and 5-7 years after the reference date. The two cohorts were largely similar except that BMI and frequency of healthcare encounters were greater in subjects with diabetes. CONCLUSION: The cohort described here will be useful for the examination of the temporal relationship between diabetes and cancer and is unique in that it allows for determination of the date of diabetes onset with reasonable accuracy.

Geographical and seasonal barriers to mammography services and breast cancer stage at diagnosis.

INTRODUCTION: Routine mammography screening and early detection are important prognostic indicators for breast cancer. Geographical and seasonal barriers to mammography services and relationship to breast cancer stage at diagnosis were examined. METHODS: Travel time to mammography center, seasonal distribution of mammogram use, mammography frequency, and stage of cancer were retrospectively examined in 1428 female patients diagnosed with primary breast cancer at a tertiary care clinic system in Wisconsin, USA, from 2002 to 2008. RESULTS: Women with no missed mammograms before diagnosis lived a median of 15 minutes from the nearest facility, while those who missed five of their past five annual mammograms lived nearly twice as far, with a median travel time of 27 minutes (p<0.0001). There was a direct relationship between travel time to nearest mammogram facility and stage of breast cancer at diagnosis, with travel time increasing from 17 to 24 minutes for stage 0 and stage 4 breast cancers, respectively (p=0.0586). Women were less likely to undergo mammography screening during the winter months (p<0.0001), especially women with greater than 30 mi (48.3 km) to travel to the nearest mammogram facility (p=0.0448). CONCLUSIONS: In the studied service area, travel time to nearest mammogram center appears inversely related to regular mammography screening and breast cancer stage at diagnosis. Mammograms are less common in the winter, especially in women with further to travel. This is the first study to demonstrate that inclement winter weather may impact on screening behaviors in rural areas and demonstrates the importance of considering climate as part of geographical access to preventative care.

Plasmodium infection induces phenotypic, clonal, and spatial diversity among differentiating CD4+ T cells.

Naive CD4+ T cells must differentiate in order to orchestrate immunity to Plasmodium, yet understanding of their emerging phenotypes, clonality, spatial distributions, and cellular interactions remains incomplete. Here, we observe that splenic polyclonal CD4+ T cells differentiate toward T helper 1 (Th1) and T follicular helper (Tfh)-like states and exhibit rarer phenotypes not elicited among T cell receptor (TCR) transgenic counterparts. TCR clones present at higher frequencies exhibit Th1 skewing, suggesting that variation in major histocompatibility complex class II (MHC-II) interaction influences proliferation and Th1 differentiation. To characterize CD4+ T cell interactions, we map splenic microarchitecture, cellular locations, and molecular interactions using spatial transcriptomics at near single-cell resolution. Tfh-like cells co-locate with stromal cells in B cell follicles, while Th1 cells in red pulp co-locate with activated monocytes expressing multiple chemokines and MHC-II. Spatial mapping of individual transcriptomes suggests that proximity to chemokine-expressing monocytes correlates with stronger effector phenotypes in Th1 cells. Finally, CRISPR-Cas9 gene disruption reveals a role for CCR5 in promoting clonal expansion and Th1 differentiation. A database of cellular locations and interactions is presented: https://haquelab.mdhs.unimelb.edu.au/spatial_gui/.

CD4+ T cells display a spectrum of recall dynamics during re-infection with malaria parasites.

Children in malaria-endemic regions can experience repeated Plasmodium infections over short periods of time. Effects of re-infection on multiple co-existing CD4+ T cell subsets remain unresolved. Here, we examine antigen-experienced CD4+ T cells during re-infection in mice, using scRNA-seq/TCR-seq and spatial transcriptomics. TCR transgenic TEM cells initiate rapid Th1/Tr1 recall responses prior to proliferating, while GC Tfh counterparts are refractory, with TCM/Tfh-like cells exhibiting modest non-proliferative responses. Th1-recall is a partial facsimile of primary Th1-responses, with no upregulated effector-associated genes being unique to recall. Polyclonal, TCR-diverse, CD4+ T cells exhibit similar recall dynamics, with individual clones giving rise to multiple effectors including highly proliferative Th1/Tr1 cells, as well as GC Tfh and Tfh-like cells lacking proliferative capacity. Thus, we show substantial diversity in recall responses mounted by multiple co-existing CD4+ T cell subsets in the spleen, and present graphical user interfaces for studying gene expression dynamics and clonal relationships during re-infection.