A novel subset of follicular helper-like MAIT cells has capacity for B cell help and antibody production in the mucosa

Mucosal-associated invariant T (MAIT) cells are innate-like T lymphocytes that respond to conserved microbial metabolites presented on the evolutionarily conserved MHC class I-related protein, MR1. MAIT cells are enriched in the mucosa and aid in protection against bacterial pathogens via release of inflammatory cytokines and cytotoxic molecules. Recent evidence suggests MAIT cells are capable of providing B cell help in vitro and in vivo. In this study, we used primary human samples and mouse models to uncover the role of MAIT cells in B cell help at the mucosa. Here we describe a novel population of CXCR5+ T follicular helper (Tfh)-like MAIT cells (MAITfh) that are enriched in human mucosal lymphoid tissues. Using in vitro culture assays and fluorescence imaging, we found that MAITfh cells preferentially locate within germinal centers in human tonsils and express the canonical Tfh transcription factor, B-cell lymphoma 6 (BCL-6), co-stimulatory markers, inducible T cell costimulator (ICOS), and programmed death receptor 1 (PD-1), and cytokines, interleukin (IL)-21, IL-10, and BAFF. Furthermore, we investigate the sufficiency of MAIT cells to aid in antibody mediated immunity in vivo using a mouse model of MAIT adoptive transfer followed by mucosal challenge with live Vibrio cholerae. We show that adoptive transfer of MAIT cells into αβ T cell deficient mice promotes B cell differentiation and increased serum V. cholerae-specific IgA and bactericidal responses. Our data demonstrate the capacity of MAIT cells to participate in adaptive immune responses at the mucosa, and suggest MAIT cells may be potential targets to improve mucosal vaccines.

Maternal Schistosomiasis Hinders B Cell Development Leading to Reduced Humoral Immunity Upon Immunization

Maternal helminth infections are a global public health concern that correlate with altered infant immune responses to childhood immunizations and infection. A mechanistic understanding of how maternal helminth infection alters the immune responses of offspring is critical to improve childhood vaccine regimens in endemic areas, decrease childhood morbidity, and to understand the consequences of specific defects in long-lived immunity. Our murine model of maternal Schistosoma mansoni infection demonstrated that pups born to mothers chronically infected with Schistosoma mansoni have reduced IL-4 production and B cell expansion. This defect continues following tetanus/diphtheria immunization, resulting in impaired immunity. To determine the origin of this humoral immunity defect, we began investigating lymphoid progenitors. We found an increase in the common lymphoid progenitors (CLPs) in the bone marrow of naïve mice from infected mothers. When immunized with a Tetanus/Diphtheria vaccination, there is a significant reduction in expansion of these progenitors in comparison to age matched controls from uninfected mothers coupled with a decrease in bone marrow B cells. RNA sequencing revealed a defect in stem cell pluripotency signaling pathway. Further analysis post-immunization shows a decrease in immature B cells in the bone marrow of pups from infected mothers, suggesting a more exclusive selection process or differential selective pressure, leading to lower B cell frequencies in the draining lymph node. We hypothesize that altered transcriptional regulation at the progenitor level caused by maternal Schistosomiasis is the mechanistic root of long-lived defects in humoral immunity to foreign antigens.

Schistosome and intestinal helminth modulation of macrophage immunometabolism

Macrophages are fundamental to sustain physiological equilibrium and to regulate the pathogenesis of parasitic and metabolic processes. The functional heterogeneity and immune responses of macrophages are shaped by cellular metabolism in response to the host's intrinsic factors, environmental cues and other stimuli during disease. Parasite infections induce a complex cascade of cytokines and metabolites that profoundly remodel the metabolic status of macrophages. In particular, helminths polarize macrophages to an M2 state and induce a metabolic shift towards reliance on oxidative phosphorylation, lipid oxidation and amino acid metabolism. Accumulating data indicate that helminth-induced activation and metabolic reprogramming of macrophages underlie improvement in overall whole-body metabolism, denoted by improved insulin sensitivity, body mass in response to high-fat diet and atherogenic index in mammals. This review aims to highlight the metabolic changes that occur in human and murine-derived macrophages in response to helminth infections and helminth products, with particular interest in schistosomiasis and soil-transmitted helminths.

Pulmonary Eosinophilic Granulomatosis with Polyangiitis Has IgG4 Plasma Cells and Immunoregulatory Features

The immunologic mechanisms promoting eosinophilic granulomatosis with polyangiitis (EGPA) are unclear. To characterize the mechanisms underlying pulmonary EGPA, we examined and compared EGPA paraffin-embedded lung biopsies with normal lung biopsies, using immunostaining, RNA sequencing, and RT-PCR. The results revealed novel type 2 as well as immuneregulatory features. These features included basophils and increased mast cell contents; increased immunostaining for tumor necrosis factor ligand superfamily member 14; sparse mast cell degranulation; numerous forkhead box protein P3 (FoxP3)+ regulatory T cells and IgG4 plasma cells; and abundant arachidonate 15-lipoxygenase and 25-hydroxyvitamin D-1 α hydroxylase, mitochondrial. Significantly decreased 15-hydroxyprostaglandin dehydrogenase [NAD(⁺)], which degrades eicosanoids, was observed in EGPA samples. In addition, there was significantly increased mRNA for chemokine (C-C motif) ligands 18 and 13 and major collagen genes, IgG4-rich immune complexes coating alveolar macrophages, and increased immunostaining for phosphorylated mothers against decapentaplegic homolog 2/SMAD2, suggesting transforming growth factor-β activation. These findings suggest a novel self-promoting mechanism of activation of alveolar macrophages by arachidonate 15-lipoxygenase-derived eicosanoids to express chemokines that recruit a combined type 2/immunoregulatory immune response, which produces these eicosanoids. These results suggest that the pulmonary EGPA immune response resembles the immune response to a tissue-invasive parasite infection.

Abstract P2-12-18: Outpatient mastectomy with reconstruction in a freestanding surgery center using multimodality opiod-sparing perioperative analgesia including liposomal bupivacaine

HYPOTHESIS:

The introduction of effective non-narcotic analgesics and the long-acting local anesthetic bupivacaine liposome (Exparel) has resulted in improved postoperative pain control and decreased reliance on opioid analgesics that often have the undesirable adverse effects of sedation, nausea, respiratory depression, and dysphoria or confusion. This has resulted in shorter postoperative care unit stays, earlier return to normal activity, and improved patient satisfaction without sacrificing appropriate pain control. Based on a positive experience with these agents in the inpatient setting, we hypothesized that mastectomy with immediate implant-based reconstruction could be performed safely in a freestanding outpatient surgery center using a multimodality opioid-sparing analgesic regimen.

METHOD:

Over a 6 month period we performed unilateral or bilateral mastectomy with concurrent implant-based reconstruction on 20 patients. One patient had a unilateral mastectomy and 19 patients had bilateral mastectomy performed. Sixteen of the patients had nipple sparing mastectomy procedures. Reconstruction was performed with tissue expanders in 6 patients and as a single stage procedure with silicone gel implants in 14 patients. Acellular dermal matrix was used to support the implant in all but 1 patient. All patients were given gabapentin 600mg on the evening prior to and morning of surgery. Acetaminophen 1gm IV was given prior to induction of anesthesia in the preoperative area and again 6 hours later in the post anesthesia care unit. Ketorolac 30mg IV was given during the last half of the surgical procedure. All patients had general anesthesia with standard inhalational agents and IV fentanyl as needed. The retropectoral and serratus fascia were infiltrated with liposomal bupivacaine after surgical removal of the breast tissue, before reconstruction was started. The drain sites were also infiltrated with liposomal bupivacaine. Patients were discharged with prescriptions for gabapentin 300mg twice daily for 7 days followed by 300mg nightly for 7 days, carisoprodol 350mg every 6 hours as needed for muscle spasms, ibuprofen 800 mg every 8 hours for 5 days, hydrocodone/acetaminophen every 4 hours as needed for pain, and oral antibiotics of the surgeon's choice.

RESULTS:

All 20 patients completed their surgery and were discharged home after a brief stay in the postoperative care unit. No patient required readmission for pain control or any other complication in the perioperative period. No patient reported inadequate pain control. All patients were highly satisfied with their perioperative care as reported during postoperative follow-up phone calls the day after surgery and during their post-operative follow up visit.

CONCLUSION:

In our experience, outpatient mastectomy with reconstruction in a freestanding surgery center is safe and has a high degree of patient satisfaction when using a multimodality opioid-sparing analgesia regimen including liposomal bupivacaine. By avoiding opioid-related adverse effects, patients have a more rapid recovery, earlier return to activities of daily living, and therefore improved quality of life. Proper patient selection requires a multidisciplinary team approach for success.

Citation Format: Rock DT, Jandik AL, Wittenborn WS, Fairfax K, Sandadi S. Outpatient mastectomy with reconstruction in a freestanding surgery center using multimodality opiod-sparing perioperative analgesia including liposomal bupivacaine. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-12-18.

Schistosoma Mansoni infection induces anti-atherogenic transcriptional changes in hepatic macrophages (MPF2P.758)

Hepatic macrophages play an essential role in the granulomatous response to infection with the parasitic helminth Schistosoma Mansoni, but the transcriptional changes that underlie this participation are poorly understood. To explore this, we sorted the two previously recognized hepatic macrophage populations (perivascular and Kupffer) from naïve and S. mansoni infected mice and performed microarray analysis as part of the Immunological Genome Project. Consistent with the pattern of great diversity identified in other organ macrophages, the two hepatic macrophage populations displayed signatures distinct from all other macrophages, with the two populations exhibiting remarkable differences between them. However, this diversity was greatly reduced following infection with S. mansoni, and in fact, many of the transcripts identified as uniquely perivascular or Kupffer cell specific were lost following infection, raising the possibility that both populations may be replenished by monocytes following infection. Our analysis showed a profound alteration in phospholipid and cholesterol metabolic pathways, including prostaglandin signaling, in addition to the expected M2 markers. These changes suggested a possible mechanism for the previously reported atheroprotective effects of S. mansoni infection. Indeed we find that ApoE null mice fed a high fat diet in combination with S. mansoni infection have reduced body mass in addition to reduced plaque area as compared to control mice.

Gata6 regulates aspartoacylase expression in resident peritoneal macrophages and controls their survival

Gata6 regulates differentiation, metabolism and survival of peritoneal macrophages.

The transcription factor Gata6 regulates proliferation and differentiation of epithelial and endocrine cells and cancers. Among hematopoietic cells, Gata6 is expressed selectively in resident peritoneal macrophages. We thus examined whether the loss of Gata6 in the macrophage compartment affected peritoneal macrophages, using Lyz2-Cre x Gata6^flox/flox mice to tackle this issue. In Lyz2-Cre x Gata6^flox/flox mice, the resident peritoneal macrophage compartment, but not macrophages in other organs, was contracted, with only a third the normal number of macrophages remaining. Heightened rates of death explained the marked decrease in peritoneal macrophage observed. The metabolism of the remaining macrophages was skewed to favor oxidative phosphorylation and alternative activation markers were spontaneously and selectively induced in Gata6-deficient macrophages. Gene expression profiling revealed perturbed metabolic regulators, including aspartoacylase (Aspa), which facilitates generation of acetyl CoA. Mutant mice lacking functional Aspa phenocopied the higher propensity to death and led to a contraction of resident peritoneal macrophages. Thus, Gata6 regulates differentiation, metabolism, and survival of resident peritoneal macrophages.

Th2 responses in schistosomiasis

Schistosomiasis is caused by infection with parasitic flatworms of the genus Schistosoma. It is characterized by the development of strong CD4(+) T cell and B cell responses that, during primary infection, fail to eliminate the parasites, but in collaboration with cells of the innate immune system allow survival in the face of ongoing tissue damage caused by the lodging of parasite eggs in the liver and the passage of eggs across the intestinal epithelium. Mounting a tightly controlled Th2 response is key to this outcome, and while this type of response is a risk factor for the development of fibrosis, it also underpins the development of resistance to further infection; as such, understanding how Th2 responses are induced and regulated in schistosomiasis remains a critical area of research.

The type III effector repertoire of Pseudomonas syringae pv. syringae B728a and its role in survival and disease on host and non-host plants

The bacterial plant pathogen Pseudomonas syringae injects a large repertoire of effector proteins into plant cells using a type III secretion apparatus. Effectors can trigger or suppress defences in a host-dependent fashion. Host defences are often accompanied by programmed cell death, while interference with defences is sometimes associated with cell death suppression. We previously predicted the effector repertoire of the sequenced bean pathogen P. syringae pv. syringae (Psy) B728a using bioinformatics. Here we show that PsyB728a is also pathogenic on the model plant species Nicotiana benthamiana (tobacco). We confirm our effector predictions and clone the nearly complete PsyB728a effector repertoire. We find effectors to have different cell death-modulating activities and distinct roles during the infection of the susceptible bean and tobacco hosts. Unexpectedly, we do not find a strict correlation between cell death-eliciting and defence-eliciting activity and between cell death-suppressing activity and defence-interfering activity. Furthermore, we find several effectors with quantitative avirulence activities on their susceptible hosts, but with growth-promoting effects on Arabidopsis thaliana, a species on which PsyB728a does not cause disease. We conclude that P. syringae strains may have evolved large effector repertoires to extend their host ranges or increase their survival on various unrelated plant species.