Mycobacterium tuberculosis (Mtb) is a serious public health concern, infecting a quarter of the world and leading to 10 million cases of tuberculosis (TB) disease and 1. 5 million deaths annually. An effective type 1 CD4 T cell (TH1) immune response is necessary to control Mtb infection and defining factors that modulate Mtb-specific TH1 immunity is important to better define immune correlates of protection in Mtb infection. Helminths stimulate type 2 (TH2) immune responses, which antagonize TH1 cells. As such, we sought to evaluate whether co-infection with the parasitic helminth Schistosoma mansoni (SM) modifies CD4 T cell lineage profiles in a cohort of HIV-uninfected adults in Kisumu, Kenya. Individuals were categorized into six groups by Mtb and SM infection status: healthy controls (HC), latent Mtb infection (LTBI) and active tuberculosis (TB), with or without concomitant SM infection. We utilized flow cytometry to evaluate the TH1/TH2 functional and phenotypic lineage state of total CD4 T cells, as well as CD4 T cells specific for the Mtb antigens CFP-10 and ESAT-6. Total CD4 T cell lineage profiles were similar between SM + and SM − individuals in all Mtb infection groups. Furthermore, in both LTBI and TB groups, SM infection did not impair Mtb-specific TH1 cytokine production. In fact, SM + LTBI individuals had higher frequencies of IFNγ + Mtb-specific CD4 T cells than SM − LTBI individuals. Mtb-specific CD4 T cells were characterized by expression of both classical TH1 markers, CXCR3 and T-bet, and TH2 markers, CCR4, and GATA3. The expression of these markers was similar between SM + and SM − individuals with LTBI. However, SM + individuals with active TB had significantly higher frequencies of GATA3 + CCR4 + TH1 cytokine + Mtb-specific CD4 T cells, compared with SM − TB individuals. Together, these data indicate that Mtb-specific TH1 cytokine production capacity is maintained in SM-infected individuals, and that Mtb-specific TH1 cytokine + CD4 T cells can express both TH1 and TH2 markers. In high pathogen burden settings where co-infection is common and reoccurring, plasticity of antigen-specific CD4 T cell responses may be important in preserving Mtb-specific TH1 responses.

Background: Helminth infections can modulate immunity to Mycobacterium tuberculosis (Mtb). However, the effect of helminths, including Schistosoma mansoni (SM), on Mtb infection outcomes is less clear. Furthermore, HIV is a known risk factor for tuberculosis (TB) disease and has been implicated in SM pathogenesis. Therefore, it is important to evaluate whether HIV modifies the association between SM and Mtb infection. Setting: HIV-infected and HIV-uninfected adults were enrolled in Kisumu County, Kenya, between 2014 and 2017 and categorized into 3 groups based on Mtb infection status: Mtb-uninfected healthy controls, latent TB infection (LTBI), and active TB disease. Participants were subsequently evaluated for infection with SM. Methods: We used targeted minimum loss estimation and super learning to estimate a covariate-adjusted association between SM and Mtb infection outcomes, defined as the probability of being Mtb-uninfected healthy controls, LTBI, or TB. HIV status was evaluated as an effect modifier of this association. Results: SM was not associated with differences in baseline demographic or clinical features of participants in this study, nor with additional parasitic infections. Covariate-adjusted analyses indicated that infection with SM was associated with a 4% higher estimated proportion of active TB cases in HIV-uninfected individuals and a 14% higher estimated proportion of active TB cases in HIV-infected individuals. There were no differences in estimated proportions of LTBI cases. Conclusions: We provide evidence that SM infection is associated with a higher probability of active TB disease, particularly in HIV-infected individuals.

Mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), follicular lymphoma (FL) and diffuse large B cell lymphoma (DLBCL) account for >70% of cases of B cell lymphoma. Targeting Bruton tyrosine kinase (BTK) with ibrutinib in B cell malignancies led to a paradigm shift in therapy. However, primary resistance to ibrutinib has been observed in about 30% MCL patients; more than 50% patients with CLL and MCL treated with ibrutinib discontinue treatment due to intolerance or emergence of resistant disease (Woyach et al., 2017; Shpilberg et al., 2018). CG'806 is an oral small molecule non-covalent pan-FLT3/pan-BTK inhibitor designed to address the shortcomings of ibrutinib. It is in development for acute myeloid leukemia (AML) and B cell lymphoma. CG'806 inhibited cell proliferation and induced apoptosis with a potency that was 50-6,000 times greater than that of ibrutinib when tested against 14 established malignant B-cell lines in vitro. When tested against 124 samples freshly isolated from the marrow of CLL patients the median IC50 for CG'806 was 0.11 µM and the median for ibrutinib was 4.09 µM, respectively, p<0.001). Since stromal-mediated signaling plays important roles in malignant B cell survival and chemoresistance, the apoptotic effect of CG'806 was further analyzed on cultured and primary malignant B cells in the presence of stromal cells. CG'806 produced similar dose-dependent apoptotic effect on Mino cells, an MCL cell line, in the absence or presence of human stromal HS5 cells indicating that its potency was not impaired by factors released by these stroma cells. Most importantly, CG'806 dose-dependently induced apoptosis in ibrutinib-refractory primary MCL samples in the presence of CD40L-expressing stromal cells (N=4). Whereas 0.1 µM and 1 µM CG'806 caused about 25% and 45% apoptotic cell death, respectively, 1 µM ibrutinib induced less than 10% cell death under the same culture conditions. CG'806 inhibited malignant B cell colony formation and migration towards SDF1α about 2-fold more effectively than ibrutinib. Given the role of activated B cell receptor (BCR) and NFκB pathways in lymphoma, CG'806 was tested for its ability to impair signaling in these pathways. CG'806 produced cell line dependent and dose/time dependent decreases in the phosphorylation of BTK, PLCγ2, PI3K, AKT, mTOR, PKC, and ERK, and reduced. These effects were correlated with induction of PARP cleavage and cell cycle arrest. We conclude that CG'806 inhibits driver and rescue pathways to directly and potently kill a broad range of malignant B cells, including both establish cell lines and freshly isolated patient samples, thereby distinguishing CG'806 from ibrutinib and supporting clinical development of CG'806 in patients with CLL and other B-cell malignancies intolerant, resistant, or refractory to ibrutinib. Disclosures Zhang: Aptose Biosciences, Inc: Employment. Local:Aptose Biosciences, Inc: Employment. Benbatoul:Aptose Biosciences, Inc: Employment. Folger:Aptose Biosciences, Inc: Employment. Sheng:Aptose Biosciences, Inc: Employment. McLaughlin:Aptose Biosciences, Inc: Other: internship. Danilov:Astra Zeneca: Consultancy; Genentech: Consultancy, Research Funding; Aptose Biosciences: Research Funding; Bayer Oncology: Consultancy, Research Funding; TG Therapeutics: Consultancy; Verastem: Consultancy, Research Funding; Gilead Sciences: Consultancy, Research Funding; Takeda Oncology: Research Funding. Tyner:Constellation: Research Funding; Aptose: Research Funding; Janssen: Research Funding; AstraZeneca: Research Funding; Genentech: Research Funding; Incyte: Research Funding; Gilead: Research Funding; Takeda: Research Funding; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Array: Research Funding. Howell:Aptose Biosciences, Inc: Research Funding. Rice:Aptose Biosciences, Inc: Equity Ownership.

Schistosoma mansoni (SM) is a parasitic helminth that infects over 200 million people and causes severe morbidity. It undergoes a multi-stage life cycle in human hosts and as such stimulates a stage-specific immune response. The human T cell response to SM is complex and varies throughout the life cycle of SM. Relative to the wealth of information regarding the immune response to SM eggs, little is known about the immune response to the adult worm. In addition, while a great deal of research has uncovered mechanisms by which coinfection with helminths modulates immunity to other pathogens, there is a paucity of data on the effect of pathogens on immunity to helminths. As such, we sought to characterize the breadth of the T cell response to SM and determine whether co-infection with Mycobacterium tuberculosis (Mtb) modifies SM-specific T cell responses in a cohort of HIV-uninfected adults in Kisumu, Kenya. SM-infected individuals were categorized into three groups by Mtb infection status: active TB (TB), Interferon-γ Release Assay positive (IGRA+), and Interferon-γ Release Assay negative (IGRA-). U.S. adults that were seronegative for SM antibodies served as naïve controls. We utilized flow cytometry to characterize the T cell repertoire to SM egg and worm antigens. We found that T cells had significantly higher proliferation and cytokine production in response to worm antigen than to egg antigen. The T cell response to SM was dominated by γδ T cells that produced TNFα and IFNγ. Furthermore, we found that in individuals infected with Mtb, γδ T cells proliferated less in response to SM worm antigens and had higher IL-4 production compared to naïve controls. Together these data demonstrate that γδ T cells respond robustly to SM worm antigens and that Mtb infection modifies the γδ T cell response to SM.

OBJECTIVES/SPECIFIC AIMS: The aims of this study are 2-fold: (1) to determine if maternal schistosomiasis affects maternal immunity to tetanus and/or transplacental transfer of antitetanus toxoid (TT) immunoglobulin G (IgG) from mother to infant and (2) determine the influence of maternal schistosomiasis on infant BCG vaccine immunogenicity. METHODS/STUDY POPULATION: The study will utilize blood samples from a historic cohort of 100 mother-infant pairs from Kisumu, Kenya, a schistosomiasis-endemic area. For the first aim, we will evaluate maternal schistosomal circulating anodic antigen, which has improved sensitivity and specificity to detect active schistosomiasis from serum, and antisoluble egg antigen IgG positivity compared with quantitative maternal anti-TT IgG at delivery and anti-TT IgG cord blood to maternal blood ratio (cord:maternal ratio). For the second aim, we will evaluate association between maternal schistosomiasis as detected by circulating anodic antigen and antisoluble egg antigen IgG at delivery and infant BCG-specific Th1-cytokine positive CD4+ cells at 10 weeks following BCG vaccination at birth. RESULTS/ANTICIPATED RESULTS: We hypothesize that active maternal schistosomiasis will be associated with decreased maternal anti-TT IgG and reduced efficiency of transplacental transfer, as measured by infant cord blood to maternal blood ratio of anti-TT IgG. We also expect that maternal schistosomiasis will be associated with decreased infant immunogenicity to BCG vaccine. DISCUSSION/SIGNIFICANCE OF IMPACT: This is a formative study on infant vaccine immunity using laboratory methodology not previously applied. Understanding infant immunity in the setting of maternal schistosomiasis will inform vaccination strategies and tailor vaccine development in schistosome-endemic areas such as Kenya, where neither TB nor neonatal tetanus have been eradicated. Additionally, our results will inform public health policies to consider integration of antischistosomal agents in antenatal care.