bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complement Factor H Immunoproteins Increase Complement-mediated Opsonophagocytic Killing of Methicillin-resistant Staphylococcus aureus
Authors: Sharp Julia A , Cranmer Katelyn A , Sage Megan G , Wycoff Keith L 
Published: January 2023

Abstract

Background
As a major cause of a myriad of superficial and invasive infections worldwide, Staphylococcus aureus is a master of immune evasion, with the complement system being a primary target. Previously, we have shown that S. aureus surface protein SdrE binds the regulator Factor H (FH) to inhibit complement. Taking advantage of this interaction, we tested the effect of a fusion protein comprised of FH(18–20) fused to an IgG Fc on complement-mediated opsonophagocytosis and killing of methicillin resistant S. aureus.

Methods
Fusions were produced via the ΔXT/FT Nicotiana benthamiana plant expression system. Binding dynamics were examined via immunoblotting, fluorescence and ELISA. The effect of fusions on complement activation was determined by examining C3-fragment opsonization of S. aureus (total C3, C3b, iC3b) and subsequent C5a generation. The effect of fusions on S. aureus survival was assessed using an opsonphagocytosis assay with human polymorphonuclear cells.

Results
S. aureus bound significantly more FH-Fc compared to Fc-controls, and competed with serum FH for S. aureus binding. FH-Fc outperformed a complement inactive fusion variant in C3-fragment deposition and C5a generation, signifying an active role for the Fc region of FH-Fc. For 75% (3/4) of clinical isolates tested, FH-Fc significantly reduced S. aureus survival. Clinical isolates were all sdrE positive, sequence type 8, SCCmec IVa and Panton-Valentine Leukocidin (pvl) positive).

Conclusion
FH-Fc competitively inhibited serum FH from S. aureus binding and increased complement-mediated opsonophagocytosis and killing of CA-MRSA. Future studies will focus on enhancing the efficacy of FH-Fc fusion molecules as potential anti-staphylococcal therapeutics.
Supported by a grant from the US Department of Defense, USAMRDC (W81XWH-19-1-0119).
Evaluation of the protective efficacy of a novel rVCG-based Chlamydia abortus vaccine in a pregnant mouse model
Authors: Richardson Shakyra S , Bell Courtnee , Jones Leandra , Medhavi F N U , Tanner Tayhlor , Lundy Stephanie , Omosun Yusuf , Eko Francis O 
Published: January 2023

Abstract
Chlamydia abortus (Cab) is the cause of ovine enzootic abortion (OEA) in small ruminants and poses a zoonotic risk to pregnant women, which may result in spontaneous abortion. Although antibiotics are effective against Cab infection, most infections are asymptomatic, suggesting alternative strategies may be required for controlling these infections. We tested the ability of a recombinant Vibrio cholerae ghost (rVCG)-based Cab subunit vaccine expressing the truncated Cab polymorphic membrane protein 18D (rVCG-Pmp18.3) to protect against Cab-induced abortion in a pregnant mouse model. Thus, groups of female C57bl/6J mice were immunized intranasally (IN) with rVCG-Pmp18.3 and mated with males 3 weeks post immunization. Immunized and control mice were infected IN or transcervically (TC) at day 10 of pregnancy and the number of pups per mouse was enumerated 7 days postpartum. Mice were sacrificed on day 8 and Cab burden in the lungs and spleens was determined. The results showed IN immunization protected mice against abortion and neonatal death while IN infected control mice lost 20% of their litter and 60% of TC infected controls lost their entire litter 7 days post-parturition. Immunized mice completely cleared the infection in the lungs and showed a significant reduction (p ≤0.0001) in bacterial burden in the spleen compared to non-immunized, infected controls. Furthermore, immunized mice were protected from uterine dilation compared to 60% of non-immunized controls that developed tubal pathology. These results demonstrate the ability of rVCG-Pmp18.3 to prevent respiratory/systemic infection and protect against Cab-induced abortion and tubal pathologies in mice, suggesting its potential development as a vaccine for ruminants.
Supported by PHS grant R01AI41231 and NIH R01AI26897
Assessing how biological sex effects tissue-resident memory T cell responses to influenza infection
Authors: Bachnak Louay , Godwin Matthew , McLachlan James B 
Published: January 2023

Abstract
The severity and outcome of influenza virus infection are dependent on various host factors including sex. During the 1918 influenza pandemic, males succumbed to viral infections more than females. Following seasonal influenza vaccination, haemagglutination inhibition titers are significantly higher in females than males. Additionally, the Tlr7 gene that recognizes influenza viruses is located on the X chromosome, resulting in higher expression in females. It is not known whether sex influences non-lymphoid tissue residency of lymphocytes during influenza infection. To explore this, we infected male and female mice intratracheally with 20 PFU influenza virus (A/PR8/H1N1). No significant change was noted in weight loss; however, females displayed a higher survival rate and milder clinical disease nine days post-infection. Lungs of female mice contained greater numbers of influenza-specific tissue-resident CD4+ T-cells compared to males. To assess the role of extra-lymphoid tissues in tissue residency in both sexes, we infected male and female lymphotoxin-a knockout (LTa KO) splenectomized mice that resulted in a total lack of all lymphoid tissues. Physiological differences trended the same for both males and females, with no significant weight difference; however, LTa KO females generated more tissue-resident CD4+ T-cells, while males displayed greater numbers of tissue-resident CD8+ T-cells. Overall, females generated a stronger immune response in the absence of lymphoid tissues in response to the virus. Taken together, our data reveal a novel sex-based effect of viral infection on tissue-resident lymphocytes and non-lymphoid tissue immunity.
Supported by a grant from the W.M. Keck Foundation
CD4+ CD151+ T cells may serve as preferential reservoir cells of latent HIV infection events.
Authors: Tidwell Christopher M , Perez Mildred , Zhang Mingce , Duverger Alexandra , Wagner Frederic , Cron Randy Q , Sabbaj Steffanie , Kutsch Olaf 
Published: January 2023

Abstract
We have demonstrated that the tetraspanin CD151 marks a hyperactivated, pro-inflammatory human CD4+ T cell population. Expansion of this population in HIV patients on ART may explain the associated risk of inflammation-related co-morbidities. However, CD151+ CD4 T cells can also proliferate independent of cognate antigen recognition, driven by just IL-2, a feature that is reminiscent of latently infected T cells which have been reported to maintain the latent reservoir size by homeostatic proliferation mechanisms. The objective of this study was to test our hypothesis that the CD4+CD151+ T cell population is more likely to host latent HIV infection events. First, we noted that all latently HIV-1 infected T cell clones we investigated had upregulated CD151 expression. Using samples from PLWH on ART (n=5) with undetectable viral loads and CD4 count &gt;500 cells/mm3 we enriched CD4+CD151+ and CD4+CD151− T cell populations. Using a nested ALU/GAG qPCR assay to determine the level of proviral HIV-1 integration events, we found a 3.6-fold increase in integration events in the enriched CD4+CD151+ T cell population. Given the demonstrated correlation of proviral DNA frequencies and latent reservoir size, this would suggest that CD151+ T cells disproportionately harbor latent HIV infection, and that CD151+ T cells could be used as a surrogate population to study pertinent features of latently HIV-1 infected T cells. We here begin to address the conundrum of how T cells with a hyperactivated phenotype can host latent HIV-1 infection events and dissect the influence of CD151 expression on latency establishment and reactivation. Characterization of this T cell compartment may reveal new molecular targets to efficiently trigger HIV-1 reactivation.
Supported by grants from NIH: NIH R01-AI122842 NIH R33-AI116188 NIH R33-AI133679
The characterization of MCMV specific Qa-1-restricted CD8+ T cells
Authors: Reilly Shanelle , Anderson Courtney , Brossay Laurent 
Published: January 2023

Abstract
While MHC class Ia-restricted classical CD8+ T cells have been widely shown to participate in the immune response to viral infection, little is known about the MHC class Ib-restricted non-classical CD8+ T cell response. Our laboratory recently demonstrated that during murine cytomegalovirus (MCMV), a well-established model system for human CMV, adoptively transferred non-classical CD8+ T cells are sufficient to protect Kb Db RAG1−/− mice from lethality. We sought to further characterize this protective population, which is largely Qa-1-restricted. Using Kb Db−/− and Kb Db−/−. SJL mice, we are able to track the same original population of T cells through iterative adoptive transfers in multiple hosts. Following MCMV infection of new hosts, these T cells continue to play an active role in viral protection and exhibit both effector and memory phenotypes. Strikingly, following multiple challenges, an enriched clonal CD8+ T cell response is observed. While certain strains of human CMV encode a mimic of the canonical peptide binding partner for Qa-1, MCMV does not have a similar mechanism. Rather, our data show that these T cells are stimulated by an MCMV-derived antigen that is recognized by CD8+ T cells with limited αβ TCR diversity. The population we describe may act as a compensatory immune mechanism when MHC class Ia is targeted by CMV immunoevasins. Taken together, these data demonstrate that an MCMV-derived peptide is presented by Qa-1, necessary for an MCMV-specific activation of non-classical CD8+ T cells, and may be of importance for viral protection when classical CD8+ T cell immunity is compromised.
This work is supported by NIH Research Grants AI046709 and AI12221, and was supported by a T32 Training Grant in Molecular and Cell Biology and Biochemistry in years 2019-2020. Shanelle Reilly is also supported by research supplement R01 3AI046709-18S1 to promote diversity.
GC Tfh Cell Metabolism and Survival of HIV-1 Infection
Authors: Syed Fahim , Li Wei , Yu Qigui 
Published: January 2023

Abstract
CD4 T cells are the primary targets for HIV-1 infection and their loss is a hallmark of HIV-1 disease. However, T follicular helper (Tfh) cells, a distinct subset of CD4 T cells that are specialized in helping B cells form germinal centers (GCs) for the generation of high-affinity class-switched antibodies, undergo expansion in people living with HIV-1 (PLHIV). Indeed, Tfh cells with latent HIV-1 are enriched in PLHIV, whether the PLHIV are on antiretroviral therapy (ART) or not. This shows that Tfh cells are preferentially infected by HIV-1 and are able to survive infection. Through total RNAseq of tonsillar subsets of T cells, including Tfh cells, our lab was able to find a sharp upregulation of an inhibitor of apoptosis family member gene (BIRC5) and a distinct metabolic gene profile in Tfhs compared to the other subsets. We further were able to find and confirm that (1) BIRC5 was highly expressed in human tonsil Tfh cells and the expression was upregulated upon HIV-1 infection, (2) human tonsil Tfh cells had high levels of Fatty Acid Oxidation related genes, but low levels of glycolytic genes, when compared with non-Tfh CD4 T cells, and (3) inhibition of FaO and BIRC5 led to changes in the survival of Tfh cells following HIV-1 infection. Our results show that Tfh survival of HIV-1 is associated with both the metabolic profile and expression of BIRC5 due to their ability to inhibit virus-induced direct and bystander apoptosis.
Supported by grants from the NIH T32: Immunology and Infectious Disease Training Program
Severe acute respiratory syndrome coronavirus 2 vaccination induces short-term polyclonal antibody response against seasonal endemic coronaviruses
Authors: Adhikari Bindu , Oltz Eugene M , Gumina Richard J , Saif Linda J , Vlasova Anastasia N 
Published: January 2023

Abstract
Antibody (Ab) responses induced by endemic human coronaviruses (HCoVs) may affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific Ab production due to cross-reactivity among these HCoVs. To explore this hypothesis, we collected serum samples of healthy healthcare workers (HCW) at four time-points: pre-vaccination, post-vaccination (1st and 2nd dose) and 6 months post-vaccination. We used N protein peptide-based enzyme-linked immunosorbent assays (ELISA) specific for alphaCoVs (NL63 and 229E) and betaCoVs (OC43 and HKU1) as well as N and S peptide-based ELISA for SARS-CoV-2. Low levels of SARS-CoV-2 N protein-specific Abs were present in some individuals prior to vaccination. The level remained constant following one or two doses of vaccine and declined after 6 months. SARS-CoV-2 S protein-specific Abs level were low in most individuals prior to vaccination, increased sharply following 1st and 2nd vaccinations and declined by 6 months.
We observed low levels of pre-existing IgG Abs against endemic HCoVs prior to COVID-19 vaccination. However, like SARS-CoV-2-specific IgG Ab titers, they increased (1.6–1.9-fold) following SARS-CoV-2 vaccination and waned 6 months later. IgG Abs surge targeting HCoV N protein suggest polyclonal activation of memory B cell responses induced by the S gene based COVID-19 vaccines. The levels of IgG Abs against endemic HCoVs were 1.1–1.5 times higher in SARS-CoV-2 seropositive vs. seronegative individuals, suggesting serological cross-reactivity between SARS-CoV-2 and other HCoVs. In summary, short-term immunity (six months) against common cold causing HCoVs can be reactivated following COVID-19 vaccination however it requires booster dose for long term protection.
Developing a model of autoimmune diseases with human tonsil organoids
Authors: Chen Xin , Ghanizada Mustafa , Sola Elsa , Davis Mark M 
Published: January 2023

Abstract
Mouse models have contributed significantly to our knowledge of the pathogenesis of autoimmune diseases. However, differences in mouse and human immune systems limit the translation of the knowledge in mechanism and therapeutic outcomes from mouse to human. Therefore, a human model of autoimmune diseases is urgently needed. Recently, our lab has developed a functional tonsil organotypic system that can recapitulate key T cells responses and germinal center response to influenza vaccine in vitro. We now want to utilize this tonsil system to study autoimmunity.
Regulatory T cells (Tregs) have been suggested to play a central role in maintaining self-tolerance. Reduced Treg cell frequencies and impaired suppressive function have been reported in a wide range of autoimmune diseases. In this study, we show that we can efficiently knock out FOXP3 in T cells from human tonsil organoids by using CRISPR technology. We also show that tonsil organoids with FOXP3 knocked-out T cells are able to induce humoral immune responses towards autoantigens stimulation and influenza vaccination. This system could be useful for studying underlying mechanisms in the functions of Tregs in the autoimmune condition in humans and provides insights into the therapeutic strategy for autoimmune diseases.
Class II Phosphatidylinositol-3-kinases Promotes CCR7 Recycling to the Cell Membrane in Human T-Cells
Authors: Brissette Michael Abraham , Cardona Cesar I , Bill Colin A , Vines Charlotte M 
Published: January 2023

Abstract
C-C Chemokine Receptor 7 (CCR7) and its ligands (CCL19 and CCL21) are important for immune cell migration/co-localization during the primary and subsequent immune responses. We have previously shown both in humans and in mice that signaling through CCR7/CCL19 promotes rapid receptor internalization via arrestin-3. Therefore, we questioned whether internalized CCR7/CCL19 recycles to the membrane in T-cells, and if so, what are the drivers for recycling. G protein-coupled receptors can activate phosphatidylinositol-3-kinase (PI3K) family members to regulate membrane remodeling events, which include receptor recycling to the cell surface. To better understand the role of PI3K in the recycling of CCR7, we used wortmannin at 5μM to block class I and class II PI3K’s and at 0.5μM to block class II PI3K during CCR7 recycling. We found that under both conditions, receptor recycling was reduced by 20% suggesting a role for PI3K family members in recycling of CCR7 to the cell membrane. Treatment of the cells with the class I δ specific inhibitor, GS-1101, however, did not affect recycling, suggesting that CCR7/CCL19 recycling to the cell membrane is dependent on class II PI3K. To determine the site within the cells where CCR7 was retained following inhibition of only class II PI3K, we used HEK-293 cells transfected with CCR7-eGFP and the trans-Golgi network (TGN) marker, TPST2-mCherry, ± 1μM wortmannin, which is required to inhibit class II PI3K in HEK-293 cells. We found that after receptor internalization with CCL19 and 30 minutes of recycling, CCR7-eGFP remained within the TGN in the presence of wortmannin, in contrast CCR7-eGFP, which recycled to the cell membrane in the absence of wortmannin, demonstrating a role for class II PI3K in CCR7 recycling.
Supported by NIH-SC1GM111172 NIH-2U54MD007592 NSF-HRD-182675 NIH-5UL1GM118970
Interleukin-2 signaling engages de novo cholesterol biosynthesis in regulatory T cells
Authors: Crouch Acacia , Malek Thomas R 
Published: January 2023

Abstract
In the absence of IL-2R signaling, Treg homeostasis is severely disrupted. This is accompanied by a decrease in the expression of enzymes related to cholesterol biosynthesis, but the function of this pathway in Tregs is unknown. To investigate this, we selectively ablated Sterol Regulatory Binding Element Protein 2 by crossing Srebp2flox/flox mice to Foxp3cre mice (Srebp2cKO). Consistent with published studies, homozygous Srebp2cKO mice are outwardly normal. However, when Srebp2cKO Tregs are placed in competition with wild-type Tregs, they are found at a reduced frequency in the spleen, lymph nodes and gut mucosa. In this setting, Srebp2cKO Tregs have reduced Foxp3 expression, suggesting that their function and/or stability may be impacted by altered cholesterol biosynthesis. These defects persist in lymphoid and non-lymphoid tissues when Tregs in competition are treated with an IL-2R agonist. In addition, a marked reduction in effector Treg differentiation is associated with Srebp2cKO Tregs, as expression of CD39, CD73, CD103, Klrg1 and ICOS is reduced while Bcl-2 and CD62L are increased. In response to IL-2R signaling, Srebp2cKO Tregs do not optimally upregulate CD25, which suggests a function for cholesterol biosynthesis in supporting the high affinity IL-2R. These results are consistent with a model whereby IL-2R signaling coordinates Treg cholesterol biosynthesis, which contributes to effector Treg development and raises the possibility that cholesterol biosynthesis could be a target in the therapeutic manipulation of Tregs.
Supported by grants from NIH (F30 AI157211-01A1, RO1 AI148675-01)
Sustained NPSLE development in the absence of systemic lupus-like disease in TLR7- deficient B6.Nba2
Authors: Kwun Audrey , Sullivan James , Mey Gabrielle , DeSilva Tara M , Jorgensen Trine N 
Published: January 2023

Abstract
Neuropsychiatric Lupus (NPSLE) is a common manifestation of systemic lupus erythematosus (SLE) which includes presentations of cognitive learning and memory deficits and anxiety disorders. The B6.Nba2 mouse model of SLE presents with anxiety and depression. Toll-like receptor (TLR7), a known driver of type I interferons and SLE, drives systemic autoimmunity in the B6.Nba2 model, but whether TLR7-deficient B6.Nba2 mice develop NPSLE remains unknown.
Age-matched female B6, B6.Nba2, and B6.Nba2.TLR7 knockout mice (KO) were tested in open field (OFT), elevated plus maze (EPM), Y maze (YM) and novel object recognition (NOR) tests between the ages of 8–32 weeks. To determine levels of systemic autoimmunity and inflammation serum autoantibody and tumor necrosis factor-related of apoptosis (TWEAK) levels were determined by ELISA.
Both B6.Nba2 and B6.Nba2.TLR7 KO mice presented with anxiety (OFT, EPM) and dysfunctional spatial memory (YM). B6.Nba2 mice displayed a general memory defect (NOR), but this was not seen in TLR7-KO mice. Only B6.Nba2 mice presented with elevated levels of anti-dsDNA autoantibodies and corresponding DWEYS-reactive antibodies. In contrast, serum levels of TWEAK were elevated in both B6.Nba2 and B6.Nba2.TLR7 KO mice, suggesting that signals other than TLR7 may drive inflammation in this model.
In conclusion, both B6.Nba2 and B6.Nba2.TLR7KO presented with elevated serum TWEAK levels, anxiety and memory deficits, despite only B6.Nba2 mice displaying anti-dsDNA and DWEYS-reactive autoantibodies. Thus in this model, NPSLE appear to develop in an autoantibody-independent fashion. Studies are ongoing to determine the nature of TLR7/autoantibody-independent NPSLE.
Supported by a grant from the Department of Defense (LR 180040)
Validation of Ferret Luminex Cytokine Assays with serum from ferrets infected with flu, stimulated whole blood and PBMCs
Authors: Race Tori C , Fletcher Ashley , Damour Marc , Brown Deborah M , Rutgers Robyn S , Stephen Laurie L 
Published: January 2023

Abstract
Ferrets represent excellent models of infectious disease due to their natural susceptibility to many human respiratory viruses including influenza A virus (IAV), respiratory syncytial virus and severe acute respiratory syndrome (SARS). Ferrets can reproduce a similar course of disease and display similar symptoms of respiratory infection as humans, while mice do not exhibit key features of disease such as sneezing, nasal discharge and fever. There is pressing need to develop reagents to better understand and characterize the immune response to infection and support biomarker and countermeasure development through immunologic analyses of respiratory infections in the ferret. IL-1β, IL-2, IL-5, IL-6, IL-12 p40, IL-12p35, IL-17, IFNγ, TNFα, & IP-10 were expressed in HEK293 cells and purified. Monoclonal antibodies were generated and screened by Luminex for matched pairs to the recombinant protein and presumed positive samples. Capture antibodies were coupled to Luminex beads and detection antibodies were biotinylated. Serum from ferrets infected with flu had 10-fold higher levels of IP-10 and 3-fold higher levels of IL-6 than control serum. Stimulation of ferret whole blood with LPS showed increases in IL-2 and IL-6 at 2, 4 and 24 hrs. IL-12p40 and TNFα increased at 24hrs after stimulation with LPS. A validated cytokine panel in the study of immune related diseases in the ferret model.
Supported by SBIR contract 75N93020C00022: Development of Ferret Reagents for use in the Characterization of Immune Responses to Respiratory Infections in the Ferret Model