bluuebunny/crossref_metadata_2025_split huggingface dataset:
ESAT-6 inhibits IFN-γ secretion by Mycobacterium tuberculosis responsive-human T cells (129.12)
Authors: Wang Xisheng , Barnes Peter F , Townsend James C , Chung Yoon-tae , Shams Homayoun , Samten Buka 
Published: January 2023

Abstract
Early secreted antigenic target of 6 kD (ESAT-6) of Mycobacterium tuberculosis (M. tb) is a potent antigen with vaccine potential, but is also a virulence factor. We studied the effect of recombinant His-tagged ESAT-6 on IFN-γ secretion by human primary T cells, using the 10 kD culture filtrate protein (CFP10) as a control. ESAT-6 but not CFP10 started to inhibit IFN-γ secretion by M-tb stimulated PBMC at 1.6 μM and this reached 90% inhibition, compared to that with CFP10 (12.5 + 5.4 vs. 1.3 + 1.2 ng/ml) at 3.3 μM (20 μg/ml). Dimerization of ESAT-6 with CFP10 did not affect inhibition. ESAT-6 inhibited IFN-γ production of α-CD3/CD28 mAb-stimulated T cells by 89% (14.5 + 1.8 vs. 1.6 + 0.4 ng/ml), and proliferation, as measured by CFSE assay. Depleting ESAT-6 with a nickel resin abrogated the inhibition. The inhibitory effect of ESAT-6 was not due to T cell toxicity or apoptosis, as measured by MTT assay and Annexin V staining. ESAT-6 inhibited expression of M. tb-induced IFN-γ mRNA (&gt; 90%) and the transcription factors, ATF-2 and c-Jun, which regulate IFN-γ transcription. ESAT-6 bound to T cells and inhibited expression of CD69 and CD25, without affecting proximal TCR signaling, ZAP70 activation. We conclude that high concentrations of ESAT-6 inhibit T cell responses to M. tb by affecting signaling pathways downstream of ZAP70, and may be a mechanism by which M. tb inhibits effective immunity. (NIH AI063514)
Host response to Tick-bone encephalitis and Omsk hemorrhagic fever (129.22)
Authors: Tigabu Bersabeh , Holbrook Michael 
Published: January 2023

Abstract
Omsk hemorrhagic fever virus (OHFV) and Russian spring-summer encephalitis virus (RSSEV) are tick-borne flaviviruses of the genus Flavivirus, Family Flaviviridae. Although OHFV and RSSEV have 90% homology at their amino acid level, they have different disease outcomes. OHFV infection mainly causes hemorrhagic fever, however RSSEV infection results in a severe form of CNS disorder. Understanding of the pathogenesis of tick-borne encephalitis and hemorrhagic fever is of major importance due to significant public health problem and the lack of treatment. Dendritic cells (DC) play a critical role for both innate and adaptive immune responses. DC function as the best antigen presenting cells to T-cells by upregulating expression of costimulatory and MHC molecules, and cytokine production. In these experiments we examined interactions between OHFV/RSSEV and murine DC to identify responses that contribute to the pathogenesis of tick-borne flaviviruses. The DC surface markers were analyzed using flow cytometry, and cytokines and chemokines were quantified by Bioplex assay. OHFV/RSSEV infection of DC resulted in the secretion of a broad array of cytokines and chemokines. OHFV/RSSEV exposure did not activate DC maturation markers as compared to LPS stimulated DC. Infected DC had similar levels of CD80 and CD86 expression relative to the mock infected DC. Our data demonstrate that the functional maturation of DC in response to OHFV/RSSEV infection is modified leading to a reduction of the capacity of DC antigen presentation and consequently T-cell activation.
This research was supported by the Western Regional Center of Excellence (U54AI056157)
HIV-1 compromises CD8+T cell effector function in Mtb- infected lung (129.26)
Authors: Lancaster Katrina  L , Hogg Alison E , Clement Cecilia G , Aronson Judith F , Endsley Janice J 
Published: January 2023

Abstract
Tuberculosis (TB) remains a global health problem with more than 8 million new cases and 1 million deaths per year worldwide. HIV-1 infected persons have a greatly increased risk of Mycobacterium tuberculosis (M. tb) co-infection. A key feature of M.tb infection is the formation of granulomas, cellular accumulations composed of macrophages, epithelial cells, and a surrounding mantle of T cells, which are important for the containment of infection. The cytolytic T cell effector molecules, perforin and granulysin, play a critical role in protective immunity to M.tb. It has been shown that decreased expression of perforin and granulysin at the site of pulmonary disease is linked to chronic TB. However, the effects of HIV-1 on CD8+T cells numbers and expression of cytolytic effector molecules such as perforin and granulysin in M. tb induced granulomas has not been explored. In this study, we used immunohistological techniques to assess the differences in T cell populations, granulysin expression, and pathology in tissue sections from Mtb- and Mtb/HIV-1-infected human lung. Our results indicate that granulomas from persons with TB/HIV-1 are characterized by dysregulated T cell organization and poor expression of granulysin. We propose that defective granulysin expression by M.tb-specific CD8+T cells contributes to the development of disease in TB/HIV-1 co-infected persons.
The chemokine receptor CXCR3 is required for optimal murine resistance against Toxoplasma gondii (129.30)
Authors: Snider Heidi M , Lockhart Gabriel , Barbi Joseph , Papenfuss Tracey L , Lu Bao , Satoskar Abhay R 
Published: January 2023

Abstract
CXC chemokine receptor 3 (CXCR3) plays a critical role in recruitment of neutrophils, natural killer cells and T cells to sites of inflammation. Since these cell types are all critical in control of Toxoplasma gondii infection we hypothesized that CXCR3 is critical for immunity against T. gondii. To test this hypothesis we compared the course of T. gondii (ME49) infection in WT and CXCR3-/- mice on a C57BL/6 background. Following ME49 challenge, CXCR3-/- mice developed high brain parasite loads and succumbed to infection significantly faster than WT mice. T. gondii antigen-stimulated splenocytes from CXCR3-/- mice produced significantly more IFN-γ than WT splenocytes, but serum levels of this cytokine were lower in the former. Flow cytometry also revealed that CXCR3-/- mice recruit fewer leukocytes into the brain than WT mice early during infection. Finally, adoptive transfer studies involving Rag2-/- mice reconstituted with CXCR3-/- or WT lymphocytes revealed that CXCR3 expression on T cells was critical for effective immunity against ME49. Taken together, these results show that CXCR3 is critical for immunity against T. gondii. Furthermore, they suggest that increased susceptibility of CXCR3-/- mice is due to impaired leukocyte trafficking - most likely CXCR3 expressing T cells - into infection sites and not due to impairments in type I CD4+ T cell responses.
Support: NIH
Functional Consequences of Increased Virus-specific CD8+ Effector Memory T cells in the Response to Influenza in Older Adults (130.4)
Authors: Zhou Xin , McElhaney Janet E 
Published: January 2023

Abstract
Background: The decline in adaptive immune function with age is a major cause for increased risk of complicated influenza illness in older adults especially those with congestive heart failure (CHF). Changes in the CD8+ T cell response to the virus may explain the increased risk of influenza in the older population. Methods: The response to influenza in 12-hour peripheral blood mononuclear cell (PBMC) cultures from vaccinated healthy young (20-40 y.o.) and older adults (age =60 y.o.) with or without CHF was measured in different CD8+ T cell subsets. Results: In unstimulated PBMC, older compared to young adults showed a higher proportion of GrB+CD8+ T cells, and these T cells also expressed higher levels of CD107a in the CHF group. Healthy young and older adults showed a significant increase in the GrzB+CD8+ T cells expressing CD107a, consistent with a cytolytic effector function; older adults with CHF had no response. Preliminary results suggest that this poor response is associated with an increased proportion of terminally-differentiated, effector memory (CD8+CD45RA+) T cells. Conclusions: An accumulation of terminally differentiated CD8+CD45RA+ T cells have an effector phenotype but do not respond to influenza virus and may explain the increased risk of influenza in the older adults.
Macrophages contribute to pathogenesis of visceral leishmaniasis via a STAT1-dependent mechanism (131.10)
Authors: Snider Heidi M , Barbi Joseph , Satoskar Abhay R 
Published: January 2023

Abstract
We previously reported that STAT1-/- mice on a susceptible BALB/c background were highly resistant to visceral leishmaniasis (VL) and developed minimal organ pathology compared with wild-type (WT) controls, despite mounting a poor Th1 response. We also found that STAT1 in non-T cells (i.e. macrophages and neutrophils) mediated susceptibility and pathology. The objective of this study was to determine whether macrophages are involved in the pathogenesis of VL cause by Leishmania donovani and to determine the role of STAT1 in phagocytes in mediating disease susceptibility. Depletion of monocytes and macrophages using clodronate-containing liposomes both prior to and after L. donovani infection impaired Th1 development in WT BALB/c mice, but rendered them highly resistant to infection and minimized liver pathology. This phenotype was strikingly similar to that seen in infected STAT1-/- mice. Further in vivo studies using an airpouch model demonstrated that both macrophages and neutrophils of STAT1-/- mice had significant impairments in parasite uptake compared with WT controls. Taken together, these results demonstrate that macrophages are involved in the pathogenesis of VL, and that STAT1 signaling may mediate disease susceptibility by facilitating parasite uptake into host phagocytes.
Support: NIH
Molecular insights into how the adenovirus E3-19K protein associates with MHC class I molecules (131.5)
Authors: Fu Jie , Bouvier Marlene 
Published: January 2023

Abstract
The immunomodulatory protein E3-19K from Adenoviruses (Ads) blocks cell surface expression of MHC class I by preventing their export from endoplasmic reticulum (ER), thus evading host's antiviral cellular immune responses. Currently, structural information on E3-19K and the biochemical properties of the E3-19K/class I complex is lacking. This knowledge will help not only to better understand host/virus interaction, but also to design effective antiviral therapies against Ad infections. Using a proteolytic approach, we showed that the recombinant, soluble E3-19K (residues 1-100) generated a large N- (residues 1-88) and small C- (residues 94-100) terminal fragments which encompass the majority of residues within the variable and conserved regions, respectively, of E3-19K. We showed that fragments corresponding to the variable and conserved regions do not remain associated together after proteolysis. Moreover, neither of these fragments associates with class I. These results strongly suggest that the ability of E3-19K to bind to class I molecules depends on a delicate structural interplay between the variable and conserved regions. We also identified residue 93 in E3-19K as critical for E3-19K association with class I molecules. Together, these results provide novel insights into the structure/function relationship of E3-19K and its effect on down regulation of class I molecules. Funded by NIH AI65943.
Enhanced NKT cell response and skewed polarization of DC in RSV infection and susceptibility to asthma (131.6)
Authors: Sun Jonathan , Durre Kainath , Qureshi Mahboob 
Published: January 2023

Abstract
RSV infection in early infancy makes individuals susceptible to develop asthma in later life due to airway hyper-responsiveness (AHR) to innocuous antigens, which is characterized by enhanced Th2 responses. Using a neonatal mouse model, we investigated whether differential NKT cell responses and skewed polarization of DC are involved in the underlying mechanism. Flow cytometry revealed a significant increase in the proportions of NKT cells (CD3-CD19-CD1d+) in RSV-infected 5 days old lungs compared to that of 7 and 34 days old lungs. A comparable increase in the proportions of plasmacytoid DCs (pDCs; CD11blo CD11clo CD45R+) to myeloid DC (mDCs; CD11blo CD11chi/med CD45R-) was also determined by flow cytometry. To note, DC phenotypes involved in antigen presentation influence the outcomes of the immune responses. In support of this notion, RSV infection induced a significantly higher production of Th2 cytokines than Th1 cytokines in the lungs of younglings. In contrast, RSV-infected adult lungs produced significantly higher amount of Th1 cytokines. Furthermore, NK cell response was not enhanced in the young lungs as opposed to that in the adult lungs in response to RSV infection. Thus, enhanced NKT cell and reduced NK cell responses to RSV infection in the neonatal lungs, along with an enhanced Th2 response, may have induced a skewed polarization of DCs to pDCs leading to development of AHR and susceptibility to asthma.
Destruction of monocyte/macrophages dictate AIDS progression in SIV infected macaques (131.9)
Authors: Kuroda Marcelo J. , Liu Huining , Ling Binhua , Sugimoto Chie , Williams Kenneth , Lackner Andrew A. , Veazey Ronald S. , Hasegawa Atsuhiko 
Published: January 2023

Abstract
It is widely accepted that destruction of CD4+ T cells and viral load are the primary markers for immunodeficiency in HIV-1-infected humans and in simian immunodeficiency virus (SIV)-infected macaques. However, the mechanisms that dictate the tempo of disease progression have yet to be elucidated. Macrophages, an important cell component of the innate immune system and link between innate and adaptive immunity, are also important targets of HIV/SIV infection. We therefore examined whether changes in cells of monocyte/macrophage lineage could be linked to the pathogenesis of AIDS in the rhesus macaque model. Here we show that massive turnover of peripheral monocytes associated with death of tissue macrophages correlates with AIDS progression in macaques. More importantly, the level of monocyte turnover was not linked to the CD4+ T cell count and was a better predictive marker for AIDS progression than viral load or lymphocyte activation. Our results show the importance of monocyte/macrophages in the pathogenesis of AIDS and suggest the dynamic changes of the monocyte/macrophages as a new marker for AIDS progression.
Priming of multifunctional Mycobacterium tuberculosis-specific CD8 T cells (132.13)
Authors: Einarsdottir Thorbjorg , Flynn JoAnne L. 
Published: January 2023

Abstract
M. tuberculosis (Mtb) infection in mice results in a slow but steady increase in bacterial numbers in the lungs, peaking at 3-4 weeks, followed by a state of chronic infection with bacterial numbers slightly lower than the peak. While T cells have been shown to be important for containing Mtb infection, the only known method of clearing the bacteria is by extended antibiotic treatment. Our previous results showed that Mtb-specific CD8 T cells were limited to either cytotoxicity or secretion of IFN-g, indicating a functional defect in the cells. The majority of Mtb-specific CD8 T cells were cytotoxic, with IFN-g production limited to early responses (at 3-4 weeks). In the current study, we used a recombinant Mtb strain expressing ovalbumin epitopes (Mtb-ova) to examine the functional profile of naïve ovalbumin-specific CD8 T cells adoptively transferred to mice at different times post-infection. Cells transferred before infection acquired primarily cytotoxic function, while cells transferred at 6 weeks became either cytotoxic or secreted IFN-g. Cells transferred at the peak of infection (at 3 weeks) were more multifunctional than cells transferred at other times, in that they could be both cytotoxic and secrete IFN-g. Future work will focus on identifying what determines the function of the cells and whether an increase in multifunctional cells provides improved bacterial control.
Funding: NIH/NIAID AI37859-10.
Anti-West Nile Virus antibodies provide protection from WNV infection: protective antibodies recognize diverse WNV proteins (132.21)
Authors: Konschak Sarah R , Petell Christopher , Schiltz James , Petell James , Bradley David S. 
Published: January 2023

Abstract
We demonstrate here that goose-derived anti-West Nile Virus (WNV) antibodies are both protective against WNV infection and specific for a broad spectrum of WNV proteins. WNV is a Flavivirus that predominantly infects birds via a mosquito vector. The majority of humans infected with WNV demonstrate mild flu-like symptoms. However, a small number of human WNV cases result in meningitis and encephalitis, which can ultimately lead to paralysis or death. The epidemiology of WNV infections indicates that a population-wide vaccine is neither necessary nor cost-effective. An effective passive therapeutic antibody treatment would, however, provide an excellent alternative for individuals with WNV infection involving the CNS. We have demonstrated that antibodies, purified from geese naturally infected with WNV, protects both avian and mammals from WNV infection. WNV-infected golden hamsters receiving goose anti-WNV antibodies demonstrated 100% survival while all of the infected animals receiving a sham treatment perished. Characterization of the WNV-specific goose antibodies indicates a polyclonal response with diverse specificities, including WNV proteins E, pre-M and NS3. This diverse reactivity suggests enhanced protection both in the recognition of various replicative and envelope components and potentially across various WNV strains.
DOE "Goose Diagnostic and Therapeutic Antibodies to West Nile Virus and AI"
JVRS-100 adjuvanted universal influenza A vaccine based on a multiple antigenic peptide of M2e protects from lethal challenge (132.6)
Authors: Callejo Bernadette J , Chang Stella , Lay Marla , Liang Lily , Fairman Jeffery 
Published: January 2023

Abstract
Background: The conventional vaccine strategy for control of influenza A is vulnerable to antigenic drift and the emergence of unmatched epidemic strains that cause primary vaccine failure. A vaccine strategy that targets an influenza antigen, which is less susceptible to antigenic variation, would be a major improvement. Methods: Balb/c mice were vaccinated three times with the M2e peptide in the context of a multiple antigenic peptide (MAP) complex and combination with the cationic lipid DNA complex adjuvant (JVRS-100). Antibody titers were monitored over the time course of vaccination and the mice received a lethal challenge with H1N1 (PR/8/34) or H3N2 (HKx31) two weeks after the final vaccination. Results: Vaccination of mice with JVRS-100-MAP4-M2e compared to MAP4-M2e resulted in increased survival following lethal challenge with 6x LD50 PR/8/34 H1N1 (100% vs. 30%, P=0.002) or 10x LD50 HKx31 H3N2 (80% vs. 20%). Recipients of 200µl serum from MAP-4-M2e/JVRS-100 vaccinated mice and challenged with H1N1 (6x LD50 PR/8/34) resulted in survival of 60% (P=0.014) compared with control mice which received 200µl naive serum (0% survival). Furthermore, recipients of 300µl serum from MAP-4-M2e/JVRS-100 vaccinated mice and challenged with H1N1 (2x LD50 PR/8/34) resulted in survival of 100% (P=0.0026) compared with control mice which received 200µl naive serum (0% survival). Conclusion: These studies demonstrate that a simple, synthetic M2e vaccine in a MAP configuration with a strong adjuvant may result in a viable vaccine candidate for universal flu vaccination and the protective immunity is primarily due to an antibody response.
Viruses Selectively Hide CD8 T Cell Epitopes. (132.7)
Authors: louzoun yoram , vider tal 
Published: January 2023

Abstract
Viruses employ various means to evade immune detection. One common evasion strategy is the removal of CD8 cytotoxic T-lymphocyte (CTL) epitopes. We here use a combination of multiple bioinformatic tools and large amount of genomic data to compute the epitope repertoire presented by over 1,300 viruses in multiple HLA alleles. We define the "Size of Immune Repertoire (SIR) score," which represents the ratio between the epitope density within a protein and the expected density. We show that virusal proteins in general have a higher epitope density than human proteins. This difference is due to a good fit to the human MHC system to the typical amino acid usage of viruses. Among different viruses, viruses infecting humans present less epitopes than non-human viruses. This selection is not at the amino acid usage level, but through the removal of specific epitopes. Within a single virus, not all the proteins express the same epitopes density. Proteins expressed early in the viral life cycle have a lower epitope density than late proteins. Such a difference is not observed in non-human viruses, The targeting of the CTL immune response to viral late structural and enzyme proteins, allow the virus time interval to propagate before its host cells are destroyed by CTLs.
Protective CD4 T cell-independent IgM responses impairs the production of isotype-switched antibodies during intracellular bacterial infection (133.14)
Authors: Racine Rachael , Chatterjee Madhumouli , Wittmer Susan , McLaughlin Maura , Jones Derek , MacNamara Katherine C , Winslow Gary 
Published: January 2023

Abstract
Ehrlichia muris, an intracellular tick-borne pathogen, generates a CD4 T cell independent (TI) protective response in C57BL/6 mice. At peak infection, the response is accompanied by the expansion splenic extrafollicular CD11clo-expressing plasmablasts that produce antigen-specific IgM. Using secretory IgM (sIgM)-deficient mice and activation-induced adenosine deaminase (AID)-deficient mice, which are unable to undergo antibody class-switching, we demonstrated that IgG is dispensable for immunity and unmutated IgM was sufficient for protection to challenge infection with a highly virulent ehrlichia. Furthermore, while IgM-secreting cells were abundant in the spleen, prior to day 21, IgG was largely absent and instead produced in infected LNs. Thus, the robust IgM response impaired the formation of germinal centers and production IgG-secreting cells in the spleen. These findings, in turn, suggested that ehrlichial infection might suppress the spleen's ability to produce isotype-switched antibodies to blood borne antigens or pathogens. Indeed, E. muris infected-mice immunized with NP-CGG exhibited an impaired NP-specific IgG response. Thus, our studies demonstrate a major protective role for CD4 T cell-independent IgM during intracellular bacterial infection, and suggest a mechanism whereby a T cell-independent response may suppress T-dependent responses during co-infecting pathogens.
Surfactant Protein D is cleaved by matrix metalloprotease-9, resulting in disruption of collectin function (133.16)
Authors: Weathington Nathaniel M , Jackson Patricia L , Wilson Landon , Gaggar Amit 
Published: January 2023

Abstract
Surfactant protein D (SP-D) is a pulmonary collectin, containing collagen and lectin domains, important in innate host defense in the lung. It agglutinates and opsonizes bacteria and leads to phagocytosis by macrophages. Matrix metalloproteinase-9 (MMP-9) is a gelatinase upregulated in many inflammatory diseases of the lung. We tested SP-D as a substrate for MMP-9, and assessed SP-D function in this context. We show cleavage at three discrete sites of the collagen domain, generating C-terminal fragments of 34, 27, and 19KDa identified by western blot and with specific cleavage sites verified by mass spectrometry. SP-D is not, however, hydrolyzed by the related protease MMP-8, nor the serine protease prolyl endopeptidase, both of which cleave collagen. Incubation with these three proteases separately or in combination did not generate any detectable quantity of the neutrophil chemoattractant proline-glycine-proline (PGP), though SP-D contains many PGP motifs in the collagen domain. Furthermore, with MMP-9 cleavage, SP-D's intrinsic neutrophil chemoattractant activity was eliminated and its ability to aggregate Pseudomonas aeruginosa was also decreased. These studies indicate that in inflammatory lung diseases where MMP-9 is upregulated, impairment of SP-D's innate immunologic properties may increase frequency and severity of pulmonary infection, emphasizing the role of MMP-9 in disease.