bluuebunny/crossref_metadata_2025 huggingface dataset:
Infant stool microbiota at the time of vaccination at 6 w of age is associated with vaccine responses measured at 2 y of age
Authors: Huda Md Nazmul , Ahmad Shaikh , Kalanetra Karen M. , Taft Diana H. , Lewis Zachery T. , Raqib Rubhana , Mills David A. , Stephensen Charles
Published: January 2023

Background

Gut microbiota in early infancy may shape a host’s vaccine response. We have previously reported that a high relative abundance (RA) of Bifidobacterium in early infancy is associated with vaccine responses measured near the time of stool collection (Huda MN et al., Pediatrics 2014 134:e362). In this study, we expanded the sample size and tested if the RA of Bifidobacterium measured at the time of vaccination (between birth and 15 w) is associated with T-cell and antibody (Ab) responses to those vaccines measured at 2 y of age.

Methods

This study included 306 healthy Bangladeshi infants (NCT01583972, NCT02027610). Stool microbiota was assayed at 6, 11 and 15 w and between 2 and 3 y of age. Vaccine-specific T-cell proliferation responses to BCG (Bacillus Calmette–Guérin), OPV (oral poliovirus), TT (tetanus toxoids), and HBV (hepatitis B virus) were measured at 15 w and 2 y of age. Plasma and stool Ab were measured at 2 y. Tuberculin skin test was performed at 15 w.

Results

Bifidobacterium RA at 6 w was positively associated with T-cell responses to BCG, OPV, HBV and TT measured at 15 w and 2 y, as predicted. Bifidobacterium was not associated with plasma Ab response. The abundance of Firmicutes and Proteobacteria were negatively associated with some vaccine responses. Microbiota at 2 y did not show consistent, significant associations with T-cell response or systemic Ab responses but Bifidobacterium was positively associated with polio-specific stool IgA levels.

Conclusion

Bifidobacterium RA at the time of vaccination is associated with systemic and mucosal vaccine-specific T-cell responses measured later in life, suggesting that interventions to enhance Bifidobacterium in early infancy may improve vaccine responses later in life.
Impairment of myeloid-derived suppressor cell expansion and enhancement of dendritic cell differentiation of MyD88-deficient bone marrow cells in graft-versus-host disease
Authors: Lee Young-Kwan , Ju Ji-Min , Kang Myung-Soo , Min Chang-Ki , Shon Woo-Jeong , Shin Dong-Mi , Choi Eun Young
Published: January 2023

Myeloid differentiation 88 (MyD88) is an adaptor molecule in toll-like receptor-associated signaling. To examine the effect of MyD88-deficiency in myeloid cell differentiation under inflammatory condition, we transplanted bone marrow (BM) cells isolated from MyD88-deficient C57BL/6 (B6) mice together with B6 T cells into MHC-matched allogeneic BALB.B strain mice. This transplantation induced more serious graft-versus-host disease in the BALB.B BM recipients, compared with the GVHD induced in the control BALB.B mice which received wild type B6 BM and T cells. The aggravation of GVHD was associated with impaired expansion of CD11b+Gr1+ myeloid derived suppressor cells (MDSCs) from the MyD88-deficient BM cells during the GVHD development. Instead of MDSC expansion, myeloid cells from MyD88-deficient BM cells showed enhanced apoptosis and dendritic cell (DC) differentiation, which resulted in enhancement of activation of allo-reactive B6 T cells. These results provide information helpful for the understanding of the role of MyD88 in myeloid cell differentiation and development of strategy to reduce the GVHD severity.
MAP1S-mediated TLR5 signaling induces autophagic cell death to inhibit breast cancer
Authors: Shi Ming
Published: January 2023

TLR5 signaling in breast cancer showed strong anti-tumor activity, which might represent a novel strategy in cancer immunotherapy. However, the underlying mechanism of TLR5 signaling-based tumor suppression is still not elucidated. Here, we found TLR5 agonist flagellin could induce excessive autophagy in breast cancer cells, and the expression level of autophagic adaptor MAP1S was elevated in response to flagellin treatment. Moreover, the elevated level of MAP1S robustly promoted tumor cell death in a TLR-dependent manner. Whereas MAP1S deletion led to decreased proinflamatory cytokines expression that induced by TLR5 signaling and blockage of autophagic process in breast cancer cells. In addition, MAP1S promoted the inhibition of inflammasome pathway and pyroptosis by TLR5 signaling. Therefore, we deducted that MAP1S played a key role in TLR5 signaling-based tumor suppression. Taken together, these results indicated a mechanism of antitumor activity that involved MAP1S-mediated TLR5 signaling in breast cancer.
Intravital 2 photon imaging approach to monitor monocyte rolling in experimental atherosclerosis
Authors: Saunders Brian T , Williams Jesse W. , Randolph Gwendalyn J , Zinselmeyer Bernd H
Published: January 2023

Atherosclerosis is the leading cause of heart disease, which is the largest contributor to deaths across the world. This disease involves the development of inflammation and plaque formation within the lumen of mid- and large-sized arteries following cholesterol-enriched diet. Our current study uses intravital two photon imaging to examine the initiating and propagating factors of this disease. Atherogenesis occurs at sites of endothelial damage most commonly near branching points and areas of high sheering stress in vasculature, including the aortic arch and carotid bifurcation. A minimally invasive technique was developed allowing us to monitor the movement of cells inside the vasculature. This technique involves isolating the right common carotid artery near the bifurcation and positioning it to monitor monocyte dynamics on the endothelium without disrupting the flow. Using a variety of fluorescent proteins on myeloid backgrounds crossed with LDLR−/− mice, we measure the monocyte dynamics on both normal diet and cholesterol diet at multiple different time points. We can trace the movement of monocytes in the blood and measure the interaction with resident cells in the luminal wall, finding that monocyte rolling is influenced by localization to plaque-areas and treatment with high cholesterol diet. Defining these differences in interactions and determining mechanisms of monocyte recruitment are key to understanding the initiation and growth of atherosclerotic plaque over time.
Immunophenotyping of chemokine receptor profile on osteoclast progenitors may help reveal mechanisms of their increased migration in collagen-induced arthritis
Authors: Flegar Darja , Sucur Alan , Markotic Antonio , Kovacic Natasa , Kelava Tomislav , Katavic Vedran , Ivcevic Sanja , Grcevic Danka
Published: January 2023

Osteoclasts, specialized bone resorbing cells of hematopoietic origin, become overactive in rheumatoid arthritis, leading to bone loss and joint destruction. Osteoclast progenitor cells (OCP) arise from myeloid precursors of monocyte/macrophage lineage and are found in the bone marrow and among circulatory monocytes. Under inflammatory conditions subpopulations of OCPs undergo through functional and phenotypic changes responsible for their increased migration to inflamed sites and osteoresorptive activity. In our study, we have been investigating frequencies of distinct OCP subsets and their expression of chemokine receptors in circulation and periarticular bone marrow (PBM) of C57BL/6 mice with collagen-induced arthritis (CIA). We found that both hematopoietic lymphoid-negative CD11b+CD115+ and CD11b−/loCD115+ subsets possess osteoclastogenic activity and are enlarged in blood and PBM of affected joints in CIA. OCP subsets substantially expressed CCR2 and CX3CR1, but had low expression of CCR5, CCR9 and CXCR4, with no difference between control and CIA group. Concurrently CCL2 serum levels were significantly increased in CIA, whereas CX3CL1 levels were comparable to control. In an in vitro migration assay, peripheral blood leukocytes from CIA mice after M-CSF and RANKL stimulation increasingly migrated toward CCL2 and CCL5 chemotactic gradients. Intravascular in vivo staining demonstrated increased recirculation of CD45+CD11b+ cells through areas of PBM affected by arthritis. These results suggest that highly induced OCP subpopulations in CIA migrate to inflamed joints due to chemotaxis and therefore blocking of chemokine signals may reduce osteoclast activity in arthritis.
RAGE antagonist decreases β-amyloid, HMGB-1, RAGE expression in the brain, and prevented long-term cognitive impairment in experimental bacterial meningitis
Authors: Barichello Tatiana , Moreira Ana Paula , Steckert Amanda V , Michels Monique , Generoso Jaqueline S , Simoes Lutiana R , Dominguini Diogo , Rafael Cassia P , Barata Joana , Petronilho Fabricia , Dal-Pizzol Felipe
Published: January 2023

Bacterial meningitis is a serious infection of the central nervous system that causes learning and memory impairment. Our central hypothesis is that during meningitis, the inflammation increases the synthesis of amyloid-beta (Aβ1-42) and up regulates receptor for advanced glycation end products (RAGE). Then the Aβ-RAGE-axis triggers long-term cognitive impairment in meningitis survivors. To test this, we evaluated Aβ1-42 deposition, RAGE, and high mobility group box-1 (HMGB-1) expression in the rat brain. We evaluated the behavioural response by treating the rats with RAGE-antagonist, N-benzyl-4-chloro-N-cyclohexylbenzamide (FPS-ZM1). The animals were separated into four groups: control/saline, control/FPS-ZM1, meningitis/saline, and meningitis/FPS-ZM1 (n=10). Experimental design: male 60-day-old Wistar rats received an intracisternal injection of 10 μL of artificial cerebrospinal fluid as a placebo or an equivalent volume of Streptococcus pneumoniae suspension at concentration of 5×109 CFU/mL. Eighteen hours after meningitis induction, all animals received ceftriaxone. Ten days after inoculation all blood cultures performed were negative showing that the animals were free from infection. At 10 day after meningitis induction the results from western-blot showed increased expression of Aβ, RAGE, and HMGB-1 in the hippocampus and prefrontal cortex of meningitis group. The FPS-ZM1 adjuvant treatment prevented the Aβ1-42, RAGE, and HMGB-1 expression in both brain structures and prevented long-term memory impairment in the meningitis group. The bacterial meningitis may trigger cognitive impairment through up-regulating Aβ-RAGE axis and RAGE-antagonist prevented cognitive impairment.
Hematopoietic MyD88 mediates protection against virulent Francisella tularensis infection via IFN-γ, but does not require myeloid or dendritic cell MyD88 signaling
Authors: Skyberg Jerod A , Lacey Carolyn A
Published: January 2023

Francisella tularensis is a highly infectious intracellular bacterium that causes the potentially fatal disease tularemia. MyD88 has previously been shown to confer protection against both attenuated and virulent strains of F. tularensis, however the underlying mechanisms of protection are largely unexplored. Here we investigated cell-specific mechanisms of protection against virulent F. tularensis infection using mice with conditional MyD88 deficiencies. MyD88 deficiency in myeloid or dendritic cells did not enhance susceptibility to F. tularensis, regardless of the route of infection. In addition, myeloid or dendritic cell MyD88 deficiency did not markedly hinder the production of inflammatory cytokines. In contrast, MyD88−/− mice, or mice with hematopoietic MyD88 deficiency display elevated bacterial burdens, and markedly reduced cytokine levels. While IL-12 levels were not diminished in MyD88−/− or hematopoietic MyD88-deficient mice infected with F. tularensis, IFN-γ production was abolished in these animals. In particular, IFN-γ production by splenic NK cells was abated in mice lacking hematopoietic MyD88. Neutralization of IFN-γ from wild-type, but not hematopoietic MyD88-deficient mice, resulted in elevated tissue F. tularensis burdens. Caspase-1/11−/− mice also displayed enhanced bacterial burdens, diminished serum IL-18 levels, and reduced IFN-γ production. Collectively, our data shows that hematopoietic MyD88 is required for IFN-γ production that is protective against F. tularensis infection. As IL-18 requires MyD88 for signaling to induce IFN-γ production, MyD88 signaling in hematopoietic cells, such as NK cells, may result in the production of protective IFN-γ via caspase1/11 dependent IL-18.
A novel role for Connexin 43 in IFN beta expression during Chlamydia trachomatis infection and cytosolic DNA-sensing
Authors: Tripathy Manoj Kumar , Zhang Yugen , Bodnar Wanda , Nagarajan Uma M
Published: January 2023

Background

The DNA sensor cGAS is essential for IFNβ expression in cells infected with Chlamydia. cGAMP generated during DNA sensing can also transfer via intercellular gap-junction proteins, connexins CX43/45 leading to IFNβ expression in adjacent uninfected cells. Present study highlights a novel role for CX43 in IFNβ expression during DNA-sensing and during Chlamydia infection, independent of its gap junction function.

Methods

Total IFNβ transcripts were measured by qRT-PCR following CX43 or CX45 siRNA mediated knockdown (KD). Single cell RNA-ISH method view RNA™ was used to visualize IFNβ mRNA in infected HeLa cells. CX43 localization was studied using IF and confocal microscopy.

Results

CX43-KD in HeLa cells reduced IFNβ expression by >90% (p<0.001) compared to control or CX45 KD, as measured by qRT-PCR. CX43-KD also reduced IFNβ mRNA in dsDNA transfected cells (p<0.001) but not with poly IC RNA. RNA-ISH showed IFNβ mRNA transcripts in infected cells (>90%) and in adjacent uninfected (~10%) cells, but not in distal uninfected cells, suggesting cell contact is required for adjacent-cell effect. Surprisingly, RNA-ISH of CX43-KD cells showed >85% reduction in IFNβ transcripts (p<0.0001) in infected cells, in addition to the loss of transcripts in cells adjacent to infected cells. CX43 localized proximal to the chlamydial inclusion membrane. Co-localization of CX43 was also observed with transfected dsDNA, but not dsRNA.

Conclusion

CX43 depletion has been shown to increase autophagy in cells. Here we show that CX43 depletion decreases IFNβ induction during DNA sensing. Our results suggest that like STING, CX43 could be a key player in both DNA sensing and autophagy, but with opposing roles. (Funded by NIAID R01-AI067678 to UN).
Ontogeny of tissue autoantigen expression influences the mechanism of tolerance by Foxp3+ regulatory T cells
Authors: Tung Kenneth S K , Lenart Dominik , Litwinowicz Agata , Harakal Jessica , Qiao Hui
Published: January 2023

We studied the ontogeny of organ-specific antigen expression and its effects on inducing tolerogenic regulatory T cells (Treg). Autoimmune ovarian disease (AOD) occurred in B6AF1-AIRE null mice, associated with antibody responses to the oocyte antigen NALP5 (syn. MATER) but not zona pellucida 3 (ZP3). Between postnatal days 1 and 2, numerous ovarian ZP3- primary oocytes undergo apoptosis, providing antigens to maintain tolerance to NALP5. Although ZP3 tolerance is AIRE-independent, transient Treg-depleted adult B6AF1-DEREG mice developed AOD and autoantibody responses to both ZP3 and NALP5. To investigate the origin of ZP3-specific Tregs, we examined the ontogeny of autoantibody responses after Treg depletion. Unlike adult mice, juvenile mice with Treg depletion from postnatal days 5 to 13 developed AOD and produced autoantibodies to NALP5 but not ZP3. In addition, juvenile AOD was Th1-dominant and adult AOD was Th2-dominant. The conversion from Th1 to Th2 was evidenced by the emergence of an IgG1+ ZP3 autoantibody response after Treg depletion on postnatal day 23, nine days after the onset of physiological follicular atresia occurring on postnatal day 14. Follicular atresia accompanies normal estrus in ~80% of growing oocytes, involving granulosa cell apoptosis and removal of dead ZP3+NALP5+ oocytes by antigen presenting cells. We conclude that ZP3-specific Treg development is a late event occurring beyond the neonatal period; and it likely occurs outside the thymus in response to ovarian ZP3 derived from the estrus cycle. Therefore, the ontogeny of tissue autoantigen exposure in an internal organ can regulate the induction of Treg-dependent tolerance to organ-specific antigens.
The transcription factor Ets1 cooperates with IL17 signaling to promote autoimmunity and immunodeficiency.
Authors: Sunshine Alex C , Luo Wei , Sinha Satrajit , Garrett-Sinha Lee Ann
Published: January 2023

Ets1 is a lineage-specific transcription factor that regulates B and T cell functions in development and disease. Mice that lack Ets1 (Ets1 KO) develop spontaneous autoimmune disease with high levels of autoantibodies. Naïve CD4+ T cells isolated from Ets1 KO mice have differentiate more readily to Th17 cells and secrete IL-17, a cytokine extensively implicated in autoimmune disease pathogenesis. To determine if increased IL-17 production contributes to the development of autoimmunity in Ets1 KO mice, we generated Ets1/IL-17 Receptor double knock out (DKO) mice. We found that the absence of IL-17 signaling did not prevent or ameliorate the phenotype of Ets1 KO mice, but rather that DKO animals exhibited worse symptoms with striking increases in the numbers of Th2 cells and Tfh cells as well as germinal center B cells, isotype-switched B cells, memory B cells and plasma cells. Furthermore, DKO mice develop spontaneous skin lesions colonized by Staphylococcus aureus (S. aureus). When DKO mice were experimentally infected with S. aureus they were unable to clear the bacteria. Curiously, the increased bacterial susceptibility was age-dependent as 2 month old DKO mice were not susceptible, whereas 4 month old mice were. Our current model is that excessive immune activation over time leads to production of autoantibodies that target immune effector mechanisms important for anti-bacterial immunity, such as anti-microbial peptides, thereby resulting in susceptibility to S. aureus. Our studies may have important implications in understanding the mechanisms that drive pathogenesis in human diseases characterized by both autoimmunity and immunodeficiency.
Naive T cells are intrinsically biased in helper T cell functions
Authors: Sood Aditi , Rogers Dakota , Mandl Judith N. , Melichar Heather J
Published: January 2023

CD5, a negative regulator of T cell receptor (TCR) signals, is a cell surface protein whose expression reflects the self-reactivity of the TCR for self-peptide. Recent studies have shown that CD5lo versus CD5hi T cells differentially respond to foreign antigen in primary and recall responses and may also have biased differentiation potential. Within the CD4+ T cell lineage, in particular, evidence points to the preferential recruitment of CD5hi CD4+ cells into the memory compartment and biased regulatory T cell development. However, the extent to which CD5 levels influence T cell differentiation and effector cytokine production is unknown. We have expanded upon these findings to show that ex vivo activated murine CD5lo CD4+ T cells produce relatively greater amounts of the Th1 cytokine IFNγ compared to their CD5hi counterparts. Interestingly, this difference is specific to IFNγ production and is not attributable to differential expression of the Th1 cell-specific transcription factor T-bet. Given the distinct metabolic programs associated with these T cell subsets and recent evidence that glycolysis regulates IFNγ production through an epigenetic mechanism, we propose that CD5 levels shape T cell function by direct or indirect regulation of cellular metabolism. Consistent with this, our preliminary data suggests that modulation of cellular acetate levels can restore IFNγ production in CD5hi cells similar to that of CD5lo cells. Our ongoing studies are focused on epigenetic and metabolic profiling of CD5lo and CD5hi cells in order to better understand the observed lineage bias.
Reciprocal regulation of Th17 and Treg cell differentiation by RhoA
Authors: Kalim Khalid Wasim , Yang Jun-Qi , Li Yuan , Zheng Yi , Guo Fukun
Published: January 2023

Th17 cells are important for protective immunity as well as tissue inflammation and autoimmune disorders. Treg cells, including induced Treg (iTreg) and natural Treg (nTreg), play a critical role in immune tolerance. RhoA of the Rho small GTPase family is an intracellular signal transducer that cycles between an inactive GDP-bound form and an active GTP-bound form. We have previously reported that RhoA plays an important role in Th2 cell differentiation by regulating glycolysis. In this study, we further examined the role of RhoA in Th17 and Treg cell differentiation. Genetic deletion of RhoA in T cells or pharmacologic inhibition of RhoA by a RhoA-specific inhibitor Y16 led to reduced Th17 differentiation in vitro as evidenced by reduction of Th17 effector cytokines, transcriptional downregulation of RORγT and reduced phosphorylation of Stat3. Accordingly, RhoA deficiency ameliorated house dust mites (HDM)-induced allergic airway inflammation and dextran sodium sulphate (DSS)-induced colitis in vivo where Th17 cells plays an important role. Inhibition of ROCK, an immediate downstream effector of RhoA, recapitulated the effect of RhoA deficiency or inhibition on Th17 differentiation, suggesting that RhoA regulates Th17 cell differentiation through ROCK. On the other hand, ablation of RhoA had no effect on iTreg cell differentiation. However, inhibition of ROCK enhanced iTreg differentiation, suggesting that ROCK has RhoA-independent role in iTreg differentiation. In contrast to its in-effect on iTreg differentiation, RhoA deficiency increased nTreg differentiation. Thus, our data have provided new insights into Th17 and Treg differentiation and identified RhoA as a potential therapeutic target for tissue inflammation.
Cooperative activities between STAT3 and Ikaros Zinc Finger transcription factors regulate Bcl-6 expression in CD4+ T helper cells
Authors: Powell Michael Duane , Read Kaitlin A. , Baker Chandra E. , Sreekumar Bharath , Martin R. Emily , Cooley Ian D. , Ringel-Scaia Veronica M. , Allen Irving C. , Oestreich Kenneth J
Published: January 2023

CD4+ T cell subtype specialization depends upon unique lineage-defining transcription factors that direct T helper cell development by both activating cell-specific gene expression programs and repressing alternative T helper cell fates. One such example is the transcriptional repressor Bcl-6, required for the development of T follicular helper (TFH) cell populations. Here, we identify the Ikaros zinc finger (IkZF) transcription factors Ikaros and Aiolos as novel regulators of Bcl-6 expression. We find that increased expression of Bcl-6 in T helper cells is associated with enhanced enrichment of Aiolos and Ikaros at the Bcl6 promoter. Additionally, we demonstrate that signal transducer and activator of transcription 3 (STAT3) physically interacts with Aiolos, suggesting a cooperative role for these factors in the activation of Bcl-6 expression. Mechanistically, the association of Ikaros, Aiolos, and STAT3 with the Bcl6 promoter was accompanied by chromatin remodeling events consistent with gene activation including increased histone acetylation. Importantly, expression of Aiolos and Ikaros was elevated in in vivo generated TFH cell populations compared to other IkZF family members. Collectively, these data describe a novel regulatory mechanism wherein STAT3 and the IkZF transcription factors Ikaros and Aiolos cooperate to regulate Bcl-6 expression. Elucidating the complex network of signals and factors that regulate Bcl-6 expression may enhance the potential to design more efficacious vaccines and develop novel immunotherapeutic approaches due to the wide-ranging importance of this transcriptional regulator.
Analysis of autophagy in activated primary human CD4+T cells under hypoxic conditions
Authors: Haug Markus , Ibrahim Hany , Kumahie Kingsley G. , Flo Trude H.
Published: January 2023

T cell mediated immunity is essential in the response to mycobacterial infection. Type 1 CD4+ T helper cells produce effector cytokines such as IFN-γ that contributes to the maintenance of granuloma integrity and reduction of bacterial load by activating macrophages. Activation of CD4+ T cells induces metabolic remodelling in which autophagy in addition to aerobic glycolysis is utilised to generate the energy required for cytokine production. The regulation of autophagy in activated CD4+ T cells present in the hypoxic environment of granuloma is not well understood.

Studying autophagy is most commonly carried out by western blotting and confocal microscopy. We attempted to quantify autophagy using flow-cytometry due to its ability to simultaneously report several cellular parameters combined with high analysis speed and statistical power. By combining a flow-cytometric assay for the detection of autophagosomes with multi-parameter phenotyping of CD4+ T cell subsets we found that autophagy is strongly induced in IFN-γ producing primary human CD4+T cells and correlates with CD25 expression at 48 and 72 h post activation. In addition, surface activation markers, effector cytokine production and autophagy were found to be altered in activated CD4+ T cells under hypoxic conditions. Our findings suggest that autophagy as well as cytokine-production are regulated in activated CD4+ T helper cells under similar hypoxic conditions as found in granuloma structures.
CD160 plays a protective role during chronic infection by enhancing CD8+ T cell functions through T-bet pathway
Authors: zhang linxia , zhang anli , ye lilin , zhang xiaoyan , fu yangxin , xu jianqing
Published: January 2023

It remains controversial on the role of glycosylphosphatidylinositol-anchored molecule CD160 during chronic infection. Here we revealed that CD160 plays a protective role during Clone 13 chronic infection by enhancing CD8+ T functionalities through T-bet pathway. In Clone 13 chronic infection, CD160 knock out mice were remarkably impaired in the capacity of containing viral infection in plasma, spleen, liver as well as in kidney. Upon LCMV specific peptides recall stimulation, CD160+CD8+ T cells were highly poly-functional and proliferative in LCMV chronic infection model. Co-transfer model demonstrated an intrinsic role of CD160 in regulating T cell functionality by sustaining T-bet expression in activated T cells. These data suggest that CD160 represents a potential target for immune intervention during chronic infection.
Differential role of CD28 and CD27 in human CD4 T cells primary and secondary responses to bacterial antigens.
Authors: Garcia Luis F , Valencia Alexis , García Ana M , Santa Luisa F , Zuluaga Carolina , Rojas Mauricio , Marín Nancy D
Published: January 2023

Although CD28 is considered the main T cell costimulatory molecule, CD27 has also costimulatory activity; nevertheless, it is not well established whether they play overlapping or complementary roles during CD4 T cell activation. Both molecules are co-expressed on a large percentage of CD4 T cells, mainly in naive and central memory T cells; but their ligands, CD80/CD86 and CD70 respectively, are differentially expressed on antigen presenting cells.

To further differentiate the costimulatory role of CD28 and CD27 in the human CD4 T cell responses, circulating T cells from healthy donors were stimulated with Mycobacterium tuberculosis Purified Protein Derivative (PPD) under conditions of selective blockade of CD80 and CD86 or CD70 binding. The costimulatory activities of CD28 and CD27 in CD4 T cells memory responses were compared by stimulating PBMC, from tuberculin positive (TST+) donors, with PPD in the presence of either anti-CD80 plus anti-CD86 or anti-CD70 and then measuring CD4 T cells proliferation, IFN-gamma production and CD30 expression by flow cytometry. Treatment with anti-CD80 plus anti-86 inhibited all CD4+ T cell responses, but anti-CD70 had no effect. To study their role in the CD4+ T cell primary responses, myeloid dendritic cells, from TST negative donors, were pulsed with PPD and cocultured with autologous T cells under the blockade conditions described above. Anti-CD80 plus anti-CD86 as well as anti-CD70 inhibited CD4+ T cell proliferation and CD30 expression. These results support that CD28-CD80/CD86 signals are needed for both primary and memory CD4 T cell responses, whereas CD27-CD70 signals are required mainly for the primary anti-PPD responses. (Supported by Colciencias, Colombia, contract 0275-2014).
BAMBI is a negative regulator of humoral immune responses.
Authors: Augustín Juan Jesús , Alvarez Pilar , Tamayo Esther , Iglesias Marcos , Merino Jesús , Merino Ramón
Published: January 2023

BAMBI (Bone Morphogenetic Protein and Activin Membrane Bound Inhibitor) is a plasma membrane-associated negative regulator of TGFβ signaling. Using mice deficient in BAMBI and anti-BAMBI monoclonal antibodies, we have recently demonstrated the contribution of this TGFβ inhibitor to the regulation of CD4 T-cell differentiation into pathogenic TH17 cells and tolerogenic regulatory T cells. In the present study, we explored the possible involvement of BAMBI in the control of humoral immune responses. We demonstrated that BAMBI-KO mice developed increased antibody responses against T-independent antigens. In addition, these mutant mice also exhibited enhanced antibody responses against several T-dependent antigens administered by different routes and even in the absence of adjuvants. Using adoptive CD4 T-cell transfer experiments and double WT/BAMBI-KO bone marrow chimeric mice we showed that in the mutant mice, B cells exhibited intrinsic defects that improved their interaction with antigen-specific activated CD4 T cells and their subsequent activation and differentiation into germinal center B cells and antibody secreting cells. In fact, B cells from BAMBI-KO mice exhibited enhanced proliferative responses in vitro and expressed higher levels of surface molecules involved in CD4:B cell interactions. Finally, we demonstrated here that the enhanced T-dependent antibody responses observed in BAMBI-KO mice were reverted after long-term treatment with an anti-TGFβ monoclonal antibody. In conclusion, our present study described for the first time a negative role of BAMBI in the control of T-independent and Tdependent antibody responses through the regulation of TGFβ signaling.
Increased Th1 cells and enhanced pulmonary fibrosis in macrophage-specific PPARγ KO mice instilled with multiwall carbon nanotubes and ESAT-6 mycobacterial antigen.
Authors: Barrington Robert A , Malur Anagha , Mohan Arjun , Leffler Nancy , Dobbs Larry , Wingard Christopher J , Barna Barbara P , Thomassen Mary Jane
Published: January 2023

In sarcoidosis, a chronic granulomatous disease of unknown etiology, alveolar macrophages are deficient in the nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARγ). Pulmonary fibrosis may accompany sarcoidosis and increase morbidity and mortality. We developed a murine model of granulomatous disease elicited by instillation of multiwall carbon nanotubes (MWCNT) and reported increased granulomas in macrophage-specific PPARγ KO mice compared to wild type mice. Because mycobacterial antigens can associate with sarcoidosis, we hypothesized that both T effector cells and pulmonary fibrosis may be exacerbated by PPARγ deficiency and exposure to Mycobacterial Early Secreted Antigenic Target Protein 6 (ESAT-6). Modified Ashcroft scoring of Trichrome staining indicated increased pulmonary fibrosis in mice receiving MWCNT + ESAT-6 compared to MWCNT alone. No changes occurred with PBS or ESAT-6. Analysis of mediastinal lymph nodes revealed increased frequency and number of Th1 cells with corresponding reductions in Th2 cells in PPARγ KO mice after MWCNT, compared to wild-type controls. Notably, the number of Th1, Th2 and Th17 cells were each increased in PPARγ KO after MWCNT + ESAT-6 compared to after administration of MWCNT alone. Our findings suggest that: (1) PPARγ deficiency exacerbates Th1 activation and pulmonary fibrogenic pathways; and (2) the murine MWCNT model may offer novel insights into fibrotic transformation and possible therapeutic options.
Lung αβ T-cells secrete IL-17A independent of ROR-γt expression and contribute to neutrophil-dependent lung damage during respiratory mycoplasma infection
Authors: Mize Maximillion Tobias , Simecka Jerry
Published: January 2023

How Mycoplasma pneumoniae promotes airway inflammation is not fully understood. Experimental vaccines induce host damage [1]. Airway inflammation, caused by neutrophils and T-cells, is often seen in infants. Children represent 20% of the hospitalized M. pneumoniae cases reported annually in the United States [2]. Secreted by T-cells, IL-17A promotes neutrophil activation. In humans, IL-17A+ T-cells and IL-17A increase during infection with M. pneumoniae [3]. Lung lesions caused by Mycoplasma mycoides are linked to IL-17A in cattle [4]. No reports link IL-17A to neutrophil-mediated host damage. Understanding how IL-17A functions will aid in developing effective vaccines.

We identify that CD3+ T-cells produce IL-17A during murine infection with Mycoplasma pulmonis. T-cells secreting IL-17A exist in the lungs before infection. These cells may contribute to neutrophil recruitment into the respiratory tract after infection. T-cells from the lungs and respiratory lymph nodes produced IL-17A alone, or together with IFN-γ. Expression of ROR-γt was not required for IL-17A production by respiratory αβ T-cells. Neutralizing IL-17A reduced host damage without impacting bacterial burden. Neutrophil-dependent lung lesions were lower in mice receiving αIL-17A antibodies. Depletion of neutrophils was more effective at reducing pathology when compared to IL-17A neutralization. The simultaneous neutralization and depletion of IL-17A and neutrophils failed to further reduce the disease characteristics studied. Neutrophils and IL-17A promote pathogenesis during respiratory mycoplasma disease.

Neutrophil recruitment is not entirely dependent upon IL-17A. Exacerbated pathology may occur if IL-17A directly binds neutrophils.
Genetic Transmission Networks Reveal the Transmission Patterns of HIV-1 CRF01_AE in China
Authors: Li Xiaoshan
Published: January 2023

The epidemic of HIV-1 CRF01_AE has become one of major public health issues in China. We sought to characterize the transmission patterns of networks for this strain nationwide and elucidate possible opportunities for prevention. All available CRF01_AE pol sequences (n = 4, 704) from China in the HIV LANL were isolated and conducted genetic transmission network analysis. A total of 1, 391 (29.6%) sequences were identified as belonging to 400 separate networks. Of men who have sex with men (MSM) in networks, 93.8% were linked to other MSM and only 2.4% were linked to heterosexual women. However, 11.8% heterosexual women in networks were linked to MSM. The lineages mainly composed of MSM had a higher transmission than those major consisted of heterosexuals. Of the 1, 391 individuals in networks, 36.9% (513) were linked to cases diagnosed in different provinces. The proportions of individuals involved in inter-province links by province was interrelated with the number of migrant people (Spearman r =0.738, P =0.001). This study could help improve our ability to understand HIV transmission among various regions and risk groups in China, and highlighted the importance of targeting MSM and migrants by prevention and intervention efforts.
Metformin suppressed human cytomegalovirus (hCMV) replication and its potential molecular mechanisms in human fibroblasts
Authors: Li Huifen , Ning Xiaoxuan , Liu Hans , Chen Yiyin , Ding Xiang , Zhang Haiyan , leng Sean X
Published: January 2023

Background

Chronic hCMV infection may contribute to T-cell immunosenenscence and chronic inflammation, and is shown to be associated with frailty and mortality in old adults. Metformin is a first-line treatment for type 2 diabetes mellitus. Emerging data have shown its additional beneficial effects including cardiovascular protection as well as anti-inflammatory, anti-cancer, and anti-aging activities. The objective of this study was to investigate the effect of metformin on hCMV infection in human fibroblasts and its underlying mechanisms.

Methods

Metformin was added (at concentration of 0, 1mM, 3mM, or 5mM) 2 h before inoculation of hCMV (Towne strain) at multiplicity of infection (MOI) of 0.01 or 0.1 to 80% confluent MRC-5 culture. Cells were cultured for additional 24h to 96 h. Viral plaques were observed under microscope, replication measured by qPCR (primers targeted to hCMV UL123 gene), cell cycle effect determined using flow cytometer, and hCMV protein expression (IE1/IE2, pp28, ICP36) and signaling pathway molecules analyzed by Western blot.

Results and discussion

Metformin at 3mM potently suppressed hCMV viral plaque formation, replication, and protein production. While hCMV infection promoted MRC-5 cells from G2 to M and S phase, metformin treatment led to G0/G1 arrest. Metformin suppressed expression of cyclin D, CDK4, and p21. It had no effect on CK2 or CDk6 expression. While AMPK pathway antagonist compound C suppressed AMPKa phosphorylation from both hCMV and metformin, it did not antagonize suppressive effect of metformin on hCMV protein expression. Taken together, metformin may suppress hCMV infection in MRC-5 cells via cell cycle regulation and molecular mechanisms independent of AMPK pathway.
Non-cytopathic Clearance of a CNS Viral Infection Following Blockade of Type I Interferon Signaling
Authors: Gossa Selamawit , McGavern Dorian B
Published: January 2023

Viral infections that enter the central nervous system (CNS) can drive immune-mediated neurological disorders such as meningitis, encephalitis, and meningoencephalitis. Developing therapeutic interventions to ameliorate these disorders is an important area of clinically relevant research. To gain insights into the immunopathogenesis of CNS viral infection, we study the fatal meningitis induced by lymphocytic choriomeningitis virus (LCMV). We have recently shown that this disease is induced by the pathogenic cooperation between virus-specific CD8+ T cells and innate myelomonocytic cells that damage CNS blood vessels. In addition, genomic studies revealed that the onset of disease is associated with a profound local type I interferon (IFN-I) signature that triggers massive immune extravasation into the meninges. In the present study, we explored approaches to therapeutically treat this disorder. Importantly, we observed that a single injection of a therapeutic antibody directed against the IFN-I receptor (IFNAR) prevented fatal disease as well as the development of symptoms in infected mice. Using a recombinant virus expressing iCre recombinase, we conducted in vivo fate mapping studies in IFNAR blocked fluorescent protein reporter mice. These studies revealed evidence of non-cytopathic viral clearance throughout meninges and glial limitans. Mechanistically, microarray studies uncovered that IFNAR blockade promoted noncytopathic viral clearance through widespread reduction of immune signaling within the CNS without altering the composition of the immune infiltrate. These studies demonstrate that it is possible to mitigate a fatal virus-induced CNS disease via modulation of innate immune signaling pathways.
Early morphine exposure reduced viral burden in the periphery and induced regional difference in brains of LP-BM5 MAIDS model
Authors: Wakley Alexa A , Arabatzis Taxia J , McLane Virginia D , Rau Sanjay , Cao Ling
Published: January 2023

Intravenous opioid use contributes to 11% of HIV infections in the U.S.A. Morphine suppresses the immune system while exacerbating the progression of HIV. To investigate morphine effects on HIV-associated neurocognitive disorders (HAND), we used the LP-BM5 infection murine AIDS (MAIDS) model. Previously, we found that morphine exposure at 7 wks post-infection (p.i.) enhanced cognitive impairment associated with MAIDS, increased hippocampal viral loads, and decreased CCL5 expression in examined brain regions, without affecting peripheral immunodeficiency. Because many HIV+ patients are exposed to opioids before infection, we examined these parameters after exposing the animals to morphine before and immediately after infection. Male mice were implanted with two placebo or 25mg morphine pellets for 6 days, with infection occurring on post-pellet implantation day 3. At 7 wks p.i., cognitive impairment was assessed by the spontaneous alternation T-maze task. At wk 8, blood, spleen and brain regions (hippocampus, striatum and frontal lobe) were harvested. LP-BM5 induced splenomegaly and higher levels of serum IgG2a and IgM, regardless of morphine treatment. Morphine significantly decreased body weight-normalized spleen weight. Morphine did not alter viral BM5Def RNA in spleen or any brain region examined. Morphine appeared to reduce LP-BM5-induced CCL5 expression in the striatum and frontal lobe. LP-BM5 alone appeared to increase the expression of both IFN-α and IFN-β in the frontal lobe only. Infection or morphine exposure did not affect animals’ performance in the T-maze task. Together with our previous results, these results suggest that timing of morphine exposure can alter the modulation and progression of MAIDS and HAND.
IL-22 signaling contributes to modulate the pathogenesis of Zika virus infection
Authors: Yi Panpan , Liang Yuejin , Chen Jinling , Hood Brandon , Azar Sasha , Rossi Shannan , Sun Jiaren
Published: January 2023

The recent outbreaks of Zika virus (ZIKV) in multiple countries are linked to increased risk of neurological disorders and congenital defects. However, host immunity and immune-mediated pathogenesis in ZIKV infection are not well understood. Interleukin-22 (IL-22) is a crucial cytokine for regulating host immunity in infectious diseases. Whether IL-22 plays a role in ZIKV infection is entirely unknown. Here, we infected 3-week-old Ifnar1−/− mice with ZIKV (Cambodian isolate, 1.0×105 pfu/mouse), and found that ZIKV infection resulted in weight loss, paralysis, and mortality at 5 to 6 days post-infection (dpi). This was accompanied by tissue injuries, neutrophil influx, and CD8+ T cell expansion in multiple organs, especially in the brain. The infection significantly up-regulated gene expression of multiple inflammatory cytokines, including IL-6, IL-1β, and TNF-α. Importantly, ZIKV infection elicited a tenfold increase in IL-22 production from non-T cells compared with that of uninfected animals. To investigate the effects of IL-22 on ZIKV infection, we challenged 1-day-old WT and IL-22−/− mice with ZIKV (4.0×103 pfu/mouse). WT mice began to develop weight loss, staggered steps, bilateral hind limb paralysis, weakness at 10 dpi, and ultimately succumbed to the infection on 16–19 dpi. Surprisingly, IL-22 deficiency lessened the weight loss, moderated the systemic inflammatory response, and greatly reduced the incidence of neurological disorders and mortality. In fact, around 90% of the IL-22−/− mice recovered from the insult on the nervous system at 20 dpi. Thus, our data revealed an obvious systemic inflammation in multiple organs induced by ZIKV, and demonstrated a novel role of IL-22 in determining the disease outcome.
Fusion of Fc domain to Factor IX (FIX) modulates the Th2 biased response to FIX and triggers Th1 immunity in hemophilia B treated mice.
Authors: Levin Ditza , Lagasse H.A. Daniel , Burch Erin , Strome Scott , Tan Siyuan , Jiang Haiyan , Sauna Zuben E. , Golding Basil
Published: January 2023

Fusion of the IgG1 constant region domain (Fc) to therapeutic proteins increases the plasma half-life of drugs via binding to the neonatal Fc receptor (FcRn). However, potential interactions with Fc gamma-receptors (FcγR) expressed by immune cells may effect the immunogenicity of these drugs. The coagulation factors VIII (FVIII) and IX (FIX) for the treatment of hemophilia A & B (HA & HB) are the only drugs available with and without Fc fusion and offer an opportunity to experimentally study the effect of Fc fusion. Anti FVIII & FIX antibodies (ADAs) and rare cases of anaphylaxis in HB patients, are serious safety concerns. Using a mouse model for HB, we compared the immune responses to infusions of recombinant human FIX (hFIX) and hFIX fused to mouse IgG2a-Fc (hFIX-mFc). The mFc allowed species-specific Fc-FcγR interactions and prevented immune response to the foreign hFc. Treatment with hFIX-mFc caused earlier onset of anti-FIX IgG and elicited higher FIX-neutralizing antibody levels. Treatment with hFIX triggered Th2 biased immunity i.e., elevated plasma IgE titers, and Th2 cytokine profile of FIX-specific CD4 T cells and a few anaphylactic events. The fusion of Fc altered the response to a Th1 type with increased plasma IFN-γ levels, and IFN-γ secretion by effector CD4 T cells. hFIX-mFc binds to soluble FcγRs and FcγRs on natural killer cells (which also secrete IFNγ) and antigen presenting cells (dendritic cells, and macrophages source of IL-12). We show that Fc fusion enhances the presentation of hFIX to CD4 T cells. We propose that high plasma availability and targeting of APC provide plausible mechanisms by which the Fc fusion may modulate the CD4 T cell response to hFIX towards a Th1 like response, thus avoiding allergic responses.
IL-4 and IL-13 modulate natural killer cell responses under inflammatory conditions
Authors: Ohayon David E , Krishnamurthy Durga , Brusilovsky Michael , Waggoner Stephen N
Published: January 2023

Natural killer (NK) cells are critical producers of IFN-g and mediators of cytotoxicity in response to type 1 inflammatory cytokine (e.g. IL-12) rich environments. Conventional thinking therefore holds that type 2 cytokines (e.g. IL-4 and IL-13) that counter production of IL-12 would inhibit NK cell effector functions and thereby limit the antiviral role of NK cells. In contrast, IL-4 unexpectedly synergized with IL-12 to enhance IFN-g production by mouse NK cells. We now extend this observation to human NK cells, where we find that stimulation with either IL-4 or IL-13 resulted in dose-dependent enhancement of IFN-g and TNF-a expression in response to IL-12. Neither IL-4 nor IL-13 stimulated IFN-g release in the absence of IL-12, suggesting that these type 2 cytokines modulate IL-12 signaling or NK cell responsiveness to IL-12. In contrast to the effect of IL-4 on IL-12 responsiveness, IL-4 (but not IL-13) markedly reduced the expression of IFN-g and TNF-a by human NK cells following engagement of the natural cytotoxicity receptor, NKp46. Likewise, IL-4-treated NK cells demonstrated reduced cytotoxicity towards K562 cells. Our results reveal that IL-4 and IL-13 modulate NK cells in a complex manner, enhancing responsiveness to inflammatory cytokines like IL-12 while diminishing activation via natural cytotoxicity receptors. We speculate that this could have important consequences for NK cell lysis of eosinophils, IFN-g-mediated airway hyperresponsiveness, and other features of allergic or asthmatic diseases associated with aberrant type 2 cytokine production.