bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD4 T cell-mediated immunopathology of a Staphylococcus aureus whole cell vaccine during systemic infection
Authors: Karauzum Hatice , Haudenschild Christian , Mahmoudieh Mahta , Moore Ian N. , Datta Sandip K. 
Published: January 2023

Abstract
Staphylococcus aureus causes a wide array of diseases, ranging from superficial skin infections to life threatening diseases like sepsis. Treatment is difficult due to emerging multidrug-resistant strains and importantly, several approaches to develop an efficacious vaccine have either failed or augmented disease in clinical trials. In the present study, gamma-irradiated S. aureus USA300 (IRS) was used as a whole-cell vaccine to evaluate the immune response towards vaccination and subsequent infection. C57BL/6 mice were vaccinated thrice intramuscularly, adjuvanted with or without Al(OH)3, at two-week intervals and challenged with USA300 intravenously 2 weeks after the last vaccination. Vaccination enhanced mortality and failed to control bacterial growth in blood and organs when compared to PBS controls and was worse without Al(OH)3. USA300-specific antibodies were induced by vaccination but did not cause enhanced mortality when tested in serum transfer studies. Furthermore, B cell deficient and WT mice were similarly susceptible to infection after vaccination. Infection increased frequency of CD44hiTbet+ and CD44hiIFNg+ (Th1 effector) cells in spleens of both vaccinated groups but was higher in mice vaccinated without Al(OH)3. Frequency of CD44hiRORgt+ and CD44hiIL-17+ (Th17 effector) cells increased only in groups vaccinated with Al(OH)3. Depletion of CD4 T cells during infection reversed the lethal phenotype. Similarly, neutralization of IFNg but not IL-17 during infection improved survival and reduced organ pathology. Taken together, our findings show a detrimental role for IFNg+CD4 Teff cells generated by vaccination with IRS, and might shed some light on recent vaccine failures.
ICOS+CD38+ cTfh in peripheral blood and thoracic duct lymph.
Authors: Vella Laura A , Buggert Marcus , Herati Ramin S , Itkin Maxim , Dori Yoav , Betts Michael R , Wherry E. John 
Published: January 2023

Abstract
T follicular helper cells provide essential B cell help within the germinal center (GC), and these cells have been shown to populate the follicular mantel once the GC reaction is complete. The significance and ontology of circulating Tfh (cTfh) is less clear. Studies in humans have suggested subsets of cTfh that correlate with humoral responses in chronic infection (HIV, malaria) and in response to acute challenge (influenza vaccination). We have previously described a subset of CXCR5+PD1+ cTfh that expresses both ICOS and CD38. This population was significantly increased 7 days after influenza vaccination as well as in patients infected with HIV. Single cell transcriptional analysis of the ICOS+CD38+ cTfh after influenza vaccination demonstrated more frequent expression of the GC Tfh transcripts CMAF, BCL6, and CD200 than was found in the ICOS−CD38− cTfh, and bulk transcriptional analysis indicated higher expression of IL-21. These data suggested that ICOS and CD38 mark the rare population of cTfh that are more recent émigrés from the lymph nodes. To evaluate this possibility, we analyzed Tfh in an immune compartment that is more proximal to the lymph nodes than peripheral blood: thoracic duct lymph (TDL). As expected, TDL Tfh had a higher frequency of ICOS+CD38+ cells than cTfh in matched peripheral blood. In addition, TDL had a population of CXCR5+PD1bright Tfh, previously only identified in lymphoid tissues. CXCR5+PD1bright Tfh in the TDL had a significantly increased frequency of ICOS+CD38+ cells. These data provide a critical missing link in the understanding of cTfh and suggest that the ICOS+CD38+ cTfh subset warrants further exploration as peripheral surrogates of the active immune responses within secondary lymphoid tissues.
BscF from Bordetella pertussis provides advantageous adjuvant activity when paired with the acellular pertussis vaccine: enhanced Th1/Th17 pertussis-specific immune response
Authors: Alvine Travis D , Knopick Peter L , Kumar Meera Ajeet , Nilles Matthew L , Bradley David S 
Published: January 2023

Abstract
Incidence of pertussis, a severe respiratory disease caused by Bordetella pertussis, have been on the rise. This resurgence has been linked to antigenic divergence in circulating pertussis strains as well as waning or ineffective immunity induced by the current acellular pertussis (aP) vaccine. The current aP vaccine replaced a whole cell pertussis (wP) vaccine in the 1990s due to adverse events associated with the wP vaccine. Alum-absorbed aP vaccine has been shown to elicit a strong antibody response and considerable Th2 type CD4+ T cells. In contrast, wP vaccine promotes Th1/Th17 type cellular immunity and associated opsonizing antibodies presumably via its PAMPs. We have previously demonstrated that BscF, a B. pertussis needle protein, acts as a strong TLR agonist. Here we characterized the contribution of BscF to a laboratory prepared aP vaccine-induced response. aP + BscF resulted in statistically greater pertussis-specific antibody titers, compared to sham aP + PBS. BscF enhanced long-term aP-specific immunity, compared to either the alum or sham controls, as measured by increased numbers of central memory T cells. Moreover, the addition of BscF resulted in skewing the pertussis-specific immunity toward Th1 and Th17 responses, compared to the addition of alum or PBS which skewed pertussis-specific immunity away from Th1/Th17 responses. Mice immunized with aP + BscF demonstrated significantly reduced bacterial burden in their lungs 5 dpi. These findings suggest that BscF induced a strong Th1 and Th17 anti-pertussis response, potentially may provide protective BscF-specific immunity, and could be a novel additional component in the next generation aP vaccine.
Pathogenic chikungunya virus evades B cell responses to establish persistence
Authors: Morrison Thomas , Fox Julie M. , Ashbrook Alison W. , May Nick A. , Schroeder Kristin M. , Torres Raul M , Dermody Terence S. , Diamond Michael S , Hawman David W. 
Published: January 2023

Abstract
Chikungunya virus (CHIKV) causes large outbreaks of acute and chronic musculoskeletal disease. To investigate mechanisms of CHIKV clearance and persistence, we performed studies in mice with an attenuated CHIKV strain (181/25) and its pathogenic parent strain (AF15561). Whereas AF15561 infection of WT mice resulted in viral persistence in joint-associated tissue, 181/25 was cleared within 4 weeks. In contrast to WT mice, 181/25 infection of Rag1−/−mice resulted in viral persistence in joint tissue at levels similar to that detected in AF15561-infected Rag1−/− mice, suggesting an important role for adaptive immunity in the clearance of 181/25 infection. Indeed, 181/25 infection of B cell-deficient μMT mice or B cell receptor transgenic mice that cannot produce virus-specific antibody resulted in viral persistence that was equivalent to AF15561-infected WT and immunodeficient mice. In WT mice, 181/25 infection resulted in a higher quality neutralizing antibody response at early times post-infection. In addition, detailed mapping studies demonstrated that the amino acid at position 82 in the A domain of the E2 glycoprotein influenced clearance and serum neutralization of CHIKV. Neutralization assays revealed that inhibition of AF15561 by monoclonal antibodies specifically targeting E2 domain B was impaired relative to that observed with 181/25. Collectively, our data suggest that virus-specific antibody responses contribute to the clearance of 181/25 infection and that AF15561 evades this response by minimizing the impact of B domain neutralizing antibodies to establish persistent infection.
Regulatory CD4+ T cells differentially modulate HIV-1 infection of polarized M1 and M2 macrophages
Authors: Robinson Tanya O , Zhang Mingce , Cron Randy 
Published: January 2023

Abstract
Macrophages are HIV-1 targets but relatively resistant to HIV-1 cytotoxicity. Effector macrophages can be functionally polarized into M1 (pro-inflammatory) and M2 (anti-inflammatory) phenotypes. M1 monocyte-derived macrophages (MDM) suppress CCR5 (R5) HIV-1 replication, while M2 MDM promote it. While CD4 regulatory T cells (Tregs) inhibit HIV-1 infection of primary CD4 T cells in co-culture, their effect on MDM infection is unknown. We generated M1 (GM-CSF+IFNγ+LPS) and M2 (M-CSF+IL-4) MDM with predicted phenotypes and infected them with R5 HIV-1BAL reporter viruses. M2 MDM had notably higher infection than M1 MDM. To explore acute stages of infection, we infected M1 and M2 MDM with 3 different R5 HIV-1 transmitted founder (T/F) viruses. Similarly, M2 MDM had higher levels of T/F HIV-1 infection than M1 MDM but lower compared to HIV-1BAL. To investigate the role of Tregs on HIV-1 infection of MDM, we co-cultured Tregs with HIV-1 infected MDM. Treg co-cultures yielded decreased HIV-1 infection of M1 but increased infection of M2 MDM. Surprisingly, Tregs mediate divergent effects on HIV-1 infection of M1 and M2 MDM. A transwell system was used to explore if Treg effects on HIV-1 infection of MDM were cell contact and/or cytokine dependent. Similar to co-culture, Tregs (compared to effector T cells) in the transwell system with HIV-1 infected polarized MDM led to decreased HIV-1 infection of M1 but increased infection of M2 MDM. However, the level of infection was significantly lower in the transwell system compared to co-culture, suggesting optimal Treg mediated effects require cell-contact. We are currently studying the roles of CTLA-4, IL-10, and TGFβ in Treg suppressive activity on HIV-1 infection of MDM to explore the mechanism.
BCG-vaccination in SIV-infected infant macaques is associated with enhanced B cell, myeloid dendritic cell and CD4+ T cell activation.
Authors: Wood Matthew P , Wood Lianna , Sodora Donald L. 
Published: January 2023

Abstract
Active tuberculosis infection is the leading cause of death for people living with HIV. HIV+ infants in resource poor settings are exposed to tuberculosis and the vaccine M. bovis BCG, which can become disseminated in immune-compromised hosts. How BCG impacts the HIV infected immune system is poorly understood. Here, we used the SIV-macaque model to evaluate BCG vaccination in infant Rhesus macaques infected with SIV (N=7) or uninfected controls (N=5). Blood was obtained from macaques (0–10 months of age) that were either SIV-infected or uninfected, and assessed at multiple timepoints following intradermal vaccination with BCG (Danish strain). The frequency of CCR5+ CD4+ T cells significantly increased following BCG, with a greater difference observed in SIV+ (33.9 fold change compared to pre-BCG vaccination) compared to uninfected (2.7 fold) infants. Markers of activation were assessed within the B cells (CD20), monocytes (CD14), mDCs (CD11c), and pDCs (CD123). We observed an increase in the costimulatory molecule CD86 in both SIV-infected and uninfected macaques following BCG vaccination, with higher overall levels observed SIV+ infants. These elevated levels of CD86+ cells were observed for both B cells (1.4% uninfected and 4% in SIV+) and mDCs (4.1% uninfected and 16.1% SIV+) after BCG vaccination, which is in part a reflection of higher baseline immune activation in the SIV+ infants. These studies identify changes associated with BCG vaccination in SIV+ infant macaques, which include an increase in potential SIV target cells (CCR5+/CD4+) and elevated activation of B cells and mDCs in the blood. Studies are now underway to evaluate these findings in tissues from these infants.
Antisense transcript derived HIV-1 cryptic epitopes are recognized by T cells during chronic infection.
Authors: Peng Binghao J , Carlson Johnathan M , Hunter Eric , Bansal Anju , Goepfert Paul A 
Published: January 2023

Abstract
Alternative reading frames (ARF) of HIV, both sense and antisense directions, have shown to produce polypeptides of unknown functions. Although the roles of these polypeptides are unclear, they can still potentially act as HIV derived antigens, eliciting host T cell responses. These ARF derived epitopes, known as cryptic epitopes (CE), occur commonly in HIV, SIV, and other retroviruses through ribosomal frame-shifting, internal ribosomal entry sites, and alternative start codon initiation.
We hypothesize that T cell responses to CE are capable of driving viral escape mutations at a population level. In order to identify CE of HIV capable of driving viral escape, sequence changes in gag, pol, and nef of HIV were identified during acute infection in a cohort of Zambian serodiscordant couples. HLA-I associated polymorphisms in ARF can thus be identified, predicting potentially immunogenic CE. Several CE were identified as a result (N=66), in which the majority appears to have been derived from antisense ARF. These CE were used to stimulate cryopreserved PBMC samples from HIV-1 patients in the chronic stage of infection.
We found 8/32 patients responded to at least one predicted CE as shown by IFNγ ELISpot. Interestingly, all 10 immunogenic CEs found in this study were derived from a single antisense reading frame in the pol coding region. Furthermore, these CE were not only capable of eliciting CD8, but also CD4 responses. When examining alternative start codons in each reading frame, we found an enrichment of CUG in the antisense frame containing the immunogenic CE. Together, our results show HIV antisense CE can be targeted by T cells and may therefore have implications for T-cell vaccines.
Omega-3 rich diet alters T cell affinity and decreases anti-viral immunity
Authors: Kolawole Elizabeth Motunrayo , Evavold Brian D 
Published: January 2023

Abstract
There has been much investigation into the influence of dietary fatty acids with regard to modulation of immune function. Omega-3 polyunsaturated fatty acids have been shown to exert beneficial anti-inflammatory effects for both chronic and acute inflammatory disease. Acute viral infection can be controlled and eliminated with an effective CD8 response. Despite studies suggesting the incorporation of omega-3 fatty acids into lipid membranes leading to the production of less inflammatory metabolites, little is known about T cell engagement with peptide-MHC (pMHC) antigen and whether omega-3 fatty acids modulate T cell responses. Here using the novel two dimensional (2D) micropipette adhesion frequency assay we determine T cell frequency and affinity for antigen on a single cell basis. Our data indicates that dietary fish oil reduces antigen affinity in T cell receptor transgenic cells. Moreover, we demonstrate decreased polyclonal numbers of antigen specific (gp-33) T cells at peak anti viral immunity to lymphocytic choriomeningitis (LCMV) infection. These data indicate that omega-3 fatty acids decrease antigen recognition to viral antigens.
Increasing strength of antigenic stimulation negatively impacts memory CD8 T cell formation and function during persistent viral infection
Authors: Maru Saumya , Haley Jeremy S , Schell Todd D , Lukacher Aron 
Published: January 2023

Abstract
Memory CD8 T cells are critical for keeping persistent viral infections in check. Here, we used a novel approach to directly study the impact of T cell stimulation strength on memory T cell differentiation in the setting of a persistent viral infection. Using site-directed mutagenesis, we generated a series of MPyV variants with substitutions in a subdominant Db-restricted epitope that modulated level of activation of TCR transgenic CD8 T cells specific for a corresponding epitope in SV40 Large T Antigen. By altering a subdominant epitope constituting approximately 1% of the total anti-MPyV CD8 T cell response, we avoided perturbing MPyV-associated inflammation, virus infection levels, antiviral CD4 T cell responses, and the dominant anti-MPyV CD8 T cell response. Moreover, by using physiologic numbers of naïve donor monoclonal CD8 T cells for adoptive transfer into immunocompetent C57BL/6 recipients, we also controlled for variability in naïve T cell precursor frequency and TCR affinity inherent in T cell recruitment to infection. Our data demonstrate an inverse relationship between antigenic stimulation strength and expression of memory precursor effector phenotype (CD127highKLRG1low) by virus-specific CD8 T cells during acute infection. Although stronger antigenic stimulation augmented expansion of functional CD8 T cells in acute infection, lower stimulation favored functional competence of memory antiviral CD8 T cells during persistent infection. Together, these data provide clear in vivo evidence that the strength of antigenic stimulation during recruitment of MPyV-specific CD8 T cells dictates the functional integrity of memory T cells during persistent infection.
Acute virus-specific responses by NK cells shape CD8+ memory T cells and protective immunity
Authors: Teoh Jeffrey , Gamache Awndre , Bullock Timothy N , Brown Michael G 
Published: January 2023

Abstract
NK cells are cytotoxic to CD8+ T cell effectors following certain viral infections, such that transient NK depletion can increase T cell effector activities. Previous studies have shown that licensed Ly49G2+ (G2) NK cells confer MCMV resistance in mice expressing MHC I Dk, a specific ligand of the inhibitory G2 receptor, which resulted in enhanced adaptive immunity due to accelerated accumulation of virus-specific CD8+ T cells. However, the longer-term impact of licensed NK-mediated virus resistance on adaptive T cell immunity was not previously investigated. Hence, we examined CD8+ T cells for KLRG1, CD127, CD62L and cytokine production at discrete times post-infection. Early on (6-10d), licensed G2+ NK-mediated resistance in Dk mice led to a profound skewing of CD8+ T cells from short-lived effectors (SLEC) into memory precursor effector cells (MPEC). By comparison, mice without Dk-licensed G2+ NK cells were biased towards SLECs throughout 10d, and upon contraction. This T cell differentiation effect endured through 21-56d postinfection such that the frequencies of memory and effector cells reflected differences observed for the strains at d10. We then transferred CD8+ T cells from latently MCMV-infected mice into naïve, G2+ NK cell-depleted hosts and challenged them with high dose MCMV. Remarkably, recipients of CD8+ T cells primed in the presence of licensed G2+ NK cells exhibited significantly lower viral titers than those that received CD8+ T cells primed in non-Dk mice. We infer that licensed NK-mediated viral resistance significantly boosted the formation of memory CD8+ T cells, and that the means of early NK cell activation and virus resistance shapes adaptive immunity.
Overcoming CD4 T helper cell fate restrictions to enhance CD8 T cell and B cell immunity to control persistent LCMV infection
Authors: Snell Laura M , Osokine Ivan , Yamada Douglas H , Elsaesser Heidi , Brooks David G 
Published: January 2023

Abstract
Persistent viral infection inhibits CD4 Th1 responses, resulting in loss of the CD8 T cell helping Th1 subset and accumulation of B cell helping Tfh cells. Yet, the mechanisms that inhibit CD4 Th1 differentiation and the repercussions of loss of Th1 cells on viral control are unclear. Herein, we demonstrate that the dual upregulation of PD-L1 and IL-10 by chronic type I interferon (IFN-I) signaling during persistent infection suppresses CD4 Th1 priming. Therapeutic blockade of IL-10R and PD-L1 could restore the differentiation of new CD4 Th1 cells, highlighting a new function for PD-L1 to co-inhibit CD4 Th1 priming and identifying a new combinatorial suppressive mechanism during persistent infection. However, CD4 Th1 cells generated by blocking IFN-I signaling in vivo could not be sustained, giving way to a Tfh based response and predominant help to B cells. In vitro polarized virus-specific CD4 Th1 cells also converted towards Tfh cells, however maintained a population of Th1 cells that could enhance exhausted CD8 T cell responses and promote augmented viral clearance. Interestingly, virus-specific CD4 Th17 and Treg cells were also redirected towards Tfh as persistent infection progressed. Thus, our studies have important implications for stability of de novo activated and immunotherapeutic T cells and demonstrate that the redirection away from Th1 responses is a mechanism of immunosuppression to limit the control of persistent viral infection.
IL-1-induced Bhlhe40 identifies pathogenic TH cells in a model of autoimmune neuroinflammation
Authors: Lin Chih-Chung , Bradstreet Tara R , Schwarzkopf Elizabeth A , Jarjour Nicholas N , Chou Chun Jim , Archambault Angela S , Sim Julia , Zinselmeyer Bernd H , Carrero Javier , Wu Gregory F , Taneja Reshma , Artyomov Maxim , Russell John H , Edelson Brian T 
Published: January 2023

Abstract
The features that define autoreactive TH cell pathogenicity remain obscure. We have previously shown that TH cells require the transcription factor Bhlhe40 to mediate experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Here, using Bhlhe40-EGFP reporter mice and analyzing both polyclonal and TCR transgenic CD4+ T cells, we found that Bhlhe40 expression was heterogeneous after EAE induction. Bhlhe40-expressing CD4+ T cells displayed marked production of IFN-γ, IL-17A, and GM-CSF, while exhibiting reduced expression of the anti-inflammatory cytokine IL-10 and the regulatory T cell transcription factor Foxp3. In adoptive transfer EAE models Bhlhe40-deficient TH1 and TH17 cells were both nonencephalitogenic. Pertussis toxin (PTX), a classical coadjuvant for actively induced EAE, promoted IL-1β production by myeloid cells in the draining lymph node and served as a strong stimulus for Bhlhe40 expression in TH cells. Furthermore, PTX coadjuvanticity was Bhlhe40 dependent. IL-1β induced Bhlhe40 expression in polarized TH17 cells, and Bhlhe40-expressing cells exhibited an encephalitogenic transcriptional signature. In vivo, IL-1R signaling was required for full Bhlhe40 expression by TH cells after immunization. Overall, we demonstrate that Bhlhe40 expression identifies encephalitogenic TH cells and define a PTX-IL-1-Bhlhe40 pathway active in EAE.
Absence of dual TCR T cells protects NOD mice from diabetes due to an increased insulin-specific Treg:Teff ratio
Authors: Schuldt Nathan J , Spanier Justin A , Auger Jennifer L , Hogquist Kristin A , Fife Brian T , Binstadt Bryce Anthony 
Published: January 2023

Abstract
Due to allelic exclusion, most αβ T cells express only a single αβ TCR specificity. However, around 10% of human and mouse T cells express two different α chains with the potential for dual specificities. Dual β-expressing T cells also exist and account for ~1% of all T cells. Expression of two different TCR specificities by a single T cell is one hypothesized mechanism by which self-reactive TCRs escape central tolerance to initiate autoimmunity. While peripheral tolerance mechanisms typically control any self-reactive T cells in healthy animals, these mechanisms are hypo-functional in NOD mice. We hypothesized that eliminating dual TCR T cells would protect NOD mice from diabetes. To test this hypothesis we generated NOD mice hemizygous at both the TCRα and β loci (TCRα+/−β+/−). Indeed, we found that NOD mice incapable of generating dual TCR T cells were protected from diabetes with both lower diabetes incidence than wildtype (WT) NOD mice (0% versus 70% at 30 weeks of age) and also lower insulitis scores at 10 weeks of age. Examination of the insulin-specific T cell population in the pancreas-draining lymph node revealed a lower Treg:Teff ratio in WT NOD mice compared to single TCR T cell NOD mice. Anti-PD-1 treatment resulted in the rapid development of diabetes in 100% of WT NOD mice but in only 30% of single TCR T cell mice, suggesting that the diabetes resistance phenotype of single TCR T cell mice is not primarily due to increased anergy. These data support the hypothesis that the presence of dual TCR T cells increases the risk of diabetes in NOD mice by altering the insulin-specific Treg:Teff ratio.