Mitigation of endemic GI-tract pathogen-mediated inflammation through development of multimodal treatment regimen and its impact on SIV acquisition in rhesus macaques

Here, we assessed the efficacy of a short-course multimodal therapy (enrofloxacin, azithromycin, fenbendazole, and paromomycin) to eliminate common macaque endemic pathogens (EPs) and evaluated its impact on gastrointestinal (GI) microbiota, mucosal integrity, and local and systemic inflammation in sixteen clinically healthy macaques. Treatment combined with expanded practices resulted in successful maintenance of rhesus macaques (RM) free of common EPs, with no evidence of overt microbiota diversity loss or dysbiosis and instead resulted in a more defined luminal microbiota across study subjects. Creation of a GI pathogen free (GPF) status resulted in improved colonic mucosal barrier function (histologically, reduced colonic MPO+, and reduced pan-bacterial 16s rRNA in the MLN), reduced local and systemic innate and adaptive inflammation with reduction of colonic Mx1 and pSTAT1, decreased intermediate (CD14+CD16+) and non-classical monocytes (CD14-CD16+), reduced populations of peripheral dendritic cells, Ki-67+ and CD38+ CD4+ T cells, Ki-67+IgG+, and Ki-67+IgD+ B cells indicating lower levels of background inflammation in the distal descending colon, draining mesenteric lymph nodes, and systemically in peripheral blood, spleen, and axillary lymph nodes. A more controlled rate of viral acquisition resulted when untreated and treated macaques were challenged by low dose intrarectal SIVmac239x, with an ~100 fold increase in dose required to infect 50% (AID50) of the animals receiving treatment compared to untreated controls. Reduction in and increased consistency of number of transmitted founder variants resulting from challenge seen in the proof of concept study directly correlated with post-treatment GPF animal’s improved barrier function and reduction of key target cell populations (Ki-67+ CD4+T cells) at the site of viral acquisition in the follow up study. These data demonstrate that a therapeutic and operational strategy can successfully eliminate varying background levels of EPs and their associated aberrant immunomodulatory effects within a captive macaque cohort, leading to a more consistent, better defined and reproducible research model.

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The Simian Immunodeficiency Virus Δnef Vaccine, after Application to the Tonsils of Rhesus Macaques, Replicates Primarily within CD4+ T Cells and Elicits a Local Perforin-Positive CD8+ T-Cell Response

Journal of Virology ◽

10.1128/jvi.76.2.688-696.2002 ◽

2002 ◽

Vol 76 (2) ◽

pp. 688-696 ◽

Cited By ~ 17

Author(s):

Christiane Stahl-Hennig ◽

Ralph M. Steinman ◽

Peter Ten Haaft ◽

Klaus Überla ◽

Nicole Stolte ◽

...

Keyword(s):

Cell Cycle ◽

T Cells ◽

Lymph Nodes ◽

Cell Response ◽

Rhesus Macaques ◽

Axillary Lymph Nodes ◽

Axillary Lymph ◽

Ki 67 ◽

Immunodeficiency Virus ◽

Infected Cells

ABSTRACT Deletion of the nef gene from simian immunodeficiency virus (SIV) strain SIVmac239 yields a virus that undergoes attenuated growth in rhesus macaques and offers substantial protection against a subsequent challenge with some SIV wild-type viruses. We used a recently described model to identify sites in which the SIVΔnef vaccine strain replicates and elicits immunity in vivo. A high dose of SIVΔnef was applied to the palatine and lingual tonsils, where it replicated vigorously in this portal of entry at 7 days. Within 2 weeks, the virus had spread and was replicating actively in axillary lymph nodes, primarily in extrafollicular T-cell-rich regions but also in germinal centers. At this time, large numbers of perforin-positive cells, both CD8+ T cells and CD3-negative presumptive natural killer cells, were found in the tonsil and axillary lymph nodes. The number of infected cells and perforin-positive cells then fell. When autopsy studies were carried out at 26 weeks, only 1 to 3 cells hybridized for viral RNA per section of lymphoid tissue. Nevertheless, infected cells were detected chronically in most lymphoid organs, where the titers of infectious virus could exceed by a log or more the titers in blood. Immunocytochemical labeling at the early active stages of infection showed that cells expressing SIVΔnef RNA were CD4+ T lymphocytes. A majority of infected cells were not in the active cell cycle, since 60 to 70% of the RNA-positive cells in tissue sections lacked the Ki-67 cell cycle antigen, and both Ki-67-positive and -negative cells had similar grain counts for viral RNA. Macrophages and dendritic cells, identified with a panel of monoclonal antibodies to these cells, were rarely infected. We conclude that the attenuated growth and protection observed with the SIVΔnef vaccine strain does not require that the virus shift its characteristic site of replication, the CD4+ T lymphocyte. In fact, this immunodeficiency virus can replicate actively in CD4+ T cells prior to being contained by the host, at least in part by a strong killer cell response that is generated acutely in the infected lymph nodes.

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Macrophage Deficiency Makes Intestinal Epithelial Cells Susceptible to NSAID-Induced Damage

BioMed Research International ◽

10.1155/2020/6757495 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Xinxin Wang ◽

Jiayang Wang ◽

Tianyu Xie ◽

Shuo Li ◽

Di Wu ◽

...

Keyword(s):

T Cells ◽

Barrier Function ◽

Molecular Mechanisms ◽

Intestinal Barrier ◽

Mucosal Barrier ◽

Intestinal Barrier Function ◽

Intestinal Epithelial ◽

Epithelial Proliferation ◽

Gm Csf ◽

Mucosal Barrier Function

Objectives. In Crohn’s disease (CD), the mechanisms underlying the regulation by granulocyte-macrophage colony-stimulating factor (GM-CSF) of mucosal barrier function in the ileum are unclear. We analyzed the molecular mechanisms underlying the regulation by GM-CSF of the mucosal barrier function. Methods. We examined the role of GM-CSF in the intestinal barrier function in CD at the molecular-, cellular-, and animal-model levels. Results. Macrophages directly secreted GM-CSF, promoting intestinal epithelial proliferation and inhibiting apoptosis, which maintained intestinal barrier function. Macrophages were absent in NSAID-induced ileitis, causing GM-CSF deficiency, increasing the apoptosis rate, decreasing the proliferation rate, increasing inter- and paracellular permeabilities, decreasing the TJP levels, and reducing the numbers of mesenteric lymph nodes, memory T cells, and regulatory T cells in Csf1op/op transgenic mice. Conclusions. GM-CSF is required for the maintenance of intestinal barrier function. Macrophages directly secrete GM-CSF, promoting intestinal epithelial proliferation and inhibiting apoptosis.

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Maintenance of Barrier Tissue Integrity by Unconventional Lymphocytes

Frontiers in Immunology ◽

10.3389/fimmu.2021.670471 ◽

2021 ◽

Vol 12 ◽

Author(s):

Joshua R. Cox ◽

Sheena M. Cruickshank ◽

Amy E. Saunders

Keyword(s):

T Cells ◽

Growth Factors ◽

Barrier Function ◽

Tissue Repair ◽

Γδ T Cells ◽

Limited Range ◽

Lymphoid Cells ◽

Mucosal Barrier ◽

Physical Trauma ◽

Mucosal Barrier Function

Mucosal surfaces, as a first barrier with the environment are especially susceptible to damage from both pathogens and physical trauma. Thus, these sites require tightly regulated repair programs to maintain barrier function in the face of such insults. Barrier sites are also enriched for unconventional lymphocytes, which lack rearranged antigen receptors or express only a limited range of such receptors, such as ILCs (Innate Lymphoid Cells), γδ T Cells and MAIT (Mucosal-Associated Invariant T Cells). Recent studies have uncovered critical roles for unconventional lymphocytes in regulating mucosal barrier function, and, in particular, have highlighted their important involvement in barrier repair. The production of growth factors such as amphiregulin by ILC2, and fibroblast growth factors by γδ T cells have been shown to promote tissue repair at multiple barrier sites. Additionally, MAIT cells have been shown to exhibit pro-repair phenotypes and demonstrate microbiota-dependent promotion of murine skin healing. In this review we will discuss how immune responses at mucosal sites are controlled by unconventional lymphocytes and the ways in which these cells promote tissue repair to maintain barrier integrity in the skin, gut and lungs.

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Faculty Opinions recommendation of Depletion of CD4⁺ T cells abrogates post-peak decline of viremia in SIV-infected rhesus macaques.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13730959.15147060 ◽

2012 ◽

Author(s):

Scott Sieg ◽

Nicholas Funderburg

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Rhesus Macaques

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Probiotic supplementation reduces inflammatory profiles but does not prevent oral immune perturbations during SIV infection

Scientific Reports ◽

10.1038/s41598-021-93918-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Rhianna Jones ◽

Kyle Kroll ◽

Courtney Broedlow ◽

Luca Schifanella ◽

Scott Smith ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Rhesus Macaques ◽

Oral Microbiome ◽

Probiotic Supplementation ◽

Siv Infection ◽

Anti Inflammatory

AbstractHIV/SIV infections lead to massive loss of mucosal CD4 + T cells and breakdown of the epithelial mucosa resulting in severe microbial dysbiosis and chronic immune activation that ultimately drive disease progression. Moreover, disruption of one of the most understudied mucosal environments, the oral cavity, during HIV-induced immunosuppression results in significant microbial and neoplastic co-morbidities and contributes to and predicts distal disease complications. In this study we evaluated the effects of oral probiotic supplementation (PBX), which can stimulate and augment inflammatory or anti-inflammatory pathways, on early SIV infection of rhesus macaques. Our study revealed that similar to the GI mucosae, oral CD4 + T cells were rapidly depleted, and as one of the first comprehensive analyses of the oral microflora in SIV infection, we also observed significant modulation among two genera, Porphyromonas and Actinobacillus, early after infection. Interestingly, although PBX therapy did not substantially protect against oral dysbiosis or ameliorate cell loss, it did somewhat dampen inflammation and T cell activation. Collectively, these data provide one of the most comprehensive evaluations of SIV-induced changes in oral microbiome and CD4 + T cell populations, and also suggest that oral PBX may have some anti-inflammatory properties in lentivirus infections.

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Sodium Alginate Modulates Immunity, Intestinal Mucosal Barrier Function, and Gut Microbiota in Cyclophosphamide-Induced Immunosuppressed BALB/c Mice

Journal of Agricultural and Food Chemistry ◽

10.1021/acs.jafc.1c02294 ◽

2021 ◽

Author(s):

Juan Huang ◽

Jinli Huang ◽

Yao Li ◽

Yilu Wang ◽

Fahe Wang ◽

...

Keyword(s):

Gut Microbiota ◽

Sodium Alginate ◽

Barrier Function ◽

Mucosal Barrier ◽

Intestinal Mucosal Barrier ◽

Mucosal Barrier Function

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CD73+ CD127high Long-Term Memory CD4 T Cells Are Highly Proliferative in Response to Recall Antigens and Are Early Targets in HIV-1 Infection

International Journal of Molecular Sciences ◽

10.3390/ijms22020912 ◽

2021 ◽

Vol 22 (2) ◽

pp. 912

Author(s):

Nabila Seddiki ◽

John Zaunders ◽

Chan Phetsouphanh ◽

Vedran Brezar ◽

Yin Xu ◽

...

Keyword(s):

T Cells ◽

Peripheral Blood ◽

Cd4 T Cells ◽

Significant Proportion ◽

Long Term Memory ◽

Ki 67 ◽

Memory Cd4 T Cells ◽

Hiv 1

HIV-1 infection rapidly leads to a loss of the proliferative response of memory CD4+ T lymphocytes, when cultured with recall antigens. We report here that CD73 expression defines a subset of resting memory CD4+ T cells in peripheral blood, which highly express the α-chain of the IL-7 receptor (CD127), but not CD38 or Ki-67, yet are highly proliferative in response to mitogen and recall antigens, and to IL-7, in vitro. These cells also preferentially express CCR5 and produce IL-2. We reasoned that CD73+ memory CD4+ T cells decrease very early in HIV-1 infection. Indeed, CD73+ memory CD4+ T cells comprised a median of 7.5% (interquartile range: 4.5–10.4%) of CD4+ T cells in peripheral blood from healthy adults, but were decreased in primary HIV-1 infection to a median of 3.7% (IQR: 2.6–6.4%; p = 0.002); and in chronic HIV-1 infection to 1.9% (IQR: 1.1–3%; p < 0.0001), and were not restored by antiretroviral therapy. Moreover, we found that a significant proportion of CD73+ memory CD4+ T cells were skewed to a gut-homing phenotype, expressing integrins α4 and β7, CXCR3, CCR6, CD161 and CD26. Accordingly, 20% of CD4+ T cells present in gut biopsies were CD73+. In HIV+ subjects, purified CD73+ resting memory CD4+ T cells in PBMC were infected with HIV-1 DNA, determined by real-time PCR, to the same level as for purified CD73-negative CD4+ T cells, both in untreated and treated subjects. Therefore, the proliferative CD73+ subset of memory CD4+ T cells is disproportionately reduced in HIV-1 infection, but, unexpectedly, their IL-7 dependent long-term resting phenotype suggests that residual infected cells in this subset may contribute significantly to the very long-lived HIV proviral DNA reservoir in treated subjects.

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