Anna-Lena Spetz - Academia.edu (original) (raw)

Papers by Anna-Lena Spetz

Amelioration of Mas-related G protein-coupled receptor X2-mediated itch and reduced mast cell deg... more Amelioration of Mas-related G protein-coupled receptor X2-mediated itch and reduced mast cell degranulation by a single-stranded oligonucleotide

Drug Resistance Updates, May 1, 2023

Infectious Diseases and Therapy, Apr 7, 2022

Introduction: The availability of new classes of antiretroviral drugs is critical for treatment-e... more Introduction: The availability of new classes of antiretroviral drugs is critical for treatment-experienced patients due to drug resistance to and unwanted side effects from current drugs. Our aim was therefore to evaluate the anti-HIV-1 activity of a new set of antivirals, dipeptides (WG-am or VQ-am) combined with a singlestranded oligonucleotide (ssON). The dipeptides were identified as naturally occurring and enriched in feces and systemic circulation in HIV-1-infected elite controllers and were proposed to act as entry inhibitors by binding to HIV-1 gp120. The ssON is DNA 35-mer, stabilized by phosphorothioate modifications, which acts on the endocytic step by binding to cell host receptors and inhibiting viruses through interference with binding to nucleolin. Methods: Chou-Talalay's Combination Index method for quantifying synergism was used to evaluate the drug combinations. Patientderived chimeric viruses encoding the gp120 (env region) were produced by transient transfection and used to evaluate the antiviral profile of the combinations by drug susceptibility assays. Results: We found that the combination WGam:ssON or VQ-am:ssON had low combination index values, suggesting strong antiviral synergism. Of the two combinations, WG-am:ssON (1 mM:1 lM) had high efficacy against all prototype or patient-derived HIV-1 isolates tested, independent of subtype including the HIV-1-A6 sub-subtype. In addition, the antiviral effect was independent of co-receptor usage in patientderived strains. Conclusion: WG-am and ssON alone significantly inhibited HIV-1 replication regardless of viral subtype and co-receptor usage, and the combination WG-am:ssON (1 mM:1 lM) was even more effective due to synergism.

International Journal of Molecular Sciences, May 26, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Gastroenterology, Apr 1, 2000

BACKGROUND: HIV preferentially infects activated, memory CD4+ lymphocytes expressing requisite co... more BACKGROUND: HIV preferentially infects activated, memory CD4+ lymphocytes expressing requisite co-receptors. The gut mucosa is the body s largest immune organ, which in the healthy, normal condition is characterised by low-level inflammation and constitutive expression of chemokines and cytokines. The gut contains the body s largest number of activated, memory T cells, which express high levels of CCR5 and CXCR4 A. Inflammation with chemotactic chemokines recruiting additional activated immune cells, would potentially further increase infectible targets for HIV spread. METHODS: Colon biopsies from 6 HIV-infected individuals, 8 Inflammatory Bowel Disease (IBD) patients and 5 seronegative, healthy controls without organic bowel disease were compared. All but one HIV infected was on HAART. Plasma viral load was undetectable in three patients and differed between 4.4 5.7 logs in three patients. IBD patients included 5 with active disease, 3 in remission. Samples were immunohistochemically stained with monoclonal antibodies against CCR5, CXCR4, RANTES, MlP-l a and MIP-l f3 with expression evaluated at the single cell level by computerized in situ imaging. RESULTS: The expression of chemokine receptors CCR5 and CXCR4 was significantly increased in HIV-infected mucosal sections compared to both IBD in remission (IBDr) and seronegative controls (p<0.05). Sections from patients with active IBD showed a similar pattern of increased chemokine receptor expression. f3-chemokines including RANTES and MIPlf3, were significantly upregulated in HIV compared to IBDr and healthy controls (p<0.05). In active IBD there was increased expression of RANTES, compared to IBDr (p<O.OI). The chemokine MIP-l a was expressed at low levels in all samples. CONCLUSIONS: HIV is characterized by a significant degree of mucosal inflammation. Our findings show that the levels of chemokines and chemokine receptors in HIV are similar to those levels seen in active IBD and are significantly higher than those from IBDr and healthy controls. This suggests that the inflammatory response in HIV is at least as potent as in IBD. Topical anti-inflammatories lead to remission and reduction in soluble and cellular markers of inflammation in IBD. Given the presence of marked inflammation, further investigation of the role of adjunctive treatment of HIV-patients with local anti-inflammatory drugs targeting the host immune response, deserves attention.

International Journal of Molecular Sciences, Nov 23, 2022

Journal of Cell Science, Jul 15, 2003

Journal of Immunology, Aug 1, 2007

Dendritic cells (DCs) can be activated by signaling via pathogen receptors, by interaction with a... more Dendritic cells (DCs) can be activated by signaling via pathogen receptors, by interaction with activated T cells or by exposure to inflammatory mediators. Clearance of apoptotic cells by DCs is generally considered a silent event that is not associated with an inflammatory response. Necrotic cell death, in contrast, leads to induction of inflammation. However, emerging data challenge the view of apoptotic cells as inherently nonimmunogenic. In this study, we report that the activation state of the apoptotic cell may determine whether the exposed DC becomes activated and rendered proficient in Ag presentation. We show that coculture with activated, but not resting, apoptotic PBMCs leads to up-regulation of surface expression of the costimulatory molecules CD80, CD83, and CD86 in human DCs as well as release of proinflammatory cytokines. Furthermore, we show that DCs exposed to allogeneic, activated apoptotic PBMCs induce proliferation and IFN-␥ production in autologous T cells. Together, these findings show that activated apoptotic PBMCs per se provide an activation/ maturation signal to DCs, suggesting that activated apoptotic PBMCs possess endogenous adjuvant properties.

AIDS Research and Human Retroviruses, 2007

Highly exposed persistently seronegative (HEPS) individuals have previously been shown to mount H... more Highly exposed persistently seronegative (HEPS) individuals have previously been shown to mount HIV-1specific humoral and cellular immune responses in the mucosa, despite their uninfected status. It is thus possible that HEPS individuals are protected from HIV-1 infection at the mucosal level. Recent work supports the hypothesis that dendritic cells are involved in the establishment of a mucosal HIV-1 infection as well as the dissemination to other target cells. However, no previous study has investigated if samples collected from HEPS individuals have the capacity to prevent HIV-1 infection in the presence of dendritic cells in vitro. We therefore established an assay that measures HIV-1 neutralization in cocultures of HIV-1-exposed dendritic cells (DC) and PBMC. Plasma and cervicovaginal lavage (CVL) samples from HIV-1-infected patients and HEPS individuals, enrolled in a well-characterized sex worker cohort in Kenya, were evaluated. Most plasma and CVL samples of HIV-1-infected patients neutralized HIV-1 in the DC/PBMC cocultures. Neither plasma nor CVL samples of most HEPS individuals had this capacity. However, they readily neutralized HIV-1 infection of PBMC alone. This may suggest that protection against HIV-1 infection in HEPS individuals occurs prior to interaction between HIV-1-exposed DC and other target cells.

International Immunology, 1990

MRL lpr/lpr mice develop a generalized autoimmune disease associated with a massive accumulation ... more MRL lpr/lpr mice develop a generalized autoimmune disease associated with a massive accumulation in the peripheral lymphoid organs of abnormal, phenotypically immature T cells. Both the lymphoadenopathy and the autoimmunity are thymus-dependent and likely to arise from an aberrant pathway of intrathymic differentiation. We here present the marked beneficial effects acquired in MRL lpr/lpr mice after in vivo administration of a novel immunomodulator called linomide. The highly altered pattern of thymic subpopulations in MRL lpr/lpr mice is normalized after linomide-treatment. Concomitantly, the peripheral T cell compartment, which in MRL lpr/lpr is highly deficient in producing and responding to IL-2, gains substantial functional reactivities. We propose that linomide acts by correcting the abnormal T cell development in autoimmune MRL lpr/lpr mice. This new immunomodulator may be a useful tool for providing insight into both the pathogenesis of autoimmune disorders and intrathymic differentiation.

The Journal of Infectious Diseases, Jul 24, 2012

Frontiers in Immunology, Sep 3, 2018

Early clearance of tuberculosis is the successful eradication of inhaled bacteria before the deve... more Early clearance of tuberculosis is the successful eradication of inhaled bacteria before the development of an adaptive immune response. We previously showed, by utilizing a non-virulent mycobacteria infection model, that C57BL/6 mice are more efficient than BALB/c in their control of bacterial growth in the lungs during the first weeks of the infection. Here, we assessed early (within 1-3 days) innate immune events locally in the lungs to identify factors that may contribute to the control of non-virulent mycobacterial burden. We confirmed that C57BL/6 mice are more resistant to infection compared with BALB/c after intranasal inoculation with mycobacterium. Transcriptomic analyses revealed a remarkably silent signature in C57BL/6 mice despite effective control of bacterial growth. In contrast, BALB/c mice up-regulated genes associated with neutrophil and myeloid cell chemotaxis and migration. Flow cytometry analyses corroborated the transcriptomic analyses and demonstrated influx of both neutrophil and myeloid cell populations in BALB/c mice, while these did not increase in C57BL/6 mice. We further detected increased release of TNF-α from BALB/c lung cells but limited release from C57BL/6-derived cells. However, C57BL/6 mice showed a marked early up-regulation of the Camp gene, encoding the cathelicidin CRAMP peptide, post-mycobacterial exposure. CRAMP (LL-37 in human) expression in the lungs was confirmed using immunofluorescence staining. Altogether, these findings show that C57BL/6 mice can clear the mycobacterial infection early and that this early control is associated with high CRAMP expression in the lungs without concomitant influx of immune cells. The role of CRAMP/LL-37 during mycobacterial infection may be relevant for novel protective strategies, and warrants further studies of human cohorts.

Journal of Immunological Methods, Dec 1, 2010

The New Zealand white rabbit model (Oryctolagus cuniculus) is widely used to test whether HIV vac... more The New Zealand white rabbit model (Oryctolagus cuniculus) is widely used to test whether HIV vaccine candidates elicit systemic antibody responses; however, its use in mucosal immunology has not been fully exploited due to the difficulty in collecting mucosal specimens longitudinally and reproducibly. Here we describe feasible and non-feasible methods to collect vaginal and nasal specimens from nulliparous rabbits. Non-feasible methods were those resulting in poor reproducibility and considerable animal twitching during sampling, whereas feasible methods resulted in no animal twitching and potential for sampling reproducibility. Standard operating procedures (SOPs) were implemented to collect vaginal swabs yielding total IgA titres ranging from 12,500 to 312,500. Intranasal immunisation with a naked DNA vaccine encoding HIV gp140 elicited HIV envelope-specific IgA detectable in nasal but not in vaginal secretions. Our methods provide an alternative to reliably assess pre-and postvaccination mucosal antibody titres longitudinally in rabbits as part of mucosal HIV vaccine immunogenicity studies.

PLOS ONE, Jun 16, 2011

Dendritic cells (DCs) are activated by signaling via pathogen-specific receptors or exposure to i... more Dendritic cells (DCs) are activated by signaling via pathogen-specific receptors or exposure to inflammatory mediators. Here we show that co-culturing DCs with apoptotic HIV-infected activated CD4 + T cells (ApoInf) or apoptotic uninfected activated CD4 + T cells (ApoAct) induced expression of co-stimulatory molecules and cytokine release. In addition, we measured a reduced HIV infection rate in DCs after co-culture with ApoAct. A prerequisite for reduced HIV infection in DCs was activation of CD4 + T cells before apoptosis induction. DCs exposed to ApoAct or ApoInf secreted MIP-1a, MIP-1b, MCP-1, and TNF-a; this effect was retained in the presence of exogenous HIV. The ApoAct-mediated induction of co-stimulatory CD86 molecules and reduction of HIV infection in DCs were partially abrogated after blocking TNF-a using monoclonal antibodies. APOBEC3G expression in DCs was increased in co-cultures of DCs and ApoAct but not by apoptotic resting CD4 + T cells (ApoRest). Silencing of APOBEC3G in DC abrogated the HIV inhibitory effect mediated by ApoAct. Sequence analyses of an env region revealed significant induction of G-to-A hypermutations in the context of GG or GA dinucleotides in DNA isolated from DCs exposed to HIV and ApoAct. Thus, ApoAct-mediated DC maturation resulted in induction of APOBEC3G that was important for inhibition of HIV-infection in DCs. These findings underscore the complexity of differential DC responses evoked upon interaction with resting as compared with activated dying cells during HIV infection.

Immunobiology, 2011

Dendritic cell derived IL-12p70 stimulates IFN-γ production in naïve T cells, thereby promoting T... more Dendritic cell derived IL-12p70 stimulates IFN-γ production in naïve T cells, thereby promoting Th1 responses, which counteracts induction of tolerance. Uptake of apoptotic cells by dendritic cells is generally considered to induce tolerance rather than immune activation and has been shown to specifically inhibit IL-12 production. However, we previously demonstrated that the activation state of apoptotic PBMC influence their immunogenic potential. Here we investigated whether dendritic cells that have engulfed apoptotic PBMC are able to produce IL-12p70 after a secondary signal. We show that dendritic cell ability to produce IL-12p70 after uptake of allogeneic apoptotic cells is dependent on the activation state of the apoptotic cells and subsequent CD40 ligation. CD40 ligation by a CD40L-transfected cell-line induced IL-12p70 in DC regardless of previous apoptotic cell uptake. Moreover, dendritic cells that were exposed to allogeneic activated apoptotic PBMC, but not to resting apoptotic PBMC, were able to produce IL-12p70 after co-culture with autologous T cells. These findings show that dendritic cells are able to produce IL-12p70 upon engulfment of apoptotic cells provided that a secondary activating signal such as CD40-ligand is delivered. In addition, resting apoptotic cell but not activated apoptotic cells reduced ongoing IL-12p70 production suggesting that the balance of activated and resting apoptotic lymphocytes influence the amount of IL-12p70 being produced.

Journal of Immunological Methods, Mar 1, 2001

Two techniques based upon flow cytometry (FCM) and in situ image analysis were developed for quan... more Two techniques based upon flow cytometry (FCM) and in situ image analysis were developed for quantification of intracellular cytokine and chemokine protein expression at the single cell level in dendritic cells (DCs). The qualitative and quantitative differences between the two methods were evaluated. In vitro differentiated DCs were stimulated with lipopolysaccaride (LPS) and thereafter stained for either IL-8, which is secreted through the Golgi-organelle, or IL-1ra, which localises diffusely in the cytoplasm. Microscopic examination, both for fluorophore and enzymatically stained cells, showed that DCs expressed IL-8 and IL-1ra with two different staining patterns. FCM analysis showed high frequencies of IL-1ra producing cells (76613%), which was similar to the frequency obtained by in situ imaging. However, in contrast to IL-1ra, the incidence of IL-8 expressing DCs showed high variability between the donors. The numbers of positive cells were 19619% as measured by FCM. The detection of IL-8 analysed by in situ imaging revealed higher frequencies (26614%). The addition of brefeldin-A, leading to cytoplasmic accumulation of proteins secreted through the Golgi endoplasmatic route, generated a significantly increased signal intensity and incidence of producer cells, resulting in similar frequencies for both methods. FCM has the advantage of being less time consuming than image analysis and is also able to facilitate multiple colour analysis. However, FCM is less accurate in detecting and quantifying cytokines and chemokines with a preserved juxtanuclear staining pattern. The correct choice of detection technique therefore depends on the study question.

Insects rely on their innate immune system to successfully mediate complex interactions with thei... more Insects rely on their innate immune system to successfully mediate complex interactions with their internal microbiota, as well as the microbes present in the environment. Given the variation in microbes across habitats, the challenges to respond to them is likely to result in local adaptation in the immune system. Here we focus upon phagocytosis, a mechanism by which pathogens and foreign particles are engulfed in order to be contained, killed and processed for antigen presentation. We investigated the phenotypic and genetic variation related to phagocytosis, in two allopatric populations of the butterfly Pieris napi. We found that the populations differ in their hemocyte composition, and overall phagocytic capability, driven by the increased phagocytic propensity of each cell type. However, no evidence for divergence in phagocytosis-related genes was observed, though an enrichment of genes involved in glutamine metabolism was found, which have recently been linked to immune cell differentiation in mammals.

7C8 is a mouse monoclonal antibody specific for the third hypervariable region (V3) of the human ... more 7C8 is a mouse monoclonal antibody specific for the third hypervariable region (V3) of the human immunodeficiency virus type 2 (HIV-2)-associated protein gp125. The three-dimensional crystal structure of the Fab fragment of 7C8, determined to 2.7 Å resolution, reveals a deep and narrow antigen-binding cleft with architecture appropriate for an elongated epitope. The highly hydrophobic cleft is bordered on one side by the negatively charged second complementarity determining region (CDR2) and the unusually long positively charged CDR3 of the heavy chain and, on the other side, by the CDR1 of the light chain. Analysis of 7C8 in complex with molecular models of monomeric and trimeric gp125 highlights the importance of a conserved stretch of residues FHSQ that is localized centrally on the V3 region of gp125. Furthermore, modeling also indicates that the Fab fragment neutralizes the virus by sterically impairing subsequent engagement of the gp125 trimer with the co-receptor on the target cell.

Journal of Biological Chemistry, Apr 1, 2012

Background: Activated apoptotic lymphocytes provide activation/maturation signals to human monocy... more Background: Activated apoptotic lymphocytes provide activation/maturation signals to human monocyte-derived dendritic cells (DCs). Results: Cell-cell contact-dependent signaling involved ␤2 integrins, DC-SIGN, and TLR4, which resulted in activation of multiple signaling pathways. Conclusion: These studies provide mechanistic insight into DC responses during encounter with cells undergoing immunogenic cell death. Significance: Learning how DCs respond to certain cell death has implications for vaccine design. Dendritic cells (DCs) are professional antigen-presenting cells playing a central role in connecting innate and adaptive immunity. Maturation signals are, however, required for DCs to undergo phenotypic and functional changes to acquire a fully competent antigen-presenting capacity. We previously reported that activated apoptotic peripheral lymphocytes (ActApo) provide activation/maturation signals to human monocyte-derived DCs. In this paper, we have characterized the signaling pathways and molecules involved in ActApo-mediated DC maturation. We found that both cellular and supernatant fractions from ActApo are required for DC maturation signaling. ActApoSup-induced CD80 and CD86 expression was significantly blocked in the presence of neutralizing antibodies against tumor necrosis factor-␣ (TNF-␣). Cell-cell contact-dependent signaling involved ␤2 integrins, dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), and TLR4 because ActApo-induced up-regulation of the maturation markers CD80 and CD86 was significantly inhibited in the presence of neutralizing antibodies against CD18, CD11a, CD11b, and DC-SIGN as well as TLR4. The role of TLR4 was further confirmed by silencing of TLR4 in DCs. In addition, the endogenous adjuvant effect exerted by activated apoptotic splenocytes (ActApoSp) was reduced after immunization with human serum albumin in TLR4 ؊/؊ mice. We detected activation of multiple signaling pathways and transcription factors in DCs upon coculture with ActApo, including p38, JNK, PI3K-Akt, Src family kinases, NFB p65, and AP1 transcription factor family members c-Jun and c-Fos, demonstrating the complex interactions occurring between ActApo and DCs. These studies provide important mechanistic insight into the responses of DCs during encounter with cells undergoing immunogenic cell death.