| 1. |
- Devito, Claudia
(författare)
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Functional properties of antibodies in resistance against HIV-1 infection
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the last years a few populations who remain uninfected despite repeated HIV-1 viral exposures have been described. Several mechanisms were suggested to be associated with this natural resistance including HIV-1-specific cell- mediated and humoral immune responses, as well as mutations affecting receptors for virus entry. Exposure to, or infection with, defective viral strains has also been postulated as a possible phenomenon of resistance in some of these risk groups. Two groups of highly exposed persistently seronegative (HEPS) individuals were examined in the present study: 1) female sex workers from Nairobi, Kenya, where HIV-1 clades A, D and C are prevalent, 2) uninfected heterosexual partners to HIV-1, clade B infected individuals from Italy. The study focused on the humoral immune response in mucosal samples of these two groups, and specifically on the presence of functionally active HIV-1 specific IgA. We have also evaluated if HIV specific IgM monoclonal antibodies may be capable of preventing HIV-1 infection in vitro. The main aim of the first paper was to develop a HIV-1 p24 antigen capture ELISA with polyclonal IgG from rabbits immunized with different gag antigens. This HIV-antigen detection assay was to be used to evaluate antibody neutralizing capacity, for instance of IgA purified from HEPS individuals. The p24 antigen capture ELISA could be used for HIV-1 p24 antigen detection of at least seven different HIV-1 clades. In the second paper, lgA was purified from plasm saliva and cervicovaginal fluid samples from female sex workers as well as from control individuals. lgA antibodies from some of the HEPS individuals were shown to neutralize an HIV-1 clade B primary isolate in an assay using peripheral blood mononuclear cells as targets. In the third paper, IgA antibodies representing both the HEPS groups were shown to inhibit HIV-1 transcytosis across an epithelial cell layer in vitro. This model system mimics HIV-1 entry into the host and is believed to be one of the mechanisms for sexual transmission of the virus. The fourth paper describes that lgA antibodies, purified from HEPS individuals, could neutralize HIV-1 primary isolates representing different HIV-1 clades in vitro. In this preliminary study, lgA from the female sex workers seemed to have a broader neutralization capacity compared with the Italian HIV-1 discordant couples. A small group of the Kenyan sex-workers that remained seronegative for many years have seroconverted after having reduced the number of clients or stopped sex-work for two months or longer. This indicates that constant antigen exposure may be necessary to maintain the HIV-1 specific immune responses. In order to evaluate the possibility of inducing long-term B cell immune responses and neutralizing antibodies the study described in the fifth paper was performed. Mice were intranasally immunized with HIV-1gp16O/DNA and boosted with gp41 and CCR5 peptides recognized by HEPS. Long term B-cell mucosal and systemic responses were obtained in addition to HIV-specific IgA responses in the mucosa. Neutralizing antibodies were detected one year after the last immunization. In order to evaluate the possible role of natural HIV envelope binding IgM in protection against HIV-1 infection in vitro, in the sixth paper we analyzed the capacity of two human monoclonal antibodies to inhibit HIV-1 transcytosis across a human intestinal epithelial cell line. Both gp120 V3 binding Mabs exhibited the capacity to limit the transcytosis of a T-cell laboratory adapted strain and a primary HIV-1 isolate. Mucosal and plasma IgA from HEPS individuals can thus neutralize HIV-1 primary isolates of different clades as well as inhibit HIV-1 transcytosis across epithelial cell linings. Natural and specific IgM antibodies may also be present in HEPS individuals representing a mechanism supporting resistance to HIV-1 infection. Because preliminary findings have shown that lgA from HEPS individuals have a unique epitope specificity on the HIV1 gp41 envelope proteins compared with HIV-1 infected individuals, and that long term immunity can be obtained in mice suggests a novel design of an HIV-1 vaccine aimed at mucosal protection against multiple HIV-1 clades.
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| 2. |
- Devito, Claudia, et al.
(författare)
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Human IgM monoclonal antibodies block HIV-transmission to immune cells in cervico-vaginal tissues and across polarized epithelial cells in vitro
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- The importance of natural IgM antibodies in protection against infections is still emerging and these antibodies have a potential role in the maintenance of homeostasis through clearance of apoptotic bodies, complement-dependent mechanisms, inflammation and exclusion of misfolded proteins. Natural IgM act as a first line of defence against unknown hazardous factors and are present in most vertebrates. We investigated the functional capacity of anti-HIV-1 IgM monoclonal antibodies, from a combinatorial Fab library derived from healthy individuals, and evaluated their protective role in inhibiting HIV-1 in vitro when passing across the human mucosal epithelial barrier. Primary HIV-1 isolates were efficiently transmitted over the tight polarized epithelial cells when added to their apical surface. Efficient inhibition of HIV-1 transmission was achieved when anti-HIV-1 IgM monoclonal antibodies were added to the basolateral side of the cells. Two of these human IgM MoAbs had the ability to neutralize HIV and reduced infection of dendritic cells in primary cervico-vaginal tissue biopsies in vitro. This indicates a potential role of natural IgM antibodies in the reduction of HIV-1 transmission in mucosal tissues and improve our understanding of how natural IgM antibodies against a neutralizing epitope could interfere with viral transmission.
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| 3. |
- Hinkula, Jorma, et al.
(författare)
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Long-Lasting Mucosal and Systemic Immunity against Influenza A Virus Is Significantly Prolonged and Protective by Nasal Whole Influenza Immunization with Mucosal Adjuvant N3 and DNA-Plasmid Expressing Flagellin in Aging In- and Outbred Mice
- 2019
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Ingår i: Vaccines. - : MDPI. - 2076-393X. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Vaccination is commonly used to prevent and control influenza infection in humans. However, improvements in the ease of delivery and strength of immunogenicity could markedly improve herd immunity. The aim of this pre-clinical study is to test the potential improvements to existing intranasal delivery of formalin-inactivated whole Influenza A vaccines (WIV) by formulation with a cationic lipid-based adjuvant (N3). Additionally, we combined WIV and N3 with a DNA-encoded TLR5 agonist secreted flagellin (pFliC(-gly)) as an adjuvant, as this adjuvant has previously been shown to improve the effectiveness of plasmid-encoded DNA antigens. Methods: Outbred and inbred mouse strains were intranasally immunized with unadjuvanted WIV A/H1N1/SI 2006 or WIV that was formulated with N3 alone. Additional groups were immunized with WIV and N3 adjuvant combined with pFliC(-gly). Homo and heterotypic humoral anti-WIV immune responses were assayed from serum and lung by ELISA and hemagglutination inhibition assay. Homo and heterotypic cellular immune responses to WIV and Influenza A NP were also determined. Results: WIV combined with N3 lipid adjuvant the pFliC(-gly) significantly increased homotypic influenza specific serum antibody responses (>200-fold), increased the IgG2 responses, indicating a mixed Th1/Th2-type immunity, and increased the HAI-titer (>100-fold). Enhanced cell-mediated IFNγ secreting influenza directed CD4+ and CD8+ T cell responses (>40-fold) to homotypic and heterosubtypic influenza A virus and peptides. Long-term and protective immunity was obtained. Conclusions: These results indicate that inactivated influenza virus that was formulated with N3 cationic adjuvant significantly enhanced broad systemic and mucosal influenza specific immune responses. These responses were broadened and further increased by incorporating DNA plasmids encoding FliC from S. typhimurum as an adjuvant providing long lasting protection against heterologous Influenza A/H1N1/CA09pdm virus challenge. View Full-Text
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| 4. |
- Nyström, Sanna, et al.
(författare)
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DNA-Encoded Flagellin Activates Toll-Like Receptor 5 (TLR5), Nod-like Receptor Family CARD Domain-Containing Protein 4 (NRLC4), and Acts as an Epidermal, Systemic, and Mucosal-Adjuvant
- 2013
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Ingår i: Vaccines. - Basel, Switzerland : MDPI AG. - 2076-393X. ; 1:4, s. 415-443
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Tidskriftsartikel (refereegranskat)abstract
- Eliciting effective immune responses using non-living/replicating DNA vaccines is a significant challenge. We have previously shown that ballistic dermal plasmid DNA-encoded flagellin (FliC) promotes humoral as well as cellular immunity to co-delivered antigens. Here, we observe that a plasmid encoding secreted FliC (pFliC(-gly)) produces flagellin capable of activating two innate immune receptors known to detect flagellin; Toll-like Receptor 5 (TLR5) and Nod-like Receptor family CARD domain-containing protein 4 (NRLC4). To test the ability of pFliC(-gly) to act as an adjuvant we immunized mice with plasmid encoding secreted FliC (pFliC(-gly)) and plasmid encoding a model antigen (ovalbumin) by three different immunization routes representative of dermal, systemic, and mucosal tissues. By all three routes we observed increases in antigen-specific antibodies in serum as well as MHC Class I-dependent cellular immune responses when pFliC(-gly) adjuvant was added. Additionally, we were able to induce mucosal antibody responses and Class II-dependent cellular immune responses after mucosal vaccination with pFliC(-gly). Humoral immune responses elicited by heterologus prime-boost immunization with a plasmid encoding HIV-1 from gp160 followed by protein boosting could be enhanced by use of pFliC(-gly). We also observed enhancement of cross-clade reactive IgA as well as a broadening of B cell epitope reactivity. These observations indicate that plasmid-encoded secreted flagellin can activate multiple innate immune responses and function as an adjuvant to non-living/replicating DNA immunizations. Moreover, the capacity to elicit mucosal immune responses, in addition to dermal and systemic properties, demonstrates the potential of flagellin to be used with vaccines designed to be delivered by various routes.
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| 5. |
- Sengupta, Anirban, et al.
(författare)
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Differential Immune Response Patterns Induced by Anionic and Cationic Lipid Adjuvants in Intranasal Anti-Influenza Immunization
- 2024
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Ingår i: Vaccines. - : MDPI. - 2076-393X. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Currently, vaccine development against different respiratory diseases is at its peak. It is of utmost importance to find suitajble adjuvants that can increase the potency of the vaccine candidates. This study aimed to determine the systemic and splenic immune mechanisms in mice models induced by anionic and cationic lipid adjuvants in the presence of the vaccine-candidate influenza antigen hemagglutinin (HA). In the presence of the HA antigen, the cationic adjuvant (N3) increased conventional dendritic cell 1 (cDC1) abundance with enhanced MHCI and CD80-CD86 costimulatory marker expression, and significantly higher CD8T and Th17 populations with enhanced interferon-gamma (IFN gamma) expression in CD8T and CD4T populations. Conversely, the anionic adjuvant (L3) increased the cDC2 population percentage with significantly higher MHCII and DEC205 expression, along with an increase in the CD4T and regulatory T cell populations. The L3-treated group also exhibited higher percentages of activated B and plasma cell populations with significantly higher antigen-specific IgG and IgA titer and virus neutralization potential. While the anionic adjuvant induced significantly higher humoral responses than the cationic adjuvant, the latter influenced a significantly higher Th1/Th17 response. For customized vaccine development, it is beneficial to have alternative adjuvants that can generate differential immune responses with the same vaccine candidate antigen. This study will aid the selection of adjuvants based on their charges to improve specific immune response arms in the future development of vaccine formulation.
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| 6. |
- Sengupta, Anirban, et al.
(författare)
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Intranasal Coronavirus SARS-CoV-2 Immunization with Lipid Adjuvants Provides Systemic and Mucosal Immune Response against SARS-CoV-2 S1 Spike and Nucleocapsid Protein
- 2022
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Ingår i: Vaccines. - Basel, Switzerland : MDPI. - 2076-393X. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- In this preclinical two-dose mucosal immunization study, using a combination of S1 spike and nucleocapsid proteins with cationic (N3)/or anionic (L3) lipids were investigated using an intranasal delivery route. The study showed that nasal administration of low amounts of antigens/adjuvants induced a primary and secondary immune response in systemic IgG, mIL-5, and IFN-gamma secreting T lymphocytes, as well as humoral IgA in nasal and intestinal mucosal compartments. It is believed that recipients will benefit from receiving a combination of viral antigens in promoting a border immune response against present and evolving contagious viruses. Lipid adjuvants demonstrated an enhanced response in the vaccine effect. This was seen in the significant immunogenicity effect when using the cationic lipid N3. Unlike L3, which showed a recognizable effect when administrated at a slightly higher concentration. Moreover, the findings of the study proved the efficiency of an intranasally mucosal immunization strategy, which can be less painful and more effective in enhancing the respiratory tract immunity against respiratory infectious diseases.
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