| 1. |
- Che, Karlhans F, et al.
(författare)
-
HIV-1 impairs in vitro priming of naïve T cells and gives rise to contact-dependent suppressor T cells
- 2010
-
Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 40:8, s. 2248-2258
-
Tidskriftsartikel (refereegranskat)abstract
- Priming of T cells in lymphoid tissues of HIV-infected individuals occurs in the presence of HIV-1. DC in this milieu activate T cells and disseminate HIV-1 to newly activated T cells, the outcome of which may have serious implications in the development of optimal antiviral responses. We investigated the effects of HIV-1 on DC-naïve T-cell interactions using an allogeneic in vitro system. Our data demonstrate a dramatic decrease in the primary expansion of naïve T cells when cultured with HIV-1-exposed DC. CD4(+) and CD8(+) T cells showed enhanced expression of PD-1 and TRAIL, whereas CTLA-4 expression was observed on CD4(+) T cells. It is worth noting that T cells primed in the presence of HIV-1 suppressed priming of other naïve T cells in a contact-dependent manner. We identified PD-1, CTLA-4, and TRAIL pathways as responsible for this suppresion, as blocking these negative molecules restored T-cell proliferation to a higher degree. In conclusion, the presence of HIV-1 during DC priming produced cells with inhibitory effects on T-cell activation and proliferation, i.e. suppressor T cells, a mechanism that could contribute to the enhancement of HIV-1 pathogenesis.
|
|
| 2. |
- El-Salhy, Magdy, 1951-, et al.
(författare)
-
Comparison between triple therapy with octreotide, galanin and serotonin vs. irinotecan or oxaliplatin in combination with 5-fluorouracil/leukovorin in human colon cancer.
- 2005
-
Ingår i: International Journal of Oncology. - 1019-6439 .- 1791-2423. ; 27:3, s. 687-691
-
Tidskriftsartikel (refereegranskat)abstract
- Human colon cancer cells were injected sub-cutaneously into 30 nude mice. After 8 days, the animals were divided into 3 equal groups. The first and second groups received an i.p. injection with 5-fluorouracil/leukovorin (5-FU/LV) for 5 days (20 mg and 10 mg/kg body weight respectively). On the first day of 5-FU/LV treatment, the first group received an i.p. injection of irinotecan (2.5 mg/kg body weight), and the second group received an i.p. injection with oxaliplatin (1 mg/kg body weight). The third group were injected i.p. with 100 microl saline solution containing octreotide, galanin and serotonin. Injections were given 3 times daily for 5 days with a total dose of 150 microg/kg body weight/day. Three days after the treatment, the animals were sacrificed. Whereas the animals treated with triple therapy held a stable body weight, animals treated with 5-FU/LV-irinotecan and 5-FU/LV-oxaliplatin had gradual weight loss, which amounted to approximately 25% of their body weight at the end of the experiment. Moreover, 2 mice in the group treated with 5-FU/LV-irinotecan died, most probably due to side effects. There was no statistically significant difference between the 3 groups regarding tumour proliferation, apoptosis, blood vessel density, EGF- and VEGF-expression. Treatment with triple therapy using octreotide, galanin and serotonin appear to be comparable to 5-FU/LV in combination with irinotecan and oxaliplatin. However, triple therapy seems to have a better safety profile.
|
|
| 3. |
- Sabado, Rachel L., et al.
(författare)
-
Pathways utilized by dendritic cells for binding, uptake, processing and presentation of antigens derived from HIV-1
- 2007
-
Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 37:7, s. 1752-1763
-
Tidskriftsartikel (refereegranskat)abstract
- The outcome following HIV infection depends on the nature and durability of the HIV-specific T cell response induced initially. The activation of protective T cell responses depends upon dendritic cells (DC), antigen-presenting cells which have the capacity to process and present viral antigens. DC pulsed with aldrithiol-2-inactivated HIV and delivered in vivo were reported to induce immune responses and promote virologic control in chronically HIV-1-infected subjects. To gain an understanding of this phenomenon, we characterized the steps involved in the presentation of antigens derived from aldrithiol-2-treated vs. infectious HIV-1 by DC. Antigen presentation, on both MHC class I and II, was independent of DC-specific ICAM-3-grabbing integrin, DEC-205 and macrophage mannose receptor, C-type lectins expressed by the DC. Inhibitor studies showed that presentation on MHC class I was dependent on viral fusion in a CD4/coreceptor-dependent manner, both at the cell surface and within endosomes, and access to the classical endosomal processing pathway. MHC class II presentation of HIV-associated antigens was dependent on active endocytosis, probably receptor-mediated, and subsequent degradation of virions in acidified endosomes in the DC. Our study brings forth new facts regarding the binding, uptake, and processing of chemically inactivated virions leading to efficient antigen presentation and should aid in the design of more effective HIV vaccines. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
|
|
| 4. |
- Tjomsland, Veronica, 1980-, et al.
(författare)
-
Anti-tumour effects of triple therapy with octreotide, galanin and serotonin in comparison with those of 5-fluorouracil/leukovorin on human colon cancer.
- 2005
-
Ingår i: International Journal of Oncology. - 1019-6439 .- 1791-2423. ; 27:2, s. 427-432
-
Tidskriftsartikel (refereegranskat)abstract
- Human colon cancer cells were injected subcutaneous in nude mice. After 8 days the animals were divided in two groups, the first group received triple therapy with octreotide, galanin and serotonin (40 microg/kg body weight/day) through an ALZET osmotic pump implanted intraperitoneally (i.p.) for 14 days, followed by 5 days of subcutaneous injections (200 microg/kg body weight/ day). The second group was injected i.p. for 5 days with 5-fluorouracil/leukovorin (5-FU/LV) at concentrations of 4 mg and 2 mg/kg body weight, respectively. After 9 days without any treatment, the mice received i.p. injection with 5-FU/LV (20 mg and 10 mg/kg body weight/day, respectively) for another 5 days. The volume and weight of the tumours were measured at the end of the experiment. Apoptosis, proliferation, blood vessels, epidermal growth factor (EGF) and vascular endothelial cell growth factor (VEGF) were detected with immunocytochemistry. Apoptosis was also detected using the TUNEL-method. Quantification was performed using computed image analysis. There was no statistical significance between tumours treated with 5-FU/LV or triple therapy regarding the volume and weights of the tumours, apoptotic, proliferation, VEGF indces and the density of tumour blood vessels. The EGF labelling index was, however significantly lower in the tumours treated with triple therapy than those treated with 5-FU/LV. In conclusion, treatment with triple therapy using octreotide, galanin and serotonin appear to be comparable with 5-FU/LV that is the standard chemotherapeutic agent for colorectal cancer.
|
|
| 5. |
- Tjomsland, Veronica, et al.
(författare)
-
Blocking of integrins inhibits HIV-1 infection of human cervical mucosa immune cells with free and complement-opsonized virions
- 2013
-
Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 43:9, s. 2361-2372
-
Tidskriftsartikel (refereegranskat)abstract
- The initial interaction between HIV-1 and the host occurs at the mucosa during sexual intercourse. In cervical mucosa, HIV-1 exists both as free and opsonized virions and this might influence initial infection. We used cervical explants to study HIV-1 transmission, the effects of opsonization on infectivity, and how infection can be prevented. Complement opsonization enhanced HIV-1 infection of dendritic cells (DCs) compared with that by free HIV-1, but this increased infection was not observed with CD4+ T cells. Blockage of the α4-, β7-, and β1-integrins significantly inhibited HIV-1 infection of both DCs and CD4+ T cells. We found a greater impairment of HIV-1 infection in DCs for complement-opsonized virions compared with that of free virions when αM/β2- and α4-integrins were blocked. Blocking the C-type lectin receptor macrophage mannose receptor (MMR) inhibited infection of emigrating DCs but had no effect on CD4+ T-cell infection. We show that blocking of integrins decreases the HIV-1 infection of both mucosal DCs and CD4+ T cells emigrating from the cervical tissues. These findings may provide the basis of novel microbicidal strategies that may help limit or prevent initial infection of the cervical mucosa, thereby reducing or averting systemic HIV-1 infection.
|
|
| 6. |
- Tjomsland, Veronica, et al.
(författare)
-
Blocking of integrins significantly inhibits HIV-1 infection of human cervical mucosa immune cells and development of founder populations
- 2011
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Slightly more than half of the HIV-1 infected individuals in the world are women and almost all acquire the infection through sexual intercourse. The initial interaction between HIV-1 and the host occurs at the mucosa site and the most common mode to access the submucosa is through dendritic cells (DCs). In the cervical mucosa, HIV-1 exist both as free and opsonized virions and this might influence initial infection. We used a cervical tissue explant model and both free and opsonized virions to study HIV-1 transmission and how it can be prevented. We found that complement opsonization significantly enhanced HIV-1 infection of DCs compared to free HIV-1, but this increased infection was not seen for CD4+ T cells. Blocking of α4, β7, and β1 integrins demonstrated significant inhibition of infection of both DCs and CD4+ T cells emigrating from mucosa, independent of the use of free or complement opsonized HIV-1. We found a higher impairment of HIV-1 infection in emigrating DCs for complement opsonized virions compared to free virions when the use of αM/β2 and α4 integrins was blocked. This study showed that block of integrins decreased the HIV-1 infection of both DCs and CD4+ T cells emigrating from the cervical explant tissues and, remarkably, the establishment of founder populations in these tissues. This indicates that preventing or severely lowering initial infection of the cervical mucosa could avert systemic HIV-1 infection and should be considered for development of microbicides to prevent HIV infection and transmission.
|
|
| 7. |
- Tjomsland, Veronica
(författare)
-
Complement activation - good or evil in HIV-1 infection? : interaction of free and complement opsonized HIV-1 with monocyte derived dendritic cells and immune cells in the cervical mucosa
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Worldwide, the heterosexual route is the most common mode of sexual transmission of HIV-1 and women are particularly susceptible to this infection. After penetration of the mucosal epithelium HIV-1 interacts with potential target cells, i.e. dendritic cells (DCs) and CD4+ T cells. The complement system, a key component of the innate immune system, is immediately activated by HIV-1 in vivo. However, HIV-1 can resist complement mediated lysis and become coated with complement fragments and this opsonization influences the viral interaction with immune cells. The DCs are the most potent antigen presenting cell. This cell effectively links the innate recognition of viruses to the generation of an adaptive immune response. However, HIV-1 exploits the function of the DCs to facilitate viral spread and infection. HIV-1 interacts with a range of receptors expressed by the DCs including C-type lectins, integrins and complement receptors (CRs). The uptake of virions by DCs leads to their activation and migration to the lymph nodes. At this site DCs present HIV-1 derived antigen on MHC class I and II molecules and trigger an HIV-1 specific T cell response. The interplay between the virus and the DCs is complex and the initial receptor binding may affect antigen uptake, infection, and antigen presentation.The fundamental questions of this thesis are the following: How is free and opsonized HIV-1 internalized, processed, and presented on MHC class I and II molecules by DCs and how do free and opsonized HIV-1 particles interact with immune cells in the cervical mucosa?Our results indicate that opsonization of HIV-1 plays a critical role in the interaction with immune cells. Complement opsonization of HIV-1 (C-HIV) significantly enhanced the internalization by the DCs compared to free HIV (F-HIV). Both C-HIV and F-HIV interacted with the CD4 receptor, C-type lectins and integrins. In addition, opsonization of HIV-1 favored an MHC class I presentation by DCs compared to F-HIV. However, the endocytic receptors macrophage mannose receptor, β7 integrin, and CR3 guided the antigens to different compartments with distinct properties and efficiencies for degradation and MHC class I and II presentation of viral antigens. MHC class I presentation of F-HIV and C-HIV was dependent of viral fusion in a CD4/coreceptor dependent manner. Moreover, MHC class II presentation of antigens derived from HIV-1 required endocytosis and proteolysis in acidified compartments. HIV-1 infection of cervical mucosa immune cells and tissue was assessed in a cervical tissue explant model. C-HIV significantly enhanced infection of DCs compared to F-HIV, whereas C-HIV decreased the infection of CD4+ T cells. Blocking the viral use of integrins in the cervical tissue explants significantly decreased the HIV-1 infection of both emigrating DCs and CD4+ T cells and the establishment of founder populations in these tissues. This thesis work has brought forward new facts that can be used to facilitate the development of an effective vaccine or microbicide.
|
|
| 8. |
- Tjomsland, Veronica, et al.
(författare)
-
Complement Opsonization of HIV-1 Enhances the Uptake by Dendritic Cells and Involves the Endocytic Lectin and Integrin Receptor Families
- 2011
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 6:8
-
Tidskriftsartikel (refereegranskat)abstract
- Interaction with the complement system is an underappreciated aspect of HIV-1 infection; even in primary infection, complement fragments are found on virions with potential to affect the interplay between the virus and dendritic cells (DC). Since opsonization may affect the efficiency of uptake and the type of receptors utilized, we compared the interactions of DC with free HIV-1 (F-HIV) and complement opsonized HIV-1 (C-HIV). We demonstrate that C-HIV significantly enhanced the uptake by immature DC (IDC) and mature DC (MDC) and that the internalization rate was dependent on both opsonization of the virus and DC maturation state. Increased DC uptake of C-HIV was not due to opsonization related increased binding of virus to the surface of DC but rather increased internalization of C-HIV despite utilizing a similar repertoire of receptors as F-HIV. Both F-HIV and C-HIV interacted with C-type lectins, integrins, and CD4 and blocking these receptor families prevented HIV-1 from binding to DC at 4 degrees C. Blocking integrins significantly reduced the binding and uptake of F-HIV and C-HIV implicating the involvement of several integrins such as beta 1-integrin, CR3, LFA-1, and alpha 4 beta 7. Distinctive for C-HIV was usage of beta 1-integrin and for F-HIV, usage of beta 7-integrin, whereas both F-HIV and C-HIV utilized both integrin chains of CR3. We have in this study identified the receptor types used by both F-HIV and C-HIV to bind to DC. Noteworthy, C-HIV was internalized more efficiently by DC than F-HIV, probably via receptor mediated endocytosis, which may entail different intracellular processing of the virus leading to both elevated infection and altered activation of HIV specific immune responses.
|
|
| 9. |
- Tjomsland, Veronica, et al.
(författare)
-
Complement opsonization of HIV-1 results in a different intracellular processing pattern and efficiency leading to an enhanced MHC I presentation by dendritic cells
- 2011
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The antigen processing and presentation processes occurring in dendritic cells (DCs) required for induction of HIV-1 specific T cell responses, which are essential for controlling the viral infection in vivo. The initial interactions of DCs with free HIV-1 (FHIV), or complement opsonized HIV-1 (C-HIV) might influence the routing and nature of pathways used for MHC class I and II restricted presentation. We have examined FHIV, C-HIV, and complement and antibody opsonized HIV-1 (C-IgG-HIV) effects on immature DCs (IDCs) and mature DCs (MDCs) antigen proteolysis, MHC class I and II antigen presentation, and the role of endocytic receptors in presentation of antigens derived from HIV-1. We found that opsonized virions promoted MHC class I presentation by both IDCs and MDCs compared to F-HIV. Indicative of that complement opsonization routes more virions towards the MHC class I presentation pathway. We found that blocking macrophage mannose receptor (MMR) rerouted the HIV-1 to a path leading to higher levels of MHC class I and II presentation. Furthermore, the blocking of β7-integrin also gave an enhanced MHC class I and II presentation by both IDCs and MDCs, whereas the block of αMβ2 integrins, i.e. complement receptor 3 (CR3), decreased the MHC class I and II presentation. In addition, we found that IDCs and MDCs proteolytic activities were modulated by the HIV-1 exposure, for example C-HIV induced an increased proteasome activity in IDCs. Taken together, these findings indicated that endocytic receptors, such as MMR, CR3, and β7 integrin, can promote or disfavor antigen presentation by routing HIV-1 into different endosomal compartments with distinct properties and efficiencies for degradation of viral antigens and MHC class I and II presentation and that HIV-1 affects the antigen processing machineries.
|
|
| 10. |
- Tjomsland, Veronica, et al.
(författare)
-
Complement opsonization of HIV-1 results in a different intracellular processing pattern and enhanced MHC class I presentation by dendritic cells
- 2013
-
Ingår i: European Journal of Immunology. - : Wiley-VCH Verlag. - 0014-2980 .- 1521-4141. ; 43:6, s. 1470-1483
-
Tidskriftsartikel (refereegranskat)abstract
- Induction of optimal HIV-1-specific T-cell responses, which can contribute to controlling viral infection in vivo, depends on antigen processing and presentation processes occurring in DCs. Opsonization can influence the routing of antigen processing and pathways used for presentation. We studied antigen proteolysis and the role of endocytic receptors in MHC class I (MHCI) and II (MHCII) presentation of antigens derived from HIV-1 in human monocyte-derived immature DCs (IDCs) and mature DCs, comparing free and complement opsonized HIV-1 particles. Opsonization of virions promoted MHCI presentation by DCs, indicating that complement opsonization routes more virions toward the MHCI presentation pathway. Blockade of macrophage mannose receptor (MMR) and β7-integrin enhanced MHCI and MHCII presentation by IDCs and mature DCs, whereas the block of complement receptor 3 decreased MHCI and MHCII presentation. In addition, we found that IDC and MDC proteolytic activities were modulated by HIV-1 exposure; complement-opsonized HIV-1 induced an increased proteasome activity in IDCs. Taken together, these findings indicate that endocytic receptors such as MMR, complement receptor 3, and β7-integrin can promote or disfavor antigen presentation probably by routing HIV-1 into different endosomal compartments with distinct efficiencies for degradation of viral antigens and MHCI and MHCII presentation, and that HIV-1 affects the antigen-processing machinery.
|
|
