Search results for "Immune tolerance"
showing 10 items of 174 documents
Kinetics of the reactive cell clones after immunosuppression and induction of tolerance: (1) Inhibition of 19 S and 7 S plaque-forming cells in the p…
1975
The kinetics of the reactive cell clones after primary and secondary immunization with SRBC1) modified by cyclophosphamide and a newly synthesized cyclophosphamide analogue 036.5122 (Asta), have been studied. After primary immunization, both substances caused a severe and dose dependent depletion of 19 S PFC2). The 7 S PFC in the late primary response were only slightly inhibited by cyclophosphamide in low dose ranges, indicating, that sensitization could not be prevented by this substance. In contrast, 0.36.5122 was fully able to suppress 7 S PFC. Thus, treatment with 0.36.5122 after primary immunization can fully prevent the expression of the specific response. Experiments dealing with in…
Oncogene transformation can induce tolerogenicity in murine macrophages after down-regulation of immunogenicity without altering major histocompatibi…
1993
In vitro studies on cell lines may allow analyses of the mechanisms of immunogenicity and tolerogenicity in cells. We used a model of oncogenic transformation of an established murine macrophage cell line and report here that one v-mos-transformed clone expressing unaltered high amounts of MHC class I and II antigens does not induce proliferation of unprimed T cells in primary mixed lymphocyte reactions, in sharp contrast to its non-transformed parental cells. Interestingly, this clone induces specific unresponsiveness, as revealed by the lack of responsiveness of MHC-specific T cells when subsequently exposed to the pertinent MHC alloantigens in immunogenic form but unaltered MHC-third par…
β2Integrin deficiency yields unconventional double-negative T cells distinct from mature classical natural killer T cells in mice
2009
Expressed on leucocytes, beta(2) integrins (CD11/CD18) are specifically involved in leucocyte function. Using a CD18-deficient (CD18(-/-)) mouse model, we here report on their physiological role in lymphocyte differentiation and trafficking. CD18(-/-) mice present with a defect in the distribution of lymphocytes with highly reduced numbers of naïve B and T lymphocytes in inguinal and axillary lymph nodes. In contrast, cervical lymph nodes were fourfold enlarged harbouring unconventional T-cell receptor-alphabeta (TCR-alphabeta) and TCR-gammadelta CD3(+) CD4(-) CD8(-) (double-negative; DN) T cells that expanded in situ. Using adoptive transfer experiments, we found that these cells did not h…
Density-dependent effects on parasite growth and parasite-induced host immunodepression in the larval helminth Pomphorhynchus laevis.
2011
SUMMARYLarval helminths exploit the physiology of their intermediate hosts: first, as a resource for energy and space and second by altering the immune system activity to ensure their survival. Whereas the growth pattern under parasite competition has been investigated, the effect of multiple infections on the level of parasite-induced immunodepression in a trophically transmitted helminth has been neglected. In this study, amphipodsGammarus pulexwere infected in the laboratory by the acanthocephalanPomphorhynchus laevisto investigate how parasite density in the intermediate host affected (i) cystacanth growth and (ii) the level of parasite-induced alterations of the host immune defences, t…
Decellularized tracheal prelamination implant: A proposed bilateral double organ technique
2021
Introduction In tracheal replacement transplantation, prelamination is a critical stage. Nowadays, the most widely used prelamination technique is the prethoracic fascia flap with lateral thoracic artery. We propose a flap based on the internal thoracic artery, which allows a relatively non-aggressive double organ implant, and we have tested its efficacy in decellularized tracheas. Material and methods Tracheas of albino New Zealand rabbits were decellularized following a protocol that uses detergents and cryogenization, sterilized with 1kGy gamma radiation and tutorized with a stent. Bilateral pedicled flaps made of pectoral fascia and a muscular component were harvested through a longitud…
Kinetics of the reactive cell clones after immunosuppression and induction of tolerance. II. Different recovery of 19 S and 7 S plaque-forming cells …
1975
By the aid of two alkylating agents (cyclophosphamide (CP) and 036.5122, (Asta), applied after a single dose of antigen, tolerance to sheep red blood cells (SRBC), has been induced in NMRI mice. Duration and characteristics of recovery were followed by a second antigenic challenge at various time intervals and by determination of 19 S and 7 S plaque-forming cells (PFC) 4 days later. During recovery from the tolerant state two phases of responsiveness could be differentiated: an early phase with no or markedly reduced numbers of total PFC, all of them being of the IgM type; a later phase with a steady increase in total PFC up to normal values, paralleled by an increase in the proportion of 7…
Late-onset myasthenia gravis - CTLA4(low) genotype association and low-for-age thymic output of naïve T cells.
2014
Abstract Late-onset myasthenia gravis (LOMG) has become the largest MG subgroup, but the underlying pathogenetic mechanisms remain mysterious. Among the few etiological clues are the almost unique serologic parallels between LOMG and thymoma-associated MG (TAMG), notably autoantibodies against acetylcholine receptors, titin, ryanodine receptor, type I interferons or IL-12. This is why we checked LOMG patients for two further peculiar features of TAMG – its associations with the CTLA4 high/gain-of-function +49A/A genotype and with increased thymic export of naive T cells into the blood, possibly after defective negative selection in AIRE-deficient thymomas. We analyzed genomic DNA from 116 …
Fulfilling the dream: tolerogenic dendritic cells to treat multiple sclerosis.
2012
Autoimmune diseases including multiple sclerosis (MS) are the result of an imbalanced immune tolerance network. Dendritic cells (DCs) are key players in both initiating immunity (immunogenic DCs) and regulating immune responses (tolerogenic DCs = tolDCs) and are potential targets for the treatment of MS. While the immunogenic potential of DCs in fighting infection and cancer has been well established, approaches that exploit their tolerogenic features to promote transplantation tolerance and autoimmunity have emerged only more recently. TolDCs usually maintain antigen-specific T-cell tolerance either directly by inducing anergy, apoptosis, or phenotype skewing or indirectly by induction of …
Increase in gut microbiota after immune suppression in baculovirus-infected larvae.
2013
Spodoptera exigua microarray was used to determine genes differentially expressed in S. exigua cells challenged with the species-specific baculovirus SeMNPV as well as with a generalist baculovirus, AcMNPV. Microarray results revealed that, in contrast to the host transcriptional shut-off that is expected during baculovirus infection, S. exigua cells showed a balanced number of up- and down-regulated genes during the first 36 hours following the infection. Many immune-related genes, including pattern recognition proteins, genes involved in signalling and immune pathways as well as immune effectors and genes coding for proteins involved in the melanization cascade were found to be down-regul…
TLR2: for or against Candida albicans?
2005
In a recent issue of Trends in Microbiology, Netea and coworkers presented their opinion that toll-like receptors (TLRs) are involved in escape from the defense mechanisms of the host [1]. In their article, the authors clearly identified three major TLR-mediated escape mechanisms that are used by microbial pathogens, such as Yersinia, Mycobacterium and Candida. Here, we wish to comment on the roll of TLR2 in Candida albicans infections. Netea's interesting hypothesis, that TLR2 expression might confer to mice an increased susceptibility to C.