Mechanism of Allergic Asthma Pathogenesis by Protease Allergen / 한양의대학술지

Asthma is a complex immune mediated chronic inflammatory lung disease characterized by chronic inflammation of the airways, airway hyper-responsiveness and airway obstruction, and the prevalence of this disease has increased in recent years. It is well known that many features of allergic asthma are consequences of Th2 cell dominated immune responses against allergens, thus allergen specific Th2 cells play a critical role in the pathogenesis. In this review, we will discuss the properties of common indoor and outdoor allergens including house dust mite, fungus, pollen and cockroach, the activation and differentiation of naive CD4 T cells by protease allergens, how specific allergens modify host's immune system to mediate immune evasion, and regulation of homing receptor expression and trafficking of allergen specific Th2 cells. Lastly, we will also overview the general course of pathogenesis of allergic asthma and discuss prospects of development of novel immuno-therapies to asthma.

In vitro Expansion of Natural Regulatory T Lymphocytes Useful for Cell Therapy in Allotransplantation

Immunotherapy with regulatory T lymphocytes is considered to be an attractive new therapeutic modality to prevent allograft rejection. The success of this new therapy is critically dependent on the preparation of highly effective and enough number of regulatory T cells. Here, we tried to establish a proper strategy for the ex vivo expansion of regulatory T cells and evaluated their characteristics. CD4+CD25h+CD62L+ T cells were isolated from the recipient mice and weekly stimulated with various stimuli in the presence of IL-2. The most efficient protocol for the expansion of regulatory T cells maintaining Foxp3 expression and regulatory activity was the three cycles stimulation with donor bone marrow-derived dendritic cells (BM-DCs) which yielded around 400 fold expansion of regulatory T cells. The in vitro-expanded regulatory T cells expressing lymph node homing receptors on their cell surface, were composed of polyclonal population, and did not acquire the ability to produce effector cytokines. Importantly, these expanded regulatory T cells induced a modest prolongation of skin allograft survival when combined with transient T cell depletion in recipient mice. These data indicate that our protocol could be used to obtain an effective population of natural regulatory T cells available for the regulatory T cell therapy to prevent allograft rejection.

Mechanism of donor T cell migration and homing in the pathophysiology of acute graft-versus-host disease - review / 中国实验血液学杂志

Migration of donor T cells to the host second lymphoid organs and homing of activated donor T cells into the target tissues play crucial role in the pathophysiology of acute graft-versus-host disease (aGVHD). More deep understanding of the mechanisms for donor T cell migration and homing reveals an important significance in preventing the initiation of aGVHD. In this review, the migration of donor T cells to host second lymphoid organs, homing of donor activated T cells into the target organs, homing of regulating T cells into target organs, the mechanisms of T cell migration and homing in process of aGVHD and its study prospects were summarised.

Stem Cells Expressing Homing Receptors Could be Expanded From Cryopreserved and Unselected Cord Blood

We assessed the cytokine combinations that are best for ex vivo expansion of cord blood (CB) and the increment for cell numbers of nucleated cells, as well as stem cells expressing homing receptors, by an ex vivo expansion of cryopreserved and unselected CB. Frozen leukocyte concentrates (LC) from CB were thawed and cultured at a concentration of 1x10(5)/mL in media supplemented with a combination of SCF (20 ng/mL)+TPO (50 ng/mL)+FL (50 ng/mL)+/-IL-6 (20 ng/mL)+/-G-CSF (20 ng/mL). After culturing for 14 days, the expansion folds of cell numbers were as follows: TNC 22.3+/-7.8~26.3+/-4.9, CFU-GM 4.7+/-5.1~11.7+/-2.6, CD34+CD38- cell 214.0+/-251.9~464.1+/-566.1, CD34+CXCR4+ cell 4384.5+/-1664.7~7087.2+/-4669.3, CD34+VLA4+ cell 1444.3+/-1264.0~2074.9+/-1537.0, CD34+VLA5+ cell 86.2+/-50.9~ 113.2+/-57.1. These results revealed that the number of stem cells expressing homing receptors could be increased by an ex vivo expansion of cryopreserved and unselected CB using 3 cytokines (SCF, TPO, FL) only. Further in vivo studies regarding the engraftment after expansion of the nucleated cells, as well as the stem cells expressing homing receptors will be required.

Studies on the homing-related adhesion activities of UCB HSPC in short-term ex vivo expansion / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effect of ex vivo expansion on the adhesion activities of umbilical cord blood hematopoietic stem and progenitor cells (HSPC).</p><p><b>METHODS</b>Fresh UCB CD(34)(+) cells were cultured in a serum and stroma-free culture system. At day 7, day 10 and day 14, CD(34)(+) cells were re-selected from the expanded products. The expression of adhesion molecules (CAMs) such as VLA-4, VLA-5, LFA-1, ICAM-1, HCAM, L-selectin and PECAM-1, and the adhesion activity of the expanded CD(34)(+) cells were evaluated and compared with those of precultured fresh CD(34)(+) cells.</p><p><b>RESULTS</b>(1) The CD(34)(+) cells expressing homing-related CAMs were increased (from 15-fold increase for CD(34)(+) CD(54)(+) subset to 72-fold increase for CD(34)(+) CD(49e)(+) subset at day 14). (2) The expressions of CD(49d), CD(44), CD(11a) and CD(49e) on the expanded CD(34)(+) cells were increased or sustained the same levels as those on fresh UCB CD(34)(+) cells, while the expression of CD(62L), CD(54) and CD(31) on expanded CD(34)(+) cells declined with the cultivating. (3) Spontaneous adhesion and SDF-1-induced adhesion tended to be increased in the course of the first 10 day's culture.</p><p><b>CONCLUSIONS</b>The culture system used in this study could substantially support the expansion of HSPCs expressing the above CAMs, and the expanded HSPCs would sustain their intrinsic adhesion potentials.</p>

The effects of cytokines mediated ex vivo expansion on the cell adhesion molecule expression of cord blood hematopoietic stem and progenitor cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the expression of cell adhesion molecules (CAMs) among VLA-4 (CD49 d), VLA-5 (CD49e), LFA-1 (CD11a), L-selectin (CD62L), and PECAM-1 (CD31) which are more related to the homing of hematopoietic stem and progenitor cells (HSPC) on the ex vivo expanded CD34+ subset with that of fresh isolated AC133+ cells.</p><p><b>METHODS</b>AC133+ cells selected from fresh cord blood (CB) samples were cultured in QBSF-60 serum-free media in the presence of Flt-3 ligand + SCF + TPO (FST), with initial addition of IL-3 for up to 2 week. Expansion potential and the expression of above CAMs were evaluated at day 0, day 7, day 10 and day 14.</p><p><b>RESULTS</b>(1) Simultaneously numerical expansion of various HSPC was constantly observed during the culture, and the fold expansion of AC133+ cells and CD34+ cells on day 14 were 33.50 and 64.56 respectively; (2) The number of CD34+ subsets expressing the above adhesions were all increased at different degrees (from 20 fold to 160 fold). (3) The expressions of CD11a, CD49d, and CD49e on ex vivo expanded CD34+ cells were increased as compared to their baseline levels, but the percentage of CD62L+ and CD31+ subpopulations in CD34+ cells were decreased.</p><p><b>CONCLUSIONS</b>Our short-term culture system can not merely support the simultaneous expansion of CB derived AC133+ cells, but the expanded hematopoietic progenitors may well sustained the expression of homing-related adhesion molecules.</p>

Cell cycling status of human cord blood CD34+ cells during ex vivo expansion is related to the level of very late antigen expression

Very late antigen-4 (VLA-4), which binds to the extracellular matrix protein fibronectin, is an integrin molecule known to be modulated during mobilization of CD34+ cells, and to be involved in signaling the mobilization stimuli. On the hypothesis that cell cycling status might be different depending on the level of VLA-4 expression, we investigated the DNA contents of human cord blood CD34+ cells during ex vivo expansion by recombinant human thrombopoietin and flt3-ligand with simultaneous measurement of surface VLA-4 at the 1st and 4th week. During this ex vivo expansion, expression of VLA-4 increased and almost all cells became VLA-4+ until the 4th day of culture. Expression of VLA-4 was maintained in the major population of the cultured cells until the 4th week. The cells in S/G2/M phase were greater in number in VLA-4 high fraction than in VLA-4 low fraction (n=4, p<.001). Furthermore, the fraction of cells in S/G2/M phase increased as the expression of VLA-4 became higher. These results suggest that cord blood CD34+ cells expressing high levels of VLA-4 have more proliferative activities.

Investigation of signal transduction pathways involved in melanoma cell spreading.

Integrins are a major family of heterodimeric adhesion receptors that are responsible for anchoring cells to extracellular matrix and they also can initiate intracellular signal pathways. Here parental and alpha 4-expressing human malignant melanoma cell lines were used to study the effect of protein kinase C (PKC), protein tyrosine kinases (PTKs) and intracellular Ca2+ on alpha 4 beta 1-mediated cell spreading on VCAM-1. Incubation of melanoma cells with PKC inhibitor inhibited alpha 4 beta 1-mediated melanoma cell spreading completely. Effect of intracellular Ca2+ on melanoma cell spreading was also investigated by non-phorbol ester tumor promotor, thapsigargin, which blocks the ability of the endoplasmic reticulum to replenish stocks of calcium which naturally leak out into the cytosol leading to a transient increase in concentration of intracellular calcium. The results showed that alpha 4 beta 1-mediated spreading was also required intracellular calcium involvement. However, in the presence of PTKs inhibitor melanoma cells showed long, thin dendiritic projections compared to control cells. Previously, data was obtained from immunofluorescense experiments showed that after genistein treatment, alpha 4-expressing cells exhibited considerable amounts of alpha 4 integrin and PTKs in both the focal contact points as well as over the whole cell. PTKs inhibitor did not have any effect on alpha 4-expressing cells spreading. This could be related to the amount of the PTKs present in these cells.

The Significance of CD44v Expression in the Pelvic LateralLymph Node in Distal Rectal Cancer

PURPOSE: The CD44 has been known a lymph node homing receptor on circulating lymphocytes. CD44 spliced variants have been found to be overexpressed in human cancers and metastatic cancers. The variant CD44v 6-7 in particular has been suggested to have a potential role in tumor metastasis. It has been reported that histopathological examination could occaisionally miss lymph node micrometastasis. PURPOSE: The aim of this study was to investigate the role of CD44v in metastasis of rectal carcinoma to the pelvic lateral lymph nodes around the obturator nerve, obturator vessel and superior vesical artery. METHODS: Thirty pelvic lateral lymph nodes reported normal histopathologically from 22 patients with rectal carcinomas, 22 rectal carcinomas and their corresponding colonic mucosas. We have used RT-PCR for the detection of CD44 gene products (CD44v and CD44 v6-7) in samples. RESULTS: The expression rates of CD44v were 2/22 (9%) for normal colonic mucosa, 20/22 (90%) for cancer tissues, and 4/30 (13.3%) for pelvic lateral lymph nodes. The rates of CD44v6-7 were also 2/22 (9%) for normal colonic mucosa 20/22 (90%) for cancer tissues, but 7/30 (23.3%) for pelvic lateral lymph nodes. CONCLUSIONS: The analysis of CD44v might be useful for determination of pelvic lateral lymph nodes metastasis, but it should not be used as a metastatic marker in general for rectal cancer patients.

CD44 Expression in T-cell lymphoblastic leukemia

1. CD44 is an adhesion molecule expressed by B and T lymphocytes that mediates cell attachment to extracellular matrix components and specific cell surface ligands. In normal process of T-cell development, CD44 can be implicated in homing of bone marrow-derived T-cell precursors into the thymus. In hematopoietic malignancies, CD44 and other adhesion molecules can mediate the behavior of neoplastic cells such as metastatic migration. In the leukemic process, CD44 and other adhesion molecules can mediate the behavior of neoplastic cell such as metastic migration. In the leukemic process, CD44 expression is correlated with increased numbers of circulating blasts and it is present at other sites such as the central nervous system. 2. In the present study, CD44 was investigated in lymphoblasts from 30 patients with T-cell lymphoblastic leukemia (T-ALL) and peripheral lymphocytes from 10 healthy individuals. CD44 expression was detected in 23 (77 per cent) of T-ALL cases studied and was correlated with clinical features such as mediatinal mass, adenomegaly, and infiltration of the central nervous system and other ortgans. Interestingly, CD44 expression in patient with tumor infiltration was higher than in patients with no tumor infiltration. 3. These data suggest that CD44 may be regarded as an additional marker for tumor expansion in T-cell leukemias