• Molecules and Cells
• /
• v.44 no.5
• /
• pp.328-334
• /
• 2021

The advent of the major histocompatibility complex (MHC) multimer technology has led to a breakthrough in the quantification and analysis of antigen-specific T cells. In particular, this technology has dramatically advanced the measurement and analysis of CD8 T cells and is being applied more widely. In addition, the scope of application of MHC multimer technology is gradually expanding to other T cells such as CD4 T cells, natural killer T cells, and mucosal-associated invariant T cells. MHC multimer technology acts by complementing the T-cell receptor-MHC/peptide complex affinity, which is relatively low compared to antigen-antibody affinity, through a multivalent interaction. The application of MHC multimer technology has expanded to include various functions such as quantification and analysis of antigen-specific T cells, cell sorting, depletion, stimulation to replace antigen-presenting cells, and single-cell classification through DNA barcodes. This review aims to provide the latest knowledge of MHC multimer technology, which is constantly evolving, broaden understanding of this technology, and promote its widespread use.

• IMMUNE NETWORK
• /
• v.10 no.4
• /
• pp.135-143
• /
• 2010

Background: Cordyceps militarys water extract (CME) has been reported to exert antitumor and immunomodulatory activities in vivo and in vitro. However, the therapeutic mechanism has not yet been elucidated. In this study, we examined the effects of CME on the antigen presenting function of antigen presenting cells (APCs). Methods: Dendritic cells (DCs) were cultured in the presence of CME, and then allowed to phagocytose microspheres containing ovalbumin (OVA). After washing and fixing the efficacy of OVA, peptide presentation by DCs were evaluated using CD8 and CD4 T cells. Also, we confirmed the protein levels of proinflammatory cytokines through western blot analysis. Results: CME enhanced both MHC class I and class II-restricted presentation of OVA in DCs. In addition, the expression of both MHC class I and II molecules was enhanced, but there was no changes in the phagocytic activity of exogenous OVA. Furthermore, CME induced the protein levels of iNOS, COX-2, proinflammatory cytokines, and nuclear p65 in a concentration-dependent manner, as determined by western blot. Conclusion: These results provide an understanding of the mechanism of the immuno-enhancing activity of CME on the induction of MHC-restricted antigen presentation in relation to their actions on APCs.

• Journal of Microbiology
• /
• v.39 no.4
• /
• pp.300-304
• /
• 2001

Epstein-Barr Virus(EBV)-transformed lymphoblastoid B cell lines, BLCL which expresse antigens, are potential antigen-presenting cells(APCs) for the induction of CTL in vitro. However transfection of BLCLs with subsequent selection by antibiotics is notoriously difficult because plating efficiencies of BLCLsare reported to be 1% or less. To generated stable transfectants of BLCLs we produced high titers of retroviruess encoding pp 65 antigen of human cytomegalovirus of foreign antigens and trans-duced them of BLCLs. The pp 65 gene was cloned into the retroviral vector pLXSN. The recombinant retroviral vector was transfected to ecotropic packaging cell line, CP&E86, and this polyclonal recom-binant retrovirus was transduced to PA317 that is amphotropic pakaging cell line. The titers of colned PA317 amphotropic retroviruses ranged from 5 to $\times$10$^{6}$ colony forming units (CFU)per ml (CFU/ml) We performed three rounds of consecutive transductions to BLCLs in order to improve the clon-ing effieiencies. The expression of recombinant HCMV-pp65 antigen was more than 20% after the final transduction. THe third-transduced BLCLs were easily selected in optimal concentration of G418. BLCLs expressing foreign antigens could be used as target cells for CTL assay and/or as APCs for induction of in vitro CTL responses specific for viral and tumor antigens.

• BMB Reports
• /
• v.30 no.6
• /
• pp.415-420
• /
• 1997

Although $CD4^+$ T cell responses to protein-derived antigen have well been understood, the epitopes recognized by hapten-specific $CD4^+$ T cells have not been fully defined. In this study, we characterized the response of a T cell hybridoma (5Di0.1B8) which is specific for a hapten. N-hydroxysuccinimidyl-4-azidobenzoate (HSAB) restricted by MHC class II $I-A^d$. Using three different antigen presenting cells (APCs) expressing $I-A^d$, the role of class II MHC proteins in haptenic antigen presentation and subsequent activation of 5D10.1B8 has been examined. Activation of 5D10.1B8 T cells by HSAB analogs was also performed. Our results show that each APC activated T cells differentially and that interleukin-2 (IL-2) augmented antigen-presenting ability of all the APCs, suggesting that increased expression of class II MHC protein by IL-2 played an important role in HSAB presentation and T cell activation. Finally, early T cell receptor-dependent signals induced by HSAB or its analogs were examined by phosphotyrosine immunoblot analysis, and showed that tyrosine phosphorylation level of a 18-20 kD protein increased upon stimulation.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.78-79
• /
• 2003

T cell activation is initited by the interaction of T cells with antigen-presenting cells (APCs) in the context of peptide antigen. Initial conjugates are formed by binding between lymphocyte-associated antigen-l (LFA-l, also known as CD11a-CD18) and intercellular adhesion molecule-l (ICAM-1), or CD2 and LFA-3, or other pairs of interactive proteins. (omitted)

• Journal of Veterinary Clinics
• /
• v.8 no.1
• /
• pp.1-10
• /
• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• IMMUNE NETWORK
• /
• v.7 no.2
• /
• pp.80-86
• /
• 2007

Background: CD40-activated B (CD40-B) cells might be an attractive source of autologous antigen-presenting cells (APCs) for immunotherapy due to the convenience to obtain from peripheral blood and expand in vitro. Moreover, CD40-B cells were found to be comparable with DCs in their capacity to raise antigen-specific CD8+ T cells. Here, we have established K562 cells expressing CD40L to expand CD40-activated B cells used for APCs. Methods: After activation of B cell by K562/CD40L, CD40-B cells were examined by counting B cell numbers. Surface expression of CD54, CD80, CD86 and HLA class II was measured by flow cytometry. The CD40-B cells were tested for its function as APC by mixed lymphocyte reactions (MLR) and by induction of T cell responses specific for pp65 peptide in vitro. Results: The expansion of B cells by K562/CD40L increased about 6-folds compared with anti-CD40 or K562. Furthermore, the expression of CD54, CD80, CD86 and HLA class II was up-regulated by K562/CD40L. B cells by K562/CD40L showed comparable antigen presentation activity with mature DCs as shown in MLR, INF-${\gamma}$ ELISPOT assay. Conclusion: These results suggest that K562/CD40L could be used to generate activated B cells as potent APCs which could be useful for cellular vaccination and adoptive immunotherapy.

• Journal of Periodontal and Implant Science
• /
• v.44 no.5
• /
• pp.235-241
• /
• 2014

Purpose: Regulatory T cells (Tregs), expressing CD4 and CD25 as well as Foxp3, are known to play a pivotal role in immunoregulatory function in autoimmune diseases, cancers, and graft rejection. Dendritic cells (DCs) are considered the major antigen-presenting cells (APCs) for initiating these T-cell immune responses, of which $CD103^+$ DCs are derived from precursor human peripheral blood mononuclear cells (PBMCs). The aim of the present study was to evaluate the capacity of these PBMC-derived $CD103^+$ DCs to promote the differentiation of antigen-specific Tregs. Methods: Monocyte-derived DCs were induced from $CD14^+$ monocytes from the PBMCs of 10 healthy subjects. Once the $CD103^+$ DCs were purified, the cell population was enriched by adding retinoic acid (RA). Peptide numbers 14 and 19 of Porphyromonas gingivalis heat shock protein 60 (HSP60) were synthesized to pulse $CD103^+$ DCs as a tool for presenting the peptide antigens to stimulate $CD3^+$ T cells that were isolated from human PBMC. Exogenous interleukin 2 was added as a coculture supplement. The antigen-specific T-cell lines established were phenotypically identified for their expression of CD4, CD25, or Foxp3. Results: When PBMCs were used as APCs, they demonstrated only a marginal capacity to stimulate peptide-specific Tregs, whereas $CD103^+$ DCs showed a potent antigen presenting capability to promote the peptide-specific Tregs, especially for peptide 14. RA enhanced the conversion of $CD103^+$ DCs, which paralleled the antigen-specific Treg-stimulating effect, though the differences failed to reach statistical significance. Conclusions: We demonstrated that $CD103^+$ DCs can promote antigen-specific Tregs from naive T cells, when used as APCs for an epitope peptide from P. gingivalis HSP60. RA was an effective reagent that induces mature DCs with the typical phenotypic expression of CD103 that demonstrated the functional capability to promote antigen-specific Tregs.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.7
• /
• pp.2665-2669
• /
• 2015

CD4+CD25+regulatory T cells (Tregs) play a key role in regulation of immnue response and maintenance of self-tolerance. Studies have found Tregs could suppress tumor-specific T cell-mediated immune response and promote cancer progression. Depletion of Tregs can enhance antitumor immunity. Dendritic cells (DCs) are professional antigen-presenting cells and capable of activating antigen-specific immune responses, which make them ideal candidate for cancer immunotherapy. Now various DC vaccines are considered as effective treatment for cancers. The aim of this study was to evaluate variation of Tregs in BALB/C mice with hepatocellular carcinoma and investigate the interaction between tumor-derived Tregs, effector T cells (Teff) and splenic DCs. We found the percentages of Tregs/CD4+ in the peripheral blood of tumor-bearing mice were higher than in normal mice. Tumor-derived Tregs diminished the up-regulation of costimulatory molecule expression on splenic DCs, even in the presence of Teff cells and simultaneously inhibited IL-12 and $TNF-{\alpha}$ secretion by DCs.

• BMB Reports
• /
• v.46 no.1
• /
• pp.17-24
• /
• 2013

Transcutaneous immunization refers to the topical application of antigens onto the epidermis. Transcutaneous immunization targeting the Langerhans cells of the skin has received much attention due to its safe, needle-free, and noninvasive antigen delivery. The skin has important immunological functions with unique roles for antigen-presenting cells such as epidermal Langerhans cells and dermal dendritic cells. In recent years, novel vaccine delivery strategies have continually been developed; however, transcutaneous immunization has not yet been fully exploited due to the penetration barrier represented by the stratum corneum, which inhibits the transport of antigens and adjuvants. Herein we review recent achievements in transcutaneous immunization, focusing on the various strategies for the enhancement of antigen delivery and vaccination efficacy.