CD26 Antigen Expression Research Articles

The Regenerative Potential of Donkey and Human Milk on the Redox-Sensitive and Proliferative Signaling Pathways of Skin Fibroblasts.

The influence of milk bioactive peptides on skin regenerative potential and rejuvenation is very often limited because of allergic reactions. The current study is aimed at exploring the influence of donkey colostrum and mature milk, human colostrum and mature milk, and β-casein and β-casomorphine-7, on the growth and inflammatory response of the culture of cultured skin fibroblasts exposed to these conditions for twenty-four hours. Their effects on the growth-regulatory kinases and redox-sensitive, proinflammatory transcriptional factor NF-κB were detected by using specific primary antibodies against NF-κB p65, Akt-1, phospho-Akt-1, Erk-1, phospho-Erk-1, JNK, phospho-JNK, phospho-STAT-1, and CD26, while logarithmic integrated fluorescence intensity patterns were recorded by flow cytometry. The downregulation of NF-κB p65 was observed after the exposure of skin fibroblasts to donkey milk and human colostrum, while β-casein and β-casomorphine-7 exerted the opposite effect, which suggests that noncasein bioactive peptides of donkey and human milk may be responsible for anti-inflammatory properties. The exposure to all milk species examined and β-casein leads to the activation of growth-regulatory kinases (Akt1/2/3 kinase, Erk kinase, JNK kinase, and Stat-1 kinase), especially for the p-Erk pathway, which suggests that essential amino acids of casein may be responsible for Erk-induced cell cycle activation and proliferation. The opposite effect was observed when cells were exposed to β-casomorphine-7, which may affect the skin fibroblast survival and their proliferative and regenerative potential. Donkey milk did not significantly change the CD26 antigen expression. In conclusion, our results suggest that among cell signaling molecules, the most sensitive but nonspecific downstream effector is p-Erk kinase, which may point to donkey milk usefulness in wound healing, regenerative, and aesthetic dermatology. The noncasein bioactive peptides of donkey milk may be responsible for the anti-inflammatory property of donkey milk and colostrum, which may indicate the usefulness in the treatment of inflammatory skin diseases.

Expression and functional role of 1F7 (CD26) antigen on peripheral blood and synovial fluid T cells in rheumatoid arthritis patients.

The expression and the functional role of the CD26 (1F7) T cell surface molecule, an ectoenzyme which seems to represent a functional collagen receptor of T lymphocytes and to have a role in T cell activation, were analysed in both peripheral blood (PB) and synovial fluid (SF) T cell samples from patients with active and inactive rheumatoid arthritis (RA). Although patients with active disease displayed higher percentages of PB CD26+ CD4+ T cells than inactive RA and control subjects, CD26 antigen expression on RA SF T lymphocytes was low. The anti-1F7 binding to the T cell surface, that led to CD26 antigen modulation and enhancement of both IL-2 synthesis by, and 3H-TdR incorporation of, anti-CD3- or anti-CD2-triggered PB T cells in RA and control subjects, was unable to affect significantly both expression and functional activity of RA SF T lymphocytes. Since the 1F7 antigen spontaneously reappeared on the surface of unstimulated SF T cells after 2-5 days of culturing, the low 1F7 antigen expression of anti-1F7 in the SF T cell compartment may be the result of in vivo molecule modulation exerted by the natural ligand in the joint, with important implications for T cell activation and lymphokine synthesis.

Cell surface characterization of T lymphocytes and allergen-specific T cell clones: Correlation of CD26 expression with T H1 subsets

To evaluate the possibility of using surface molecules as markers for human T helper cell subsets, we studied the expression of surface molecules on T cell clones (TCCs) specific for the major birch pollen allergen, Bet v 1. No difference in the expression of the respective receptors for interferon-γ (IFN-γ), IL-4, IL-6, or IL-10 could be detected on T H subsets, nor did CD25 expression (IL-2R α-chain) differ significantly. However, high expression of CD26 antigen (dipeptidyl peptidase IV) correlated with a T H1/T H0-like phenotype, whereas T H2-like clones displayed a lower expression of CD26 antigen. Comparing cytokine production and CD26 expression simultaneously, we found a correlation between the IL-4/IFN-γ ratio and the density of CD26 per cell. We could show that the amount of IL-4 secretion, and not of IFN-γ secretion, was responsible for this correlation. To evaluate whether CD26 antigen expression is regulated by stimuli inducing a T H1- or T H2-like phenotype, peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-4, IFN-γ, and IL-12, respectively. Incubation with IL-4 led to T cells with a T H2-like cytokine pattern and a significantly lower expression of CD26; IFN-γ and IL-12 led to a T H1 shift associated with an increased expression of CD26 on CD4 + T cells. By means of intracellular cytokine detection we analyzed expression of CD26 on CD4 + PBMC stimulated to produce IFN-γ or IL-4 on a single cell level. All activated, cytokine-producing CD4 + T cells expressed CD26, but the increase in CD26 expression was higher in cells producing IFN-γ. These data suggest that regulation of CD26 cell surface expression correlates with the production of T H1-like cytokines. (J Allergy Clin Immunol 1997;100:348-55.)

Increased Protein Kinase C Activity in Human Memory T Cells

A number of T cell surface antigens including CD45R0, CD58, CD11α. CD29, CD44, and CD26 are present on differentiated T cells and identify T cell populations that respond to recall antigens. To further study the biochemical basis for this immune memory, we used an anti-CD26 mAb to identify the memory T cell population. We have previously shown that CD26+ T cells display an increased proliferative response to anti-CD3 and anti-CD2 mAbs and furthermore have significantly greater PMA-induced phosphorylation of the invariant γ and δ chains of the T cell receptor (TCR)/CD3 complex when compared to CD26- T cells. This suggested that differential distribution of protein kinase C (pkC) in the CD26 subsets may be related to the reduced activation requirements observed in memory T cells upon recall antigen challenge. We now directly demonstrate that when peripheral blood T cells are sorted into CD26+ and CD26- T cells the majority of pkC activity can be recovered from the cytosol fraction of the memory (CD26+) T cell population. When activated through the TCR/CD3 pathway, the CD2 pathway, or directly by the phorbol ester, PMA, the memory (CD26+) T cells showed an increased proliferative response that was inhibited by the pkC inhibitor, staurosporine. When CD26+ T cells were cultured in the presence of PMA, which depletes pkC activity, CD26 antigen expression was down-regulated. PMA was also able to inhibit phytohemagglutinin (PHA)-induced expression of the CD26 antigen in CD26- T cells. These data demonstrate a relation between CD26 expression and pkC activity and suggest that enhanced pkC activity is associated with memory T cell function.

Expression of the rat CD26 Antigen (dipeptidyl peptidase IV) on subpopulations of rat lymphocytes

The T cell activation antigen CD26 has been recently identified as the cell surface ectopeptidase dipeptidyl peptidase W. (DPP-IV). DPP-IV is found on many cell types, including lymphocytes, epithelial cells, and certain endothelial cells. The MRC OX61 monoclonal antibody (MAb) which specifically recognises rat DPP-IV was used to examine the expression of CD26/DPP-IV on rat lymphocytes. The molecular nature of the antigen was examined by immunoprecipitation from thymocytes, splenocytes, and hepatocytes. Analysis by one- and two-dimensional gel electrophoresis indicated that the native form of CD26 includes a 220-kDa homodimer. On tissue sections MRC OX61 MAb stained nearly all thymocytes and in the spleen and lymph nodes predominantly stained the T cell areas. However, in immunofuorescence experiments OX61 stained 80 to 87% of lymph node cells and 78 to 85% of spleen cells. Furthermore, two-colour immunofluorescence analysis of the CD4+, CD8+, and Ig+ lymphocyte subsets indicated that only 2 to 5% of each of these subsets lacked OX61 staining. Spleen cells and thymocytes of both CD4+ and CD8+ subsets stained much more intensely with OX61 after these cells were stimulated with phytohemagglutinin. These findings indicate that rat CD26 antigen expression is not confined to the T cell population as has been suggested, but also occurs on B cells, and is increased on T cells following their activation.