LFA-1/ICAM-1 costimulation plays an important role in immunologic reaction of many different T cell populations. After TCR/CD3 complex cross-linking MHC/peptide, LFA-1, expressed on T cell increases a higher affinity and avidity for ICAM-1 rapidly. LFA-1 is a key molecule in formation of the immune synapse. LFA-1/ICAM-1 costimulation can engage various signaling events of T cell by up-regulating the activities of PI 3-kinase, sphingomyelinase, and c-Jun NH2-terminal kinase. With the costimulation of LFA-1/ICAM-1, engagement of TCR molecules results in a significant increase of T cell activities, including higher Th1 cytokines production, strongly proliferative response and higher T cell cytotoxicity.
Animals ; Cytokines ; biosynthesis ; Cytotoxicity, Immunologic ; Humans ; Intercellular Adhesion Molecule-1 ; physiology ; Lymphocyte Activation ; Lymphocyte Function-Associated Antigen-1 ; physiology ; Signal Transduction ; T-Lymphocytes ; immunology

LFA-1 and ICAM-1 mediate a bi-directional signaling across the cell membrane which is essential for biological functions of lymphocyte, including exudation, activation, adhesion, immunosurveillance as well as immuno-logical synapse formation. The signal transducing is a dynamic process and dependent on the binding capacity between LFA-1 and ICAM-1. The affinity and the avidity of LFA-1 are two major regulation forms in this process. Phosphorylation of LFA-1 and cytoskeleton protein talin 1 play a critical role in signal transducing. In biology of lymphocyte, LFA-1 and ICAM-1 interaction forms the co-stimulatory signal to promote activation, proliferation and division. In this article the regulation of binding capacity between LFA-1 and ICAM-1, the regulation of LFA-1 subunit phosphorylation, the role of talin1 in signaling transduction of LFA-1 and ICAM-1, the synergic stimulatory signaling of LPA-1 and ICAM-1 were reviewed.
Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; physiology ; Ligands ; Lymphocyte Function-Associated Antigen-1 ; metabolism ; physiology ; Lymphocytes ; cytology ; immunology ; metabolism ; Phosphorylation ; Signal Transduction ; physiology ; Talin ; metabolism

The functional immaturity of PMNs is one of the major causes of overwhelming sepsis in newborns. In this study, we observed functions and surface markers of PMNs to investigate what causes the functional immaturity of PMNs in newborns. As results, the percentage of EA rosette forming PMNs (58.5 +/- 15.5%) and the chemotactic movement (0.14 +/- 0.09 mm) of cord blood PMNs were significantly lower than those of adult peripheral blood PMNs (70.8 +/- 9.9%, 0.60 +/- 0.34 mm). Cord blood PMNs showed decreased glass adherence and ADCC activity. The expression of Fc gamma RII or Fc gamma RIII was a little lower than those of adult peripheral blood PMNs, but the expression of Fc gamma RI (43.1 +/- 26.8%) was significantly higher than that of adult peripheral blood PMNs (3.2 +/- 1.8%). There was a significant difference in LFA-1 expression between EA rosette forming PMNs (92.9 +/- 9.1%) and EA rosette non-forming PMNs (25.6 +/- 22.6%). From these results, it is assumed that neonatal PMNs may consist of heterogeneous populations. And the relatively high percentage of EA rosette non-forming PMNs which express a low level of LFA-1 may be responsible for the functional immaturity of cord blood PMNs.
Antibody-Dependent Cell Cytotoxicity ; Cell Adhesion ; Chemotaxis, Leukocyte ; Fetal Blood/*cytology ; Human ; Lymphocyte Function-Associated Antigen-1/*physiology ; Neutrophils/*physiology ; Receptors, IgG/*physiology ; Rosette Formation

OBJECTIVETo explore the impact of mobilization with recombinant human granulocyte colony stimulated factor (rhG-CSF) on the migration and adhesive function and their related signal mechanism mediated by the CXCR4 and lymphocyte function antigen-1 (LFA-1) molecules on the surfaces of CD4(+) T cells.

METHODSBefore and at day 5 on rhG-CSF mobilization, the expression rates of CXCR4 and LFA-1 (CD11a) on CD4(+) T cells in the peripheral blood were detected by tricolor fluorescence labeling, and the migration and adhesive activities of CD4(+) T cells to stroma cell-derived factor 1 alpha (SDF-1 alpha) and intercellular adhesion molecule-1 (ICAM-1) were also tested.

RESULTSThe expression of CXCR4 on CD4(+) T lymphocytes was (84.58 +/- 20.31)% before mobilization and (81.23 +/- 22.46)% at day 5 on mobilization. The expression of LFA-1 on CD4(+) T lymphocytes before and at day 5 on mobilization was 100%. There was no significant difference in the expression CXCR-4 and LFA-1 on CD4(+) T lymphocytes whether mobilization (P > 0.05). SDF-1 alpha induced 4 hours' CD4(+) T cells migration didn't change markedly before and after mobilization \[(28.5 +/- 10.3)% vs (31.2 +/- 8.9)%\] (P > 0.05). The adhesive activity of CD4(+) T cells to ICAM-1 was decreased from (85.59 +/- 14.21)% to (61.45 +/- 15.07)% after mobilization (P < 0.05).

CONCLUSIONSThe expression of CXCR4 and LFA-1 on CD4(+) T lymphocytes didn't change markedly during rhG-CSF mobilization, but the adhesive activity of CD4(+) T cells to ICAM-1 was frustrated after that.

CD4-Positive T-Lymphocytes ; drug effects ; immunology ; metabolism ; physiology ; Cell Adhesion ; Cell Movement ; Cells, Cultured ; Chemokine CXCL12 ; physiology ; Granulocyte Colony-Stimulating Factor ; pharmacology ; Humans ; Intercellular Adhesion Molecule-1 ; physiology ; Lymphocyte Function-Associated Antigen-1 ; metabolism ; Receptors, CXCR4 ; metabolism ; Recombinant Proteins

We examined the role of cell adhesion molecules (CAM) by which tumor cells bind to the endothelial cells using human umbilical vein endothelial cells (HUVEC) and cultured melanoma cells. Endothelial cells from human umbilical veins were isolated and examined for CAM expression and its modulation by tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6) or interferon-gamma (IFN-gamma). The expression of intercellular adhesion molecule 1 (ICAM-1) on HUVEC was increased by TNF-alpha, IL-1 and IFN-gamma when measured by ELISA or flow cytometric (FACS) analysis. IL-6 did not increase ICAM-1 expression on HUVEC. Two melanoma cell lines, Malme-3M and SK-Mel-28, showed increased expression of ICAM-1 after treatment with TNF-alpha, IL-1 and IFN-gamma in FACS analysis. IFN-gamma induced increased expression of HLA-DR only in SK-Mel-28 melanoma cells, not in Malme-3M melanoma cells. Neither HUVEC nor melanoma cells expressed lymphocyte function-associated antigen 1 (LFA-1) in either the basal (i.e., cytokine untreated) condition or the cytokine treated condition. Melanoma cells showed minimal increment in adhesion to TNF-alpha or IL-1 treated HUVEC than to cytokine untreated HUVEC. HUVEC and melanoma cells did not express LFA-1 and increased ICAM-1 expression by TNF-alpha, IL-1 and IFN-gamma treatment in FACS analysis did not coincide with minimal increase of melanoma cells adhesion to cytokine treated HUVEC. These results suggest that adhesion between melanoma cells and HUVEC is probably mediated by molecular interaction other than ICAM-1/LFA-1.
Cell Adhesion/drug effects ; Cell Adhesion Molecules/*analysis ; Cell Division/drug effects ; Cells, Cultured ; Cytokines/*pharmacology ; Endothelium, Vascular/cytology/*physiology ; HLA-DR Antigens/analysis ; Humans ; Intercellular Adhesion Molecule-1 ; Lymphocyte Function-Associated Antigen-1/analysis ; Melanoma/*pathology ; Tumor Cells, Cultured

To investigate whether lymphocyte function-associated antigen 1 (LFA-1) and very late antigen 4 (VLA-4) are involved in vasoendothelial adhesion and transendothelial migration of high proliferative potential endothelial progenitor cells (HPP-EPCs), flow cytometry was used to analyze the expression of integrin beta1 and beta2, the expression of intercellular adhesion molecule (ICAM-1, 2) and vascular cell adhesion molecule (VCAM-1) in mouse bone marrow endothelial cells (mBMECs). The adhesion and transmigration through endothelial cells of the HPP-EPCs blocked by functional grade neutralizing antibodies of VLA-4 and LFA-1 were studied in vitro. The results revealed that HPP-EPCs were positive for CD11a and CD49d in HPP-EPCs. The expression of ICAM-1and VCAM-1 of mBMECs increased after activated by IL-1beta and TNF-alpha. The results of adhesion in vitro revealed that the numbers of the adhered and migrated cells in the CD11a antibody group, in the CD49d antibody group and in the combinational antibody group were less than those in the isotype control antibody group. Furthermore, the number of adhered and migrated cells in the combinational antibody group was less than that in the CD11a or the CD49d antibody group (p < 0.05). It is concluded that both LFA-1 and VLA-4 are involved in vasoendothelial adhesion and transendothelial migration of HPP-EPCs.
Animals ; Antigens, CD ; metabolism ; Bone Marrow Cells ; cytology ; Cell Adhesion ; Cell Adhesion Molecules ; metabolism ; Cell Movement ; Cells, Cultured ; Endothelial Cells ; cytology ; Humans ; Integrin alpha4beta1 ; physiology ; Intercellular Adhesion Molecule-1 ; metabolism ; Lymphocyte Function-Associated Antigen-1 ; physiology ; Mice ; Stem Cells ; cytology ; Vascular Cell Adhesion Molecule-1 ; metabolism