Platelet Leukocyte Interactions II in-Vivo Correction of Chediak-Higashi Leukocyte Function with Serotonin or Normal Platelets

Abstract To ascertain the effects of protein deprivation on hemopoietic parameters in otherwise healthy subjects, three volunteers were placed on diets containing 0.15 g protein/kg body weight for 8 days followed in 2 mo by another 8-day study period during which they ingested their usual diets containing more than 0.9 g protein/kg body weight. Complete blood counts, serum protein determinations, and tests of in vitro and in vivo leukocyte chemotaxis were performed prior to and at the conclusion of each study period. Subjects were phlebotomized of 500 ml on day 7 of each study period. Twenty-four-hour urinary erythropoietin excretion rates were assayed just prior to and again postphlebotomy. Reticulocyte counts were performed at intervals up to 1 wk postphlebotomy. Some of these determinations were replicated during a subsequent study. The hemoglobin and hematocrits decrased slightly but significantly after 8 days on low protein diets. Erythropoietin excretion rates and reticulocyte responses to phlebotomy were also less marked while subjects were on protein depleted diets. Leukocyte chemotaxis, measured both in vitro and in vivo, was also markedly reduced while subjects were on protein-depleted diets. We conclude that 8 days of moderately severe protein deprivation significantly impairs erythropoiesis and leukocyte function in otherwise healthy individuals.

Download Full-text

Involvement of leukocyte function-associated antigen-1 (LFA-1) in the invasion of hepatocyte cultures by lymphoma and T-cell hybridoma cells.

The Journal of Cell Biology ◽

10.1083/jcb.105.1.553 ◽

1987 ◽

Vol 105 (1) ◽

pp. 553-559 ◽

Cited By ~ 33

Author(s):

E Roos ◽

F F Roossien

Keyword(s):

T Cell ◽

Tumor Cells ◽

Cell Types ◽

Hybridoma Cells ◽

Lymphoma Cells ◽

Hepatocyte Cultures ◽

Leukocyte Function ◽

Vitro Model

We studied the interaction of MB6A lymphoma and TAM2D2 T cell hybridoma cells with hepatocyte cultures as an in vitro model for in vivo liver invasion by these tumor cells. A monoclonal antibody against leukocyte function-associated antigen-1 (LFA-1) inhibited adhesion of the tumor cells to the surface of hepatocytes and consequently strongly reduced invasion. This effect was specific since control antibodies, directed against Thy.1 and against T200, of the same isotype, similar affinity, and comparable binding to these cells, did not inhibit adhesion. This suggests that LFA-1 is involved in the formation of liver metastases by lymphoma cells. TAM2D2 T cell hybridoma cells were agglutinated by anti-LFA-1, but not by control antibodies. Reduction of adhesion was not due to this agglutination since monovalent Fab fragments inhibited adhesion as well, inhibition was also seen under conditions where agglutination was minimal, and anti-LFA-1 similarly affected adhesion of MB6A lymphoma cells that were not agglutinated. The two cell types differed in LFA-1 surface density. TAM2D2 cells exhibited 400,000 surface LFA-1 molecules, 10 times more than MB6A cells. Nevertheless, the level of adhesion and the extent of inhibition by the anti-LFA-1 antibody were only slightly larger for the TAM2D2 cells.

Download Full-text

Coblockade of the LFA1:ICAM and CD28/CTLA4:B7 pathways is a highly effective means of preventing acute lethal graft-versus-host disease induced by fully major histocompatibility complex-disparate donor grafts

Blood ◽

10.1182/blood.v85.9.2607.bloodjournal8592607 ◽

1995 ◽

Vol 85 (9) ◽

pp. 2607-2618 ◽

Cited By ~ 87

Author(s):

BR Blazar ◽

PA Taylor ◽

A Panoskaltsis-Mortari ◽

GS Gray ◽

DA Vallera

Keyword(s):

Graft Versus Host Disease ◽

Cytotoxic T Lymphocyte ◽

Effective Means ◽

Intercellular Adhesion Molecule ◽

Host Disease ◽

Graft Versus Host ◽

Leukocyte Function ◽

Highly Effective

We have developed an in vitro system in which C57BL/6 donor splenocytes are exposed to B10.BR host alloantigens in the context of deficient CD28:B7 signaling as a means of preventing graft-versus-host disease (GVHD). Although 54% to 82% of MLR alloresponse was inhibited by cytotoxic T-lymphocyte antigen 4 (CTLA4)-Ig treatment of host stimulator cells, treated splenocytes were still capable of causing GVHD when infused in vivo. By adding anti-leukocyte function antigen 1 (anti-LFA1) antibody to hCTLA4-Ig in vitro to coblock the LFA1:intercellular adhesion molecule (ICAM) signaling, splenic alloresponse was inhibited by > or = 89%, yet GVHD induction capabilities were retained. Because antigen-primed cells might be more susceptible to CD28:B7 blockade, we investigated whether hCTLA4-Ig alone, anti-LFA1 antibody alone, or the combination of both added to donor-antihost in vitro primed cells could reduce GVHD. To facilitate hyporesponsiveness induction and to block B7 and ICAM ligands that are upregulated during GVHD, these reagents were also administered to recipients post-BMT. We have shown that hCTLA4-Ig plus anti-LFA1 antibody is highly effective in preventing GVHD-induced lethality (88% to 100% of treated mice surviving versus 0% to 28% of controls surviving). For optimal prevention, both hCTLA4-Ig and anti-LFA1 must be used in vitro in the context of donor-antihost primed splenocytes and continued in vivo. This in vitro-in vivo combined approach was associated with donor engraftment, and recipients were not globally immunosuppressed. We conclude that blocking both the CD28/B7 and the LFA1:ICAM pathways are critical to effective GVHD prevention and may offer advantages to in vitro donor T-cell removal.

Download Full-text

Adenosine, an endogenous anti-inflammatory agent

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.1.5 ◽

1994 ◽

Vol 76 (1) ◽

pp. 5-13 ◽

Cited By ~ 430

Author(s):

B. N. Cronstein

Keyword(s):

Cell Function ◽

Signaling Proteins ◽

Adenosine Receptor Agonists ◽

Inflammatory Agent ◽

Therapeutic Uses ◽

Leukocyte Function ◽

Anti Inflammatory ◽

Oxygen Metabolites ◽

A2 Receptors

Adenosine receptors are present on most cells and organs, yet, although the physiological effects of adenosine were first described over 60 years ago, the potential therapeutic uses of adenosine have only been recognized and realized recently. A decade ago the potent anti-inflammatory effects of adenosine were first described; adenosine, acting at specific A2 receptors, inhibits some, but not all, neutrophil functions. Adenosine inhibits phagocytosis, generation of toxic oxygen metabolites, and adhesion (to some surfaces and to endothelial cells) but does not inhibit degranulation or chemotaxis. Occupancy of adenosine A2 receptors modulates leukocyte function by a novel mechanism. Although adenosine A2 receptors are classically linked to heterotrimeric GS signaling proteins and stimulation of adenylate cyclase, adenosine 3′,5′-cyclic monophosphate does not act as the second messenger for inhibition of leukocyte function. By a mechanism that still remains obscure, occupancy of adenosine A2 receptors on neutrophils “uncouples” chemoattractant receptors from their stimulus-transduction proteins. The concentrations of adenosine that inhibit inflammatory cell function are similar to those observed in vivo and suggest a role for adenosine in the modulation of inflammation in vivo. Indeed, recent studies indicate that nonmetabolized adenosine receptor agonists are potent anti-inflammatory agents, and other studies indicate that methotrexate, a commonly used anti-inflammatory agent, diminishes inflammation by increasing adenosine release at inflamed sites. The observations reviewed here suggest that adenosine and agents that act through adenosine are excellent candidates for development as anti-inflammatory agents.

Download Full-text

Modulation of polymorphonuclear leukocyte function by cetiedil

Blood ◽

10.1182/blood.v62.2.274.bloodjournal622274 ◽

1983 ◽

Vol 62 (2) ◽

pp. 274-279

Author(s):

JB Wolach ◽

TD Coates ◽

DY Tzeng ◽

RL Baehner ◽

LA Boxer

Keyword(s):

Polymorphonuclear Leukocyte ◽

Myristate Acetate ◽

Leukocyte Function ◽

Dose Dependent Fashion ◽

Induced Aggregation ◽

Dose Dependent ◽

Aggregation Of Platelets ◽

Primary Granule ◽

Granule Product

Cetiedil citrate monohydrate inhibits sickling of red cells and aggregation of platelets. We assessed its ability to attenuate polymorphonuclear leukocyte (PMN) function. PMN aggregation in response to 2 X 10(-7) M formyl-met-leu-phe (FMLP) was inhibited in a dose- dependent fashion by cetiedil concentrations ranging from 60 to 250 microM. Additionally, 125 microM cetiedil inhibited PMN aggregation in response to 2 X 10(-7) M FMLP, 20 ng/ml phorbol myristate acetate (PMA), and 1 X 10(-6) M A23187 by 69% +/- 18%, 72% +/- 20%, and 65% +/- 4%, respectively. Inhibition of FMLP-induced aggregation was provided by only 5 min of incubation of the drug with the cells and was partially reversible. Cell viability was unaffected by exposure of PMN to the drug. Correspondingly, 125 microM cetiedil prevented the translocation of calcium from the PMN membrane as assessed by chlorotetracycline fluorescence. Paralleling the effect of the drug on PMN aggregation, 125 microM cetiedil inhibited release of superoxide by 55% and decreased the number of available 3H-FMLP receptors. However, its effect on release of the primary granule constituent, myeloperoxidase, was minimal (4.5% inhibition), while the effect on release of the specific granule product, lactoferrin (27% inhibition), was modest. These studies indicate that cetiedil affects PMN aggregation and superoxide release to a much greater extent than PMN degranulation. Thus, cetiedil may have potential uses in modulating inflammatory response in vivo.

Download Full-text

Fibrin(ogen)-αMβ2Interactions Regulate Leukocyte Function and Innate Immunity In Vivo

Experimental Biology and Medicine ◽

10.1177/153537020422901104 ◽

2004 ◽

Vol 229 (11) ◽

pp. 1105-1110 ◽

Cited By ~ 70

Author(s):

Matthew J. Flick ◽

Xinli Du ◽

Jay L. Degen

Keyword(s):

Innate Immunity ◽

Leukocyte Function

Download Full-text

Bltr Mediates Leukotriene B4–Induced Chemotaxis and Adhesion and Plays a Dominant Role in Eosinophil Accumulation in a Murine Model of Peritonitis

Journal of Experimental Medicine ◽

10.1084/jem.192.3.439 ◽

2000 ◽

Vol 192 (3) ◽

pp. 439-446 ◽

Cited By ~ 143

Author(s):

Andrew M. Tager ◽

Jennifer H. Dufour ◽

Katayoon Goodarzi ◽

Scott D. Bercury ◽

Ulrich H. von Andrian ◽

...

Keyword(s):

Dominant Role ◽

Leukotriene B4 ◽

Calcium Flux ◽

Leukocyte Activation ◽

Functional Roles ◽

Leukocyte Function ◽

Inflammatory Processes ◽

Ltb4 Receptor

Leukotriene B4 (LTB4) is a potent chemoattractant active on multiple leukocytes, including neutrophils, macrophages, and eosinophils, and is implicated in the pathogenesis of a variety of inflammatory processes. A seven transmembrane–spanning, G protein–coupled receptor, called BLTR (LTB4 receptor), has recently been identified as an LTB4 receptor. To determine if BLTR is the sole receptor mediating LTB4-induced leukocyte activation and to determine the role of LTB4 and BLTR in regulating leukocyte function in inflammation in vivo, we generated a BLTR-deficient mouse by targeted gene disruption. This mouse reveals that BLTR alone is responsible for LTB4-mediated leukocyte calcium flux, chemotaxis, and firm adhesion to endothelium in vivo. Furthermore, despite the apparent functional redundancy with other chemoattractant–receptor pairs in vitro, LTB4 and BLTR play an important role in the recruitment and/or retention of leukocytes, particularly eosinophils, to the inflamed peritoneum in vivo. These studies demonstrate that BLTR is the key receptor that mediates LTB4-induced leukocyte activation and establishes a model to decipher the functional roles of BLTR and LTB4 in vivo.

Download Full-text