FMLP- and TNF-stimulated monoclonal Lym-1 antibody-dependent lysis of B lymphoblastoid tumour targets by neutrophils.

Human neutrophils, incubated with Cr51-labelled B lymphoblastoid Raji cells in the presence of the anti-target monoclonal antibody (mAb) Lym-1 plus formyl-methionyl-leucyl-phenylalanine (FMLP) or tumour necrosis factor alpha (TNF-alpha), were found to induce significant C51 release, i.e. significant cytolysis. The lytic process was inhibited by mAb IV.3, specific for the Fcgamma receptor (FcgammaR) type II. The mAb 3G8, which reacts with FcgammaR type III, was ineffective. Moreover, the lysis was inhibited by the anti-CD18 mAb MEM-48. These data suggest that FMLP/Lym-1 as well as TNF-alpha/Lym-1 cytolytic systems strictly require FcgammaRII and CD18 integrins. As the lysis induced by TNF-alpha/Lym-1 was prevented by pertussis toxin (PT), PT-sensitive G-proteins are likely to intervene in post-FcgammaRII signal transduction. Both the FMLP- and the TNF-alpha-dependent systems were also found to be equally susceptible to inhibition by various inhibitors of kinases (genistein, staurosporin, 1-(5-isoquinolinnylsulphonyl)-2-methylpiperazine and wortmannin). On the contrary, an inhibitor of protein kinase C (bis-indolyl-maleimide, BIM) was effective only in the FMLP/Lym-1 cytolytic system. Therefore, it appears that signals delivered by FMLP or TNF-alpha, BIM-sensitive and insensitive respectively, converge and synergize with those from G-protein-coupled FcgammaRII and, probably, CD18-integrins to promote the expression of the neutrophil cytolytic potential.

Monoclonal Lym-1 antibody-dependent cytolysis by neutrophils exposed to granulocyte-macrophage colony-stimulating factor: intervention of FcgammaRII (CD32), CD11b-CD18 integrins, and CD66b glycoproteins.

Murine monoclonal antibody (MoAb) Lym-1 is an IgG2a able to bind HLA-DR variants on malignant B cells and suitable for serotherapeutic approaches in B-lymphoma patients. We have previously shown that Lym-1 can synergize with granulocyte-macrophage colony-stimulating factor (GM-CSF) to trigger neutrophil cytolysis towards Raji cells used as a model of B-lymphoma targets. Here we provide evidence for the intervention of certain neutrophil receptors or surface molecules in this model of cell-mediated lysis. The lysis was completely inhibited by the anti-FcgammaRII MoAb IV.3 and unaffected by the anti-FcgammaRIII MoAb 3G8. This suggests that neutrophil cytolysis involves FcgammaRII without cooperation of this receptor with FcgammaRIII. Moreover, the lysis was inhibited by an anti-CD18 MoAb (MEM48) and by a MoAb specific for carcinoembryonic antigen (CEA)-like and glycophosphatidyl inositol (GPI)-linked glycoproteins (CD66b). Using an immunofluorescence staining procedure, cross-linking of CD66b induced the redistribution of CD11b on neutrophils with distinct areas of CD11b clustering via a process susceptible of inhibition by D-mannose. This is consistent with the ability of CD11b-CD18 and CD66b to undergo lectin-like physical interactions on the neutrophil surface. Such a type of interaction is presumably instrumental for neutrophil cytolytic activity in that the lysis was inhibited by D-mannose and enhanced by the MoAb VIM-12, which mimics the cooperation between CD11b and GPI-anchored molecules by specifically interacting with CD11b lectin-like sites. Therefore, the present results prove the absolute requirement for FcgammaRII in neutrophil GM-CSF/Lym-1-mediated cytolysis and, on the other hand, define the crucial role of CD66b and CD11b/CD18 in the expression of the cell lytic potential.

Inhibitory effect of salmeterol on the respiratory burst of adherent human neutrophils.

Human neutrophils, plated in fibronectin-coated wells and stimulated with N-formyl-methionylleucyl-phenylalanine (fMLP), were found to undergo a massive and prolonged respiratory burst, as measured by monitoring superoxide production. The beta 2-agonist salmeterol inhibited the respiratory burst in a dose-dependent manner. In contrast, salbutamol was ineffective. Moreover, the neutrophil respiratory burst was partially suppressed by prostaglandin E2 (PGE2) and the phosphodiesterase type IV (PDE-IV) inhibitor RO 20-1724. When salmeterol was used in combination with PGE2 or RO 20-1724, additive inhibitory effects were observed. The inhibitory activity of salmeterol was not reversed in the presence of the beta-blocker propranolol, and did not correlate with its ability of increasing cyclic AMP (cAMP) levels. Finally, the compounds used did not affect neutrophil adherence to fibronectin-coated wells. The results suggest that salmeterol is capable of down-regulating the neutrophil oxidative response to fMLP, also of co-operating with PGE2 and PDE-IV inhibitor RO 20-1724 in a manner not related to its beta 2-receptor binding activity. In other words, salmeterol displays neutrophil-directed effects, susceptible to be amplified by natural mediators such as PGE2 or PDE-IV inhibitors, consistent with possible anti-inflammatory properties of the drug.

Monoclonal Lym-1 antibody-dependent lysis of B-lymphoblastoid tumor targets by human complement and cytokinine-exposed mononuclear and neutrophilic polymorphonuclear leukocytes.

Lym-1 is a murine IgG2a monoclonal antibody that recognizes a polymorphic variant of HLA-DR antigens on malignant B cells, with minimal cross-reactivity with normal tissues. Because it can be safely administered in vivo, a detailed knowledge of its ability to recruit and trigger the antitumor immune effector systems is required to optimize potential serotherapeutic approaches in B-lymphoma patients. By using Raji cells as a model of B-lymphoma targets, we found that Lym-1 activates complement-mediated lysis efficiently. Moreover, Lym-1 was capable of triggering the antibody-dependent cellular cytolysis (ADCC) by peripheral blood mononuclear cells (MNCs). On the contrary, it failed to trigger neutrophilic polymorphonuclear leukocyte (PMN)-mediated ADCC activity. In an attempt to enhance Lym-1 ADCC by MNCs and PMNs, nine biologic response modifiers were tested. MNC-mediated Lym-1 ADCC was significantly stimulated by interleukin-2 (IL-2) and unaffected by other mediators, including gamma-interferon (gamma-IFN), tumor necrosis factor a (TNFalpha), and granulocyte-macrophage colony-stimulating factor (GM-CSF). On the other hand, PMN-mediated Lym-1 ADCC was induced or significantly augmented by various cytokines, such as GM-CSF, TNFalpha, and gamma-IFN, and chemotaxins, such as formyl peptides (FMLP), complement fragment C5a, and IL-8. Both MNC- and PMN-mediated ADCC was unaffected by granulocyte colony-stimulating factor (G- CSF) and insulin-like growth factor-1 (IGF-1). Finally, only GM-CSF and TNFalpha augmented the number of PMNs actually engaged in the binding of Raji target cells. The findings presented here, in particular those showing stimulatory activity of biologic response modifiers, may inspire new attempts for developing Lym-1 antibody-based approaches to the therapy of B lymphomas.

Avaliacao do enxerto de crista iliaca em mandibula, atraves da cintilografia ossea. / Evaluation of iliac crest bone graft in mandible, by bone seanning

Os autores apresentam um caso de enxerto osseo de crista iliaca em mandibula, regiao ventral, por tumor giganto-celular. O acompanhamento da area enxertada foi realizado atraves da cintilografia ossea e da radiografia, devido a necessidade da associacao destes metodos para a confirmacao de sua aceitacao biologica