Laminin concentration in ascites of patients with hepatic cirrhosis and peritoneal carcinomatosis

Laminin levels in ascitic fluid have been proposed as a marker for neoplastic ascites. We compared the concentration of laminin in serum and in ascitic fluid from patients with hepatic cirrhosis and peritoneal carcinomatosis and assessed the diagnostic value of serum laminin levels in differentiating neoplastic from benign ascites. Laminin concentrations were determined by ELISA with antibodies against laminin extracted from the human placenta, in patients with ascites due to peritoneal carcinomatosis (N = 20) and hepatic cirrhosis (N = 33). Patients with infected or hemorrhagic ascites were excluded. The receiver operating characteristic curve was used to determine the sensitivity and specificity of serum laminin for the diagnosis of neoplastic ascites. When compared to the group with cirrhosis, the carcinomatosis group presented significantly higher mean laminin levels in serum (3.3 ± 0.5 vs 2.1 ± 0.4 æg/ml, mean ± SD, P < 0.05) and ascites (2.8 ± 0.5 vs 1.6 ± 0.4 æg/ml, P < 0.05). Although laminin concentration was higher in serum than in ascites, the laminin serum/ascites ratio and serum-ascites gradient did not differ between the studied groups. A significant correlation (r = 0.93, P < 0.0001) was observed between the serum and ascites laminin values. Serum laminin levels >2.25 æg/ml showed 100 percent sensitivity and 73 percent specificity for the diagnosis of neoplastic ascites. Serum concentration seems to be the main determinant of laminin levels in ascitic fluid and its values can be used as a diagnostic parameter in the study of neoplastic ascites.

Functional differences between two morphologically distinct cell subpopulations within a human colorectal carcinoma cell line

The LISP-I human colorectal adenocarcinoma cell line was isolated from a hepatic metastasis at the Ludwig Institute, Säo Paulo, SP, Brazil. The objective of the present study was to isolate morphologically different subpopulations within the LISP-I cell line, and characterize some of their behavioral aspects such as adhesion to and migration towards extracellular matrix components, expression of intercellular adhesion molecules and tumorigenicity in vitro. Once isolated, the subpopulations were submitted to adhesion and migration assays on laminin and fibronectin (crucial proteins to invasion and metastasis), as well as to anchorage-independent growth. Two morphologically different subpopulations were isolated: LISP-A10 and LISP-E11. LISP-A10 presents a differentiated epithelial pattern, and LISP-E11 is fibroblastoid, suggesting a poorly differentiated pattern. LISP-A10 expressed the two intercellular adhesion molecules tested, carcinoembryonic antigen (CEA) and desmoglein, while LISP-E11 expressed only low amounts of CEA. On the other hand, adhesion to laminin and fibronectin as well as migration towards these extracellular matrix proteins were higher in LISP-E11, as expected from its poorly differentiated phenotype. Both subpopulations showed anchorage-independent growth on a semi-solid substrate. These results raise the possibility that the heterogeneity found in the LISP-I cell line, which might have contributed to its ability to metastasize, was due to at least two different subpopulations herein identified

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determie whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo

Characterization of glycoprotein gp43, the major laminin-binding protein of Paracoccidioides brasiliensis

We have demonstrated that laminin mediates the adhesion of P. brasiliensis to monolayers of epithelial cells through specific binding to the surface glycoprotein gp43. This binding seems to be related to the fungal pathogenesis. We now report the confirmation of these findings by scanning electron microscopy and show that some isolates that do not secrete gp43 do express the protein as seen studying whole cell extracts. This results confirm the ability of these strains to produce paracoccidioidomycosis but should not be used for serological purposes since the absence of gp43 in exoantigens may lead to false negative results

On the association between HLA-A1 and B5 and clinical forms of schistosomiasis mansoni

The association between both HLA-A1 and B5 antigens and chronic forms of human schistosomiasis was studied in 64 patients and 26 normal controls from a southern Brazilian hospital. No apparent correlation between the chronic forms of the disease and the expression of those antigens was detected. However, the analysis of these date together with those observed on an Egyptian sample suggests that the presence of either of the antigens and the hepatomegalic forms of schistosomiasis is significant, without heterogeneity. Converseley, the association of histocompatibility antigens with splenogegaly is consistent and significant only for HLA-B5, but not HLA-A1

The immunodominant surface antigen of Plasmodium gallinaceum is present in both the salivary gland and oocyst sporozoites

1. Monoclonal antibodies (MAbs) against surface antigens of Plasmodium gallinaceum sporozoites, an avian malaria parasite, were produced using spleen cells from mice immunized with sporozoites from mosquito salivary glands (SGS) or from midadgusts containing oocysts (OoS). 2. All of the 15 MAbs teted (11 anti-SGS and 4 anti-OoS) reacted with SGS and OoS by indirect immunofluorescence and circumsporozoiter precipitation reactions. Fourteen of these MAbs (11 anti-SGS and 3 anti-OoS) produced a Western blot (WB) patten identical to that produced with serum from mice lyperimmunized with viable intacts sporozoites. 3. All MAbs and the immune sera recognized only two polypeptide bands of approximate molecutlar weight 78 and 64KDa. 4. No difference in the WB pattern was observed when-or 12-day SGS or OoS extracts were used as antigens in WB. This antigenic similary was confirmed when the total protein extracts were visualized on silver-stained SDS-PAGE gel

Two-site immunoassays for the measurement of serum laminin: correlation with breast cancer staging and presence of auto-antibodies

Binding to and destruction of basement membrane (BM) are necessary steps for cancer cells to extravasate and metastasize. Serum levels of released BM components may correlate with the staging of human cancers or with inflammatory disorders. Furthermore, released material may also induce autoantibodies. Since Iaminin, an 800-kDa glycoprotein, is present in the extracellular matrix, serum laminin levels may be markers of BM injury. A two-site enzyme immunoassay and a radioimmunoassay were developed to test sera from patients with breast cancer or systemic lupus erythematosus (SLE). A significant difference in laminin concentrations was demonstrated between early (T0-T2) and advanced (T3-T4) tumors (P = 0.001). However, specimens from SLE patients did not differ in laminin concentration from normal individuals and no correlation was observed between laminin levels and anti-laminin auto-antibody titers. These results suggest that serum laminin levels are useful markers of BM damage and could be of prognostic value in cancer

Evolutionary conservation of laminin-binding proteins

The virulence of pathogens and metastatic capacity of cancer cells seems to correlate with the ability to adhere to cells and/or to basement components. A key feature of this mechanism in the expression of specific receptors for the basement membrane protein laminin. There different receptors have been already described in cells phylogenetically very distant, such as human white blood cells, Trichomonas vaginalis and Stapgylococcus aureus, all recognizing laminin with the same range of affinity. We have shown that laminin, which is also found in the circulation, enchances phagocytosis of S. aureus by macrophages in a species-specific fashion. Also, monoclonal antibodies (MAb) raised against the bacterial receptor inhibit the phagocytic enhancement mediated by laminin and recognize laminin-binding proteins in unicellular parasites and mammalian cells. The same Mab 1.H12 elutes a 52-kDa protein from bacterial extracts and a 67-kDa band from cancer cells extracts. Since the MAb is a monospecific reagent, results with 1.H12 strongly suggest and evolutionary conservation of the biding site of phylogenetically different laminin receptors

Production of monoclonal antibodies against Schistosoma mansoni and a trypanosomatid: a methodological report.

Anticorpos monoclonais foram produzidos contra dois diferentes organismos: o tripanosomatideo Herpetomonas muscarum muscarum e Schistosoma mansoni. Verificou-se que a obtencao desses anticorpos depende de variaveis como esquemas de imunizacao, origem e peso molecular do polietilenoglicol, lotes de soro fetal bovino, feederlayers de macrofagos, linhagens de celulas e condicoes de cultura de celulas mielomatosas de camundongo. Aplicando um protocolo aqui descrito, foram obtidos 35 anticorpos monoclonais estaveis contra H.m.muscarum e 10 contra S. mansoni. Com relacao ao tripanosomatideo, um esquema de intervalos menores entre as imunizacoes resultou em anticorpos da classe IgM; ao contrario, intervalos mais longos resultaram em anticorpos predominantemente da classe IgG. Com S. mansoni, infeccoes mais ou menos longas produziram igualmente anticorpos predominantemente da classe IgG.Padroes diferentes de reacao foram observados atraves de imunofluorescencia indireta: alguns anticorpos mostraram predominancia de reacao contra o flagelo do tripanosomatideo. Os anticorpos monoclonais anti-S. mansoni reagiram contra o tegumento ou contra o tubo digestivo em cortes de vermes adultos. A importancia biologica dos dois tipos de anticorpos esta agora sendo investigada