Paronetto F

Distribution of basement membrane components in human hepatocellular carcinoma.

The distribution of fibronectin (FN), laminin (LAM), and collagen IV (Coll IV), three components of the basement membranes (BM), was investigated in human hepatocellular carcinoma (HCC) and the surrounding uninvolved liver and was compared with the grade of differentiation of the tumor. The following three patterns of BM antigens were observed in HCC: (1) peritrabecular or periacinar, (2) pericellular, and (3) stromal‐vascular. In the more differentiated tumors, FN, LAM, and Coll IV were observed in a peritrabecular or periacinar pattern whereas a pericellular pattern was only seen with anti‐FN antisera that occasionally stained the content of acini. Double staining showed that the four antigens were usually codistributed. Occasionally, however, there was a different distribution along the BM suggesting an heterogeneity in the composition of BM. In the more anaplastic tumors and in the intrahepatic metastasis, BM components were seen around vessels and in the stroma and they were usually fragmented. The finding that FN can be located pericellularly or within acini supports the concept that FN is synthesized, at least in part, by hepatoma cells. The peritrabecular and periacinar location of Coll IV and LAM suggests a sinusoidal cell derivation of these two antigens. The immunohistochemical staining patterns for BM in HCC reflect the differentiation of the tumor, with differentiated tumors showing a relatively intact BM and poorly differentiated tumors showing a sharply defective BM.

Pokeweed mitogen-induced immunoglobulin-secreting cells in Hepatitis B surface antigen-positive -negative chronic active hepatitis: Evaluation by a protein A plaque assay

Abstract The response to pokeweed mitogen (PWM) of peripheral blood mononuclear cells was evaluated in 7 patients with Hepatitis B surface antigen (HBsAg)-positive and 16 patients with HBsAg-negative chronic active hepatitis (CAH). Immunoglobulin-secreting cells were assessed by a reverse hemolytic plaque assay with protein A-coated sheep red blood cells. HBsAg-negative patients with CAH, but not HBsAg-positive patients with CAH, showed a markedly impaired response to PWM compared to healthy controls. Coculture experiments of mononuclear cells from most unresponsive patients with HBsAg-negative CAH and mononuclear cells from healthy controls demonstrated a higher than expected response to PWM, suggesting that a quantitative or functional defect of a cell population with a “helper” effect for the in vitro response to PWM may be present in some patients. The hyporesponsiveness to PWM in HBsAg-negative patients with CAH, but not in patients with HBsAg-positive CAH, represents and additional difference in immunologic parameters between these two types of chronic liver disease.

Subpopulations of T lymphocytes in primary biliary cirrhosis

Abstract The distribution of T lymphocytes that bear Fc receptors for IgG and IgM (TG and TM) has been investigated in 22 patients with primary biliary cirrhosis. Absolute numbers and percentages of T lymphocytes and of TG and TM lymphocytes were decreased, while percentages and absolute numbers of lymphocytes without a detectable Fc receptor for IgG and IgM (TnonG-nonM) were markedly increased. These results are not completely explained by the masking of the Fc receptor by immune complexes since enzymatic treatment of lymphocytes corrected these alterations only partially. These data suggest a faulty regulation of immunocompetent cells in patients with primary biliary cirrhosis.

Elimination of the yeast Candida parapsilosis from lymphoid cells and monolayer cells in culture

SummaryIn our laboratory, airborne yeast contaminants of cell cultures have consistently been of the genusCandida (speciesCandida parapsilosis), which are difficult to control with fungicidal agents. To salvage cell lines that show the presence of this fungus, two effective methods may be employed. In early stages of infection, the addition of activated mouse peritoneal macrophages (5×105 cells/ml) to the culture medium containing 5 μg Fungizone/ml eliminates all spores by phagocytosis. More heavily contaminated cultures can be depleted of fungi by density centrifugation on a layer of 38% Percoll. Remaining single spores, often not detectable by light microscopy, can be removed by the addition of macrophages (2×105/ml) and Fungizone (5 μg/ml) to the culture medium. Contaminated monolayer cells can be freed of blastospores by several washes with balanced salt solution and subsequent culturing for 4 d in medium containing 10 μg Fungizone/ml without any toxic effects to the cells. These procedures can rescue valuable cell lines and hybridomas that would otherwise be lost.

The Role of the Reticuloendothelial System in Viral Hepatitis

In the last decade it became apparent that the liver can be attacked by a number of viruses that have affinity for it, that the host responds in a complex manner to the viral insult, and that the tissue damage or recovery depends to a great extent on the host’s immune response. Thus, the reticuloendothelial system (RES) has a cardinal importance in the outcome of this disease. In this chapter the term reticuloendothelial system in not restricted to the mononuclear phagocyte system, but it is used in the more comprehensive sense to include a complex of macrophages, lymphocytes, and plasma cells, as well as cells involved not only in the clearance of infectious agents but also in the immune response (Friedman et al, 1980).