Detection of the lymphokine migration inhibitory factor in normal and disease-affected lung by antibody and by its major binding protein, the interferon antagonist sarcolectin

Effects of sarcolectin (SCL) on human peripheral blood mononuclear cells

Sarcolectin (SCL) is a tissue growth factor found in various human or animal tissues, functioning in balance with interferons (IFNs) that can inhibit growth and affect cell differentiation. Like somatotropin, SCL is found in the pituitary gland. In humans, the SCL gene is located on chromosome 12 (q12-q13) and expressed as a 55 kDa protein consisting of 469 amino-acids. After a single activation of peripheral blood mononuclear cells (PBMC) obtained from more than 30 individuals, highly significant cell proliferation was found to peak after 7 days in culture. The presence of adherent cells was necessary for cell proliferation. SCL induced over-expression of alpha-IL-2 receptor (CD25) leading to proliferation of CD3+/CD4+/CD45RO+ T cells. Thus in PBMC, SCL induced CD4+ T cell growth and expression of inflammatory cytokine genes, including TNF-alpha, IL-1beta, IL-6 and IL-8. IFNs are also produced following activation as a feedback response which is maintained for about 20 days.

Release of macrophage migration inhibitory factor and CXCL8/interleukin-8 from lung epithelial cells rendered necrotic by influenza A virus infection

Bronchiolar epithelial cells are the prime targets for influenza A virus infection. It still remains to be clarified which signals are generated from these cells to initiate an immune response. Among chemokines, viral infection of primary lung epithelial cells triggered exclusively the release of CXCL8/interleukin-8 (IL-8), which contrasts with our previous observation that influenza A virus induced in monocytes the expression of mononuclear-leukocyte-attracting chemokines and even suppressed the production of neutrophil-attracting chemokines. Therefore, we speculated that it may be advantageous for respiratory epithelial cells to release primarily neutrophil-attracting CXCL8/IL-8 since neutrophils rapidly remove necrotic debris and are the first line of defense against bacterial superinfections. This concept has also been supported by our finding that influenza A virus infection led to necrosis of lung epithelial cells. This is in striking contrast to previous studies where influenza A virus infection induced apoptosis in monocytes and epithelial cells from origins other than the lung. Thus, the cell type instead of the virus determines which death pathway will be followed. In addition to the release of CXCL8/IL-8, we obtained a massive release of macrophage migration inhibitory factor (MIF) from virus-infected lung cells. However, whereas the CXCL8/IL-8 secretion was accompanied by induced gene activation, the transcription rate of MIF remained unchanged during the infection course and the virus-induced MIF release was predominantly a discharge from intracellular stores, suggesting that MIF is passively released upon cell death. Despite virus induced necrosis, the passively liberated MIF remained bioactive. Considering the well-established immunostimulatory effects of MIF on different leukocyte subsets, is its very likely that enhanced levels of MIF may contribute to the host immune response during the acute phase of influenza A virus infection in humans.

Correlation of expression of binding sites for synthetic blood group A-, B- and H-trisaccharides and for sarcolectin with survival of patients with bronchial carcinoma

Carrier-immobilised carbohydrates were used to monitor the presence of specific carbohydrate-binding sites in tissue sections. Sarcolectin, an interferon-alpha/beta antagonist and growth regulator, had been shown to bind the lymphokine macrophage migration inhibitory factor (MIF). The lectin is thus a MIF-specific probe. Biotinylated sarcolectin, neoglycoproteins with lactose or N-acetylglucosamine residues, and polyacrylamide-attached trisaccharides, that represent the ABH histo-blood group antigens, were applied to sections of 187 primary lung carcinomas. The panel of cases consisted of 57 epidermoid carcinomas, 55 adenocarcinomas, 43 large cell anaplastic carcinomas and 32 small cell anaplastic carcinomas. 47 cases with intrapulmonary metastatic tumours were also included. Expression of binding sites of both sarcolectin and trisaccharides of histo-blood group antigens A and H correlated with patient survival in lung cancer. In view of the widely performed analysis of the presence of histo-blood group antigens, concomitant profiling of binding sites for these sugar components is suggested to be of potential benefit.