Tumor development is retarded in mice lacking the gene for urokinase-type plasminogen activator or its inhibitor, plasminogen activator inhibitor-1.

In vivo tumor progression in mice with targeted deficiencies in urokinase-type plasminogen activator (UPA-/-) and its inhibitor, plasminogen activator inhibitor-1 (PAI-1-/-), was studied using a fibrosarcoma tumor model. Murine T241 fibrosarcoma cells were s.c. implanted into three groups of mice with the following genotypes, wild-type (WT), UPA-/-, and PAI-1-/-. A significantly diminished primary tumor growth in UPA-/- and PAI-1-/- mice occurred, relative to WT mice. Tumors in UPA-/- and PAI-1-/- mice displayed lower proliferative and higher apoptotic indices and displayed a different neovascular morphology, as compared with WT mice. These results are consistent with the decreased growth rates of this tumor in these gene-deleted mice. Immunohistochemical analyses of the tumors revealed a decrease in vascularity and vascular endothelial growth factor expression only in tumors in PAI-1-/- mice. Analyses of the relative extents of corneal angiogenesis in these same animals, induced by basic fibroblast growth factor, corroborated the resistance of PAI-1-/- mice to neovascularization. The results obtained suggest that the host fibrinolytic system plays an important role in tumor growth in this model. Alterations in host expression of components of this system may alter tumor growth and dissemination by affecting the balance between tumor cell death and proliferation, as well as extracellular matrix changes needed for invasiveness and angiogenesis.

Immunocytochemical reaction of sera from chagasic patients against Trypanosoma cruzi, intestine of Triatoma infestans and normal human heart.

Chagas disease has been considered by some authors as an autoimmune pathology and denied by others. In this paper we present by means of immunocytochemical reactions with sera of chagasic patients, evidence in favor of the presence of similar antigens in the parasite, vector and non chagasic human heart. The immunocytochemical technique used permits the localization by electron microscopy of the antigens in the peritrophic membrane of the parasite and basement membranes of the vector's midgut and of the myosin band of the normal human heart. These observations support the assumption of an autoimmune response in Chagas disease.

The Fas/Fas-ligand system: a mechanism for immune evasion in human breast carcinomas.

Breast tumors are frequently associated with a predominantly lymphocytic infiltrate, which constitutes an immune response against the tumor. In spite of this massive infiltrate, the immune response appears to be inefficient and the tumor is able to evade it. We propose that in breast cancer, tumor escape from immunological surveillance results from the induction of apoptosis of Fas-bearing activated lymphocytes by FasL-bearing breast cancer cells. To test this proposal we studied the expression of FasL by human breast carcinomas and the MCF-7 breast cancer cell line by RT-PCR, immunohistochemistry, and Western Blot. Moreover, we describe the presence of apoptosis and Fas expression in the lymphocytic population surrounding the tumor. Strong membranous and cytoplasmic staining was detected in ductal carcinomas and hyperplastic breast tissue, but it was absent from normal breast tissue. No staining was found in normal glands in the non-tumor quadrants; however, the normal appearing ducts surrounding the carcinoma (tumor quadrant) showed intense immunoreactivity. Apoptosis was found predominantly among the lymphocytic population, as well as in the blood vessels and fibro-fatty tissue close to the tumor. Further characterization of apoptotic cells demonstrated that they were CD3+ cells. Our results suggest the breast tumors may elude immunological surveillance by inducing, via the Fas/FasL system, the apoptosis of activated lymphocytes. Recent data have demonstrated FasL RNA in other tumor types. Upregulation of FasL expression in hyperplastic and normal breast ducts close to the tumor also suggests a possible role in early neoplastic transformation and proliferation.

Monocyte chemotactic protein-1 expression in human corpus luteum.

Invasion of the corpus luteum by macrophages is a characteristic of luteal regression. Monocyte chemotactic protein-1 (MCP-1), a chemokine that recruits macrophages, is expressed in the rat corpus luteum where it increases in amount during luteolysis. In this study we examined the temporal and spatial expression of MCP-1 and changes in macrophage concentration in the human corpus luteum. Corpora lutea (n = 39) were grouped according to menstrual cycle phase and were examined by immunohistochemistry for MCP-1 and macrophages, and by Northern blot for MCP-1 mRNA. We found increasing amounts of macrophages with progressing luteolysis (P < 0.001). Staining for MCP-1 was stronger in the regressing corpora lutea compared with the staining in corpora lutea of early luteal phase (P < 0.05). MCP-1 was more prominent in blood vessel walls surrounding the corpus luteum than in vessels located far from it. The mean MCP-1 mRNA expression in regressing corpora lutea was higher than that observed in corpora lutea of the early and mid-luteal phase (P = 0.003). In conclusion, we found that MCP-1 expression and the number of macrophages increase with regression of the corpus luteum. MCP-1 is mostly expressed in blood vessel walls surrounding the corpus luteum and may play a role in the recruitment of macrophages to the corpus luteum during its regression.

Immunocytochemical reaction of sera from chagasic patients against Trypanosoma cruzi, intestine of Triatoma infestans and normal human heart.

Chagas disease has been considered by some authors as an autoimmune pathology and denied by others. In this paper we present by means of immunocytochemical reactions with sera of chagasic patients, evidence in favor of the presence of similar antigens in the parasite, vector and non chagasic human heart. The immunocytochemical technique used permits the localization by electron microscopy of the antigens in the peritrophic membrane of the parasite and basement membranes of the vectors midgut and of the myosin band of the normal human heart. These observations support the assumption of an autoimmune response in Chagas disease.

alpha-Mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface.

This study demonstrates that alpha-mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface. This enzyme was bound to intact epididymal spermatozoa with high affinity and in saturable form, and the binding was inhibited by mannose-6-phosphate but not by phosphorylated derivatives of fructose. Treatment of the enzyme with sodium periodate inhibited the binding of alpha-mannosidase, confirming that a carbohydrate residue is involved in the interaction with spermatozoa. Evidence is also presented that the cation-independent phosphomannosyl receptors are responsible for the interaction with alpha-mannosidase. These findings suggest a new role for extracellular transport mediated by the mannose-6-phosphate receptor.

Fas-fas ligand system-induced apoptosis in human placenta and gestational trophoblastic disease.

PROBLEM: The low frequency of maternal immune responses to paternally inherited fetal antigens raises the following question: What regulates the immunobiology of pregnancy? Data suggest that this state is the result of peripheral immune-tolerance, an active process of immune-regulation in which activated T cells undergo apoptosis. We studied Fas ligand (FasL) expression and apoptosis in normal and pathologic placentas to find out whether the Fas-FasL-induced apoptosis takes place during implantation. METHOD OF STUDY: FasL expression in paraffin sections was detected using specific antibodies and confirmed with reverse transcriptase-polymerase chain reaction of total RNA from frozen placentas. Apoptosis was detected using the terminal deoxy (d)-UTP nick end-labeling assay. RESULTS: FasL was found in the normal placenta and in gestational trophoblastic disease. Apoptotic leukocytes were localized to the maternal-fetal interface corresponding in localization with the distribution of FasL. CONCLUSIONS: We propose that FasL expression in the placenta is a mechanism responsible for the development of maternal immune tolerance specific for paternal alloantigens and operates in pathologic states characterized by trophoblastic invasion/proliferation.

The effect of monocyte chemotactic protein 1 in intraperitoneal adhesion formation in a mouse model.

OBJECTIVE: Intraperitoneal adhesions are a significant cause of morbidity among women of reproductive age. Monocyte chemotactic protein 1 plays a role in the chemotaxis of mononuclear cells and fibroblasts into the peritoneal injury site. To evaluate its role in intraperitoneal adhesion formation, we used an established postsurgical adhesion model in mice. STUDY DESIGN: Surgical adhesions in mice were induced by scraping and crushing peritoneal sites. We analyzed the injury sites for the temporal expression of monocyte chemotactic protein 1 messenger ribonucleic acid and cellular infiltration at 12 to 24 hours across 10 days and evaluated the effects of monocyte chemotactic protein 1 and anti-monocyte chemotactic protein 1 neutralizing antibody on adhesion formation. On induction of adhesions animals were randomly assigned to 1 of 4 groups: (1) control, (2) nonspecific immunoglobulin G, (3) monocyte chemotactic protein 1, (4) anti-monocyte chemotactic protein 1 antibody. Animals received daily intraperitoneal injections for 6 days. Adhesions were scored on day 14 and immunostained for fibroblasts and macrophages. RESULTS: Adhesions developed consistently by the fifth postoperative day. We detected an increase in monocyte chemotactic protein 1 messenger ribonucleic acid expression at 48 hours; this remained until the fourth postoperative day. By the second day macrophages were present at the injury site. Animals treated with anti-monocyte chemotactic protein 1 antibody had significantly fewer adhesions develop than did the other three groups. CONCLUSION: This study demonstrates that monocyte chemotactic protein 1 may play a role in adhesion formation. Inhibiting the action of this chemokine may help to prevent adhesions.

Interleukin-8 in the human endometrium.

We have previously shown that interleukin-8 (IL-8), a cytokine with neutrophil chemotactic/activating and T cell chemotactic activity, is produced by human endometrial stromal and glandular cells in culture. The present study investigated the temporal and spatial expression of IL-8 messenger ribonucleic acid (mRNA) and protein in the human endometrium. Endometrial tissue (n = 52) was obtained from human uteri after hysterectomy conducted for reasons other than endometrial disease or from endometrial biopsies. The day of the menstrual cycle was established from women's menstrual history and was confirmed by histology. Half of the tissues (n = 26) were snap-frozen in liquid nitrogen, cellular RNA was extracted, and Northern blots were hybridized with a riboprobe complementary to a specific sequence of IL-8 mRNA. The remaining tissues (n = 26) were processed for frozen sections, and immunohistochemistry was performed using mouse antihuman IL-8 antibody. Comparison of IL-8 mRNA levels throughout the menstrual cycle revealed that late secretory and early to midproliferative phase IL-8 expression was significantly greater than midcycle expression (P < 0.02). Analysis of the IL-8 immunohistochemistry revealed that IL-8 protein is found in the surface epithelium and glands throughout the menstrual cycle. There was no detectable immunoreactive IL-8 in the stromal cells. We conclude that IL-8 is produced in the human endometrium in vivo, and the variations of IL-8 mRNA throughout the menstrual cycle suggest that sex hormones may regulate its gene expression. We speculate that IL-8 may modulate the timely recruitment of neutrophils and lymphocytes into the endometrium.

Antibodies from Chagas patients serum bind to the gut epithelial cell surface of Triatoma infestans.

Serum of chagasic patients with a high title of specific antibodies against T. cruzi antigens, binds epitopes in the midgut and hindgut of the insect vector Triatoma infestans free of parasites. These antigens were recognized at ultrastructural level by immunocytochemistry with serum of chagasic patients as first antibody and protein "A"-gold as marker. Controls with normal human serum were negative. The positive reaction occurs principally in the apical epithelial portion (microvilli and peritrophic membrane) of the midgut and in the cuticular layer and adjacent cytoplasm of the hindgut. In vectors infected with trypanosomes, the antigen-antibody reaction occurs similarly in the epithelium and also in the trypanosomes present in the lumen. These results suggest that there are antigenic factors in the vector gut that are incorporated by the parasite and are recognized by the immunitary system of the human patient with production of specific antibodies.

Interaction of Trypanosoma cruzi with macrophages influence of temperature.

The interaction of macrophages and T. cruzi has been studied in vitro culture under three different temperatures. After 24 hours incubation at 29 degree C a large number of recognizable parasites inside macrophages is observed with evidences of cell divisions. At video microscopy they show a slow motion and a predominance of epimastigotes and some round shapes (amastigotes). This was corroborated at the light and electron microscopes. No evidence of lysis in the phagosome vacuoles was observed. At 40 degrees C, macrophages show a large number of residual bodies and phagocytic vacuoles with digested parasites. At 37 degrees C, an intermediate stage with normal and digested parasites inside macrophages is observed. No significant evidences of affected phagocytic and degradative properties of the macrophages were obtained at those temperatures. It is postulated that temperature mainly affects the parasite resistance to intracellular digestion.

Antibodies from Chagas patients serum bind to the gut epithelial cell surface of Triatoma infestans

Serum of chagasic patients with a high title of specific antibodies against T. cruzi antigens, binds epitopes in the midgut and hindgut of the insect vector Triatoma infestans free of parasites. These antigens were recognized at ultrastructural level by immunocytochemistry with serum of chagasic patients as first antibody and protein [quot ]A[quot ]-gold as marker. Controls with normal human serum were negative. The positive reaction occurs principally in the apical epithelial portion (microvilli and peritrophic membrane) of the midgut and in the cuticular layer and adjacent cytoplasm of the hindgut. In vectors infected with trypanosomes, the antigen-antibody reaction occurs similarly in the epithelium and also in the trypanosomes present in the lumen. These results suggest that there are antigenic factors in the vector gut that are incorporated by the parasite and are recognized by the immunitary system of the human patient with production of specific antibodies.

Antibodies from Chagas patients serum bind to the gut epithelial cell surface of Triatoma infestans

Serum of chagasic patients with a high title of specific antibodies against T. cruzi antigens, binds epitopes in the midgut and hindgut of the insect vector Triatoma infestans free of parasites. These antigens were recognized at ultrastructural level by immunocytochemistry with serum of chagasic patients as first antibody and protein [quot ]A[quot ]-gold as marker. Controls with normal human serum were negative. The positive reaction occurs principally in the apical epithelial portion (microvilli and peritrophic membrane) of the midgut and in the cuticular layer and adjacent cytoplasm of the hindgut. In vectors infected with trypanosomes, the antigen-antibody reaction occurs similarly in the epithelium and also in the trypanosomes present in the lumen. These results suggest that there are antigenic factors in the vector gut that are incorporated by the parasite and are recognized by the immunitary system of the human patient with production of specific antibodies.

Interaction of Trypanosoma cruzi with macrophages influence of temperature.

The interaction of macrophages and T. cruzi has been studied in vitro culture under three different temperatures. After 24 hours incubation at 29 degree C a large number of recognizable parasites inside macrophages is observed with evidences of cell divisions. At video microscopy they show a slow motion and a predominance of epimastigotes and some round shapes (amastigotes). This was corroborated at the light and electron microscopes. No evidence of lysis in the phagosome vacuoles was observed. At 40 degrees C, macrophages show a large number of residual bodies and phagocytic vacuoles with digested parasites. At 37 degrees C, an intermediate stage with normal and digested parasites inside macrophages is observed. No significant evidences of affected phagocytic and degradative properties of the macrophages were obtained at those temperatures. It is postulated that temperature mainly affects the parasite resistance to intracellular digestion.

Antibodies from Chagas patients serum bind to the gut epithelial cell surface of Triatoma infestans.

Serum of chagasic patients with a high title of specific antibodies against T. cruzi antigens, binds epitopes in the midgut and hindgut of the insect vector Triatoma infestans free of parasites. These antigens were recognized at ultrastructural level by immunocytochemistry with serum of chagasic patients as first antibody and protein [quot ]A[quot ]-gold as marker. Controls with normal human serum were negative. The positive reaction occurs principally in the apical epithelial portion (microvilli and peritrophic membrane) of the midgut and in the cuticular layer and adjacent cytoplasm of the hindgut. In vectors infected with trypanosomes, the antigen-antibody reaction occurs similarly in the epithelium and also in the trypanosomes present in the lumen. These results suggest that there are antigenic factors in the vector gut that are incorporated by the parasite and are recognized by the immunitary system of the human patient with production of specific antibodies.

Antibodies from Chagas patients serum bind to the gut epithelial cell surface of Triatoma infestans.

Serum of chagasic patients with a high title of specific antibodies against T. cruzi antigens, binds epitopes in the midgut and hindgut of the insect vector Triatoma infestans free of parasites. These antigens were recognized at ultrastructural level by immunocytochemistry with serum of chagasic patients as first antibody and protein [quot ]A[quot ]-gold as marker. Controls with normal human serum were negative. The positive reaction occurs principally in the apical epithelial portion (microvilli and peritrophic membrane) of the midgut and in the cuticular layer and adjacent cytoplasm of the hindgut. In vectors infected with trypanosomes, the antigen-antibody reaction occurs similarly in the epithelium and also in the trypanosomes present in the lumen. These results suggest that there are antigenic factors in the vector gut that are incorporated by the parasite and are recognized by the immunitary system of the human patient with production of specific antibodies.