Bromodeoxyuridine, an analogue of thymidine, can be detected by means of monoclonal antibodies and utilized as a marker of the S-phase of the cell cycle. In vitro immunohistochemical application of the BrdU/anti-BrdU-MAb method permits a quantitative assessment of the proliferative activity of a tissue as well as the direct location of the actively replicating cells in histological sections. In this paper, a method for the detection of the labeling index of S-phase cells in normal and neoplastic tissues with in vitro BrdU labeling and standard immunohistochemical techniques using anti-BrdU-MAb and avidin-biotin peroxidase complex is described. We have employed this method in 47 human solid tumor samples, including squamous cell carcinomas of head and neck and cervix uteri, adenocarcinomas and malignant lymphomas, and also evaluated the possible application of the BrdU labeling index to estimate the cycling S-phase cells in neoplastic cell populations. In our data, the in vitro labeling index varied greatly in an individual case (3.56-29.2%) and from an area to an area within the same case. Squamous cell carcinomas of the head and neck showed higher LI than those of the cervix uteri. A case of metastatic carcinoma to the lung from ductal carcinoma of the breast had the highest LI (29.2%), in contrast to the low LI (3.6%) in the primary ductal carcinoma of breast.
Adenocarcinoma/immunology/pathology ; Antibodies, Monoclonal/*immunology ; Breast Neoplasms/immunology/pathology ; Bromodeoxyuridine/*immunology ; Carcinoma, Squamous Cell/immunology/pathology ; Cell Nucleus/immunology/*physiology ; Head and Neck Neoplasms/immunology/pathology ; Humans ; Immunohistochemistry ; *Interphase ; Lymphoma/immunology/pathology ; Neoplasms/immunology/*pathology

OBJECTIVETo investigate the tumorigenic mechanisms of human leukemia cell line HL60-n in nude mice.

METHODSDifferent clone strains of HL60-n cells were established by limited dilution and their biological features were compared with parental HL-60 cells.

RESULTSThe colony yields in soft agar, especially the large colony yields of the high tumorigenic clone strains HL60-n/A, HL60-n/B were significantly higher than that of the HL-60 cells (P < 0.01). There was no significant difference between the low tumorigenic clone strains HL60-n/E, HL60-n/F and the HL-60 cells. Ultrastructurally, the nucleus was highly abnormal, the euchromatic element of nuclear chromatin increased, the heterochromatin sparse, and the microfilaments in cytoplasm increased and disarranged in the high tumorigenic cells as compared with HL-60 cells. Cell cycle analysis by flow cytometer showed higher S phase fractions in the high tumorigenic cells. The killing activities of NK cells to the high tumorigenic clone strains were significant lower than to the contrast (P < 0.01). The histopathological features produced by the low tumorigenic leukemia cells showed that there were many inflammatory cells infiltrated, the majority of them were lymphocytes, and many tumor cells were killed especially in vessel abundant areas. By contrast, there were few inflammatory cells infiltrated in the tumors produced by the high tumorigenic cell strains.

CONCLUSIONThe mechanism of the high tumorigenic activity of the HL60-n cell line involved higher colony yields in soft agar, higher S phase fraction, decreased susceptibility to NK cell killing, and the inhibition of the host immunity.

Animals ; Carcinogenicity Tests ; Cell Division ; physiology ; Cell Nucleus ; pathology ; ultrastructure ; Disease Models, Animal ; HL-60 Cells ; Humans ; Killer Cells, Natural ; cytology ; immunology ; Leukemia ; pathology ; physiopathology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; pathology ; Tumor Stem Cell Assay

Porcine epidemic diarrhea virus (PEDV) is a highly infectious pathogen that can cause severe diseases in pigs and result in enormous economic losses in the worldwide swine industry. Previous studies revealed that PEDV exhibits an obvious capacity for modulating interferon (IFN) signaling or expression. The newly discovered type III IFN, which plays a crucial role in antiviral immunity, has strong antiviral activity against PEDV proliferation in IPEC-J2 cells. In this study, we aimed to investigate the effect of PEDV nucleocapsid (N) protein on type III IFN-λ. We found that the N proteins of ten PEDV strains isolated between 2013 and 2017 from different local farms shared high nucleotide identities, while the N protein of the CV777 vaccine strain formed a monophyletic branch in the phylogenetic tree. The N protein of the epidemic strain could antagonize type III IFN, but not type I or type II IFN expression induced by polyinosinic-polycytidylic acid (poly(I:C)) in IPEC-J2 cells. Subsequently, we demonstrated that the inhibition of poly(I:C)-induced IFN-λ3 production by PEDV N protein was dependent on the blocking of nuclear factor-κB (NF-κB) nuclear translocation. These findings might help increase understanding of the pathogenesis of PEDV and its mechanisms for evading the host immune response.
Active Transport, Cell Nucleus ; Animals ; Coronavirus Infections ; immunology ; veterinary ; virology ; Genes, Viral ; Host-Pathogen Interactions ; immunology ; Interferons ; antagonists & inhibitors ; biosynthesis ; genetics ; Interleukins ; antagonists & inhibitors ; biosynthesis ; genetics ; NF-kappa B ; metabolism ; Nucleocapsid Proteins ; genetics ; immunology ; physiology ; Porcine epidemic diarrhea virus ; genetics ; pathogenicity ; physiology ; Promoter Regions, Genetic ; Swine ; Swine Diseases ; immunology ; virology