Production of Prostaglandin E2 and I2 Is Coupled with Cyclooxygenase-2 in Human Follicular Dendritic Cells

BACKGROUND: Prostaglandins (PGs) play pathogenic and protective roles in inflammatory diseases. The novel concept of PGs as immune modulators is being documented by several investigators. By establishing an in vitro experimental model containing human follicular dendritic cell-like cells, HK cells, we reported that HK cells produce prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2) and that these PGs regulate biological functions of T and B cells. METHODS: To investigate the respective contribution of cyclooxygenase-1 (COX-1) and COX-2 to PGE2 and PGI2 production in HK cells, we performed siRNA technology to knock down COX enzymes and examined the effect on PG production. RESULTS: Both PGE2 and PGI2 productions were almost completely inhibited by the depletion of COX-2. In contrast, COX-1 knockdown did not significantly affect PG production induced by lipopolysaccharide (LPS). CONCLUSION: The current results suggest that mPGES-1 and PGIS are coupled with COX-2 but not with COX-1 in human follicular dendritic cell (FDC) and may help understand the potential effects of selective COX inhibitors on the humoral immunity.

Immunomodulating and Antitumor Activities of Exo-secretion from Phellinus linteus

BACKGROUND: The chemical characteristics of the exo-secretion from Phellinus linteus (referred to as exo-secretion) including the compositions of amino acids and monosaccharides were investigated. In addition, cytotoxicity of the exo-secretion on 5 tumor cell lines derived from human cancers and its antitumor activity against ascitic sarcoma-180 cells were examined. METHODS: The antitumor activity of exo-secretion from Phellinus linteus was determined by measuring parameters including tumor weight, life span of mice, chemotatic activity of leukocytes, counts of immune cells, and activity of cytokines. RESULTS: The exo-secretion from Phellinus linteus showed no direct cytotoxicity to the five tumor cell lines tested, but it had a strong antitumor activity against sarcoma-180 cells in ICR mice as measured by tumor weight and life span of mice. The exo-secretion stimulated the chemotaxis of leukocytes and production of immune cells and cytokines. CONCLUSION: These results suggest that the exo- secretion from Phellinus linteus do not act as a direct cytotoxic substance to cancer cells but as an immunomodulator.

Study of Exoparasites, Rickettsia and Hantaan virus in Bats

To study the relation between ectoparasite, Rickettsia and hantaan virus in bats, four order of Athropoda were collected from Rhinolophus ferrumequinum captured in Cheju and Eptesicus serotinus captured in Chungnamin from July 1989 to March 1998. Also antibody of Rickettsia and hantaan virus were detected by immunofluoroscent antibody technique and RT-PCR. The results are as follows. 1. Five species of Acarina were identified from E. serotinus: Leptotrobidium subakamushi of Trombiculidae, Macronyssus coreanus, Steatonyssuss spinosuss and Steatonychus superans of Macronyssidae, Argas vespertilionis of Metastigmata. 2. Ischnopsyllus needhami of Siphonaptera and Cimex of Hemiptera were identified from E. serotinus. 3. Cyteribia uenoi and Brachytarsina kanoi of Diptera were identified from R. ferrumequinum. 4. The positive rate of rickettsial antibodies in E. serotinus were 17.58%, 15.15%, 22.22%, 52.73% against R. tsutsugamushi, R. typhi, R. sibirica and R. thai tick typhus, respectively. The high positive rate of antibody related to the high content of Arthropoda. 5. The Positive rate of hantaan virus IFA antibodies were 3.4% (27 of 802) and hanntan virus infection rate 36.7% (22 of 60) by RT-PCR in bats. According these result, we showed that certain species of Athropoda isolated play a role as vector of Rickettsia in E. serotinus. Also bats play a role as a reservoir of hantaan virus in nature.

Studies on the antibody distribytion against the etiological virus of hemorrhagic fever with renal syndrome to bats in Korea

No abstract available.

Relationship between the activities of enterotoxin, cytotoxin and haemolysin of clinical aeromonas spp

No abstract available.