| Project/Area Number |
16390177
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Hygiene
|
|---|
| Research Institution | National Institute of Infectious Diseases |
|---|
Principal Investigator |
FURUYA Koji National Institute of Infectious Diseases, Department of Parasitology, Chief, 寄生動物部, 室長 (40045555)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KAWANAKA Masanori National Institute of Infectious Disease, Department of Parasitology, Chief, 寄生動物部, 室長 (50109964)
SUGIURA Wataru National Institute of Infectious Disease, AIDS Research Center, Group Head, エイズ研究センター, グループ長 (70300936)
KUDO Shinichi Hokkaido Institute of Public Health, Department of Biological Science, Director, 生物科学部, 部長
東 寛 北海道赤十字血液センター, 研究部, 部長
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Project Status |
Completed (Fiscal Year 2005)
|
| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2005: ¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 2004: ¥7,700,000 (Direct Cost: ¥7,700,000)
|
|---|
| Keywords | Microsporidia / Encephalitozoon cuniculi infection / IgM antibodies / seroepidemiology / proteome analysis / healthy residents / blood donors / HIV-infected persons / Microsporidia / IgM抗体 / 自然抗体 / プロテオーム / 遺伝子型 / 感染予防 / 微胞子虫 / Encephalitozoon / プロテオーム解析 |
|---|
| Research Abstract |
Encephalitozoon cuniculi is a microsporidian parasitic pathogen listed in a 1996 WHO report as an emerging infectious agent. The pathogen is also considered a zoonotic parasite. Various animals can be naturally infected by E.cuniculi and its geographical distribution is worldwide. In Japan, E.cuniculi infection in rabbits and in squirrel monkeys in zoos is of current concern ; it is considered to increase each year and to have spread throughout Japan. However, to the best of our knowledge, human microsporidiosis has not been reported in Japan except for the case of a 9-y-old boy, in 1958. Although immunological conditions of the Japanese case were not recorded, almost all other affected patients with this pathogen in other nations have been described among immuno-compromised groups of HIV-infected patients. A few cases have also been found in renal transplant recipients. E.cuniculi can thus be regarded as an opportunistic pathogen. Cases of HIV associated infections with E.cuniculi are
… More
increasingly reported, although they remain less common than those due to E.bieneusi and E.intestinalis infections.
Many reports on the seroprevalence of human E.cuniculi infection have been published. However, reported rates of microsporidial seropositivity vary greatly depending on the serological technique used, probably due to the use of unsuitable antigens for measuring specific antibodies, and the use of secondary antibodies without differential specificities. Recently, specific IgG antibodies against the polar tube of E.cuniculi were demonstrated in a healthy laboratory worker accidentally infected with E.cuniculi. The PT is a typical microsporidian spore structure with an extrusion that is essential for invasion of a host cell, as sporoplasm flows through the discharged PT and into the host cell.
Using an enzyme immunostaining assay in which germinated E.cuniculi spores were coated onto plastic surfaces, we serologically detected IgM antibodies against the polar tube of E.cuniculi in 61(36.7%) of 180 healthy residents. Further, anti-E.cuniculi polar tube IgM antibodies were detected in 72 (36%) of 200 blood donors. The highest rate of positivity to anti-polar tube IgM antibodies was seen in 20-y-old or younger individuals in both healthy residents and donors. Sixty one % (18/31) and 60% (6/10) of the individuals aged 20 or younger in healthy residents and donors, respectively, were anti-polar tube IgM antibody-positive. These high rates tended to decrease in older groups. However, no anti-polar tube IgM antibodies were detected in 21 HIV-infected persons younger than 30 years old and with a CD4 cell level below 200. Using immunoblotting after 2-dimensional polyacrylamide gel electrophoresis we also demonstrated that the 2 sera that gave the highest titers of anti-polar tube IgM antibodies predominantly reacted with ca. 50-kDa spots of E.cuniculi polar tube protein1. These seroepidemiological and immunoproteomic results suggest that anti-E.cuniculi polar tube IgM antibodies in healthy people are not primary antibodies produced after infection or exposure with the pathogen but are natural specific antibodies. Further studies focused on human anti-E.cuniculi polar tube IgM antibodies need to be performed from the parallel perspectives of protective immunity and preventive medicine. Less
|
