Biomedical subjects

Mika Nishimura

Publications and source records attributed to Mika Nishimura.

3 recordsLinked to original sources

PubMed2005

CD27(+) (memory) B cell decrease and apoptosis-resistant CD27(-) (naive) B cell increase in aged humans: implications for age-related peripheral B cell developmental disturbances.

To investigate age-related alterations in human humoral immunity, we analyzed the quantity and quality of peripheral B cell subsets, CD27-negative (CD27(-)) and CD27-positive (CD27(+)) B cells, by flow cytometry analysis in 54 aged individuals (mean age +/- SE, 74.6 +/- 0.7 years) and 30 young individuals (mean age +/- SE, 26.1 +/- 0.5 years). CD27(-) and CD27(+) B cells are regarded as naive and memory B cells, respectively. CD38, Ki-67, CD95 and bcl-2 were used as activation, proliferation and apoptotic markers. Susceptibility to apoptosis was evaluated by cell size and annexin-V binding in culture cells. The percentage of CD27(+) B cells was significantly lower in aged (mean, 19.2%) individuals than that in young individuals (mean, 28.2%). The opposite was true for CD27(-) B cells (mean, 80.8% in aged and 71.8% in young) (P < 0.01). The absolute number of CD27(+) B cells in aged individuals was significantly less than the number of CD27(-) B cells. The CD27(+) B cells from aged individuals showed little susceptibility to apoptosis, although CD95 expression on the CD27(+) B cells was significantly higher in the aged individuals than in the young individuals (P < 0.05). The CD38 and bcl-2 expression on the CD27(-) B cells was significantly higher in the aged individuals than in the young individuals (P < 0.05). In addition, the CD27(-) B cells from the aged individuals showed a decreased susceptibility to apoptosis compared with that of the young individuals. These findings suggested that human aging leads to both quantitative and qualitative alterations in the peripheral B cell developmental system, including memory and naive B cell balance and their surface phenotypes.

ADP-ribosyl Cyclase↗

PubMed2004

Increased frequency of CD27- (naive) B cells and their phenotypic alteration in HIV type 1-infected patients.

To investigate HIV-1-related B cell disorders, the quantity of peripheral CD27 negative (CD27-) B cells, their CD38, CD95, and bcl-2 intensities, and their apoptosis susceptibility were examined by flow cytometry analysis in 16 drug-naive patients, 27 HAART-treated patients, and 20 uninfected controls. CD27- B cells have been recognized as naive B cells. The mean percentage of CD27- B cells was significantly higher in drugnaive patients (88.1%) and in HAART-treated patients (83.9%) than in controls (68.6%) (p < 0.01). The intensities of CD38 and CD95 on CD27- B cells were significantly higher in drug-naive patients than in controls (p < 0.01). The intensity of CD95 on CD27- B cells in HAART-treated patients was lower than that of drug-naive patients, but significantly higher than that of controls (p < 0.01). The intensity of bcl-2 on CD27- B cells in drug-naive patients was lower than that of controls. In drug-naive patients, CD27-B cells with high CD38 expression represented low bcl-2 expression. The CD27- B cells of drug-naive patients showed an increased susceptibility to apoptosis, characterized by diminished cell size and a high frequency of annexin-V binding, compared with controls and HAART-treated patients. These findings suggested that HIV-1 infection affects peripheral CD27- (naive) B cells as well as CD27+ (memory) B cells and that CD27- B cells might be activated and rendered highly susceptible to apoptosis by HIV-1 infection. Some phenotypic alterations in CD27- B cells may continue after the reduction of HIV-1 loads by effective antiviral therapy.

ADP-ribosyl Cyclase↗

PubMed2004

Selective CD27+ (memory) B cell reduction and characteristic B cell alteration in drug-naive and HAART-treated HIV type 1-infected patients.

To investigate HIV-1-related B cell disorders, the quantity of CD27 positive (CD27+) B cells and their CD38, CD95, and bcl-2 intensities were examined by flow cytometry analysis in 16 drug-naive patients, 27 highly active antiretroviral therapy (HAART)-treated patients, and 20 uninfected controls. CD27+ B cells have been recognized as memory B cells. The mean percentage of CD27+ B cells was significantly lower in drug-naive patients (11.9%) and in HAART-treated patients (16.1%) than in controls (31.4%) (p < 0.01). The intensities of CD38 and CD95 on CD27+ B cells were higher in drug-naive patients than in controls (p < 0.01 in CD95). The intensity of CD95 on CD27+ B cells in HAART-treated patients was lower than that of drug-naive patients, but significantly higher than that of controls (p < 0.01). The intensity of bcl-2 on CD27+ B cells was equivalent among the three groups. These findings suggest that disturbance of peripheral B cell composition, exemplified by CD27+ B cell reduction, exists in both drug-naive and HAART-treated HIV-1-infected patients. In addition, the augmented apoptotic state of CD27+ B cells found in HAART-treated patients with undetectable viral loads, indicated by CD95 elevation, suggests that some HIV-1-related B cell disorders last for years after effective antiviral therapy.

ADP-ribosyl Cyclase↗