Effects of Human Soluble BAFF Synthesized in Escherichia coli on CD4⁺ and CD8⁺ T Lymphocytes as well as NK Cells in Mice

X. SHAN¹, L. CHEN^1,2, M. CAO¹, L. XU¹, S. ZHANG<sup>1

1</sup>Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, ²Jiangsu Engineering Research Center for Bio-medical Function Materials, Nanjing, Jiangsu, China China

Received date June 15, 2005
Accepted date August 1, 2005
On-line available August 5, 2005


Summary
B cell-activating factor belonging to the TNF family (BAFF, also called BLyS, TALL-1, zTNF-4, or THANK) is an important survival factor for B lymphocytes. In this study, we injected mouse abdominal cavity with human soluble BAFF (hsBAFF, 0.01, 0.1, 0.5, 2 mg/kg body mass) synthesized in Escherichia coli. On the 8th day after injection, we investigated the effects of hsBAFF on immune functional activities of splenic B lymphocytes, CD4+ and CD8+ T lymphocytes and natural killer (NK) cells in mice. The results showed that B lymphocyte proliferation significantly increased in hsBAFF-treated groups with dosages of 0.1 mg/kg (p<0.05), 0.5 and 2 mg/kg (p<0.01). We observed a dose-dependent increase of CD4+ T lymphocyte percentage and significantly higher values in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05 and p<0.001, respectively) compared to control group, but CD8+ T lymphocyte percentage remained unchanged. The ratio of CD4+ to CD8+ T lymphocytes rose with increasing hsBAFF dosage (p<0.05 for 2 mg/kg hsBAFF vs. control). Significantly stronger NK cell activities were found in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05). The main finding of this study is that the hsBAFF can enhance immune responses in the body by increasing B lymphocyte and CD4+ T lymphocyte function as well as elevating NK cell activity.


Key words
hsBAFF • B lymphocyte • CD4+ T lymphocyte • CD8+ T lymphocyte • NK cell