Objective To investigate the role of CD4 ~+ CD25~+ regulatory T lymphocytes (Treg)in modulating the cellular immune response and pathogenesis of murine pulmonary tuberculosis.Methods Inactivation of Treg was achieved by intraperitoneal injection anti-CD25 (clone PC61,50 μ/mouse) in PC61 group, and rat-IgG (50 μ/mouse) was injected intraperitoneally in control group. All the mice were inoculated intravenously with H37Rv 0. 1 mL (1 × 10~6 CFU) 3 days after Treg inactivation. The effects of Treg inactivation in different tissues were analyzed by flow cytometry. The cellular immune response, pulmonary histopathology and bacterial load were determined in vitro at different time points. The data were compared using homogeneity of variance F test and non-paired t test. Results In spleen, the percentages of Treg/CD4 T lymphocytes in PC61 group and control group were (21. 13± 3. 58)% and (30. 42± 4. 20)%, respectively at day 10 of inoculation (t = 2. 38, P < 0. 05), and those were (16. 12 ± 1. 26)% and ( 17. 34± 1. 62)%,respectively at day 30 of inoculation (t = 0. 84,P>0. 05). The percentages of Foxp3~+/CD4~+ T lymphocytes in PC61 group and control group were (32. 07 ± 3. 95)% and (60. 55 ± 5. 48)%,respectively at day 10 of inoculation (t = 5. 96, P<0. 05). Similar results were achieved in the peripheral blood. Bacillus calmette-guerin (BCG)-specific 1L-17 (ng/L) secreted by murine spleen cells in PC61 group and control group at day 10, 30 and 60 of inoculation were 5. 1± 0.9 vs 0, 43. 1± 10.0 vs5. 9± 2. 8 and 124.8 ± 5.8 vs 102. 5±8. 1, respectively (t = 7. 90, t=5. 10,t = 3. 19; all P<0.05); those of BCG-specific IFN-γ (ng/L) were 28. 4 ± 8. 2 vs 4. 0±1. 3, 685. 9± 128. 6 vs418. 7±20.4 and 310.9±119. 7 vs 32. 8±7. 5, respectively(tO = 4. 21,t = 8. 43, t = 3. 27; all P<0.05);those of TNF-a (ng/L) were 38. 6±5.0 vs 16. 3±4. 0, 112. 9 ±12. 3 vs 71. 5±12. 6 and 86. 2±8. 2vs0, respectively(t = 4. 95, t=3. 33,t/=14.8; all P<0. 05). The lung bacterial load at day 10 of inoculation in PC61 group was lower than that in control group (t = 4. 63, P < 0. 01), but the differences were not significant thereafter. The changes of lung histopathology at late stage of infection (day 120) in PC61 group were less severe than those in control group. Conclusions Murine Tregs increase dramatically after Mycobacterium tuberculosis infection. Treg could inhibit the specific cellular immunity against Mycobacterium tuberculosis, and therefore, may facilitate the persistent infection of Mycobacterium tuberculosis and development of tuberculosis.

Objective: To determine whether intrauterine infection with hepatitis B virus (HBV) occurs in early pregnancy and to characterize associated virulence factors. Methods: Villi tissues and blood samples of 45 HBV surface antigen (HBsAg)-positive pregnant women were collected during the first trimester and HBV DNA loads were quantified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression of GCM1, HBsAg and hepatitis B core antigen (HBcAg) in villi tissues were detected by immunohistochemical method. Results: Data from qRT-PCR showed that HBV DNA was detected in 14 of 45 villi tissues (positive rate of 31.11%), and 24 of 45 blood samples (positive rate of 53.33%), further statistical analysis showed that the positive rates of HBV DNA between blood samples and villi tissues were not significantly different (χ²=4.555, P=0.054). Among them, 12 samples were consistently positive between the villi and blood specimens, and HBsAg, HBeAg, HBeAb, HBV DNA from peripheral blood in these pregnant women were significantly higher than those of the other women (P value was 0.007, 0.004, 0.000, and 0.000 respectively). The multivariate logistic regression analysis showed that blood HBV DNA greater than 106 IU/ml was independently associated with HBV DNA positive in villi, and the HBsAg, HBeAg, villi tissues HBV DNA positive rates of these pregnant women were significantly higher than those of the other pregnant women (all P value were 0.000). Immunohistochemistry results showed that all 45 cases were positive for GCM1 expression in the cell nucleus. Nine cases also had HBsAg expression in the cytoplasm. Only one case was found to express HBV core antigen (HBcAg) in the nucleus. Conclusions HBV DNA and HBsAg can be detected from villi tissues harvested during the first trimester in HBsAg-positive pregnant women, and the results suggest an early occurrence of intrauterine infection of fetuses with high HBV levels.