Stimulation of human lymphocyte proliferation and CD40 antigen expression by phosphorothioate oligonucleotides complementary to hepatitis B virus genome

Responses of human B cells to DNA and phosphorothioate oligodeoxynucleotides

Emerging information has documented that certain DNA and sODNs can be both immunogenic and immunostimulatory. sODNs, but not DNA, induce T-cell-independent polyclonal activation of human B cells by engaging cell-surface receptors. Manifestations of sODN-induced human B-cell activation include expression of activation markers, proliferation, Ig production and anti-DNA antibody production. IL-2 and intact T cells enhanced B-cell responses to sODNs but were not required. Monocytes also provided a modest enhancement of human B-cell responses induced by sODNs. The chemical nature of sODNs capable of stimulating human B cells and the specific cell-surface receptors involved have not been completely delineated. Further studies will be necessary to elucidate the potential role of stimulatory sODNs in disease pathogenesis and to develop a means to employ ODNs as therapeutic agents in humans.

The presence of high amounts of HBV-DNA in serum is associated with suppressed costimulatory effects of interleukin 12 on HBV-induced immune response

BACKGROUND/AIMS

The aim of this study was to examine the influence of the viral load on costimulatory effects of rhIL-12 on the hepatitis B virus (HBV)-induced immune response.

METHODS

Peripheral blood mononuclear cells of HBsAg positive patients without cirrhosis were stimulated with HBsAg, HBcAg, preS1Ag and tetanus toxoid in the absence or presence of IL-12 (0.01, 0.1 and 1 ng/ml). Stimulation by alpha-CD3+alpha-CD28, pokeweed mitogen (PWM) and lipopolysaccharide (LPS) were used as controls. Then, proliferation and cytokine production were determined by 3H-thymidine uptake and ELISA after 72 h. The patients were divided into group 1 (n=21): HBV-DNA: not detectable, group 2 (n=13): HBV-DNA: <300 pg/ml, and group 3 (n= 10): HBV-DNA: >300 pg/ml.

RESULTS

After stimulation with only HBV antigens, the highest amounts of IL-10 were found in group 3, while interferon (IFN)-gamma was rarely detectable. After stimulation with IL-12 and HBV antigens, strong costimulatory effects on IFN-gamma production, as well as proliferation, were observed in all patients except individuals from group 3. With regard to antigen-unrelated stimulation, significantly lower amounts of LPS-induced IFN-gamma production and alpha-CD3+28 induced proliferative responses, but higher amounts of LPS-induced IL-10 were observed in group 3.

CONCLUSIONS

These data suggest that the presence of high amounts of HBV-DNA in serum is associated with suppressed co-stimulatory and regulatory effects of IL-12 on the immune response to HBV antigens. This may be one explanation for the poor response to immunostimulating therapy in patients with a high viral load.