Synergistic action of immunostimulatory DNA and fcgamma receptor IIB-crosslinking on B-cell phenotype and function

A safety study of a B-class CpG ODN in Sprague-Dawley rats

Oligodeoxynucleotides containing CpG motifs (CpG ODNs) are potent immune activators and are being tested as anti-tumor, antimicrobial agents and as adjuvants in vaccines. Little has been reported, however, about the systematic and comprehensive safety evaluation on repeated CpG ODN administration. To investigate the safety profile of a newly developed CpG ODN, CpG 684, we conducted a 28-day repeated dose toxicity study in rats, at dose levels of 5, 20 and 150 µg CpG 684 per rat. No abnormalities in clinical observations, growth, urinalysis and bone marrow cell counts were found in CpG 684 treated rats. CpG 684 was proved biologically active, capable of up-regulating the expressions of CD40 and CD86 molecules. The monocyte numbers were increased at the dose levels of 20 and 150 µg per rat. The spleen weights were increased in female rats at the dose level of 150 µg per rat. Microscopically, 5, 20 and 150 µg per rat CpG 684 caused local inflammatory cell infiltration and hyperplasia of fibrous tissue at injection sites; the treatment of 5 and 150 µg per rat CpG 684 induced enhanced inflammatory reaction in inguinal lymphoid tissue, and the dose of 150 µg per rat induced cell hyperplasia in white pulp of spleen and white pulp expansion. CpG 684 at 150 µg per rat led to decreases in peripheral lymphocyte, serum globulin, glucose, alkaline phosphatase and K+ levels in female rats, and induced the decrease in serum albumin and total protein in rats of both sexes. The data from this study will provide an important reference for developing CpG 684 as an adjuvant for vaccines of human use.

The role of toll-like receptors in systemic lupus erythematosus

Systemic lupus erythematosus is an autoimmune disease characterized by the production of autoantibodies against a relatively limited range of nuclear antigens. These autoantibodies result in the formation of immune complexes that deposit in tissues and induce inflammation, thereby contributing to disease pathology. Growing evidence suggests that recognition of nucleic acid motifs by Toll-like receptors may play a role in both the activation of antinuclear B cells and in the subsequent disease progression after immune complex formation. The endosomal localization of the nucleic acid-sensing Toll-like receptors (TLRs), TLR3, 7, and 9, is believed to contribute to the distinction between endogenous nucleic acids and those of foreign origin. In this article we review recent work that suggests a role for the B-cell receptor and Fcgamma receptors in delivering nuclear antigens to intracellular compartments allowing TLR activation by endogenous nucleic acids. A number of in vitro studies have presented evidence supporting a role for TLRs in SLE pathology. However, recent studies that have examined the contributions of individual TLRs to SLE by using TLR-deficient mice suggest that the situation is far more complicated in vivo. These studies show that under different circumstances TLR signaling may either exacerbate or protect against SLE-associated pathology. Further understanding of the role of TLRs in pathological autoreactivity of the adaptive immune system will likely lead to important insights into the etiopathogenesis of SLE and potential targets for novel therapies.