Dendritic cells (DCs) are the most potent antigen presenting cells that can activate naive T cells. Mature DCs exress high levels of MHC and costimulatory molecules on their surface and have capacity to produce IL-12, a 75 kDa heterodimeric cytokine composed of p35 and p40 subunit. IL-12 is currently thought to be one of most critical determinants for skewing the immune response towards Th1. Expression of IL-12 in dendritic cells seems to be regulated by various stimuli including CD40L. In the present study we investigated expression of IL-12 in mature DCs, which were cultured from bone marrow cells in the presence of GM-CSF. Maturity of the DCs was confirmed by morphologic characteristics, immunophenotypes, and allostimulatory activities. Exprssion levels of IL-12 p40 in the DCs were measured by semi-quantitative RT-PCR. Increases in IL-12 p40 expression were observed after treatment with lipopolysaccharide (LPS), an anti-MHC class II monoclonal antibody, or an anti-CD40 monoclonal antibody. The most remarkable increases, however, were observed in the DCs treated with an anti-CD40 monoclonal antibody. These results support a previous notion that signals through CD40/CD40L interaction may be important for the production of IL-12 by DCs. Moreover, results of this study show a possibility of using monoclonal antibodies against CD40 molecules for preparing DCs producing high amount of IL-12, which can be used for anti-tumor or anti-viral immunotherapy.
Animals ; Antibodies, Monoclonal ; Antigen-Presenting Cells ; Bone Marrow Cells ; CD40 Ligand ; Dendritic Cells* ; Granulocyte-Macrophage Colony-Stimulating Factor ; Immunotherapy ; Interleukin-12* ; Mice* ; T-Lymphocytes

We produced two murine monoclonal antibodies designated S2E1 and S2C11, which recognize S antigen of hepatitis B virus (HBsAg). S2E1 could bind to denatured form of recombinant HBsAg as well as native form of HBsAg, but S2C11 could bind only to native form of HBsAg. Both antibodies reacted with HBsAg in the hepatocyte of patient infected with hepatitis B virus. Analyses of the nucleotide sequences encoding the variable regions of these antibodies revealed that S2E1 and S2C11 utilize variable gene segment which belong to V4/5 gene family and utilize the J5 and Jk4 gene segments, respectively. In addition, the heavy chain of S2E1 express a member of V14 gene family and a member of DSP2.9 and Jh3 gene families. S2C11 is related to the V1 gene family and expresses DFL16.1 gene regions in conjunction with the Jh3 gene segment.
Antibodies ; Antibodies, Monoclonal* ; Base Sequence ; Clone Cells* ; Cloning, Organism* ; Hepatitis B Surface Antigens ; Hepatitis B virus* ; Hepatitis B* ; Hepatitis* ; Hepatocytes ; Humans

Anti-idiotype antibody (anti-id Ab) which recognizes idiotope in the variable region of immunoglobulin (Ig) can regulate Ab production by B cells in vivo and in vitro. Although it has been reported that anti-id Ab can suppress IgM production by lymphocytes or hybridoma cells without suppression of cell proliferation, the regulatory mechanism of anti-id Ab is not completely understood. We studied the effects of anti-id Ab on the production of IgG class anti-DNA Ab by hybridoma cells, on the proliferation of cells, and on the transcription levels of Ig genes. In contrast to suppressive effect of anti-id Ab on the production of IgM previously reported by others, stimulatory effects of anti-id Ab on the production of IgG by hybridoma cells as well as the proliferation of these .cells were observed. However, little effect of anti-id Ab on the transcription levels of Ig genes was observed. These results suggest that anti-id Ab can increase Ab production by stimulation of cell proliferation. Furthermore, these results suggest that the effect of anti-id Ab on the production of Ab may be determined by the difference in class of Ab produced by hybridoma cells following the treatment with anti-id Ab.
Antibody Formation* ; B-Lymphocytes ; Cell Proliferation ; DNA* ; Genes, Immunoglobulin ; Hybridomas* ; Immunoglobulin G ; Immunoglobulin M ; Immunoglobulins ; Lymphocytes