[Auto-dendritic cell vaccines pulsed with PSA, PSMA and PAP peptides for hormone-refractory prostate cancer].

OBJECTIVE: To investigate the clinical safety and effects of auto-dendritic cells pulsed with HLA-A201-binding peptides prostate-specific antigen (PSA) , prostate-specific membrane antigen (PSMA) and prostatic acid phosphatase (PAP) in the treatment of hormone-refractory metastatic prostate cancer (HRPC). METHODS: Sixteen HRPC patients with positive HLA-A201 were enrolled and their monocytes isolated and induced into dendritic cells with the combination of rhGM-CSF and rhIL4. The patients were inoculated subcutaneously near the inguinal region with auto-DCs pulsed with peptides PSA (KLQCVDLHV) , PSMA (ALDVYNGL L) and PAP (LLHETDSAV) every 2 weeks for 4 times, and the immunological and clinical responses were examined within 1 -2 weeks after the final vaccination. RESULTS: Vaccination of dendritic cells was well tolerated and no toxicity was observed. The cytokine levels in the serum such as IL-2, IL-12 and IFN-gamma were significantly increased after the vaccination (P < 0.01). The delayed type hyper- sensitivity (DTH) test was positive in 4 of the patients (4/11), the percentage of antigen-special IFN-gamma+ CD8+ T increased in 5 (5/11), the level of the tumor marker PSA decreased in 6 (6/16) , hydrops abdominis reduced in 1 (1/16), and the size of the cervical lymph node lessened in 1 (1/16). Three patients showed partial remission (PR), 7 stability of the disease (SD), and the other 6 progression of the disease (PD). CONCLUSION: Auto-DC vaccines loaded with PSA, PSMA and PAP peptides, capable of eliciting specific immune responses in HRPC patients, is a safe and effective option for the treatment of advanced HRPC.

Expression of Human Soluble CD40 Ligand in Pichia pastoris and Its Effects on Dendritic Cells and Malignant B Cells.

CD40 ligand (CD40L) is a member of the tumor necrosis factor (TNF) superfamily and is expressed primarily on the activated CD4( )T lymphocytes. The CD40 molecule, the cognate receptor of CD40L presents on many immunocytes such as B lymphocytes, dendritic cells (DCs) as well as on some neoplastic cells. Triggering of CD40 through CD40L plays a central role in the initiation and regulation of the human immune response. In order to further investigate the possible biological roles of CD40 signaling triggered by CD40L, we subcloned the DNA fragment encoding the extracellular region of human CD40L into the pSK plasmid. After being sequenced, the target fragment was introduced into the pPICZalphaA plasmid to construct the pPICZalphaA-sCD40L expressing vector which was then transduced into Pichia pastoris GS115 cells by electroporation. The tansformant expressed sCD40L in culture supernatants with a maximum yield of about 35 mg/L. Furthermore, we found that the recombinant human soluble CD40 ligand (rhsCD40L) could effectively induced human peripheral blood monocytes(PBMCs) in vitro in the absence of TNFalpha into dendritic cells (DCs) with the typical morphology and special surface markers of dendritic cells including CD1a, CD80, CD83, and HLA-DR etc. To our surprise, the rhsCD40L also could inhibit directly in vitro proliferation of the CD40-positive multiple myeloma cell line XG-2 and the B lymphoma cell line Daudi significantly at an optimal concentration from 2.5 to 15.0 mg/L, while CD40 negative ovarian carcinoma cell lines, SKB and SKR, were not effected by either high or low concentration of rhsCD40L. Moreover, rhsCD40L had the same effects as CD40L-transfected cell in inducing XG2 cell apoptosis. Our results demonstrated that functional human soluble CD40L could be successfully expressed in the Pichia pastoris system and that the recombinant human soluble CD40L might be a potential immune adjuvant and a new powerful molecule for tumor bio-therapy.

[Inhibition of human glioma cell growth by a soluble recombinant human CD40 ligand].

BACKGROUND & OBJECTIVE: CD40 presents on B cells, monocytes, dendritic cells, and endothelial cells, as well as a variety of neoplastic cell types, including carcinomas. CD40 stimulated by its antibody or CD40 ligand previously had been demonstrated to induce activation-induced cell death in ovarian carcinoma cell lines, colon carcinoma cell lines, breast carcinoma cell lines, and lung carcinoma cell lines and to inhibit their growth in vivo. This study was designed to assess the effects of a recombinant soluble human CD40 ligand (srhCD40L) on human glioma cell lines. METHODS: The specimens of human glioma were examined for CD40 expression by immunohistochemistry. The human glioma cell lines were examined for CD40 expression by flow cytometry. The cell lines were incubated with srhCD40L for 24h and 72h, then the markers of proliferation and apoptosis of these cells were determined, respectively. RESULTS: CD40 expression could be detected in 7/23 human glioma specimens and 1/3 cell line. The srhCD40L inhibited the proliferation of CD40+ human glioma cell line. The viability of these cells was decreased from 98% to 87%. The apoptosis and death of these cells were increased by 17.4%. CONCLUSIONS: CD40 stimulated by its ligand directly inhibits human glioma cell growth in vitro. These results suggest that srhCD40L may be of clinic use to inhibit glioma growth.