Recombinant bacille Calmette–Guérin (BCG) expressing human interferon-alpha 2B demonstrates enhanced immunogenicity

Abstract

SUMMARYTo increase its immunostimulatory properties, BCG was genetically engineered to secrete recombinant human interferon-alpha 2B (rhIFN-a ) under control of the mycobacterial heat shock protein (hsp)60 promoter and the a antigen signal sequence. Expression of rhIFN-a was readily detectable by ELISA and on Western blotting. When compared with control BCG, rhIFN-a BCG was substantially more active in inducing the production of IFN-g and IFN-inducible protein 10 (IP-10) from human peripheral blood mononuclear cells, while IL-10 production was correspondingly decreased. These effects were reversible upon antibody neutralization of rhIFN-a . Among 10 patients tested, rhIFN-a BCG enhanced IFN-g production in all patients ranging from 1´4-to 23´7-fold with a general trend toward greatest enhancement among those with weakest baseline responses to control BCG. Correspondingly, rhIFN-a BCG decreased IL-10 production in all patients by 1´2±4´8-fold. The onset of IFN-g production induced by rhIFN-a BCG was also more rapid, occurring within 4 h after stimulation versus . 24 h with wildtype BCG. The observation that the maximum IFN-g induction depends on the simultaneous presence of both IFN-a and BCG highlights the advantages of rhIFN-a BCG. Taken together, these immunostimulatory properties of rhIFN-a BCG suggest that it may be a superior agent for immunotherapeutic protocols involving live BCG in humans.

Synergistic potentiation of interferon activity with maitake mushroom d‐fraction on bladder cancer cells

“…In addition, IFN-α therapy has several drawbacks, such as high cost and repeated administration. A standard intravesical IFN-α instillation (combined with BCG) is carried out with 50-100 x 10 6 IU of IFN-α [23], although such a high dosage appears to be in excess of the actual amount needed for an effective antitumour immunity. Moreover, even a high dose of IFN-α may not be sufficient to induce optimal immunity because of its short retention time inside the bladder [23].…”

Construction of recombinant human IFNα-2b BCG and its antitumor effects on bladder cancer cells in vitro

“…Previous studies have demonstrated that IFN-g, TNF-a, and IL-12 are antiproliferative to cancer cells, as well as induce apoptosis (Thanhäuser et al, 1995;Brandau et al, 2000a). In addition, Luo et al (2001) showed that the restructuring of hIFNa-2b-rBCG effectively induced generation of hIFN-g, hTNF-a, and hIL-12, which was clearly higher than that in wild-type BCG and wild-type BCG plus IFN.…”

“…Immunotherapy with intravesical administration of Bacillus Calmette-Guérin (BCG) is an effective alternative approach to chemotherapy for managing superficial transitional cell carcinoma of the bladder (Alexandroff et al, 1999;Luo et al, 2001). In 1976, Morales et al first reported the intravesical use of BCG for treating superficial carcinoma of the bladder.…”

Antitumor effects of human interferon-alpha 2b secreted by recombinant bacillus Calmette-Guérin vaccine on bladder cancer cells

“…During its attachment to the bladder wall, rBCG-IFNα-2b continues to express IFNα-2b to a level high enough to induce immune responses to BCG. Although this IFNα-2b level is lower than the high dosage of exogenous IFNα-2b, a continuous low level of IFNα-2b is expected to suffice to function as a tumor suppressor (Luo et al, 2001). It has been reported that an IFNα-2b level as low as 100 U/ml is adequate for stimulating PBMC proliferation and the antitumor effects (Luo et al, 2001).…”

“…PBMCs were prepared by glucan-diatrizoate meglumin density gradient centrifugation as described by Luo et al (2001) and cultured in RPMI-1640 (10% FBS) at a density of 10 6 cells/ml. A total of 100 μl of cells were added in triplicates into a 96-well plate.…”