Cellular cytotoxicity mediated by isotype-switch variants of a monoclonal antibody to human neuroblastoma

Cellular immunotherapy for neuroblastoma: a review of current vaccine and adoptive T cell therapeutics

Immunotherapy is an attractive option for patients with high risk neuroblastoma due to their poor long-term survival rates after conventional treatment. Neuroblastoma cells are derived from the embryonic neural crest and therefore express tumor antigens not widely seen in normal cells, making them potential targets for immunologic attack. There is already considerable experience with monoclonal antibodies that target these tumor associated antigens, and in this review we focus on more exploratory approaches, using tumor vaccines and adoptive transfer of tumor-directed T cells.

Actin-binding protein filamin A is displayed on the surface of human neuroblastoma cells

We previously reported the identification of natural human IgM antibodies, which recognize a M(r) 260 000 surface protein (NB-p260) and induce both complement-mediated cytotoxicity and apoptosis of human neuroblastoma cells. NB-p260 was shown to belong to the family of filamin proteins. Filamin A is a high molecular weight actin-binding protein, previously thought to be only located intracellularly. Here we show that NB cells as well as three NB-unrelated human cell lines express filamin A also on the cell surface. Our findings suggest new biological functions for filamins, including a role as mediators in anti-NB IgM-induced apoptosis, and they add to the growing body of evidence of the interaction of cytoskeletal proteins with the extracellular matrix.

The functional relevance of NK-cell-mediated upregulation of antigen-specific IgG2a responses

We have previously shown that activation of NK cells by poly(I:C) or tumor treatment of mice increases the level of antigen-specific IgG2a (1, 2). We have now assessed the functional relevance of this effect of the innate immune system on the specific immune response. We found that the increased IgG2a significantly augments antibody-dependent cellular cytotoxicity mediated by NK cells both in vivo and in vitro. Furthermore, we show that both IgG3 producing plasma cells induced by T-independent antigens and IgG2a plasma cells induced in the presence of activated NK cells may be just as long-lived as plasma cells induced by T-dependent antigens. These results indicate that if NK cells are activated early in the immune response, before T cells are recruited, they could exert long-lasting effects.

Fc receptors as targets for immunotherapy

Human membrane and soluble Fc epsilon receptors (Fc epsilon RI, Fc epsilon RII/CD23) and Fc gamma receptors (Fc gamma RI/CD64, Fc gamma RII/CD32, Fc gamma RIII/CD16) have been implicated in a number of diseases. Their functional roles such as capture and clearance of immune complexes, antibody-dependent cell cytotoxicity, or cytokine or inflammatory mediator release, make them potential targets for immuno-intervention. In the present review, we will describe how membrane and soluble human Fc epsilon R and Fc gamma R have been already used as targets/tools for immuno-interventions by using monoclonal and bispecific engineered antibodies. Some therapeutic uses of these molecules both in cancer, infectious, and auto-immune diseases are presented.