Genetic idiotypic and tumor cell-based vaccine strategies for indolent non Hodgkin’s lymphoma
ABSTRACT
B cell malignancies express a clear tumor-specific antigen (B cell immunoglobulin variable regions) known as idiotype (Id). It is now possible to immunize patients against autologous Id generating humoral and cellular immune responses that correlate with clinical and molecular remissions and the possibility of improved disease-free survival. In its present form, however, individual vaccine preparation by generating heterohybridomas is a technical and financial challenge. DNA vaccination provides a unique opportunity to streamline individual vaccine manufacture by circumventing the need for protein purification. DNA fusion vaccines have been developed in which genetic carriers promote adaptive immunity against the attached Id. Such carriers can specifically bind receptors on dendritic cells (DC) for targeted antigen delivery, or supply high levels of T cell help. Ideally, the carrier should be able to activate innate immunity to enhance the antigen-presenting capacity of DC. The correlates of immunity may vary depending upon the genetic carrier used. Translation to patients has begun with preliminary evidence of Id-specific immune responses. An alternative vaccination strategy that allows for the potential to vaccinate against multiple tumor antigens without the need to identify individual antigens is based on tumor cells themselves to be used as vaccine. To this purpose, however, each patient’s tumor cells must be genetically modified to increase their immunogenicity. To overcome the technical limitations inherent with a fully autologous approach, strategies have been devised where a universal, genetically modified bystander cells is expected to provide the immunoenhancing cytokines to allow immune recognition of unmodified patients‘ tumor cells.