PROGRESS WITH TUMOR VACCINES

Immunological treatment of malignant tumours is based on the inherent immunogenicity of tumours. Apart from some exceptions, however, tumour s of humans are only weakly immunogenic. They induce an immune respons e that, after skin tests with autologous tumour cells, becomes primari ly evident as sensitisation of T lymphocytes to different types of tum our-associated antigens. Active specific immunisation pursues the aim of amplifying this pre-existing sensitisation into an effective antitu mour immune response. Besides adjuvants there are several ways of incr easing the immunogenicity of tumour cells and soluble tumour-associate d antigens. However, newly developed strategies to prepare tumour vacc ines, such as transfection of tumour cells with the genes of immunolog ical effector molecules or insertion of tumour-associated antigen gene s into viral or mycobacterial vectors, may be more effective. Current clinical trials of active specific immunisation, still highly experime ntal, are focused especially on patients with malignant melanoma or co lorectal carcinoma. Their results may nourish the hopes of clinicians, but cannot yet refute the objections of sceptics.