RE: <<Will it work? Certainly not be the mechanisms that they discuss, and that's what bugs me... they know damn well that every solid study known to man has failed to show the existence of tumor-specific antigens associated with spontaneous cancers.>>
Here is what Dr Srivastava has previously stated about tumor-specific antigens:
Attempts to find truly tumor-specific single antigens common to large numbers of patients have generally come to naught,” says Srivastava. Those so occupied have usually had to content themselves with antigens that were not unique to, but merely overrepresented on, tumor cell surfaces. These antigens are more likely to be tissue- rather than strictly tumor-specific. Researchers thus have had to steer a middle course between the Scylla of side effects inherent in attacking innocent cells displaying diminutive quantities of these antigens and the Charybdis of immunotolerance.
Indeed, Srivastava believes that each tumor’s in vivo immunogenicity may be inherently individualized. This immunogenicity, he suspects, is attributable to the idiosyncratic peptide products of random mutations that inevitably arise in undisciplined tumor cell populations. Of the myriad of other antigenic components present on a cell’s surface, even those drastically overrepresented in cancer cells are likely to have been rendered tolerogenic in early development. They may be found at lower levels on healthy cells as well, raising the possibility of side effects even if an approach succeeds in overcoming that immunotolerance.
There exists a class of exceptions to the rule that no single antigen a) is found on all tumors of a given type, b) never appears on healthy cells, and c) is nontolerogenic: antigens produced by pathogens’ oncogenes. Because they’re of foreign origin, they are capable of producing a strong immune response. One of Antigenics’ competitors has adopted a vaccination technique that employs a bacterial HSP covalently linked to a single antigen from a viral oncogene implicated in cervical cancer. Early clinical trials indicate some measure of success, although some researchers, such as the Mayo Clinic’s Vile, wonder whether serial injections of bacterial HSPs — the amino acid sequences of which bear similarities to those of mammals, but nonetheless differ significantly — might themselves trigger the formation of neutralizing antibodies at levels that could interfere with the vaccine.
antigenics.com
Did you figure anything out from the yahoo discussions? As a non-biologist it seems to me that there is some considerable doubt about the viability of AGENs cancer vaccine approach which perhaps accounts for some of the short interest. Yet the approach seems to work on at least some cancer patients and the Antigentics discussion above seemed plausible to me. Let us know if you figure it all out <g>.
Thanks,
Area51 |
