Immunogenicity of a plasmid DNA vaccine encoding chimeric idiotype studied.

2003 JAN 1 - (NewsRx.com & NewsRx.net) -- According to recent research from the United States, "B-cell lymphomas express tumor-specific immunoglobulin, the variable regions of which idiotype (Id) can serve as a target for active immunotherapy. Promising results have been obtained in clinical studies of Id vaccination using Id proteins. However, Id protein is laborious and time-consuming to produce."

J.M. Timmerman and colleagues at Stanford University, California, said, "DNA vaccination is an attractive alternative for delivering Id vaccines, because Id DNA can be rapidly isolated by PCR [polymerase chain reaction] techniques. DNA coding for lymphoma Id can provide protective immunity in murine models."

They conducted "a phase I/II clinical trial to study the safety and immunogenicity of naked DNA Id vaccines in 12 patients with follicular B-cell lymphoma. The DNA encoded a chimeric immunoglobulin molecule containing variable heavy and light chain immunoglobulin sequences derived from each patient's tumor, linked to the IgG2a and kappa mouse immunoglobulin (MsIg) heavy- and light-chain constant regions chains, respectively. Patients in remission after chemotherapy received 3 monthly [intramuscular (i.m.)] injections of the DNA in three dose escalation cohorts of four patients each (200, 600, and 1800 micrograms)."

Timmerman and coworkers reported that "[a]fter vaccination, 7 of 12 patients mounted either humoral (n=4) or T-cell proliferative (n=4) responses to the MsIg component of the vaccine. In one patient, a T-cell response specific to autologous Id was also measured. Anti-Id antibodies were not detectable in any patient."

Then another "series of vaccinations was...administered using a needle-free injection device (Biojector) to deliver 1800 micrograms both i.m. and intradermally (i.d.); 9 of 12 patients ...