Vaccine against carcinoembryonic antigen does not induce autoimmunity.

2003 JUL 16 - (NewsRx.com & NewsRx.net) -- by Maria G. Essig, MS, ELS, senior medical writer - A vaccine directed against human carcinoembryonic antigen (CEA), which is naturally expressed by some tissues in adults and is overexpressed by some tumors, did not induce autoimmunity, according to a report in the journal Clinical Cancer Research.

"Many current clinical trials involve vaccination of patients with vaccines directed against tumor-associated antigens, which are, in actuality, 'self-antigens' over-expressed in tumors as compared with normal tissues," explained James W. Hodge and colleagues at the National Cancer Institute in the United States. "As tumor vaccines become more potent through the addition of costimulatory molecules and cytokines and the use of diversified prime and boost regimes, the level of concern rises regarding the balance between antitumor immunity and pathological autoimmunity.

"Here we investigate the mechanism of tumor therapy and evaluate the safety of such a regimen in a self-antigen system. To our knowledge, the study reported here is the first description of a vaccine to a defined antigen where the regimen is potent enough to induce tumor therapy in the absence of autoimmunity."

The investigators immunized transgenic mice carrying 2-week-old CEA-expressing tumors with a vaccine consisting of recombinant poxviral vectors [recombinant vaccinia, recombinant fowlpox (rF)] encoding the CEA transgene plus three costimulatory molecules [B7-1, ICAM-1, and LFA-3 (TRICOM)], along with murine granulocyte macrophage colony-stimulating factor followed by low-dose interleukin 2.

"Mice were monitored for survival and compared with groups of mice vaccinated in a similar manner with poxviral vectors containing CEA/B7-1 or CEA transgenes," reported Hodge and his collaborators.

Treated mice that showed no signs of tumors were monitored for 1 year along with the age-matched control animals (Vaccine therapy of established tumors in the absence of autoimmunity. Clin Cancer Res, 2003;9(5):1837-1849).

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