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Biomedical subjects

H Pihko

Publications and source records attributed to H Pihko.

6 recordsLinked to original sources
PubMed1977

Effect of specific immunotherapy with preimmunization against alpha-fetoprotein on a mouse transplantable hepatoma.

Antibodies to autologous alpha-fetoprotein (AFP) were produced in mice by immunization with rat AFP. C57L/J mice with or without such antibodies were inoculated sc or ip with controlled numbers of cells of the syngeneic, AFP-producing, BW 7756 hepatoma. There was a linear relationship between circulating AFP and tumor mass, with elevated AFP being detectable earlier than the tumor. The AFP levels of the immunized mice were generally lower than those of control mice, and tumors could be detected before elevated concentrations of AFP appeared in the circulation. An extensive series of transplantations with varying protocols for immunization did not protect against tumor and did not affect the rate of tumor growth.

Animals↗
PubMed1976

Characterization of homologous anti-alpha-fetoprotein antibodies produced in rabbits.

The natural tolerance to alpha-fetoprotein (AFP) was broken in rabbits by immunizations with purified AFP from different species and homologous AFP chemically modified by haptenation. Some of the rabbits were boostered with rabbit AFP. The highest titers were obtained with human AFP, which shows a strong cross-reaction with rabbit AFP. The homologous antibodies were of lower avidity than heterologous (sheep) antisera. Injections with rabbit AFP did not alter the avidity or titer. All antibodies produced by injections with human AFP could be absorbed with the original immunogen, and no reactivity against determinants unique to rabbit AFP could be found. These results indicate that the antibody activity against autologous AFP is based on cross-reactivity and that the immunizations did not make the autologous AFP immunogenic. These findings may be important in view of the possible use of AFP as a target antigen in tumor immunotherapy.

Animals↗
PubMed1975

Carcinoembryonic antigen and alpha fetoprotein in malignant tumors of the female genital tract.

Circulating carcinoembryonic antigen (CEA) and alpha fetoprotein (AFP) levels were measured by radioimmunoassay in 53 patients with carcinoma of the ovary, 16 patients with other malignant genital tumors, and 31 women with nonmalignant diseases of the genital tract. The serum CEA concentration was elevated (greater than 5 ng/ml) in 11 patients with ovarian cancer, 2 patients with endometrial cancer, 1 patient with carcinoma of the cervix, and 1 patient with a benign embryonal cystic teratoma. Elevated CEA levels were found only in patients with advanced malignant disease, while early stages were associated with normal CEA concentrations. AFP levels were normal in all but 1 patient. Both CEA and AFP levels were markedly raised in a case of advanced genital carcinoma arising probably from the ovary. Ascitic fluid of another patient with ovarian cancer contained a high concentration of CEA, giving an identical reaction in immunodiffusion with CEA from colon cancer. The present results indicate that while the increased expression of carcinofetal components takes place in some malignant tumors of the female genital tract, it is usually a late phenomenon.

Alpha-Globulins↗
PubMed1975

Rabbit alpha-fetoprotein: normal levels and breakage tolerance with haptenated homologous alpha-fetoprotein.

Nanogram quantities of alpha-fetoprotein (AFP), a tumor associated fetal protein, were found in the serum of normal adult rabbits by radioimmunoassay. This AFP was isolated and shown to be immunologically identical to fetal AFP by immunodiffusion. Immunizations of rabbits with unmodified to desialylated AFP in complete Freund's adjuvant did not cause antibody formation, indicating the existence of tolerance against homologous AFP. The tolerance could be terminated by immunizing with hapten-coupled AFP, which resulted in production of rabbit antibodies reacting with unmodified rabbit AFP.

Animals↗