Pregnancy-induced antitumor cytotoxicity of T cell-rich fraction against mammary adenocarcinoma cells in rats.
Our earlier observations indicated that splenocytes from parous rats have high cytotoxic activity against mammary tumor cells in vitro. It has also been observed that this cytotoxic activity of splenocytes from parous rats can be adoptively transferred to virgin rats of same age. The present investigation is an attempt to determine the cell type in spleens of parous rats that cause the cytotoxicity against mammary tumors. The spleens from both virgin and parous rats were removed aseptically and T and B cell-rich fractions were separated. 7,12-Dimethylbenz[a]anthracene-induced rat mammary tumor epithelial cells were used as targets and the T and B cell-rich fractions from either virgin or parous rats were used as effectors. The parous rats were divided into two groups according to the time period after parturition. Group I contained rats that were 5-13 days after delivery, while the rats in group II were 14 or more days post parturition. In vitro cytotoxicity was determined by incubating the tumor cells with spleen cells in the target/effector ratio of 1:3, 1:10 and 1:30 and using the standard 51Cr release assay. In all ratio groups of T cell-rich fractions particularly in group II, there was significantly higher cytotoxicity against mammary tumor cells. None of the B cell-rich fractions from parous rats were significantly more cytotoxic than those from virgin controls.
Chakravarty
P K
PK
Department of Breast Surgery, Roswell Park Cancer Institute, Buffalo, NY 14263.
Sinha
D K
DK
D015127:9,10-Dimethyl-1,2-benzanthracene; D000230:Adenocarcinoma / Q000139:chemically induced / Q000276:immunology*; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000276:immunology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*
D015127:9,10-Dimethyl-1,2-benzanthracene