Effects of irradiation on the expression of major histocompatibility complex class I antigen and adhesion costimulation molecules ICAM-1 in human cervical cancer.
OBJECTIVE
We initiated studies to analyze the effects of high doses of gamma irradiation on the surface antigen expression of MHC Class I, Class II, and ICAM-1 on human cervical carcinoma cell lines.


METHODS
The expression of surface antigens (MHC Class I, Class II, and ICAM-1) was evaluated by FACS analysis on two cervical cell lines at different time points, following their exposure to high doses of gamma irradiation (i.e., 25.00, 50.00, and 100.00 Gy).


RESULTS
The CaSki and SiHa cervical cancer cells we analyzed in this study expressed variable levels of MHC Class I and ICAM-1 antigens, while Class II surface antigens were not detectable. Whereas irradiation doses of 25.00 Gy were not sufficient to totally block cell replication in both cell lines, exposure to 50.00 or 100.00 Gy was able to completely inhibit cell replication. Range doses from 25.00 to 100.00 Gy significantly and consistently increased the expression of all surface antigens present on the cells prior to irradiation but were unable to induce neoexpression of antigens previously not expressed by these cells (i.e., MHC Class II). Importantly, such upregulation was shown to be dose dependent, with higher radiation doses associated with increased antigen expression. Moreover, when the kinetic of this upregulation was studied after 2 and 6 days after irradiation, it was shown to be persistent and lasted until all the cells died.


CONCLUSIONS
These findings may partially explain the increased immunogenicity of tumor cells following irradiation and may suggest enhanced immune recognition in tumor tissue in patients receiving radiation therapy.
Santin
A D
AD
Department of Obstetrics and Gynecology, University of Arkansas, Little Rock 72205-7199, USA.
Hermonat
P L
PL
Hiserodt
J C
JC
Chiriva-Internati
M
M
Woodliff
J
J
Theus
J W
JW
Barclay
D
D
Pecorelli
S
S
Parham
G P
GP
D000951:Antigens, Neoplasm / Q000378:metabolism / Q000528:radiation effects*; D019583:Dose Fractionation, Radiation; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000378:metabolism / Q000528:radiation effects*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism / Q000528:radiation effects*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism / Q000528:radiation effects*; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000528:radiation effects; D015854:Up-Regulation; D002583:Uterine Cervical Neoplasms / Q000276:immunology* / Q000532:radiotherapy
D000951:Antigens, Neoplasm; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D018799:Intercellular Adhesion Molecule-1