T-cell responses to mitogens in atomic bomb survivors: a decreased capacity to produce interleukin 2 characterizes the T cells of heavily irradiated individuals.
Significant decreases in the fraction of lymphocytes that are CD4(+) and increases in serum levels of some classes of immunoglobulin have been reported to occur in atomic bomb (A-bomb) survivors and in victims of the Chernobyl nuclear plant accident. To investigate the long-term effects of nuclear radiation on cellular immunity in more detail, we used limiting dilution assays with peripheral blood mononuclear cell preparations to analyze the T-cell responses of 251 A-bomb survivors exposed to less than 0.005 Gy and 159 survivors exposed to more than 1.5 Gy. The percentages of CD2-positive cells that were capable of proliferating in response to phytohemagglutinin (PHA) in the presence of exogenous interleukin 2 (IL2) did not differ substantially between distally exposed and more heavily exposed survivors. The heavily exposed survivors appeared to possess fewer T cells that were capable of proliferating in response to concanavalin A (Con A) or of producing interleukin 2. Assuming that CD4 T cells were the ones primarily responsible for producing IL2 in response to Con A, we were able to estimate how many cells in any given CD4 T-cell population were actually producing IL2. The results indicated that peripheral blood samples from heavily exposed survivors contained significantly fewer IL2-producing CD4 T cells than did similar samples from distally exposed survivors, indicating that significant exposure to A-bomb radiation may have a long-lasting negative effect on the capacity of CD4 T-cell populations to produce IL2.
Kusunoki
Y
Y
Department of Radiobiology, Radiation Effects Research Foundation, Hiroshima, Japan.
Hayashi
T
T
Morishita
Y
Y
Yamaoka
M
M
Maki
M
M
Bean
M A
MA
Kyoizumi
S
S
Hakoda
M
M
Kodama
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018801:CD2 Antigens / Q000096:biosynthesis / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism / Q000528:radiation effects*; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D008934:Mitogens / Q000494:pharmacology*; D009689:Nuclear Warfare; D010835:Phytohemagglutinins / Q000494:pharmacology; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000276:immunology / Q000528:radiation effects
D018801:CD2 Antigens; D007376:Interleukin-2; D008934:Mitogens; D010835:Phytohemagglutinins; D003208:Concanavalin A