Cellular cooperation during in vivo anti-hapten antibody responses. II. The effect of in vivo and in vitro x-irradiation on T and B cells.

The effect of x-irradiation on T and B cells involved in an in vivo adoptive anti-hapten antibody response has been studied. In vitro x-irradiation inactivates both B cells and T cells. B cells are somewhat more sensitive than T cells to such treatment, the dose required to reduce B cell activity by 50% being about 50 R, whereas 200 R will reduce helper cell activity by 50%. By contrast, if recipient mice are primed with carrier, they develop helper activity that is totally resistant to 500 R x-irradiation within 3 days of immunization. This activity can not be transferred from irradiated, carrier-primed mice by either spleen cells or serum, although anti-carrier antibody is shown to give a modest helper effect late after boosting. However, this radioresistant helper effect can be reproduced in a cell transfer system by giving carrier-primed spleen cells to normal recipients that are then x-irradiated (500R) and given a large dose of carrier protein. Neither cells nor carrier alone will give rise to such radioresistant helper effects. Similar helper activity is occasionally observed when normal mice are irradiated 24 hr after being given helper cells, in the abscence of carrier and boosted shortly thereafter. The differences between these radioresistant helper effects, and the radiosensitivity of helper cells transferred after x-irradiation, may be related to x-ray induced changes in cell migration patterns.