Differential Recovery of Antibody Production Potential After Sublethal, Whole‐Body Irradiation of Mice

Mice were given single injections of sheep erythrocytes (SE) or polyvinylpyrrolidone (PVP) at various times after sublethal, whole‐body irradiation (550 rad 60 CO) and direct, antigen‐specific, plaque‐forming cell (PFC) responses were quantified. Irradiated mice did not respond to SE or PVP when immunized 15 d postirradiation (PI); by day 30 PI, the responses by irradiated mice were 40–126% of normal to SE and 3–38% of normal to PVP. The impaired recovery after irradiation of immune responses to PVP was not due to altered antigen dose requirements or altered time of peak PFC response and occurred after irradiation of mice by doses as low as 200 rad. Both athymic and euthymic mice had impaired responses to PVP after whole‐body irradiation. The impaired response of irradiated mice to PVP was repaired by adoptive transfer of normal bone marrow, fetal liver, or spleen cells and also by spleen cell preparations enriched in Ig + cells but not by spleen cell preparations enriched in Thy.1 + or Ig − cells. With the aid of additional antigens it was observed that by day 30 PI, mice had recovered ability to respond to the T‐cell‐dependent antigen SE and the T‐cell‐independent type‐1 antigens 2,4,6‐trinitrophenyl‐ Brucella abortus and butanol‐extracted bacterial lipopolysaccharide, but at that time they gave impaired responses to the T‐cell‐independent type‐2 antigens PVP, type III pneumococcal polysaccharide, and phenol‐extracted bacterial lipopolysaccharide; they had an immune response pattern similar to that of CBA/N mice having an X‐linked immunodeficiency.