Maturation of the delayed-type hypersensitivity response in SJL mice: absence of effector cell induction.

Immunization of young adult SJL mice (6 weeks of age) with a wide variety of particulate and soluble antigens does not elicit a delayed-type hypersensitivity (DTH) response. Young adult SJL lack a DTM response through 8 weeks of age but attain the mature adult level of responsiveness at 10 weeks of age. Nylon wool-enriched TDTH effectors and an antigen-specific T cell clone both elicited DTH responses when transferred into 6-week-old SJL. Thus, the cascade of events at the local site appears to be functionally intact in 6-week-old SJL. However, T cells from immunized 6-week-old SJL fail to transfer DTH responsiveness to naive 6-week-old SJL recipients unless macrophages from 12-week-old SJL supplemented the immunization. Thus, the unresponsiveness of 6-week-old SJL appears to be due to a lack of induction of TDTH effectors. In addition, SJL mice immunized at 6 weeks of age and challenged with antigen at the DTH responsive age of 12 weeks did not mount a DTH response. Immunized 6-week-old SJL, supplemented with macrophages from 12-week-old SJL, and 12-week-old SJL did respond to a second antigenic challenge when held for an equivalent 6-week period. Thus, 6-week-old SJL fail to induce TDTH effectors and to generate memory TDTH cells. Finally, antigen-pulsed macrophages from 12-week-old SJL transferred DTH responsiveness into naive 6-week and 12-week-old SJL recipients, while antigen-pulsed cells from 6-week donors were unable to transfer DTH responsiveness. These data indicate that the maturational deficit in the DTH responsiveness of 6-week-old SJL resides in the inability of macrophages to induce TDTH effectors.