Abstract
Splenic enriched T-cells and sera were obtained from inbred CBA/J mice injected 7 or 35 days earlier with either 10(3) viable Cryptococcus neoformans or sterile physiological saline. The transfer of enriched T-cells collected 7 days after immunization or of normal enriched T-cells did not transfer immunity to C. neoformans or delayed-type hypersensitivity responsiveness to cryptococcal culture filtrate (CneF) antigen to the recipients. However, enriched T-cells harvested 35 days after immunization, when transferred to recipient mice, were able to confer immunity as indicated by the reduction in numbers of C. neoformans cells in the tissues, and they also transferred delayed-type hypersensitivity responsiveness to CneF antigens. Sera from either sensitized or normal mice were unable to transfer immunity to recipient animals. These results suggested that there was a time requirement for development of the immune response in the donor mice and that T-cells were crucial in the host defense against a cryptococcal infection. Culturing of day-35 C. neoformans-sensitized T-cells in the presence of homologous antigen (CneF) but not in the presence of heterologous antigen (purified protein derivative or 2, 4-dinitro-1-fluorobenzene) induced the production of migration inhibition factor, thus indicating that lymphocytes from C. neoformans-injected mice were specifically sensitized to CneF antigen.