Requirement for multiple lymphocyte subsets in protection by a live attenuated
vaccine against retroviral infection
Ulf Dittmer, Diane M. Brooks
& Kim J. Hasenkrug
Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, 903 S. 4th St., Hamilton, Montana 59840
Correspondence should be addressed to Kim J. Hasenkrug
Infection by live attenuated retroviruses provides excellent protection
from challenge with pathogenic viruses in several animal models, but little
is known about which immune effectors are necessary for protection. We examined
this using adoptive transfer experiments in the Friend virus mouse model.
Transfers of immune spleen cells into naive mice conferred complete protection,
and transfers of purified lymphocyte subsets demonstrated that this effect
required complex immune responses involving CD4+ and CD8
+ T cells and also B cells. In addition, passive immunization experiments
demonstrated that antibodies alone reduced virus loads but did not prevent
infection. These findings may have implications for retroviral vaccine design
in general.
