Sundararaj T, Agarwal S C
Infect Immun. 1977 Oct;18(1):253-6. doi: 10.1128/iai.18.1.253-256.1977.
Guinea pigs immunized with ribonucleic acid protein fraction from Nocardia asteroides developed high cell-mediated immunity within 2 weeks, as shown by increased macrophage microbicidal activity and macrophage migration inhibition. This immunity protected against intravenous and subcutaneous challenge with N. asteroides and persisted for at least 70 days.