Intranasal vaccination of mice against infection with Mycobacterium tuberculosis

The intranasal (i.n.) route of immunisation, has recently been of active in terest in endeavours to improve the efficacy of vaccination against a numbe r of respiratory infections. Here, we examined the outcome of tuberculous i nfection in BALB/c mice. I.n. application of the BCG-Pasteur strain was fou nd to be highly protective against challenge infection with the pathogenic H37Rv strain given after a 4-week interval, reflected by the 100-fold reduc tion of CFUs in both lungs and spleens. Vaccination with the recombinant Ps tS-1 antigen and cholera toxin significantly protected against the challeng e given 10 days later, but only marginally after 12 weeks. Histological exa mination showed, that i.n. vaccination abrogated the confluent infiltration of lungs with inflammatory cells, which surrounds the granulomas in H37Rv challenged control mice. In conclusion, the strong protection demonstrated by BCG suggests that the i.n. route of vaccine delivery deserves further at tention toward improving vaccination against tuberculosis. (C) 2000 Elsevie r Science Ltd. All rights reserved.