Intravenous BCG vaccination provides better protection for neonatal mice than for adult mice infected with Mycobacterium tuberculosis 9221

Abstract Description Here we compare the immune responses of intravenously (IV) BCG-vaccinated neonatal and adult mice infected with Mycobacterium tuberculosis (Mtb). We found that IV BCG vaccination significantly reduced lung and spleen bacterial burdens in Mtb-infected neonatal mice compared with Mtb-infected adult mice. The reduced bacterial burden in the spleens of IV BCG-vaccinated Mtb-infected neonatal mice was more noticeable than that in the lungs. IV BCG vaccination significantly increased IL-2, IL-3, IL-15 and IP-10 levels and reduced IL-1α and Gro-α production in the lungs of neonatal mice infected with Mtb. IV BCG vaccination significantly increased the number of CD8+ T cells and reduced the CD11b+Ly6G+ and CD4+ cell populations in the lungs of neonatal mice infected with Mtb compared with the lungs of Mtb-infected adult mice. In the spleen, neonatal BCG vaccination increased the number of CD11b+Ly6G+, CD11b+CD11c+, B220+, and CD3-NK1.1+CD27+ cells and decreased the number of CD11b+ and CD11c+MHCII+ cells in Mtb-infected mice. Our findings suggest that IV BCG vaccination can provide better protection against pulmonary and extrapulmonary tuberculosis in neonates compared to adults. Funding Sources NIH, CRDF Global Topic Categories Vaccines and Immunotherapy (VAC)