Resolution of an infection with Leishmania braziliensis confers complete protection to a subsequent challenge with Leishmania major in BALB/c mice.
Both Leishmania major and L. braziliensis induce cutaneous leishmaniasis in BALB/c mice. Whereas BALB/c mice die of infection with L. major, they cure an infection with L. braziliensis. We report here that after curing an infection with L. braziliensis, BALB/c mice are resistant to challenge with L. major. When challenged with L. major, L. braziliensis pre-treated BALB/c mice mounted a delayed-type hypersensitivity response to L. major and produced high amounts of interferon-gamma (IFN-gamma) but low amounts of interleukin-4. The IFN-gamma produced by the L. braziliensis pre-infected mice was involved in the protection seen against L. major challenge since treating the mice with a neutralizing anti-IFN-gamma abrogated the protection. This suggests that cross-reactive antigen epitopes exist between L. braziliensis and L. major and that pre-infection with L. braziliensis primes BALB/c mice to epitopes on L. major that can elicit a protective Th1 response to the parasite.
Lima
H C
HC
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523-1671, USA.
DeKrey
G K
GK
Titus
R G
RG
D000818:Animals; D016207:Cytokines; D005260:Female; D007371:Interferon-gamma; D015847:Interleukin-4; D007892:Leishmania braziliensis / Q000276:immunology*; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C
D016207:Cytokines; D015847:Interleukin-4; D007371:Interferon-gamma