ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Interleukin-4 has been reported to critically modulate Borrelia burgdorferi infection and Lyme arthritis in experimental murine models. To determine the in vivo role of IL-4 in controlling Lyme carditis, we compared immunological responses and the severity of cardiac inflammation in wild-type BALB/c (IL-4 +/+) and IL-4 deficient BALB/c (IL-4 −/−) mice infected with B. burgdorferi by tick-bite. At day 15 and 30 post-infection IL-4 −/− mice produced significantly greater titers of spirochete-specific IgG2a than the wild-type IL-4 +/+ mice, which produced significantly more spirochete-specific IgG1. Following in vitro antigenic stimulation with B. burgdorferi antigen, splenocytes from infected IL-4 −/− and IL-4 +/+ mice displayed similar magnitudes of proliferative responses at day 15 and 30 post-infection. At day 30 antigen-stimulated splenocytes from infected IL-4 −/− mice, however, produced significantly more IFN-γ than those derived from similarly infected IL-4 +/+ mice, suggesting that Th1-influenced responses predominated in IL-4 −/− mice. Moreover, inflamed hearts from IL-4 −/− mice displayed higher levels of IFN-γ and TNF-α transcripts as compared to IL-4 +/+ mice. At both time points antigen-stimulated splenocytes from IL-4 +/+ and IL-4 −/− mice produced significant amounts of IL-10 but those from IL-4 +/+ mice produced either no or little IL-4. Histopathology demonstrated typical Lyme carditis in both IL-4 +/+ and IL-4 −/− mice at day 15 and day 30. Although Borrelia-infected IL-4 −/− mice developed a more severe carditis on day 30, the carditis resolved by day 50, as it did in IL4 +/+ mice. These results indicate that although IL-4 may help limit the severity of Lyme carditis, its absence does not preclude resolution of cardiac lesions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.2000.tb08978.x
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