Burgdorferi-induced Arthritis Research Articles

Borrelia burgdorferi arthritis-associated locus Bbaa1 regulates Lyme arthritis and K/B×N serum transfer arthritis through intrinsic control of type I IFN production.

Localized upregulation of type I IFN was previously implicated in development of Borrelia burgdorferi-induced arthritis in C3H mice, and was remarkable due to its absence in the mildly arthritic C57BL/6 (B6) mice. Independently, forward genetics analysis identified a quantitative trait locus on Chr4, termed B. burgdorferi-associated locus 1 (Bbaa1), that regulates Lyme arthritis severity and includes the 15 type I IFN genes. Involvement of Bbaa1 in arthritis development was confirmed in B6 mice congenic for the C3H allele of Bbaa1 (B6.C3-Bbaa1), which developed more severe Lyme arthritis and K/B×N model of rheumatoid arthritis (RA) than did parental B6 mice. Administration of a type I IFN receptor blocking mAb reduced the severity of both Lyme arthritis and RA in B6.C3-Bbaa1 mice, formally linking genetic elements within Bbaa1 to pathological production of type I IFN. Bone marrow-derived macrophages from Bbaa1 congenic mice implicated this locus as a regulator of type I IFN induction and downstream target gene expression. Bbaa1-mediated regulation of IFN-inducible genes was upstream of IFN receptor-dependent amplification; however, the overall magnitude of the response was dependent on autocrine/paracrine responses to IFN-β. In addition, the Bbaa1 locus modulated the functional phenotype ascribed to bone marrow-derived macrophages: the B6 allele promoted expression of M2 markers, whereas the C3H allele promoted induction of M1 responses. This report identifies a genetic locus physically and functionally linked to type I IFN that contributes to the pathogenesis of both Lyme and RA.

Interval-Specific Congenic Lines Reveal Quantitative Trait Loci with Penetrant Lyme Arthritis Phenotypes on Chromosomes 5, 11, and 12

The observation that Borrelia burgdorferi-induced arthritis is severe in C3H mice and milder in C57BL/6 (B6) mice has allowed a forward genetics approach for the identification of genetic elements that regulate the arthritis response. Quantitative trait loci (QTL) on five chromosomes (Chr) were identified previously in segregating crosses between C3H and B6 mice and collectively designated B. burgdorferi arthritis-associated (Bbaa) QTL. Reciprocal interval-specific congenic lines (ISCL) that encompass Bbaa1, Bbaa2-Bbaa3, Bbaa4, Bbaa6, and Bbaa12 on Chr 4, 5, 11, 12, and 1, respectively, have now been generated. Bidirectional transfer of the arthritis severity phenotype in association with Bbaa2-Bbaa3 and Bbaa4 was observed, and unidirectional transfer with the B6 allele of Bbaa6 was noted. These findings confirm the existence of polymorphic loci within Bbaa2-Bbaa3, Bbaa4, and Bbaa6 that regulate the severity of B. burgdorferi-induced arthritis. ISCL were used to assess the regulation of a previously identified interferon transcriptional profile associated with severe disease in C3H mice. The regulation of this transcriptional signature was found to be independent of penetrant Bbaa QTL, both in joint tissues and in isolated macrophages. These results clearly demonstrate the utility of forward genetics for the discovery of novel genes and pathways involved in the regulation of the severity of Lyme arthritis and predict the involvement of regulatory elements not evident from other experimental approaches.

Borrelia burgdorferi, an extracellular pathogen, circumvents osteopontin in inducing an inflammatory cytokine response

A classic proinflammatory T helper cell type 1 (TH1) response directed against intracellular pathogens includes the cytokine osteopontin, which acts predominantly on macrophages, where it induces the secretion of interleukin (IL)-12 and suppresses the secretion of IL-10. As cell-mediated immune responses play an important role in the resistance to Lyme arthritis, a manifestation of infection by the extracellular pathogen Borrelia burgdorferi, we tested the hypothesis that osteopontin may be required to induce T(H)1 responses and inflammation. The role of osteopontin was tested in vivo and using ex vivo macrophages in B6129F3 mice susceptible to experimental Lyme arthritis. Mice of this genetic background and those fully backcrossed to C57BL/6, which lacked osteopontin expression (spp1-/-), were as susceptible to B. burgdorferi-induced arthritis as littermate controls. Furthermore, equal numbers of spirochetes, as measured by quantitative polymerase chain reaction of the B. burgdorferi gene recA in spp1-/- and B6129F3 wild-type littermates, suggested that susceptibility to infection was not dependent on this cytokine. Neither of the B6129F3 parental mouse strains lacked the ability to secrete osteopontin. spp1-/- mice and controls had immunoglobulin G2 titers, suggestive of a TH1 response. B. burgdorferi was able to directly stimulate the secretion of the proinflammatory cytokines IL-12 and tumor necrosis factor alpha from wild-type and spp1-/- macrophages alike. These results indicate that the usually critical role of osteopontin in the induction of cellular immune responses to intracellular pathogens was circumvented by the ability of the extracellular pathogen B. burgdorferi to induce macrophages directly to produce proinflammatory cytokines.

Macrophages interact with enriched populations of distinct T lymphocyte subsets for the induction of severe destructive Lyme arthritis.

Severe destructive Lyme arthritis was detected in the hind paws of hamsters infused with enriched populations of either CD4+ or CD4- T lymphocytes along with macrophages exposed in vitro to formalin-inactivated Borrelia burgdorferi and then infected with the Lyme spirochete. Swelling was detected 4 days after infection, increased rapidly, peaked on day 8 of infection, and gradually decreased. Similarly, severe destructive arthritis was induced in hamsters infused with enriched populations of unfractionated T lymphocytes and macrophages exposed to spirochetes after infection with B. burgdorferi. Histopathological examination affirmed that hamsters infused with CD4+, CD4-, or unfractionated T lymphocytes and macrophages exposed to B. burgdorferi-induced arthritis. In addition, macrophages exposed in vitro to B. burgdorferi demonstrated both conventional and coiling phagocytosis, suggesting a mechanism by which CD4+ and CD4- T lymphocytes induce arthritis, respectively. These findings demonstrate that both CD4+ and CD4- subpopulations of T lymphocytes are capable of interacting with macrophages for the induction of severe destructive Lyme arthritis.

E and P selectins are not required for resistance to severe murine lyme arthritis.

Borrelia burgdorferi-induced arthritis in mice is characterized by tendonitis, synovitis, and inflammatory-cell infiltrate, predominantly of neutrophils. Because genetic deficiency in E and P selectins results in delayed recruitment of neutrophils to sites of inflammation, mice with this deficiency were tested for their response to infection with B. burgdorferi. E and P selectins were not required for the control of B. burgdorferi numbers, nor did deficiency in E and P selectins result in alteration of arthritis severity.

Heritable susceptibility to severe Borrelia burgdorferi-induced arthritis is dominant and is associated with persistence of large numbers of spirochetes in tissues

In human Lyme disease, symptoms with widely varying levels of severity have been observed. A mouse model of Lyme disease has been developed which allows analysis of mice with mild, moderate, and severe pathologies after inoculation with the spirochete Borrelia burgdorferi. To determine whether the differences in symptoms reflect differences in the number of spirochetes persisting in affected tissues, a sensitive PCR technique was developed to detect B. burgdorferi DNA in virtually any tissue of an infected mouse. This analysis, which detects DNA from as few as three spirochetes, revealed the presence of B. burgdorferi DNA in many tissues from severely arthritic C3H/HeJ mice as early as 1 week postinfection. The heart, ear, and ankle were particularly heavily infected, although B. burgdorferi DNA was also detected in spleen, liver, brain, kidney, bladder, uterus, and lymph nodes. In contrast, much lower levels of spirochete DNA were detected in tissues of infected BALB/c mice, which develop less severe arthritis when infected with B. burgdorferi than do C3H/HeJ mice. This difference was evident throughout the 5-week analysis. A competitive PCR method allowed determination of the absolute number of spirochete gene sequences in infected tissues. Ankles and hearts from C3H/HeJ mice were found to harbor 10(7) copies of the B. burgdorferi ospA gene, while these tissues from BALB/c mice contained 5- and 10-fold less B. burgdorferi DNA, respectively. The genetic regulation of severe pathology was analyzed by infecting the offspring of a cross between C3H/HeJ and BALB/c mice. The F1 mice developed severe arthritis and contained high levels of Borrelia DNA in the heart and ankle, similar to the C3H/HeJ parent. These findings indicate that susceptibility to severe arthritis is a dominant trait and suggest that it may correlate with high levels of persisting spirochetes. Models of pathology in Lyme disease should take into consideration the fact that severity of pathology may be directly related to the number of organisms in infected tissues.

Heritable susceptibility to severe Borrelia burgdorferi-induced arthritis is dominant and is associated with persistence of large numbers of spirochaetes in tissues

Heritable susceptibility to severe Borrelia burgdorferi-induced arthritis is dominant and is associated with persistence of large numbers of spirochaetes in tissues

Efficacy of clarithromycin for treatment of experimental Lyme disease in vivo

Clarithromycin provided effective therapy against arthritis induced by Borrelia burgdorferi infection in the hamster. In vitro, clarithromycin was at least 1 log more potent than tetracycline against two isolates of B. burgdorferi from human sources, as measured by MICs and 50% inhibitory concentrations. Clarithromycin was effective in preventing the onset of B. burgdorferi-induced arthritis, as determined by several parameters of paw swelling. When administered after the onset of arthritis, clarithromycin therapy reduced the degree of swelling and decreased recovery time. These results suggest that clarithromycin has potential as an effective therapy for Lyme disease.

Experimental Borrelia burgdorferi infection in inbred mouse strains: Antibody response and association of H‐2 genes with resistance and susceptibility to development of arthritis

We have investigated the specific humoral immune response and its correlation to the development of disease after experimental inoculation of B. burgdorferi in different inbred strains of mice. All mouse strains tested showed high levels of specific IgM antibodies during the initial 10 days of infection. Specific IgG antibodies predominantly of the IgG2a, IgG2b and IgG3 isotypes were found in increasing amounts by 14 days post infection. Antibody titers peaked at days 65 and 110. Particularly low titers of specific IgM and/or IgG antibodies were detected in sera of AKR/N and B10.BR mice. Antibodies specific for numerous B. burgdorferi antigens including the outer surface proteins A (31 kDa) and B (34 kDa) and a protein(s) of molecular mass of approximately 40 kDa, most probably 41 kDa (flagellin) and/or 39 kDa (p39), were induced in all inbred mouse strains within 2 weeks inoculation albeit in varying concentrations. Later during infection, the patterns of antibody specificities were much more complex. With regard to development of disease all strains of mice tested fall into three groups: (a) mice of H-2k haplotype (AKR/N, C3H/HeJ, C3H/HeN, B10.BR) developed a chronic progressive arthritis in the tibiotarsal joints, (b) mice of H-2 haplotypes, H-2b (C57BL/6), H-2j (B10.WB), H-2r (B10.R111) and H-2s (B10.S) developed arthritis of variable duration and intensity which was not progressive and (c) mice of H-2d haplotype (BALB/c, DBA/2, C.B-17, B10.D2, Cal.20), irrespective of their background genes or Igh allotype, showed no clinical signs of arthritis at any time point following inoculation of B. burgdorferi organisms. The finding of similar patterns of apparently protective antibodies in all mouse strains tested together with the striking association between the H-2d haplotype and resistance, and between the H-2k haplotype and the occurrence of B. burgdorferi-induced arthritis suggest a critical role of T cells in the development of the disease in mice.