Early murine Lyme carditis has a macrophage predominance and is independent of major histocompatibility complex class II-CD4+ T cell interactions.
To compare the role of macrophages and CD4+ T lymphocytes in early Lyme carditis, immunohistochemical techniques were used to analyze cardiac infiltrates in immunocompetent mice infected with Borrelia burgdorferi spirochetes. Macrophages predominated in the infiltrate during the first 4 weeks after infection. CD4+ and CD8+ lymphocytes each constituted < 5% of the infiltrate; B lymphocytes were rare. Infected mice deficient in class II major histocompatibility complex (MHC) antigen and depleted of CD4+ lymphocytes developed similar infiltrates, suggesting that class II MHC-CD4+ lymphocyte interactions do not play a critical role in disease initiation. Expression of mRNA encoding JE within areas of cardiac inflammation implicates this chemokine in the recruitment and activation of macrophages in this disease. These data demonstrate that early murine Lyme carditis requires neither class II antigen expression nor presentation of antigen to CD4+ T lymphocytes and suggest a direct response of macrophages to cardiac tissue invasion by B. burgdorferi.
Department of Cancer Biology, Harvard School of Public Health, Boston, Massachusetts.
E M
EM
Ruderman
J S
JS
Kerr
S R
SR
Telford
A
A
Spielman
L H
LH
Glimcher
E M
EM
Gravallese
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D015748:Borrelia burgdorferi Group / Q000302:isolation & purification; D015704:CD4 Antigens / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002465:Cell Movement; D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000032:analysis; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood; D007150:Immunohistochemistry; D008193:Lyme Disease / Q000175:diagnosis / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009205:Myocarditis / Q000276:immunology*; D009206:Myocardium / Q000473:pathology
D000907:Antibodies, Bacterial; D015704:CD4 Antigens; D018932:Chemokine CCL2; D002630:Chemotactic Factors; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M