Requirement of CD4-positive T cells for cellular recruitment to the lungs of mice in response to a particulate intratracheal antigen.
To determine whether CD4+ T cells participate in the recruitment of other lymphocyte subsets to the lungs, we examined pulmonary immune responses in C57BL/6 mice treated in vivo with the MAb GK1.5, either intact (which depletes CD4+ cells) or as F(ab')2 fragments (which block CD4 molecules). After intratracheal challenge with sheep erythrocytes, antigen-primed mice treated with intact GK1.5 had marked decreases in lymphocytes and macrophages in bronchoalveolar lavage fluid and minimal parenchymal inflammation, compared to primed mice treated with an isotype-matched irrelevant antibody or with no antibody. At 7 d after challenge, flow cytometric analysis showed that numbers of Thy 1.2+ and B220+ cells, but not of CD8+ cells, were markedly decreased in lavage fluid of CD4-depleted mice. Similar suppression of the pulmonary immune response to intratracheal challenge was found in primed mice injected repeatedly with F(ab')2 fragments of GK1.5, which did not deplete CD4+ T cells, and in athymic mice. These findings indicate that, in response to a single intratracheal antigen challenge, recruitment to the lungs of leukocytes other than CD8+ T cells depends largely on CD4+ T cells, possibly because of signals requiring T cell activation via interactions with antigen-presenting cells.
Respiratory Care Section, San Francisco Veterans Administration Medical Center, California.
J L
JL
Curtis
P K
PK
Byrd
M L
ML
Warnock
H B
HB
Kaltreider
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000941:Antigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D016827:CD8 Antigens / Q000032:analysis; D016207:Cytokines / Q000502:physiology; D005260:Female; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007278:Injections, Spinal; D008168:Lung / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude
D000911:Antibodies, Monoclonal; D000941:Antigens; D016827:CD8 Antigens; D016207:Cytokines; D007140:Immunoglobulin Fab Fragments