Stimulation of mature unprimed CD8+ T cells by semiprofessional antigen-presenting cells in vivo.
To test whether unprimed CD8+ cells can recognize class I alloantigens presented selectively on non-bone marrow (BM)-derived cells, unprimed parental strain CD8+ cells were transferred to long-term parent-->F1 BM chimeras prepared with supralethal irradiation. Host class I expression in the chimeras was undetectable on BM-derived cells and, in spleen, was limited to low-level staining of vascular endothelium and moderate staining of follicular dendritic cells (a population of nonhemopoietic cells in germinal centers). Despite this restricted expression of antigen, acute blood-to-lymph recirculation of parental strain T cells through the chimeras led to selective trapping of 95% of CD8+ cells reactive to normal F1 spleen antigen presenting cells (APC) in vitro. Subsequently, a small proportion of the trapped cells entered cell division and gave rise to effector cells expressing strong host-specific CTL activity. The activation of host-specific CD8+ cells was also prominent in double-irradiated chimeras, and cell separation studies showed that the effector cells were generated from resting precursor cells rather than from memory-phenotype cells. It is suggested that the non-BM-derived cells in the chimeras acted as semiprofessional APC. These cells were nonimmunogenic for most host-reactive CD8+ cells but were capable of stimulating a small subset of high-affinity T cells. The possible relevance of the data to the prolonged immunogenicity of vascularized allografts in humans is discussed.
Kosaka
H
H
Department of Immunology, Scripps Research Institute, La Jolla, California 92037.
Surh
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CD
Sprent
J
J
D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology*; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D006086:Graft vs Host Disease / Q000209:etiology; D006183:H-2 Antigens / Q000032:analysis; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D016827:CD8 Antigens; D006183:H-2 Antigens; C024755:H-2K(K) antigen