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Langerhans cell, lymph node, lymphatic system, monoclonal antibody


Dendritic cells (DC) are a small subpopulation of lymphoid cells with distinctive cytologic features, surface properties, and functions. This report describes the DC-specific antibody (Ab) secreted by clone 33D1. Rat spleen cells immune to mouse DC were fused to the P3U myeloma. Hybrid culture supernatants were screened simultaneously against DC, a macrophage (MΦ) cell line, and mitogen-stimulated lymphoblasts. 33D1 Ab specifically killed 80-90% of DC from spleen and lymph node, but no other leukocytes, including Ia+ and Ia- MΦ (Ia, I-region-associated antigen). Quantitative binding studies with 3H-labeled 33D1 Ab showed that DC had an average of 14,000 binding sites per cell. Binding to DC was inhibited with Fab fragment of 33D1 Ab but not with a panel of other monoclonal antibodies, including anti-Ia Ab. Adherence and flotation procedures that enriched for DC enriched for 3H-labeled 33D1 Ab binding in parallel. 33D1 antigen was not detectable on: MΦ from spleen, peritoneal cavity, and blood; three MΦ cell lines; lymphocytes; granulocytes; platelets; and erythroid cells. DC continued to express the 33D1 antigen after 4 days in culture, whereas MΦ and lymphocytes did not acquire it. Quantitative and autoradiographic studies confirmed that spleen and lymph node suspensions contain less than 1% DC. We conclude that 33D1 Ab detects a stable and specific DC antigen and can be used to monitor DC content in complex lymphoid mixtures.


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