Optimal conditions for in vitro T cell depletion of human bone marrow by Campath-1a plus complement as demonstrated by limiting dilution analysis.
Quantitations of residual T cells by limiting dilution analysis (LDA), immunofluorescence analysis, sheep red cell rosetting, and proliferative responses to phytohemagglutinin were done to identify treatment conditions that maximized the ex vivo T cell depletion (TCD) of human bone marrow (BM) with the rat monoclonal antibody Campath-1 (CP1) and complement (C'). Different treatment approaches achieved levels of TCD varying from 0.4 to 2.6 log10. However, under optimal treatment conditions, a mean (+/- SEM) log10 TCD of 2.60 +/- 0.12 was demonstrated by LDA. Concentrations of CP1 ranging from 5 micrograms to 300 micrograms/10(7) cells/ml achieved equally effective TCD as determined by LDA. An inverse relationship between the concentration of BM cells/ml and the extent of TCD was observed. Additional C' treatment did not increase TCD as detectable by LDA. Mean recoveries of CFU-GM (day 7), CFU-GM (day 14), CFU-GEMM, and BFU-E growth following CP1 + C' were 51, 43, 42, and 45% respectively. These results demonstrate the importance of cell concentration and treatment conditions for maximizing the depletion of BM T cells with CP1 + C'.
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Human Immunogenetics Laboratory, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
Sheehy
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D
Cartagena
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T
Cirrincione
C
C
O'Reilly
R J
RJ
Dupont
B
B
Kernan
N A
NA
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation / Q000276:immunology; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003165:Complement System Proteins / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051381:Rats; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D007075:Immunoglobulin M; D003165:Complement System Proteins