BACKGROUND: We developed a single-color multitarget flow cytometry (SM-FC) assay, a single-tube assay with graded mean fluorescence intensities (MFIs). We evaluated the repeatability of SM-FC, and its correlation with multicolor flow cytometry (MFC), to assess its application as a routine FC assay. METHODS: We selected CD19, CD3, CD4, and CD8 as antigen targets to analyze a lymphocyte subset. MFIs were graded by adjusting monoclonal antibody (mAb) volumes to detect several cell populations. Dimly labeled mAb was prepared by decreasing mAb volume and the optimum diluted volume was determined by serial dilution. SM-FC repeatability was analyzed 10 times in 2 normal controls. The correlation between SM-FC and MFC was evaluated in 20 normal and 23 patient samples. RESULTS: CV values (0.8-5.0% and 1.3-4.1% in samples 1 and 2, respectively) acquired by SM-FC with CD3-fluorescein alpha-isothyocyanate (FITC)dim+CD4-FITCbright and with CD19-FITCdim+CD3-FITCbright showed good repeatability, comparable to that acquired by MFC (1.6-3.7% and 1.0-4.8% in samples 1 and 2, respectively). Excellent correlation was observed between the 2 methods in the 20 normal samples (B cells, T cells, non-Thelper cells, and Thelper cells; r2=0.87, 0.97, 0.97, and 0.98, respectively; P<0.05). There were also linear relationships between SM-FC with CD19-FITCdim+CD3-FITCbright and CD8-PEdim+CD4-PEbright, and MFC, in the 23 patient samples (B cells, T cells, Tcytotoxic cells, and Thelper cells; r2> or =0.98, 0.99, 0.99, and 0.99, respectively; P<0.05). CONCLUSIONS: The multicolor, single-tube SM-FC technique is a potential alternative tool for identifying a lymphocyte subset.
Antibodies, Monoclonal/chemistry/*immunology ; Antigens, CD19/chemistry/metabolism ; Antigens, CD3/chemistry/metabolism ; Antigens, CD4/chemistry/metabolism ; Antigens, CD8/chemistry/metabolism ; B-Lymphocyte Subsets/immunology/metabolism ; Color ; Flow Cytometry/*methods ; Fluorescein-5-isothiocyanate/*chemistry ; Humans ; T-Lymphocyte Subsets/immunology/metabolism

OBJECTIVETo evaluate the therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis (EAE).

METHODSEAE was induced in the low-sensitive strain C57BL/6 mice with intraperitoneal injection of myelin basic protein (MBP) to simulate the human disease multiple sclerosis, followed by intramuscular injection of cationic liposome carrying the plasmid DNA SRalpha-mMIP-1alpha-DT390 in the leg muscle to elicit resistance to EAE development. The mice were then examined daily for clinical signs of EAE by an observer blind to the treatment protocol. For immunohistochemistry the mice were anesthetized and perfused with sterile PBS and paraformaldehyde, and the cerebrum, cerebellum, medulla and spinal cord were removed for preparation of serial sections. The mononuclear cells (MNCs) from the EAE mouse spleens were prepared for three-color flow cytometry analysis of the surface markers with appropriate antibodies following the BD Pharmingen cytokine staining protocol.

RESULTSEAE model was successfully established by active MBP immunization in C57BL/6 mice. Administration of the immunotoxin mMIP-1alpha-DT390 significantly delayed the disease onset and lowered the mean clinical score for EAE as compared with the control mice. Immunohistochemistry demonstrated much less CCR5(+) infiltrating cells in the central nervous system in mMIP-1alpha-DT390-treated mice than in the control. The treatment also eliminated reactive T cells in the periphery blood without affecting the number of B cells.

CONCLUSIONThe immunotoxin mMIP-1alpha-DT390 can attenuate the disease activity of EAE in mice, suggesting its potential use in the treatment of other autoimmune disorders.

Animals ; Antigens, CD19 ; analysis ; B-Lymphocytes ; cytology ; metabolism ; CD3 Complex ; analysis ; Chemokine CCL3 ; genetics ; metabolism ; Diphtheria Toxin ; genetics ; metabolism ; Disease Models, Animal ; Encephalomyelitis, Autoimmune, Experimental ; drug therapy ; Female ; Flow Cytometry ; Immunoglobulin Fragments ; genetics ; metabolism ; Immunohistochemistry ; Immunologic Factors ; therapeutic use ; Immunotoxins ; therapeutic use ; Meninges ; chemistry ; pathology ; Mice ; Mice, Inbred C57BL ; Multiple Sclerosis ; drug therapy ; NIH 3T3 Cells ; Receptors, CCR5 ; analysis ; Recombinant Fusion Proteins ; genetics ; metabolism ; therapeutic use ; T-Lymphocytes ; cytology ; metabolism