Fluorescence-activated Flow Cytometry Research Articles

Characteristics of immunocompetent cells in synovial membranes from multiple sites in patients with rheumatoid arthritis.

The phenotypic characterization of enzymatically dissociated mononuclear cells in synovial membrane samples from multiple sites in two patients with rheumatoid arthritis (RA) were examined by fluorescence activated flow cytometry. In synovial membrane samples from each patient there was a consistent increase in the proportion of CD8+ cells (suppressor/cytotoxic), CD14+ cells (monocytes/macrophages), and HLA-DR+ cells compared with paired peripheral blood mononuclear cells. The proportion of CD4+ cells (helper/inducer) in synovial membrane was variable. Studies of in vitro production of IgM and IgM rheumatoid factor in one patient showed strikingly similar values for synovial membrane rheumatoid factor production at the two sites, which was enhanced compared with production in peripheral blood. These results suggest that in individual patients with RA the intra-articular immune response is comparable at multiple anatomical sites and that it is distinct from that in peripheral blood.

Flow cytometric analysis of P-glycoprotein in normal and leukemic cells.

Classical multidrug resistance is characterized by overexpression of a membrane protein, P-glycoprotein, which acts like a drug-extruding pump, reducing accumulation of cytotoxic drugs inside malignant cells. We have developed a simple method for detecting an intracellular epitope of P-glycoprotein in normal and leukemic cells by the monoclonal antibody JSB-1 and fluorescence-activated flow cytometry. Permeabilization of blood and bone marrow cells in unprocessed samples is achieved by a commercially available red blood cell lysing solution which excellently preserves the light scatter properties of leukocytes. The method is suitable for analyzing samples in clinical routine. Lower than 1% reactivity was seen in the lymphoid gate of normal peripheral blood and bone marrow samples as compared with over 60% of reacting cells in some leukemic samples. Twelve patients with acute de novo leukemia were studied at presentation, 13 patients at a refractory stage, and 28 in remission. There was a positive correlation between the P-glycoprotein and the CD34 expression in acute myelogenous leukemia and an association between the P-glycoprotein expression and the blast count in both acute myelogenous and lymphatic leukemias.

Gonadotropin surge increases fluorescent-tagged low-density lipoprotein uptake by macaque granulosa cells from preovulatory follicles.

In the primate ovary, luteal steroidogenesis is largely dependent upon cholesterol derived from receptor-mediated uptake of circulating low-density lipoprotein (LDL). However, granulosa cells (GC) of preovulatory follicles possess few LDL binding sites compared to those present in developing and mature corpora lutea. We recently reported (Endocrinology 1991; 129:3247-3253) that uptake of LDL tagged with the fluorescent probe 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) can be monitored in macaque luteal cells by fluorescence-activated flow cytometry. This study was designed to determine whether an ovulatory stimulus induced uptake of DiI-LDL in GC aspirated from preovulatory follicles of macaques undergoing ovarian stimulation. Development of multiple large follicles was stimulated in adult rhesus macaques with human gonadotropin treatment for 9 days. On Day 10, monkeys received either no ovulatory stimulus or 1000 IU hCG to initiate ovulatory events. GC were aspirated on Day 10 in monkeys receiving no ovulatory stimulus (nonluteinized GC) or 27 h or 34 h after hCG injection (luteinizing GC). GC were resuspended in Ham's F-10 medium + 0.1% BSA and incubated with several concentrations (0-25 micrograms/ml) of DiI-LDL (Biomedical Technologies, Stoughton, MA) for various time intervals (2-60 min). DiI-LDL uptake by GC was time- and concentration-dependent. Coincubation of cells with DiI-LDL and unlabeled LDL dose-dependently suppressed the percentage of fluorescent cells. In contrast, coincubation with up to a 250-fold excess of acetylated LDL or high-density lipoprotein did not alter the percentage of fluorescent GC.(ABSTRACT TRUNCATED AT 250 WORDS)

CD5+ B cells are decreased in peripheral blood of patients with Crohn's disease.

B cells bearing the CD5 surface marker comprise a substantial minority of the circulating lymphocyte population in healthy individuals. These recently described cells have been implicated in T-independent humoral responses, immunoregulation, and autoimmunity. We undertook to enumerate circulating CD5+ B cells by three-color fluorescence activated flow cytometry in 28 patients with Crohn's disease (CD). None of the CD patients were using immunosuppressive medication. The CD patients were subdivided into "inactive" and "active" groups based upon their Crohn's disease activity index (CDAI). Thirty-two normal subjects served as a control population. The percentage of CD19+ B cells was significantly reduced in both active and inactive CD patients as compared with normal controls (P less than or equal to 0.01). CD5+ B cells were likewise found to be significantly decreased in both inactive and active CD patients (P less than or equal to 0.01) as compared with normal controls. The proportion of CD5+ B cells was significantly lower in the peripheral blood of active as compared with inactive CD patients (P less than or equal to 0.05). The finding that CD5+ B cells are reduced in CD may provide an important clue to immunological dysfunction in inflammatory bowel disease and merits further study.

A member of the selectin family (gmp-140/padgem) is expressed on thrombin-stimulated rat platelets in vitro

1. 1. Granule membrane protein (GMP-140) is an integral α-granule membrane glycoprotein, expressed on the surface of human platelets following degranulation, and is pan of a new family of adhesion molecules (selectins) related to the endothelial leukocyte adhesion molecule (ELAM-1) and to the lymphocyte homing receptors in man (Leu-8/TQ1) and in mouse (gp90 MEL-14). 2. 2. The cross-reactivity with rat platelets of the monoclonal antibodies (MAb), LYP20 and S12, directed against human GMP-140 was examined, with the purpose of assessing the homology of GMP-140 between human and rat platelets and of using positive MAbs to detect platelet activation in vivo in response to vascular disease in rats. 3. 3. By ELISA technique, LYP20 gave a greater OD reading with thrombin-stimulated rat platelets than with resting platelets. 4. 4. 125I-LYP20 bound significantly more to thrombin-stimulated rat platelets (3875 ± 750 molecules/ platelet) than to resting platelets (645 ± 240 molecules/platelet, P < 0.01) with 50% maximum binding at 0.13 ± 0.02 μg/ml; 125I-S12 did not bind to rat platelets. 5. 5. By fluorescence-activated flow cytometry there were significantly more fluorescent thrombin-stimulated platelets (56 ± 7% of total), compared with resting platelets (8 ± 1% of total, P < 0.001). 6. 6. Western blots of rat platelet lysates showed that LYP20 bound to a single band identified, under non-reducing conditions, as having the same apparent M r as GMP-140. 7. 7. LYP20 immunoprecipitated a protein which became radiolabelled on the surface of thrombin-activated rat platelets; S12 did not recognize any protein. 8. 8. It appears that LYP20 and S12 are directed against different epitopes on the GMP-140 molecule and that the LYP20 epitope, but not the S12 epitope, is preserved in GMP-140 in rat platelets. 9. 9. LYP20 can, therefore, be used as a marker of GMP-140 expression on activated platelets in vivo in rats.

Flow cytometric analysis of porcine preadipocytes.

In this report, conditions have been established for utilizing monoclonal antibodies and fluorescence activated flow cytometry in studying antigen expression by primary porcine stromal-vascular cells cultured under various conditions. Single cells were isolated from cultures maintained in DME/F12 medium containing 10% fetal bovine serum, 2% pig serum, and containing 2% pig serum and 10 nM dexamethasone supplemented with growth hormone (GH), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta). Flow cytometric analyses revealed that the proportion of cells expressing detectable levels of the AD-1 cells surface antigen was greater in cultures supplemented with 2% pig serum and 10 nM dexamethasone than in other media. In cultures, GH, TNF-alpha and TGF-beta each inhibited lipid deposition, whereas TNF-alpha and TGF-beta, but not GH, inhibited AD-1 antigen expression. Inhibition of lipid deposition as well as antigen expression by TNF-alpha and TGF-beta was reversible, but inhibition of cluster formation by GH was not reversed upon removal from cultures. In summary, differential effects of factors on surface antigen expression by preadipocytes are detectable by flow cytometry. Flow cytometric analysis using monoclonal antibodies produced against key developmentally regulated cell surface antigens is potentially a powerful analytical approach to the study of adipocyte development.

Autologous Bone Marrow Transplantation in High-Risk Remission B-Lineage Acute Lymphoblastic Leukemia Using a Cocktail of Three Monoclonal Antibodies (BA-1/CD24, BA-2/CD9, and BA-3/CD10) Plus Complement and 4-Hydroperoxycyclophosphamide for Ex Vivo Bone Marrow Purging

Fourteen patients with high-risk B-lineage acute lymphoblastic leukemia (ALL) in complete remission underwent autologous bone marrow transplantation (BMT) using a combined immunochemopurging protocol. A monoclonal antibody (MoAb) cocktail of BA-1, BA-2, and BA-3 plus rabbit complement (C') plus 4-hydroperoxycyclophosphamide (4-HC) was used to eliminate residual occult leukemia cells from autografts. All patients were conditioned with single-dose total body irradiation (TBI) followed by high-dose Ara-C. All 14 patients engrafted at a median of 24 days (range, 12 to 36 days). Three patients are alive and disease free at 3.5 years, 3.9 years, and 4.1 years post-BMT. The Kaplan-Meiser estimate and standard error of the probability of sustained remission was 23% +/- 12% at 3.5 years post-BMT with a mean relapse-free interval of 1.4 +/- 0.4 years. The disease-free survival (DFS) at 3.5 years was 21% +/- 11%, with a mean DFS time of 1.3 +/- 0.4 years. A novel and quantitative minimal residual disease (MRD) detection assay, which combines fluorescence-activated multiparameter flow cytometry and cell sorting with leukemic progenitor cell (LPC) colony assays, was used to analyze remission BM samples from B-lineage ALL patients for residual LPC, and to evaluate the efficacy of ex vivo BM purging. Notably, the minimal residual leukemia burden before BMT, as measured by the percentage of B-lineage LPC in the pre-BMT remission BM samples, indicated the outcome of the BMT. The median value for the minimal residual leukemia burden before BMT was 0.0035% (35 LPC/10(6) mononuclear cells). The Kaplan-Meier estimates and standard errors of the probability of remaining in remission after BMT were 43% +/- 19% for patients whose BM samples contained less than or equal to 0.0035% LPC and 0% +/- 0% for patients whose BM samples contained greater than 0.0035% B-lineage LPC (P less than .05). In contrast to the minimal residual leukemia burden measured by the described MRD assay system, the percentage of blasts or TdT+ cells in the remission BM samples did not correlate with the probability of relapse. The applied purging protocol showed variable success in destroying target B-lineage LPC populations contaminating the autografts. While in some cases purging was highly effective, eliminating up to greater than or equal to 4 logs of residual B-lineage LPC, in other cases only 0.1 to 0.2 logs of B-lineage LPC were purged.(ABSTRACT TRUNCATED AT 400 WORDS)

Autologous bone marrow transplantation in high-risk remission B-lineage acute lymphoblastic leukemia using a cocktail of three monoclonal antibodies (BA-1/CD24, BA-2/CD9, and BA-3/CD10) plus complement and 4- hydroperoxycyclophosphamide for ex vivo bone marrow purging

Fourteen patients with high-risk B-lineage acute lymphoblastic leukemia (ALL) in complete remission underwent autologous bone marrow transplantation (BMT) using a combined immunochemopurging protocol. A monoclonal antibody (MoAb) cocktail of BA-1, BA-2, and BA-3 plus rabbit complement (C′) plus 4-hydroperoxycyclophosphamide (4-HC) was used to eliminate residual occult leukemia cells from autografts. All patients were conditioned with single-dose total body irradiation (TBI) followed by high-dose Ara-C. All 14 patients engrafted at a median of 24 days (range, 12 to 36 days). Three patients are alive and disease free at 3.5 years, 3.9 years, and 4.1 years post-BMT. The Kaplan-Meiser estimate and standard error of the probability of sustained remission was 23% +/- 12% at 3.5 years post-BMT with a mean relapse-free interval of 1.4 +/- 0.4 years. The disease-free survival (DFS) at 3.5 years was 21% +/- 11%, with a mean DFS time of 1.3 +/- 0.4 years. A novel and quantitative minimal residual disease (MRD) detection assay, which combines fluorescence-activated multiparameter flow cytometry and cell sorting with leukemic progenitor cell (LPC) colony assays, was used to analyze remission BM samples from B-lineage ALL patients for residual LPC, and to evaluate the efficacy of ex vivo BM purging. Notably, the minimal residual leukemia burden before BMT, as measured by the percentage of B-lineage LPC in the pre-BMT remission BM samples, indicated the outcome of the BMT. The median value for the minimal residual leukemia burden before BMT was 0.0035% (35 LPC/10(6) mononuclear cells). The Kaplan-Meier estimates and standard errors of the probability of remaining in remission after BMT were 43% +/- 19% for patients whose BM samples contained less than or equal to 0.0035% LPC and 0% +/- 0% for patients whose BM samples contained greater than 0.0035% B-lineage LPC (P less than .05). In contrast to the minimal residual leukemia burden measured by the described MRD assay system, the percentage of blasts or TdT+ cells in the remission BM samples did not correlate with the probability of relapse. The applied purging protocol showed variable success in destroying target B-lineage LPC populations contaminating the autografts. While in some cases purging was highly effective, eliminating up to greater than or equal to 4 logs of residual B-lineage LPC, in other cases only 0.1 to 0.2 logs of B- lineage LPC were purged.(ABSTRACT TRUNCATED AT 400 WORDS).

Quantification of platelet specific antiboides by fluorescence activated flow cytometry

Biology of the CellVolume 76, Issue 2 p. 282-282 Quantification of platelet specific antiboides by fluorescence activated flow cytometry Sartiaux Claudine, Sartiaux Claudine C.R.T.S BP 2018 LILLE cedexSearch for more papers by this authorBourel Dominique, Bourel Dominique C.R.T.S BP 2018 LILLE cedexSearch for more papers by this authorHuart Jean-Jacques, Huart Jean-Jacques C.R.T.S BP 2018 LILLE cedexSearch for more papers by this author Sartiaux Claudine, Sartiaux Claudine C.R.T.S BP 2018 LILLE cedexSearch for more papers by this authorBourel Dominique, Bourel Dominique C.R.T.S BP 2018 LILLE cedexSearch for more papers by this authorHuart Jean-Jacques, Huart Jean-Jacques C.R.T.S BP 2018 LILLE cedexSearch for more papers by this author First published: 1992 https://doi.org/10.1016/0248-4900(92)90417-YAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume76, Issue21992Pages 282-282 RelatedInformation

Characterization of apoptosis-like endonuclease activity in avian thymocytes

In the current study the internucleosomal DNA cleavage activity associated with apoptosis was investigated in avian thymocytes. Thymocyte nuclear proteins from glucocorticoid-treated chickens were incubated with chicken red blood cell (cRBC) nuclei, and DNA degradation was analyzed by agarose gel electrophoresis and fluorescence-activated flow cytometry. The thymocyte nuclear extract contained an endonuclease activity that degraded cRBC chromatin at internucleosomal sites as detected by agarose gel electrophoresis. Flow cytometry analysis of cRBC nuclei that were treated with thymocyte nuclear proteins demonstrated a loss of cellular DNA as a function of the amount of added nuclease activity. Furthermore, it was demonstrated that the thymocyte nuclear extract contained a nuclease activity that was capable of degrading radiolabelled naked 32P-DNA into acid soluble DNA fragments. All three assay methods demonstrate that the thymocyte nuclease activity can be inhibited by EDTA, zinc ions and the nuclease inhibito aurintricar☐ylic acid. Based on the analysis of cofactor requirement of this nuclease activity and its susceptibility to inhibitors, the endonuclease activity present in avian apoptotic thymocytes appears to be identical to the mammalian counterpart.

Studies of Fibrinogen Binding to Platelets by Flow Cytometry: An Improved Method for Studies of Platelet Activation

Platelet function is dependent upon membrane receptors and their interaction with other proteins. Platelet activation appears to cause a structural change of the glycoprotein IIb/IIIa complex that exposes the fibrinogen binding site, which subsequently binds fibrinogen. Fluorescence-activated flow cytometry (FACS) is an efficient method for studying membrane proteins. Flow cytometry gives single-cell data, allowing the detection of only a small proportion of labelled platelets in whole blood without any washing steps. One problem with this method is that the labelled antibodies and the antigen, if present in plasma, form an immune complex, which may cause false positive reactions due to interaction between mammalian IgG and Fc gamma receptors on the platelets. We show that immune complexes with chicken IgG do not activate human platelets. We have developed a method for measuring platelet-bound fibrinogen in whole blood and platelet-rich plasma utilising fluorescein isothiocyanate (FITC)-conjugated chicken antibodies directed towards human fibrinogen. As low as 1% activated platelets could be detected without interference from Fc-interactions.

Effect of gamma-interferon on the expression of major histocompatibility complex class I and II gene products in neural cells isolated from the developing human fetal peripheral nervous system.

The effect of gamma-interferon (gamma-IFN) on the expression of major histocompatibility complex (MHC) gene products was examined in the developing human fetal peripheral nervous system. RNA blot hybridization analysis of total RNA isolated from human fetal dorsal root ganglia (DRG) neural cell populations cultured in vitro for 5 days resulted in the detection of both MHC class I- and class II-specific RNAs. As determined by protein immunoblotting and fluorescence-activated flow cytometry, MHC class I and II proteins were also readily detectable in cultured human fetal DRG neural cell populations 5 days after isolation. In addition, treatment of 3-day human fetal DRG neural cells with gamma-IFN (100 U/ml; 48 h) resulted in a marked increase in the level of MHC class I- and class II-specific RNA and protein without inhibiting the proliferation of the neural cell population. These results suggest that changes in the levels of selected cytokines such as gamma-IFN may alter the ability of specific neural cell populations present in the developing human nervous system to participate in immune reactions by alteration of MHC class I and II antigen expression which may lead to perturbation in glial cell function and ultimately to nervous system dysfunction in general.

Quantitative fluorescence activated flow cytometry for determination of antibody levels

Quantitative fluorescence activated flow cytometry for determination of antibody levels

The evaluation of various methods and antigens for the detection of antibodies against Pityrosporum ovale in patients with seborrhoeic dermatitis

Sera from 10 patients with seborrhoeic dermatitis and from 10 age-matched healthy individuals were examined for IgG activity against Pityrosporum ovale. The IgG activity was analysed using the following techniques: an enzyme-linked immunosorbent assay (ELISA) against whole P. ovale cells, purified cell-wall carbohydrate or protein extract, an indirect slide-immunofluorescence assay and fluorescence-activated flow cytometry using the whole organism as antigen. The ELISA method using the protein antigen was the only technique that showed a significant difference between patients and controls; a lower antibody response was found in the seborrhoeic dermatitis patients compared to healthy controls.

Serological responses to cytomegalovirus during renal transplant rejection.

We studied the role played by CMV in kidney transplant rejection by recording serological responses to CMV replication in cadaver graft recipients and recording clinical graft rejection by monitoring acute changes in renal function and the appearance of antidonor lymphocyte antibody (anti-Dab). If CMV plays a significant role in rejection, clinical rejection should correlate with CMV activity; if CMV does not play a role, clinical rejection would be likely to correlate with anti-Dab but not necessarily with CMV activity. We selected retrospectively 18 rejectors and 18 nonrejectors by clinical criteria and assayed for anti-Dab (by fluorescence-activated flow cytometry) and CMV antibody (by complement fixation and Western blot for IgG and IgM) over a 3-6-month period after transplantation. Primary CMV infection occurred in 8 of 12 (67%) CMV seronegative graft recipients and reactivation or reinfection occurred in 16 of 24 (67%); 12 of 14 (86%) rejectors developed anti-Dab compared with 2 of 18 (11%) nonrejectors (P less than 0.00001). Active CMV infection occurred in 11 of 18 (61.1%) rejectors and 13 of 18 (72.2%) nonrejectors (P = 0.36), and in 8 of 15 (53.3%) of those who developed anti-Dab and 12 of 17 (70.6%) of those who did not (P = 0.26). The results show no evidence to link CMV activity with kidney graft rejection.

Neuraminidase‐induced thrombocytopenia in mice: Effects on thrombopoiesis

Previous studies to examine the effects of thrombocytopenia on thrombopoiesis have generally utilized immune-mediated platelet depletion. We have developed a nonimmune model to exclude the possibility that adverse immune-mediated effects have been misinterpreted as the physiological response to stimulation of thrombopoiesis. Thrombopoiesis was examined in mice after induction of thrombocytopenia with a single injection of the nonimmunologic agent neuraminidase (Ndase). Utilizing electron microscopy, we examined platelets and megakaryocytes (MK) obtained 8, 12, 24, 48, 72, 96, and 120 hr after administration of Ndase. Eight to 48 hr after induction of acute, severe thrombocytopenia (mean platelet count less than 50,000/microliters), the medians of the platelet sectional area distributions, as measured morphometrically, were significantly greater than the median platelet sectional area of pooled controls. The maximum median value for platelet sectional area was observed at 24 hr. The largest platelets in these samples contained more profiles of endoplasmic reticulum and Golgi cisternae, and a lower concentration of surface-connected canalicular system, as compared with normal platelets. By 72 hr post-injection of Ndase, virtually all platelets exhibited normal size and organelle complement. Mean platelet volumes, determined by electrical impedance analysis, paralleled the serial changes in platelet sectional areas. MK frequency and ploidy, measured by two-color fluorescence activated flow cytometry, were unchanged 12 and 24 hr following Ndase. At 48 hr, total MK frequency increased significantly (P less than 0.01) from 0.11% to 0.17%, and MK ploidy distribution shifted with a reduction in 16N MK (P less than 0.005) and an increase in 32N MK (P less than 0.01). MK ploidy was maximally altered from normal at 72 hr with increased 32N MK frequency (32.0%, P less than 0.001) and increased 64N MK frequency (2.4%, P less than 0.005). Morphologic and morphometric examination of MK at all time points did not reveal detectable changes from normal in cytoplasmic appearance or size, respectively. Therefore, we have demonstrated marked alterations of morphology and size of platelets, and of MK ploidy, using this nonimmunologic model. These studies further support our previous observations that megakaryocyte ploidy and platelet volume are independently regulated in response to depletion of the circulating platelet mass, and they show that these changes are not dependent upon the mechanism of thrombocytopenia.

Lymphocyte subset responses to repeated submaximal exercise in men

The effects of repeated bouts of submaximal cycle ergometry exercise on changes in the percentage of peripheral blood T-lymphocytes, the T-helper/inducer and T-cytotoxic/suppressor subsets, and natural killer (NK) cells were studied in 18 healthy young men who had no history of regular exercise training. Subjects were matched on the basis of maximal O2 uptake and assigned randomly to exercise or control groups, with controls resting quietly during the exercise sessions. The percentage of peripheral blood mononuclear leukocytes that reacted with monoclonal antibodies specific for T-lymphocytes (CD3+ cells), the helper/inducer subset (CD4+ cells) and cytotoxic/suppressor subset (CD8+ cells) of T-lymphocytes, and cells with NK activity (Leu7+ cells) were enumerated by fluorescence-activated flow cytometry for samples obtained immediately before and after exercise on days 1, 3, and 5 of a 5-day exercise regimen. The results of this study were mixed with decreases in the percentage of T-lymphocytes before vs. after exercise on days 1 and 3 (P less than 0.001), a decrease in the percentage of T-helper/inducer cells before vs. after exercise on day 3 (P less than 0.05), no effect of exercise on the percentage of T-cytotoxic/suppressor cells, and a marked increase in the percentage of NK cells after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01). The total number of recovered NK cells in the mononuclear leukocyte fraction of blood also increased significantly after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Major Histocompatibility Complex Gene Products in Tissues Isolated from the Developing Human Nervous System

We have examined the expression of the major histocompatibility complex (MHC) class I and II gene products in the developing human fetal peripheral nervous system. As determined by RNA blot hybridization analysis, MHC class I RNA was readily detectable in extracts prepared from dorsal root ganglia (DRG) obtained from aborted human fetal material. However, utilizing similar methodology, it was not possible to detect MHC class II RNA. In conjunction with these studies, expression of MHC class I and II proteins in primary human fetal DRG tissue was examined by fluorescence-activated flow cytometry and protein immunoblotting. Consistent with the detection of MHC-specific RNA, the accumulation of MHC class I-specific protein was readily detectable in human fetal DRG neural cell populations with little, if any, accumulation of MHC class II-specific protein evident. These studies suggest that MHC gene products may be expressed early in the development of the human nervous system resulting in the generation of specific immunocompetent neural cell populations.

Strain polymorphism in progression of aging: changes in CD4, CD8 bearing subpopulations

Polymorphism of age-related changes in CD4 (L3T4) and CD8 (Lyt-2) determinants of spleen and thymus cells was assessed by fluorescence-activated flow cytometry. Cells from mice ranging from 5 weeks to > 2 years of age were examined. There is little age-related change in the proportion of CD4 + CD8 − splenocytes in A, C57BL/6, DBA/1, DBA/2, and SJL mice (slopes 0.04, 0.06, 0.08, 0.17 and 0.17, respectively, when age in weeks was plotted against % of positive cells). Changes in the composition of the thymus are much more profound: CD4 + CD8 + cells of SJL mice decrease from 70% to < 10% as the animals age from 5 to 69 weeks (slope −1.03), and in DBA/2 mice from 5 to 110 weeks (slope −0.88). While this decrease in CD4 + CD8 − cells occurs, there is a compensatory increase in CD4 + CD8 − and CD4 − CD8 + cells; this is a shift in the relative proportion of subpopulations rather than an increase in absolute cell numbers of a particular sub-population. In contrast to the age-related changes of SJL and DBA/2 mice, there is relatively little change in the proportion of CD4 + CD8 + thymus cells in mice of strains C57BL/6, DBA/1 and A (slopes −0.03, −0.14 and −0.15, respectively).

Functional characteristics of 197+ CD4- CD8- sheep T lymphocytes: expansion and differentiation of peripheral T cells.

This report describes the results of functional studies on the CD3+ 197+ CD4- CD8- TCR gamma/delta + peripheral T lymphocyte of sheep. Cell types were identified by immunofluorescent and immunoenzymic staining and separated by fluorescence activated flow cytometry. Newly synthesized DNA was labelled in vivo by incorporation of 5-bromo-2-deoxyuridine (BrdU), and total DNA by in vitro incubation with propidium iodide. Cells were challenged in vivo with alloantigens, in vitro with alloantigens or a range of mitogens, and activation/differentiation was assessed by determination of cell number, phenotype, and thymidine incorporation. In normal lambs the 197+ cells showed no in vivo DNA synthesis except at a low level in the ileocaecal lymph node. A similarly low level of synthesis in the prescapular node was induced by local allogeneic challenge. A higher proportion of 197+ cells than of other T cells isolated from blood and lymph had G2/M phase DNA content, while very few had S phase DNA content. The response of 197+ cells in terms of change in relative numbers following in vivo allogeneic challenge was quite different to that of CD4+ or CD8+ cells. Instead of rising to a peak at 5-8 days after challenge and then declining, the percentage of 197+ cells rose steadily with no evidence of decline by 14 days. Purified 197+ cells were activated in vitro by phytohaemagglutinin (PHA) and concanavalin-A (Con-A) but not by B cell mitogens; such activation was dependent on the inclusion of feeder cells or interleukin-2 (IL-2).(ABSTRACT TRUNCATED AT 250 WORDS)