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Genetic alterations in B-cell non-Hodgkin's lymphoma.

BACKGROUND: Although the patients with diagnosed B-NHL are classified into the same disease stage on the basis of clinical, histopathological, and immunological parameters, they respond significantly different to the applied treatment. This points out the possibility that within the same group of lymphoma there are different diseases at molecular level. For that reason many studies deal with the detection of gene alterations in lymphomas to provide a better framework for diagnosis and treatment of these hematological malignancies. AIM: To define genetic alterations in the B-NHL with highest possibilites for diagnostic purposes and molecular detection of MRD. METHODS: Formalin fixed and paraffin embedded lymph node tissues from 45 patients were examined by different PCR techniques for the presence of IgH and TCR gamma gene rearrangement; K-ras and H-ras mutations; c-myc amplification and bcl-2 translocation. There were 34 cases of B-cell non-Hodgkin's lymphoma (B-NHL), 5 cases of T-cell non-Hodgkin's lymphoma (T-NHL) and 6 cases of chronic lymphadenitis (CL). The mononuclear cell fraction of the peripheral blood of 12 patients with B-NHL was analyzed for the presence of monoclonality at the time of diagnosis and in 3 to 6 months time intervals after an autologous bone marrow transplantation (BMT). RESULTS: The monoclonality of B-lymphocytes, as evidenced by DNA fragment length homogeneity, was detected in 88 % (30/34) of B-NHL, but never in CL, T-NHL, or in normal PBL. Bcl-2 translocation was detected in 7/31 (22.6%) B-NHL specimens, c-myc amplification 9/31 (29%, all were more than doubled), K-ras mutations in 1/31 (3.23%) and H-ras mutations in 2/31 (6.45%) of the examined B-NHL samples. In the case of LC and normal PBL, however, these gene alterations were not detected. All the patients (12) with B-NHL had dominant clone of B-lymphocyte in the peripheral blood at the time of diagnosis while only in 2 of 12 patients MRD was detected 3 or 6 months after BMT. CONCLUSION: Because it is quic and simple, PCR analysis of clonal IgH rearrangements is very useful when diagnostic assistance is required. This technique is also very effecient for tracking minimal residual disease in lymphomas and leukemias and for monitoring clonal evolution in acute and chronic lymphoblastic leukemias and lymphomas. The presence of other genetic alterations, which we detected, should serve as an additional prognostic or predictive factor in the patients with B-NHL.

Gene Rearrangement, gamma-Chain T-Cell Antigen Rec↗

Differential expression and cytoplasm/membrane distribution of endoglin (CD105) in human tumour cell lines: Implications in the modulation of cell proliferation.

Endoglin (CD105, an accessory component of the TGF-beta receptor complex) expression and distribution on different human tumour cells and its role in cellular proliferation were evaluated. We examined: 1) sixteen human carcinoma cell lines, 2) eight human sarcoma cell lines, 3) five miscellaneous tumour cell lines. HECV (endothelial cells) were employed as a positive control for endoglin expression. Normal Human Dermal Fibroblasts (NHDF) and 293 cells (epithelial kidney cells) were used as normal controls for connective and epithelial tissues, respectively. The results showed that CD105 was poorly expressed in the majority of human carcinoma cells (10/16), whereas it was highly expressed in most human sarcoma cells (7/8), and differently expressed by miscellaneous tumour cell lines. These data reflect endoglin expression by the normal counterparts of tumour cell lines, i.e. NHDF and 293 cells. However, CD105 levels in sarcoma cell lines, even though consistently lower than in NHDF, were significantly higher than those observed in carcinoma cells. Interestingly, CD105 presented a strong expression in the cytoplasm of MDA-MB-453 (breast carcinoma), NPA (papillary thyroid carcinoma), COLO-853 (melanoma) and SaOS-2 (osteosarcoma), but was weakly expressed on their cell membrane. This differential expression in the cytoplasm and on the membrane of some tumour cells, suggests a complex mechanism of translocation for this protein. The analysis of clonal growth in soft agar of some cell lines, characterized by high CD105 expression, showed an increased colony formation potential that was antagonized by the addition of anti-CD105 blocking mAb. The results indicated that endoglin is differentially expressed in human carcinoma and sarcoma cells and its overexpression modulates the proliferative rate of human solid tumour cells. Moreover, these data suggest that CD105 is involved in the regulation of TGF-beta effects in human solid malignancies, and therefore it could play an important role in tumour diagnosis and treatment.

Antigens, CD↗

gamma delta T-cell lymphoma: a clinicopathologic study of 6 cases including extrahepatosplenic type.

We report 6 cases of gamma delta T-cell lymphoma (GDTL) among 115 peripheral T-cell lymphomas over a 12-year period. All patients exhibited extranodal lymphomas, comprising 3 hepatosplenic, 1 cutaneous, 1 intestinal, and 1 thyroidal lymphoma. Despite therapies, all but 1 patient died of disease within 16 months of diagnosis. The cytologic features of lymphoma cells in 4 of 5 cases examined were very similar: coarsely reticulated nuclear chromatin, multiple small nucleoli, abundant faintly eosinophilic granular cytoplasm, and focal angiocentric proliferation. All 6 lymphomas showed Cd3+CD4-CD8-/+ phenotype. CD56 was positive in 3 cases, 1 of which was also CD16 positive. Perforin and T-cell intracellular antigen-1 were positive in all 5 cases examined. Southern blot analysis revealed clonal gene rearrangements of the T-cell receptor delta-chain gene in all 5 cases examined. Based on these findings, together with a review of the literature, GDTLs seem to have several common lineage-specific features, although clinical presentation and course of GDTL are heterogeneous.

Adolescent↗

A case of T-lineage lymphoblastic lymphoma/leukemia with t(4;11)(q21;p15) that switched to myelomonocytic leukemia at relapse.

A 51-year-old Japanese woman, initially diagnosed with T-lineage (CD2+, CD7+, CD3-, CD4-, CD8-) lymphoblastic lymphoma with t(4;11)(q21;p15), relapsed with acute myelomonocytic leukemia with the identical chromosomal abnormality. Southern-blot analysis revealed clonal rearrangements of an immunoglobulin heavy chain gene (JH) and T-cell receptor genes (J delta 1, J gamma 1, C beta 1) at first presentation, but germ line configurations of these genes at relapse. Leukemias with t(4;11)(q21;p15) may involve a hematopoietic progenitor capable of multilineage differentiation.

CD3 Complex↗

Heteroduplex analysis of VDJ amplified segments from rearranged IgH genes for clonality assessments in B-cell non-Hodgkin's lymphoma. A comparison between different strategies.

BACKGROUND AND OBJECTIVE: The main difficulty of PCR-based clonality studies for B-cell lymphoproliferative disorders (B-LPD) is discrimination between monoclonal and polyclonal PCR products, especially when there is a high background of polyclonal B cells in the tumor sample. Actually, PCR-based methods for clonality assessment require additional analysis of the PCR products in order to discern between monoclonal and polyclonal samples. Heteroduplex analysis represents an attractive approach since it is easy to perform and avoids the use of radioactive substrates or expensive equipment. DESIGN AND METHODS: We studied the sensitivity and specificity of heteroduplex PCR analysis for monoclonal detection in samples from 90 B-cell non Hodgkin's lymphoma (B-NHL) patients and in 28 individuals without neoplastic B-cell disorders (negative controls). Furthermore, in 42 B-NHL and in the same 28 negative controls, we compared heteroduplex analysis vs the classical PCR technique. We also compared ethidium bromide (EtBr) vs. silver nitrate (AgNO(3)) staining as well as agarose vs. polyacrylamide gel electrophoresis (PAGE). RESULTS: Using two pair consensus primers sited at VH (FR3 and FR2) and at JH, 91% of B-NHL samples displayed monoclonal products after heteroduplex PCR analysis using PAGE and AgNO(3) staining. Moreover, no polyclonal sample showed a monoclonal PCR product. By contrast, false positive results were obtained when using agarose (5/28) and PAGE without heteroduplex analysis: 2/28 and 8/28 with EtBr and AgNO(3) staining, respectively. In addition, false negative results only appeared with EtBr staining: 13/42 in agarose, 4/42 in PAGE without heteroduplex analysis and 7/42 in PAGE after heteroduplex analysis. INTERPRETATION AND CONCLUSIONS: We conclude that AgNO(3) stained PAGE after heteroduplex analysis is the most suitable strategy for detecting monoclonal rearrangements in B-NHL samples because it does not produce false-positive results and the risk of false-negative results is very low.

B-Lymphocytes↗

Incidence and characterization of secondary myelodysplastic syndromes following autologous transplantation.

BACKGROUND AND OBJECTIVE: Secondary myelodysplastic syndromes (sMDS) and secondary acute myeloid leukemias (sAML) have been observed after conventional chemo/radiotherapy and autologous hematopoietic stem cell transplantation. The aim of the present study was to analyze Spanish experience regarding the incidence and characteristics of sMDS and sAML following autologous transplantation. DESIGN AND METHODS: We obtained information from 7 institutions which perform autologous transplantation in Spain. Data from 1,081 and 1,411 patients who had received allogeneic and autologous transplantation, respectively, were available. RESULTS: None of the allografted patients had developed a sMDS/sAML so far. Thirteen cases of sMDS/sAML following autologous transplantation were reported. The mean age of these 13 patients at the time of transplantation was 40 years (range 16-58). Five had non-Hodgkin's lymphoma, 6 had Hodgkin's disease, 1 had acute myeloblastic leukemia and 1 had multiple myeloma. The crude overall incidence of sMDS/sAML was 0.9%. The incidence did not differ according to the source of progenitor cells (1% and 0.8% for bone marrow and peripheral blood, respectively). Cytogenetic analysis showed clonal abnormalities in 11 of the 13 cases. Patients with sMDS/sAML had received more doses of alkylating agents than non-sMDS patients (p = 0.0015). The median time between transplantation and diagnosis of sMDS/sAML was 28 months (range 1.5-63). This time was significantly longer for patients who received bone marrow than for those who received peripheral blood (45 versus 18 months, p = 0.01). Median overall survival after diagnosis of sMDS/sAML was 13 months. INTERPRETATION AND CONCLUSIONS: The crude incidence of sMDS/sAML in our series was similar to other published incidences. We did not find any difference in incidence between patients who had received bone marrow or peripheral blood; however, the medi an time elapsed between transplantation and sMDS diagnosis was shorter when peripheral blood was infused. Higher doses of alkylating agents were associated with the appearance of sMDS/AML.

Acute Disease↗

[An analysis of the viability of clonal plants based on a morphometric approach (exemplified by Calamagrostis langsdorffii)].

Clonal plants viability has been studied on the basis of morphostructure variability of clone modules. The research has been carried out on the Calamagrostis langsdorffii (Poaceae) in the flood-lands of the Amur River Basin (Khabarovsk Territory). Plants vitality has been evaluated by 26 morphometric parameters, characterizing their growth, productivity and reproduction. Clone ramets differed from each other by considerable variability and plasticity. Significant changes of all morphometric parameters according to humidity and alluvion gradients were very specific. Reproductive parameters were the most stable ones. Parameters of growth and dimension were characterised by increased variability. Wide reaction of morphometric parameters of C. langsdorffii to the changes in ecological conditions can be considered as an adaptation to the existence in dynamical environment of the flood-land.

Cloning, Organism↗

[Advances in immunoserology tests in clinical medicine: autoantibodies, immune complexes and DNA analysis].

I reviewed first the history of detection for autoantibodies and the methods to detect the circulating immune complexes. Then I presented several unusual tests for detecting autoantibodies which I had experienced. They are agglutination tests in agarose gel using the particulate antigens of human tissues or lipid antigens and the mixed agglutination test using the cultured cells. The characteristics of rheumatoid factor(RF) were analyzed by the following methods: 1) solid-phase radioimmunoassay for IgG-RF using the formalinized sheep RBC, 2) mixed agglutination test for IgG-RF on the slide glass smeared with the sensitized sheep RBC, 3) hemolysis in agarose gel for competitive reaction of RF with complement to the IgG hemolysin and 4) ELISA for detecting the complement-fixation of the monoclonal IgM-RF. The IgG-Fc and C3b receptors on the tissue sections of the mammalian aorta were detected by an adhesion of the IgG-sensitized or C3b-bound RBC. DNA-analysis studies using the molecular biology techniques which were done in the Department of Internal Medicine II, Fukushima Medical University were presented. 1) Nucleic acid sequences of the cloned DNA polypeptide fragments in the serum of patients with systemic lupus erythematosus. 2) SSCP analysis for clonality of Vb repertoires in T cell receptors in the patients with rheumatoid arthritis, primary biliary cirrhosis or CREST syndrome. 3) Detection of mRNA of TNFa and Fas ligand in the mononuclear cells(FICL-PCR) in the synovial fluids of RA patients.

Agglutination Tests↗

Non-random chromosome rearrangements in herpes simplex virus type 1 transformed diploid CHEF cells.

The effects of Herpes simplex virus type 1 (HSV-1) on diploid, non-tumourigenic Chinese hamster embryo fibroblasts (CHEF/18-1D-3) were studied. Six independent lines transformed by HSV-1 alone or by HSV-1 in combination with acyclovir or aqueous tobacco extract were isolated. In contrast to uninfected CHEF/18-1D-3 cells, all transformants grew in soft agar and were tumourigenic in nude mice. Neither infectious virus nor viral antigens could be detected in any of the lines. Cytogenetic analysis revealed clonal chromosome abnormalities in all lines including trisomy for the long arm of chromosome 3 in five lines. In three of these the extra 3q was translocated onto 6p. All lines showed loss of the corresponding 3p arm. The remaining line had a hypodiploid stemline with loss of one chromosome 7. This line also showed a pronounced chromosomal instability with a multitude of mainly sporadic rearrangements. These results show that HSV-1 induced transformation and tumourigenesis in CHEF cells is associated with the induction of chromosome rearrangements, in particular trisomy for 3q.

Acyclovir↗

Combined differentiation therapy in myelodysplastic syndrome with retinoid acid, 1 alpha,25 dihydroxyvitamin D3, and prednisone.

The myelodysplastic syndrome (MDPS) provides an opportunity for identifying host factors (genetic, endocrine, immune) involved in initiation and progression of preleukemia into frank acute myeloid leukemia. The aim of this study was to identify bone marrow (BM) cellular and humoral dysfunctions central to the development of MDPS and useful in therapeutic follow-up studies. Our preclinical studies have shown that (1) the characteristic stromal cell composition of the normal BM microenvironment was impaired in MDPS and in AML in 67 and 86% of the cases, respectively; (2) the 1 alpha,25(OH)2D3 concentration in BM plasma was abnormal in 50% of MDPS and 30% of AML; and (3) an inverse correlation existed in MDPS between the 1 alpha,25(OH)2D3 concentration and the frequency of F-CFU, (r = 0.41, p < 0.02), suggestive of a regulatory interaction between this secosteroid hormone and BM stromal cells. The analysis of clonal extinction of BM blast cells in response to all trans retinoic acid (RA), 1 alpha,25(OH)2D3, and colony stimulating factors (PHA-LCM), either alone or in various combinations, revealed individual patterns of responses in the cases of MDPS or AML. The results indicate the necessity for preclinical studies to select patients for combined differentiation therapy. Our ongoing clinical trials suggest that RA (Roaccutan, 20 mg/day continuously) as induction therapy, followed at weeks 6 to 8 by prednisone (40 mg/day for 15 days) and 1 alpha,25(OH)2D3 (Rocaltrol, 3 x 0.25 micrograms/day for 3 months) may induce a long-lasting hematological remission in MDPS.

Bone Marrow↗

Outbreak of otitis media caused by Burkholderia gladioli infection in immunocompromised mice.

An athymic nude mouse with severe head tilt due to otitis media was identified. Within weeks of identification of this first case, immune-deficient mice of various genotypes from the same facility were similarly affected, and cases from other facilities were found within two months. Culture of ear exudate specimens from affected mice yielded bacteria that were initially identified as Burkholderia cepacia, a plant pathogen considered an important opportunistic pathogen in persons with cystic fibrosis or chronic granulomatous disease. Several of these isolates, however, were subsequently identified as B. gladioli on the basis of results of biochemical analysis and a species-specific polymerase chain reaction (PCR) assay. Genotyping analysis revealed clonality among the isolates, indicating a shared strain among affected mice. A 16S rDNA-based PCR assay specific for the genera Burkholderia and Ralstonia, and a selective culture medium were used in efforts to characterize the epidemiology of this outbreak. In addition to culture of specimens from the oropharyngeal cavity of affected mice, samples were obtained from the environment, feces, sipper tubes, drinking water, and soiled bedding from cages of affected individuals. Burkholderia gladioli was most consistently detected in oropharyngeal swab specimens from affected mice. The PCR assay was equivalent to selective culture in identifying mice in the carrier state that did not have clinical signs of infection. However, neither detection method had sufficient sensitivity to reliably identify all carrier mice, causing the organism to persist at low levels unless entire colonies of immune-deficient mice were removed. The organism was highly resistant to antibiotic therapy. The source and epidemiology of this organism remain unknown. This epizootic serves as an important reminder that immunocompromised rodent colonies may harbor important human opportunistic pathogens.

Animals↗

Analysis of T-cell clonality pattern in tumor samples of breast cancer patients.

PURPOSE AND METHODS: A large body of experimental evidence has confirmed that different tumors, including breast carcinomas, can stimulate specific T-cell-mediated immune responses. In this study we have analyzed patterns of T-cell clonality in tumor samples of 54 breast cancer patients classified as lymph node negative, N0 (n=16), or lymph node positive, N+ (n=38). The clonality of T-cells was analyzed by the PCR-PAGE method. RESULTS: Monoclonal/oligoclonal (M/O) T-cell populations were found in 15 breast cancer patients, nine N+ and six N0. In all analyzed groups (N+ + N0, N+, N0) the incidence of relapse was not significantly different between patients with M/O and patients with polyclonal T-cells. Comparison of disease-free interval (DFI) between patients divided according to the presence of TCRgamma monoclonality/oligoclonality showed a marginally significant difference only in the group of N+ patients within the first 24 months of follow-up. Patients with a M/O T-cell population had a shorter DFI than patients with a polyclonal T-cell population. This difference was not observed when the complete follow-up period was considered in the same group of patients. Furthermore, there was no significant difference in overall survival (OS) between patients with M/O and patients with polyclonal T-cells. CONCLUSION: Our results imply that tumor infiltrating T-cells are usually polyclonal. The pattern of T-cell clonality does not correlate with the incidence of relapse and the duration of DFI and OS in the analyzed groups of breast cancer patients, excluding N+ patients with M/O T-cells who had a shorter DFI in the first 24 months of follow-up. This observation suggests that polyclonal T-cell populations may provide a broader spectrum of T-cell-mediated antitumor response.

Adult↗

A novel microsatellite within intron 8 in caspase10 gene in Chinese of Han nationality.

OBJECTIVE: To investigate polymorphisms in the coding exons and their splicing areas of caspase10 gene (CASP10) in Chinese of Han nationality. METHODS: Polymerase chain reaction (PCR), denaturing high-performance liquid chromatography (DHPLC), direct sequencing and clonal sequencing were used to analyze the exon 9 and its flanking sequences. RESULTS: In 70 blood samples of Chinese subjects researched the known single nucleotide polymorphisms (SNPs) in the exon 9 of CASP10 gene published in dbSNP of NCBI were not identified. We found a short sequence with more than ten continuous and repeated T nucleotides within the intron 8 near the exon 9 and the length of repeated sequence nucleotides T was different in samples. Clonal sequencing analysis indicated that it was a microsatellite of single nucleotide-repeated sequence. The recurrence and specificity of same result was further confirmed by PCR with high fidelity polymerase and sequencing. Furthermore all of 70 blood samples detected by DHPLC showed heterozygous profiles. We named it as IVS8-13(T)n temperately. CONCLUSION: Our research suggested that the site be a microsatellite of single nucleotide-repeated sequence. Meanwhile, our data further showed that it was quite different from that by querying SNP database of non-Chinese population in NCBI, in the same region a SNP of type of insertion deletion existed. It could be inferred that the difference between the populations might be associated with the genetic characteristics of ethnics. The significance of the microsatellite in CASP10 gene in Chinese of Han nationality remains to be elucidated.

Asian People↗

Evolution of HVR-1 quasispecies after 1-year treatment in HIV/HCV-coinfected patients according to the pattern of response to highly active antiretroviral therapy.

Hepatitis C virus (HCV) variability is mainly attributed to the ability of the virus to respond to host immune pressure, acting as a driving force for the evolution of quasispecies. This study was aimed at studying the changes in HVR-1 heterogeneity and the evolution of HCV quasispecies in HIV/HCV-coinfected patients according to the pattern of response to highly active antiretroviral therapy (HAART). Sixteen HIV/HCV-coinfected patients harbouring HCV genotype 1 and who had been on HAART for at least 1 year, 8 showing increasing CD4+ T-cell counts (immunological responders) and 8 showing a stable or decreasing CD4+ T-cell counts (immunological nonresponders), were selected from a prospective cohort study. After 1 year of HAART, 11 patients showed HIV viral load <2.6 log10 cp/ml (virological responders), and 5 showed HIV viral load above this value (virological non-responders). Plasma samples, collected before starting therapy and after 1 year of HAART, underwent clonal sequence analysis for HVR-1 region of HCV. Nonsynonymous/synonymous substitutions ratio (Ka/Ks), aminoacidic complexity (normalized Shannon entropy) and diversity (p-distance), were considered as parameters of quasispecies heterogeneity. After 1 year of HAART, heterogeneity of HVR-1 quasispecies significantly decreased in virological non-responders, whereas the heterogeneity tended to increase in virological responders. The differences in the evolution were less stringent, when considering immunological response. On the other hand, profound qualitative modifications of HVR-1 quasispecies were observed only in patients with both immunological and virological HAART response. On the whole, these findings suggest that, in patients undergoing HAART, the extent of HCV variability and the evolution of HVR-1 quasispecies is influenced by the pattern of response to antiretroviral therapy.

Adult↗

v-jun oncogene prevents terminal differentiation and suppresses muscle-specific gene expression in ASV-17-infected muscle cells.

Infection of replicating quail myoblasts with avian sarcoma virus 17 (ASV-17) results in the inhibition of terminal differentiation into multinucleated myotubes and in the acquisition of anchorage-independent proliferation. Expression of v-jun, the ASV-17 oncogene, concomitantly leads to the accumulation of the gag-jun polyprotein P65 in the nucleus and to the lack of expression of typical differentiation-specific genes such as myosin heavy chain (MHC) and alpha-actinin. Surprisingly, expression of desmin, the muscle-specific subunit of intermediate filaments, is conserved in ASV-17-transformed myoblasts. Analysis of clonal strains of transformed myoblasts suggests that (i) suppression of morphological and biochemical differentiation depends on the absence of muscle-specific gene transcripts; (ii) inhibition of muscle differentiation by v-jun does not depend on the transcriptional silencing of MyoD, a muscle-specific regulatory gene; (iii) expression of desmin is compatible with proliferation of ASV-17-transformed cells and is independent of v-jun and MyoD levels of expression. The present data suggest that nuclear localization of v-jun prevents terminal differentiation in myoblasts and selectively down-regulates muscle-specific genes in terminally differentiated myotubes. In this respect, the behaviour of v-jun is quite different from that of v-myc, thus suggesting that these two oncogenes, although both encoding nuclear proteins, may have different mechanisms of action.

Animals↗

Detection of breakpoint cluster region- negative and nonclonal hematopoiesis in vitro and in vivo after transplantation of cells selected in cultures of chronic myeloid leukemia marrow.

Philadelphia (Ph1) chromosome-positive clonogenic progenitors usually disappear within 4 to 6 weeks in long-term cultures established from the marrow of patients with chronic myeloid leukemia (CML). In contrast, coexisting chromosomally normal hematopoietic cells are relatively well maintained. Thus, even though normal cells are initially undetectable, they may become the predominant population. Recently, we have begun to explore the potential of such cultures as a strategy for preparing CML marrow for autografting, and based on cytogenetic studies of the differential kinetics of Ph1-positive and Ph1-negative clonogenic cells, have chosen a 10-day period in culture to obtain maximal numbers of selectively enriched normal stem cells. Here we present the results of molecular analyses of the cells regenerated in vivo for the initial three CML patients to be treated using this approach by comparison with the differentiated cells generated by continued maintenance of an aliquot of the autograft in vitro (using a slightly modified culture feeding procedure to enhance the production and release of cells into the nonadherent fraction after 4 weeks) for the one patient whose genotype made molecular analysis of clonality status also possible. These analyses showed that cells with a rearranged breakpoint cluster region (BCR) gene were not detectable by Southern blotting in either in vitro or in vivo populations of mature cells that might be assumed to represent the progeny of primitive cells present at the end of the initial 10 days in culture. Production of BCR-negative cells was also shown to be temporally correlated with the appearance of nonclonal hematopoietic cells both in culture and in vivo. These findings provide support for the view that prolonged maintenance of CML marrow cells in long-term culture may allow molecular characterization of both the BCR-genotype and clonality status of cells with in vivo regenerative potential.

Bone Marrow↗

Immunological phenotyping in situ of myeloid colonies in agar cultures.

A technique to immunologically stain hematopoietic colonies in agar cultures would make the analysis of clonal aggregates in situ possible without destroying their architecture and avoid the necessity of picking and washing the cells from semi-solid media. A method is described employing mild glutaraldehyde fixation of agar cultures grown directly on polysiloxane-coated slides. This procedure provided agar plugs which were thin enough to allow the complete penetration of reagents without any loss in plating efficiency. Incubation with primary antibodies for 1.5 h and final development in an indirect enzyme immunoassay using an alkaline phosphatase-conjugated secondary antibody gave excellent morphological and immunological results. As an example, the immunological characterization of normal myeloid colonies with a number of monoclonal antibodies is demonstrated.

Agar↗

Production of lymphokine mRNA by CD45R+ and CD45R- helper T cells from human peripheral blood and by human CD4+ T cell clones.

The expression of lymphokine mRNA by human CD4+CD45R+ and CD4+CD45R- Th cells was assessed after mitogen stimulation. These Ag have previously been shown to relate closely to virgin and primed T cells, respectively. CD4+CD45R+ (virgin) and CD4+CD45R- (primed) cell fractions were isolated by sorting double-labeled cells with a fluorescence-activated cell sorter. CD4+CD45R+ cells produced high levels of IL-2 mRNA when stimulated with either PMA together with calcium ionophore, or with PHA, but they expressed only trace quantities of mRNA for IL-4 or IFN-gamma. In contrast, CD4+CD45R- cells produced high levels of mRNA for IL-2, IL-4, and IFN-gamma. After 14 days of continuous culture, CD4+CD45R+ Th cells lost expression of the CD45R Ag, but gained high level expression of CDw29, such that they were indistinguishable from the cell population which originally expressed this Ag. At the same time, they acquired the ability to synthesize IL-4 mRNA. It seemed likely that the broad lymphokine profile of primed Th cells might mask clonal heterogeneity. Analysis of 122 CD4+ T cell clones showed that all of them synthesized IL-2 mRNA. One clone failed to express IL-4 mRNA, but did produce those for IL-2 and IFN-gamma. A total of 34 of the clones was investigated to determine expression of IFN-gamma mRNA; two of these clones were negative for IFN-gamma mRNA, and both expressed IL-2 and IL-4 message. These data suggest that while fresh virgin and primed peripheral blood T cells show a clear resolution of lymphokine production, a simple subdivision of human CD4+ T cell clones on the basis of their lymphokine production (such as that reported for mouse Th cell clones) is not possible.

Antigens, Differentiation↗