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PubMed1998

Concepts in imaging and microscopy: color image processing for microscopy.

Digital image analysis has long been applied to monochrome images from the light microscope. Using these techniques one can locate, measure, identify, and count the objects of interest in a microscope field of view. Since microscope images often contain color information of interest, it is now becoming more common to analyze the spectral content of images as well. Although most of the digital imaging techniques developed for monochrome microscopy work well with color images, there are a few considerations specific to the analysis of multispectral imagery. These include obtaining a properly balanced multicolor digital image, specifying the color components of the image, and compensating for imperfect separation among the color channels.

Color↗
PubMed2002

Interphase fluorescence in-situ hybridization in the diagnosis of bladder cancer.

Interphase FISH is a technique that uses fluorescent molecules to detect chromosomes or specific regions of DNA. It is a rapid and powerful technique for detection of cytogenetic abnormalities in malignant cells independent of their cell cycle status. Using variety of pericentromeric and locus-specific probes, numerical chromosomal changes (aneusomy) as well as loss or gain/amplification of specific genetic regions can be detected in clinical samples. Numerous studies have identified genetic alterations at the DNA level, occurring in the pathogenesis of variety of human neoplasms including bladder cancer, some of which can be used for detection, prognosis, and as intermediate endpoints for evaluating the response to therapy. Recently, sensitivity and specificity of a multicolor FISH assay consisting of four probes (3, 7, 17 and 9p21) was analyzed in several prospective and retrospective studies. The data suggest that this method applicable to voided urine specimens may allow safe extension of the interval between cystoscopies in routine surveillance of patients with transitional cell carcinoma of the bladder. FISH analysis of cells isolated from bladder washings or voided urine is also holding promise for monitoring of treatment outcome and predicting recurrence and progression of the disease. Therefore, this technique can be an important aid in the efforts to reduce mortality from transitional cell carcinoma of the bladder, since it increases our ability to prevent progression to incurable muscle invasive disease.

In Situ Hybridization, Fluorescence↗
PubMed2000

Fluorescence in situ hybridization: molecular probes for diagnosis of pediatric neoplastic diseases.

Fluorescence in situ hybridization (FISH) has become an important tool for diagnosing neoplasia in children. With probes designed to identify specific chromosomes and chromosomal regions, FISH is commonly used to detect the specific chromosomal abnormalities associated with hematologic diseases and solid tumors. Variations of FISH currently being investigated, such as comparative genomic hybridization, multicolor FISH, and microchip arrays, will probably result in additional uses of FISH in both research and clinical cytogenetic laboratories. Although FISH has disadvantages when compared with conventional cytogenetics and molecular methods, FISH will continue to be important in analyzing chromosomal abnormalities of tumors in children.

Child↗
PubMed2001

Identification of isochromosome 1q as a recurring chromosome aberration in skull base chordomas: a new marker for aggressive tumors?

OBJECT: The authors conducted a study of 22 skull base chordomas. METHODS: A series of 22 skull base chordomas was analyzed with G banding. Subsequently, metaphase cells obtained from three tumors were reexamined using multicolor spectral karyotyping. Clonal chromosome aberrations were identified in 11 cases, all of which were recurrent tumors. Three tumors showed a remarkable similarity in cytogenetic features, and these features appear to characterize a recurring combination of nonrandom chromosome aberrations, including isochromosome 1q, gain of chromosome 7, and monosomy for chromosomes 3, 4, 10,13, and 18. Isochromosome 1q was identified as the sole recurring structural chromosome rearrangement in these tumors. The pattern of chromosome loss reported in the progression of lumbosacral chordoma also appears to be true of skull base chordomas with the additional findings of isochromosome 1q, gain of chromosome 7, and loss of chromosome 18. CONCLUSIONS: Skull base chordomas characterized by isochromosome 1q and monosomy 13 provide support for the concept of the loss of putative tumor suppressor loci on 1p and 13q and aggressive tumor behavior.

Adolescent↗
PubMed2000

Molecular cytogenetic analysis of medulloblastomas and supratentorial primitive neuroectodermal tumors by using conventional banding, comparative genomic hybridization, and spectral karyotyping.

OBJECT: Medulloblastomas and related primitive neuroectodermal tumors (PNETs) of the central nervous system are malignant, invasive embryonal tumors with predominantly neuronal differentiation that comprise 20% of pediatric brain tumors. Cytogenetic analysis has shown that alterations in chromosome 17, particularly the loss of 17p and the formation of isochromosome 17q, as well as the gain of chromosome 7 are the most common changes among this group of tumors. Comparative genomic hybridization (CGH) studies have largely confirmed these cytogenetic findings and have also identified novel regions of gain, loss, and amplification. The advent of more sophisticated multicolored fluorescence in situ hybridization (FISH) procedures such as spectral karyotyping (SKY) now permits complete recognition of all aberrations including extremely complex rearrangements. The authors report a retrospective analysis of 19 medulloblastoma and five PNET cases studied using combinations of classic banding analysis, FISH, CGH, and SKY to examine comprehensively the chromosomal aberrations present in this tumor group and to attempt to identify common structural rearrangement(s). METHODS: The CGH data demonstrate gains of chromosomes 17q and 7 in 60% of the tumors studied, which confirms data reported in the current literature. However, the authors have also combined the results of all three molecular cytogenetic assays (Giemsa banding, CGH, and SKY) to reveal the frequency of chromosomal rearrangement (gained, lost, or involved in structural rearrangement). CONCLUSIONS: The combined results indicate that chromosomes 7 and 17 are the most frequently rearranged chromosomes (10.1% and 8.9%, respectively, in all rearrangements detected). Furthermore, chromosomes 3 (7.8%), 14 (7%), 10 (6.7%), and 22 (6.5%) were also found to be frequently rearranged, followed by chromosomes 6 (6.5%), 13 (6.2%), and 18 (6.2%). Eight (33%) of 24 tumors exhibited high-level gains or gene amplification. Amplification of MYCN was identified in four tumors, whereas amplification of MYCC was identified in one tumor. One tumor exhibited a high-level gain of chromosome 9p. Additionally, desmoplastic medulloblastomas and large-cell medulloblastomas exhibited higher karyotype heterogeneity, amplification, and aneusomy than classic medulloblastomas.

Brain Neoplasms↗
PubMed2026

Integrated Cytokine and Immune Cell Profiling Reveals a Distinct Immune Signature Associated with High-Altitude Pulmonary Edema.

High-altitude pulmonary edema (HAPE) is a rapidly progressive, life-threatening disorder arising in otherwise healthy individuals upon ascent to high altitude, yet the mechanisms underlying maladaptive vascular leak remain poorly defined. Although elevated pulmonary arterial pressure and capillary stress failure are recognized as central hemodynamic drivers, accumulating evidence indicates that innate immune dysregulation is an equally critical, largely unexplored determinant of HAPE. To systematically delineate the immune and molecular programs that distinguish pathological responses to hypobaric hypoxia from acclimatization, peripheral blood along with clinical details was collected from low-altitude controls (LA-Cntrl, number of participants, (n = 19), healthy high-altitude sojourners (HA-Cntrl, n = 47), and HAPE patients (n = 90). Plasma proteomic markers were quantified using a targeted panel, while monocyte and dendritic cell subsets in peripheral blood mononuclear cells were immunophenotyped by multicolor flow cytometry. HA-Cntrl subjects displayed an anti-inflammatory profile, marked by the suppression of CXC chemokine receptor 3 axis chemokines. HAPE patients, in contrast, exhibited a pro-inflammatory, vascular injury signature, with elevated levels of inflammatory interleukins and myeloid and chemotactic factors. This inflammatory signature was accompanied by the expansion of classical monocytes, implicating a myeloid vascular program associated with HAPE.

Humans↗
PubMed2006

Chronic Epstein-Barr virus-related hepatitis in immunocompetent patients.

AIM: To investigate reactivated Epstein-Barr virus (EBV) infection as a cause for chronic hepatitis. METHODS: Patients with occasionally established elevated serum aminotransferases were studied. HIV, HBV and HCV-infections were excluded as well as any other immunosuppressive factors, metabolic or toxic disorders. EBV viral capsid antigen (VCA) IgG and IgM, EA-R and EA-D IgG and Epstein-Barr nuclear antigen (EBNA) were measured using IFA kits. Immunophenotyping of whole blood was performed by multicolor flow cytometry. CD8(+) T cell responses to EBV and PHA were determined according to the intracellular expression of IFN-gamma. RESULTS: The mean alanine aminotransferase (ALT) and gamma glutamyl transpeptidase (GGTP) values exceeded twice the upper normal limit, AST/ALT ratio < 1. Serology tests showed reactivated EBV infection in all patients. Absolute number and percentages of T, B and NK cells were within the reference ranges. Fine subset analysis, in comparison to EBV(+) healthy carriers, revealed a significant decrease of naive T cells (P < 0.001), accompanied by increased percentage of CD45RA(-) (P < 0.0001), and terminally differentiated CD28(-)CD27(-)CD8(+) T cells (P < 0.01). Moderately elevated numbers of CD38 molecules on CD8(+) T cells (P < 0.05) proposed a low viral burden. A significantly increased percentage of CD8(+) T cells expressing IFN-gamma in response to EBV and PHA stimulation was registered in patients, as compared to controls (P < 0.05). Liver biopsy specimens from 5 patients revealed nonspecific features of low-grade hepatitis. CONCLUSION: Chronic hepatitis might be a manifestation of chronic EBV infection in the lack of detectable immune deficiency; the expansion of CD28(-)CD27(-) and increase of functional EBV-specific CD8(+) T cells being the only surrogate markers of viral activity.

Adult↗
PubMed2003

Evaluation of liver functional reserve by combining D-sorbitol clearance rate and CT measured liver volume.

AIM: Our research attempted to evaluate the overall functional reserve of cirrhotic liver by combination of hepatic functional blood flow, liver volume, and Child-Pugh's classification, and to discuss its value of clinical application. METHODS: Ninety two patients with portal hypertension due to hepatic cirrhosis were investigated. All had a history of haematemesis and hematochezia, esophageal and gastric fundus varices, splenomegaly and hypersplenia. A 2-year follow-up was routinely performed and no one was lost. Twenty two healthy volunteers were used as control group. Blood and urine samples were collected 4 times before and after intravenous D-sorbitol infusion. The hepatic clearance (CL(H)) of D-sorbitol was then calculated according to enzymatic spectrophotometric method while the total blood flow (Q(TOTAL)) and intrahepatic shunt (R(INS)) were detected by multicolor Doppler ultrasound, and the liver volume was measured by spiral CT. Data were estimated by t-test, variance calculation and chi-squared test. The relationships between all these parameters and different groups were investigated according to Child-Pugh classification and postoperative complications respectively. RESULTS: Steady blood concentration was achieved 120 mins after D-sorbitol intravenous infusion, which was (0.358+/-0.064) mmol x L(-1) in cirrhotic group and (0.189+/-0.05) mmol x L(-1) in control group (P<0.01). CL(H) =(812.7+/-112.4) ml x min(-1), Q(TOTAL) =(1280.6+/-131.4) ml x min(-1), and R(INS) =(36.54+/-10.65) % in cirrhotic group and CL(H)=(1248.3+/-210.5) ml x min(-1), Q(TOTAL)=(1362.4+/-126.9) ml x min(-1), and R(INS)=(8.37+/-3.32) % in control group (P<0.01). The liver volume of cirrhotic group was 1057+/-249 cm(3), 851+/-148 cm(3) and 663+/-77 cm(3) in Child A, B and C group respectively with significant difference (P<0.001). The average volume of cirrhotic liver in Child B, C group was significantly reduced in comparison with that in control group (P<0.001). The patient, whose liver volume decreased by 40 % with the CLH below 600 ml x min(-1), would have a higher incidence of postoperative complications. There was no strict correspondent relationship between CL(H), liver volume and Child-Pugh's classification. CONCLUSION: The hepatic clearance of D-sorbitol, CT measured liver volume can be reliably used for the evaluation of hepatic functional blood flow and liver metabolic volume. Combined with the Child-Pugh's classification, it could be very useful for further understanding the liver functional reserve, therefore help determine reasonable therapeutic plan, choose surgical procedures and operating time.

Adult↗
PubMed2005

[Preparation and characterization of a directly labeled mouse anti-human CD14 monoclonal antibody ZCH-2F9-FITC].

OBJECTIVE: To prepare fluorescein isothiocyanate (FITC) directly conjugated to monoclonal antibody (McAb) anti-human CD14, ZCH-7-2F9 (2F9-FITC). METHODS: After generation and purification, the purity and the murine immunoglobulin subtype of the antibody were evaluated with SDS-PAGE and multicolor flow cytometry (FCM). 2F9 McAb was directly labeled with FITC through modified Marsshall's method and the positive rate of the 2F9-FITC on different types of leukemic cells were compared with the standard CD14-FITC by FCM. RESULT: A large quantity of purified 2F9 McAb was prepared. The subtype of 2F9 was murine IgG1kappa. 2F9-FITC was successfully manufactured with A295/A280 ratio of 0.44. The positive cell percentages of 2F9-FITC and CD14-FITC on the monocytes were 84.50% and 90.08%, respectively, while those on lymphocytes were only 0.52% and 1.01%. There was no significant difference between the CD14 expressions with 2F9-FITC and CD14-FITC on each type of leukemia (n=23, t=0.922, P=0.367). CONCLUSION: 2F9-FITC has been successfully prepared and it can be applied in diagnosis and differentiation of monoblastic leukemias.

Animals↗
PubMed2005

CHOP plus rituximab therapy in Waldenstrom's macroglobulinemia.

Recently, a consensus panel of experts recommended that patients with Waldenstrom's macroglobulinemia (WM) who are candidates for future autologous transplantation should have limited alkylator or nucleoside analogue exposure due to potential stem cell harm. Cyclophosphamide/doxorubicin/vincristine/prednisone/rituximab (CHOP-R) is a stem cellsparing regimen that has been extensively evaluated in patients without WM or non-Hodgkin's lymphoma. As such, we analyzed the outcome of 13 patients with WM who received CHOP-R at our institution. Patients had a median age of 54 years and a median of 1 previous therapy. Ten of 13 patients (77%) had relapsed (n = 3) or refractory (n = 7) disease. Eight and 6 patients had previously received fludarabine and rituximab, respectively. Intended therapy consisted of 6 cycles of standard-dose CHOP and 6 infusions of rituximab (375 mg/m2). Three patients received additional rituximab as maintenance therapy. Median immunoglobulin M and serum viscosity for all patients decreased from 5230 mg/dL to 1690 mg/dL (P < or = 0.001) and from 2.9 cP to 1.6 cP (P = 0.01), respectively, and the median hematocrit level rose from 30.5% to 39.3% (P < or = 0.001). Clinical responses were as follows: 3 complete responses unconfirmed, 8 partial responses, 1 minor response. At a median follow-up of 9 months (range, 6 to > 37 months), 10 of the 11 patients who had a major response remained in remission. Therapy was well tolerated for most patients. Two patients had febrile neutropenia with documented bacteremia and recovered without complications. Circulating effector cell levels were also evaluated in 6 patients before and after CHOP-R, because rituximab activity is mediated in part by antibody-dependent cell-mediated cytotoxicity activity. No significant change in CD3+, CD4+, CD8+, and CD16+/CD56+ effector cell levels occurred following CHOP-R as assessed by multicolor flow cytometry.

Adult↗
PubMed2006

CD52 is expressed on human mast cells and is a potential therapeutic target in Waldenstrom's Macroglobulinemia and mast cell disorders.

BACKGROUND: Alemtuzumab is a monoclonal antibody used in the treatment of CD52-expressing B-cell malignancies, including Waldenstrom's macroglobulinemia (WM). Recent studies demonstrate high levels of alemtuzumab activity in relapsed/refractory disease. One potential target of alemtuzumab is bone marrow mast cells (BMMCs), which provide growth and survival signaling for WM lymphoplasmacytic cells. PATIENTS AND METHODS: We therefore examined BMMCs (FceRI+, CD117+) from WM and other mast cell (MC) disorders for expression of CD52. RESULTS: We identified cell surface antigen expression by multicolor flow cytometric analysis and found CD52 expressed on human mast-derived cell line-1 (HMC-1) and LAD2 MC lines, on BMMC from 13 of 15 patients with WM, and on BMMCs from 4 of 4 patients with systemic mastocytosis (SM). None of 4 healthy donors expressed CD52. Reverse-transcriptase polymerase chain reaction analysis confirmed CD52 expression in the HMC-1 and LAD2 MC lines, in BMMCs from 14 of 15 patients with WM, and 3 of 3 patients with SM. CD52 transcripts were also detected in BMMCs from 6 of 6 healthy donors, despite the absence of CD52 cell surface expression. Importantly, we observed high levels of alemtuzumab-mediated, antibody-dependent, cell-mediated cytotoxicity against LAD2 MCs and BMMCs from patients with WM and SM. CONCLUSION: These studies demonstrate that CD52 is widely expressed on human MCs and WM bone marrow lymphoplasmacytic cells and provide the preclinical rationale for the use of alemtuzumab in the treatment of WM and possibly other MC-related disorders.

Alemtuzumab↗
PubMed1998

Classical and molecular cytogenetic methods in diagnosis of a rare translocation t(3;21).

We report the characterization by traditional cytogenetic methods and fluorescence in situ hybridization (FISH) of a rare balanced reciprocal translocation t(3;21) in a male spouse connected with several miscarriages. G- and C-banding analysis of the male karyotype was suggestive of breakpoints in chromosomal bands 3q11.1 and 21p11.1. Multicolor-FISH analysis using chromosome-specific alpha-satellite probes in combination with a locus-specific bacterial artificial chromosome (BAC) from 21q22.3 allowed us both to identify the origin of centromeres in the derivative chromosomes and to establish centromere-telomere orientation of the translocated chromosome 21 segment. Characterization of the translocated chromosomes by FISH analysis permitted describing the exact karyotype of the carrier as: 46,XY,-3,-21,+der(3)(21qterO21q11. 2::3p11.2O cenO3qter),+der(21)(3pterO3p11.2::21q11.2OcenO21pte r).

Abortion, Spontaneous↗
PubMed2003

Evidence for a new microdeletion syndrome in 15q21.

We report on the fourth known case with an interstitial deletion in 15q21. In the present case the breakpoints have been determined by GTG-banding, microdissection and the recently developed multicolor banding (MCB) technique as 15q21.1-q21.3. Common features in all four cases are mental retardation, growth retardation, a beak-like nose with hypoplastic alae nasi and a thin upper lip. Additional frequent features are small hands and feet, hypotonia, low hair implantation, low set ears, clinodactyly and obesity. The possibility that a critical region for a new microdeletion-syndrome is situated in 15q21 is discussed.

Abnormalities, Multiple↗
PubMed2000

Clinical significance of minimal residual disease in leukemia.

Considerable progress has been made in the treatment of acute and chronic leukemias. Remission rates are generally high and cure rates of up to 80% can be achieved in children with acute lymphoblastic leukemia (ALL). However, in many patients the disease will ultimately recur. In most if not all of these patients, relapse is thought to result from subclinical levels of residual leukemia, termed minimal residual disease (MRD). Therefore, the study of MRD holds a significant potential to understand the biology of relapse and remission and to design new therapies to improve the cure rate of patients. A major goal of these studies is to be able and identify patients at a defined risk of relapse which can lead to risk-adapted therapy approaches. Laboratory assays such as polymerase chain reaction (PCR) and multicolor flow cytometry are sensitive enough to detect one leukemic cell in up to 104-105 normal cells and have become ideal tools to monitor MRD. Especially PCR has been used extensively. Although a wealth of data has been generated, some questions remain as to the impact of monitoring MRD on clinical outcome and are the object of this review.

Acute Disease↗
PubMedDate not supplied

Complex chromosomal rearrangements in a secondary acute myeloblastic leukemia after chemotherapy in TRAPS.

We report on the cytogenetic findings from a patient with a de novo TNF-receptor-associated periodic syndrome (TRAPS), who showed first symptoms at the age of four months. Thus, he obtained a long-term therapy with cortisone, chlorambucile, methotrexate and cyclophosphamide. At the age of 14 he developed a secondary acute myeloblastic leukemia. Highly complex chromosomal rearrangements were detected after banding analysis. The exact definition of karyotype and the involved breakpoints could only be resolved after application of sophisticated multicolor-FISH techniques: 44,XY,-5,der(6)t(6;7)(6pter right curved arrow 6q12::7p22.2 right curved arrow 7pter or 7pter right curved arrow 7p22.2), dic(7;19)t(6;19;6;7;19;7;19)(19qter right curved arrow 19q12::7p13 right curved arrow 7p11.1::19q12 right curved arrow 19p12 or 19p12 right curved arrow 19q12::7p11.1 right curved arrow 7q21.3::6q12 right curved arrow 6q26::19p13.3 right curved arrow 19p12::6q26-6qter),dic(12;13)(13qter right curved arrow 13p11.2::12p13.1 right curved arrow 12qter),ace(12;13)(13pter right curved arrow 13p11.2::12p13.1 right curved arrow 12pter), -19. The simultaneous presence of two dicentric chromosomes has not been reported previously and is striking, as such chromosomes are suggested to be instable. However, such chromosomes are observed frequently after chemo- or radiotherapy and in secondary, i.e. therapy related AML (tAML). Thus, AML in this case may result from a long-term therapy of TRAPS with methotrexate, cyclophosphamide, chlorambucile and cortisone.

Adolescent↗
PubMed2002

Functional expression of the chemokine receptor CCR5 on virus epitope-specific memory and effector CD8+ T cells.

Because the chemokine receptor CCR5 is expressed on Th1 CD4(+) cells, it is important to investigate the expression and function of this receptor on other T cells involved in Th1 immune responses, such as Ag-specific CD8(+) T cells, which to date have been only partially characterized. Therefore, we analyzed the expression and function of CCR5 on virus-specific CD8+ T cells identified by HLA class I tetramers. Multicolor flow cytometry analysis demonstrated that CCR5 is expressed on memory (CD28+CD45RA-) and effector (CD28-CD45RA- and CD28-CD45RA+) CD8+ T cells but not on naive (CD28+CD45RA+) CD8+ T cells. CCR5 expression was much lower on two effector CD8+ T cells than on memory CD8+ T cells. Analysis of CCR7 and CCR5 expression on the different types of CD8+ T cells showed that memory CD8+ T cells have three phenotypic subsets, CCR5+CCR7-, CCR5+CCR7+, and CCR5-CCR7+, while naive and effector CD8+ T cells have CCR5-CCR7+ and CCR5+CCR7- phenotypes, respectively. These results suggest the following sequence for differentiation of memory CD8+ T cells: CCR5-CCR7+-->CCR5+CCR7+-->CCR5+CCR7-. CCR5+CD8+ T cells effectively migrated in response to RANTES, suggesting that CCR5 plays a critical role in the migration of Ag-specific effector and differentiated memory CD8+ T cells to inflammatory tissues and secondary lymphoid tissues. This is in contrast to CCR7, which functions as a homing receptor in migration of naive and memory CD8+ T cells to secondary lymphoid tissues.

CD28 Antigens↗
PubMed2004

E-selectin, thymus- and activation-regulated chemokine/CCL17, and intercellular adhesion molecule-1 are constitutively coexpressed in dermal microvessels: a foundation for a cutaneous immunosurveillance system.

The success of the cutaneous immune system reflects its ability to rapidly and efficiently recruit leukocytes to areas of trauma and infection. Skin-homing memory T cells expressing cutaneous lymphocyte-associated Ag tether on the walls of postcapillary venules in inflamed skin via interaction with endothelial E-selectin and roll in response to the shear stress imparted by flowing blood. Rolling cells sample the vascular surface for chemoattractant compounds (e.g., thymus- and activation-regulated chemokine/CCL17 interacting with CCR4 on the leukocyte surface) and, if successfully stimulated, progress to firm arrest and transmigration mediated by LFA-1 and vascular ICAM-1. Although it is established that this sequence of events draws T cells into inflamed skin, the mechanisms directing trafficking of T cells to noninflamed skin are less well characterized. We hypothesized that basal expression and colocalization of E-selectin, chemokine (e.g., CCL17), and ICAM-1 in dermal vessels could serve to recruit T cells to noninflamed human skin. Immunohistochemical staining for E-selectin and CD31 demonstrated E-selectin expression in a restricted subset of dermal vessels in noninflamed human skin from three different sites. Confocal multicolor immunofluorescence imaging revealed a nonuniform distribution of E-selectin in dermal vessels as well as colocalization of E-selectin with CCL17 and ICAM-1. Coexpression of these molecules on blood vessels in noninflamed skin provides the basis for a model of cutaneous immunosurveillance system active in the absence of pathologic inflammation.

Cell Movement↗
PubMed2004

HIV-infected Langerhans cells preferentially transmit virus to proliferating autologous CD4+ memory T cells located within Langerhans cell-T cell clusters.

Langerhans cells (LC) are likely initial targets for HIV following sexual exposure to virus and provide an efficient means for HIV to gain access to lymph node T cells. The purpose of this study was to examine the nature of the CD4(+) T cell that becomes infected by HIV-infected LC. We infected human LC within tissue explants ex vivo and then, 3 days later, cocultured HIV-infected LC with different subsets of autologous CD4(+) T cells. Using multicolor flow cytometric analyses of LC-CD4(+) T cell cocultures, we documented that HIV-infected LC preferentially infected memory (as compared with naive) CD4(+) T cells. Proliferating and HIV-infected CD4(+) memory T cells were more frequently detected in conjugates of LC and autologous CD4(+) T cells, suggesting that T cells become activated and preferentially get infected through cluster formation with infected LC, rather than getting infected with free virus produced by single HIV-infected LC or T cells. p24(+) Memory CD4(+) T cells proliferated well in the absence of superantigen; by contrast, p24(+) T cells did not divide or divided only once in the presence of staphylococcal enterotoxin B, suggesting that virus production was rapid and induced apoptosis in these cells before significant proliferation could occur. These results highlight that close interactions between dendritic cells, in this case epidermal LC, and T cells are important for optimal HIV replication within specific subsets of CD4(+) T cells. Disrupting cluster formation between LC and memory CD4(+) T cells may be a novel strategy to interfere with sexual transmission of HIV.

Antigens, Bacterial↗