bluuebunny/crossref_metadata_2025 huggingface dataset:
Thymic Stromal‐Cell Abnormalities and Dysregulated T‐Cell Development in IL‐2‐Deficient Mice
Authors: Reya Tannishtha , Bassiri Hamid , Biancaniello Renée , Carding Simon R.
Published: June 2008

The role that interleukin‐2 (IL‐2) plays in T‐cell development is not known. To address this
issue, we have investigated the nature of the abnormal thymic development and autoimmune
disorders that occurs in IL‐2‐deficient (IL‐2–/–) mice. After 4 to 5 weeks of birth, IL‐2–/– mice
progressively develop a thymic disorder resulting in the disruption of thymocyte maturation.
This disorder is characterized by a dramatic reduction in cellularity, the selective loss of
immature CD4-8- (double negative; DN) and CD4+8+ (double positive; DP) thymocytes and
defects in the thymic stromal‐cell compartment. Immunohistochemical staining of sections of
thymuses from specific pathogen‐free and germ‐free IL‐2–/– mice of various ages showed a
progressive ,loss of cortical epithelial cells, MHC class II‐expressing cells, monocytes, and
macrophages. Reduced numbers of macrophages were apparent as early as week after birth.
Since IL‐2–/– thymocyte progenitor populations could mature normally on transfer into a normal
thymus, the thymic defect in IL‐2–/– mice appears to be due to abnormalities among thymic
stromal cells. These results underscore the role of IL‐2 in maintaining functional microenvironments
that are necessary to support thymocyte growth, development, and selection.
Langerhans Cell Migration in Murine Cutaneous Leishmaniasis: Regulation by Tumor Necrosis Factor α Interleukin‐1β, and Macrophage Inflammatory Protein‐1α
Authors: Arnoldi Jörg , Moll Heidrun
Published: June 2008

After intradermal infection of mice with the obligatory intracellular parasite Leishmania major, Langerhans cells (LC) are intimately involved in the induction of the primary T‐cell immune response. LC can phagocytose Leishmania and transport ingested parasites from the infected skin to the regional lymph nodes. Since TNFα and IL‐1β have been shown to induce LC migration after epicutaneous exposure to skin‐sensitizing chemicals, we investigated the involvement of both cytokines in the migration of Leishmania‐infected LC. In addition, the relevance of two chemokines of theβ subfamily, macrophage inflammatory protein 1α(MIP‐1α) and macrophage chemoattractant protein 1 (MCP‐1), was analyzed.In vivo depletion of TNFα significantly reduced the amount of infected LC and the parasite load in the draining lymph nodes. Administration of recombinant TNFα caused the reverse effect. In contrast, the depletion of IL1β enhanced the parasite‐induced LC migration, whereas treatment with recombinant IL‐1β, as well as recombinant MIP‐ c, reduced the rate of infected LC in the lymph nodes. MCP‐ did not influence LC migration. Our data demonstrate that TNFα and IL‐1β are regulating the LCmediated transport of Leishmania and also provide evidence for the involvement of macrophage attractant chemokines in this process.
Appearance and Maturation of T‐Cell Subsets During Rat Thymus Ontogeny
Authors: Vicente A. , Varas A. , Acedón R.S , Jiminez E. , Mulqoz J. J. , Zapata A. G.
Published: June 2008

In previous papers, we have described the ontogenetical development of thymic stromal‐cell
components (epithelium, macrophages, dendritic cells) of Wistar rats. Here, we correlate those
results with the maturation of rat T‐cell precursors along the fetal and postnatal life. First T‐cell
precursors, which colonize the thymus anlage around days 13‐14 of gestation, largely express
CD45, CD43, CD53, and Thy 1 cell markers, and in a lesser proportion the OX22 antigen. Rat
CD3-CD4-CD8- thymocytes present in the earliest stages of gestation could be subdivided in
three major cell subpopulations according to the CD44 and CD25 expression: CD44-/+CD25- →
CD44+CD25+ → CD44+CD25- On fetal days 17‐18, a certain proportion of CD4-CD8-cells weakly,express the TcRβ chain, in correlation with the appearance of the first immature
CD4-CD8+ thymocytes. This cell subpopulation, in progress to the CD4+CD8+ stage, upregulates CD8α before the CD8β chain, expresses the CD53 antigen, and exhibits a high proliferative rate. First mature thymocytes arising from the DP (CD4+CD8+) cells appear on fetal
days 20‐21. Then, the CD4+:CD8+ cell ratio is ≤1 changing to adult values (2‐3) just after birth.
Also, the percentage of VβTcR repertoire covered in adult thymus is reached during the
postnatal period, being lower during the fetal life. Finally, in correlation with the beginning of
thymocyte emigration to the periphery a new wave of T‐cell maturation apparently occurs in the
perinatal rat thymus.
Development of Accessory Cells in B‐Cell Compartments Is Retarted in B‐Cell‐Depleted Fetal Sheep
Authors: Press Charles Mcl. , Reynolds John D. , McClure Susan J. , Landsverk Thor
Published: June 2008

Accessory‐cell populations in the lymphoid tissues of fetal sheep were investigated following depletion of
B cells. An intraperitoneal injection of an anti‐IgM antibody early in gestation resulted in a marked depletion of IgM+
cells in lymphoid tissues. Immune and enzyme histochemical techniques were used to identify accessory‐cell
populations in the ileal Peyer′s patch, spleen, and lymph nodes of B‐cell‐depleted fetal sheep. The rudimentary
follicles in the ileal Peyer′s patch showed strong enzyme reactivity for 5′ nucleotidase, indicating the presence
of follicular dendritic cells (FDCs). Enzyme reactivities for FDCs in primary follicles of the spleen and lymph nodes
were absent, as were reactivities for metallophilic macrophages in the marginal zone of the spleen. MgATPase
reactivity associated with dendritic‐cell populations in the gut‐associated lymphoid tissues was detected.
A monoclonal antibody against complement receptor‐2 (CD21) reacted with FDCs in the rudimentary follicles of
the ileal Peyer′s patch and immature FDCs in lymph nodes. The results suggest that the development of accessory‐cell
populations in B‐cell compartments of peripheral but not central lymphoid tissues is dependent on the presence of B cells.
Adrenergic/Cholinergic Immunomodulation in the Rat Model—In Vivo Veritas?
Authors: Rinner I. , Felsner P. , Liebmann P. M. , Hofer D. , Wölfler A. , Globerson A. , Schauenstein K.
Published: June 2008

For several years, our group has been studying the in vivo role of adrenergic and cholinergic mechanisms in the immune‐neuroendocrine dialogue in the rat model. The main results of these studies can be summarized as follows: (1) exogenous or endogenous catecholamines suppress PBL functions through alpha‐2‐receptor‐mediated mechanisms, lymphocytes of the spleen are resistant to adrenergic in vivo stimulation, (2) direct or indirect cholinergic treatment leads to enhanced ex vivo functions of splenic and thymic lymphocytes leaving PBL unaffected, (3) cholinergic pathways play a critical role in the “talking back” of the immune system to the brain, (4) acetylcholine inhibits apoptosis of thymocytes possibly via direct effects on thymic epithelial cells, and may thereby influence T‐cell maturation, (5) lymphocytes of the various immunological compartments were found to be equipped with the key enzymes for the synthesis of both acetylcholine and norepinephrine, and to secrete these neurotransmitters in culture supernatants
Enhanced Follicular Dendritic Cell‐B Cell Interaction in HIV and SIV Infections and its Potential Role in Polyclonal B Cell Activation
Authors: Rosenberg Yvonne J. , Lewis Mark. G. , Kosco-Vilbois Marie H.
Published: June 2008

Human immunodeficiency virus (HIV) infections have been characterized by both polyclonal Bcell activation and enhanced responsiveness to B‐cell growth factors on one hand and the loss of specific antibody (Ab) responses and refractoriness to the normal signals for B‐cell activation on the other. Histopathological studies of lymph node from HIV‐ and simian immunodeficiency virus (SIV)‐infected individuals have indicated initial follicular hyperplasia and the appearance of large irregular germinal centers that undergo progressive involution concomitant with follicular dendritic‐cell (FDC) disruption. During this process, follicular dendritic‐cell ‐enriched
lymph‐node‐cell cultures exhibit increased ability to induce cluster formation (“in vitro germinal centers”), lymphocyte proliferation and antibody production compared to uninfected controls. This paper discusses how enhanced FDC‐B‐cell interaction within SIV‐infected germinal centers may result in a reduced ability to select high‐affinity B cells and alter the dynamics of antibodyproducing‐ cell and memory‐cell generation resulting in the observed hyperactivity.
Tinigible Body Macrophages in Regulation of Germinal Center Reactions
Authors: Smith John P. , Burton Gregory F. , Tew John G. , Szakal Andras K.
Published: June 2008

Tingible body macrophages (TBM), long thought simply as scavengers of apoptotic lymphocytes, are located in the unique microenvironment of germinal centers in close proximity to antigen‐retaining follicular dendritic cells (FDC). Observations that TBM endocytose FDC‐iccosomal (immune‐complex coated bodies) antigen suggested that TBM might present this antigen and help regulate the germinal center reaction. To test for antigen presentation, the ovalbumin (OVA)‐specific TH hybridoma, 3DO‐54.8, which produces IL‐2 on receiving effective presentation of OVA, were used as responders to OVA‐bearing TBM. Results showed that OVA‐bearing TBM failed to induce IL‐2 production. Furthermore, addition of TBM to IL‐ 2‐inducing positive controls (B cells) not only failed to augment IL‐2 production, but rather TBM significantly (55‐90%) reduced B‐cell induction of IL‐2. We found that TBM were rich in prostaglandin by comparison with other nongerminal center lymph node macrophages and that addition of indomethacin to the cultures reversed the inhibitory effect of TBM. Depletion of TBM from enriched preparations, prior to addition to positive control cultures, also abrogated the inhibitory effect on IL‐2 production. These data support the concept that TBM, within the unique microenvironment of germinal centers, may be specialized to downregulate the germinal center reaction.
Neuropeptides Exert Direct Effects on Rat Thymic Epithelial Cells in Culture
Authors: Head Gail M. , Mentlein R. , Patay Birte Von , Downing J. E.G. , Kendall Marion D.
Published: June 2008

To determine if major thymic neuropeptides and neurotransmitters can directly influence the functional activity of cultured rat thymic epithelium, neuropeptides and neurotransmitters were applied, and intercellular communication, proliferation, and thymulin secretion assessed. After injections of a mixture of lucifer yellow dextran (too large to pass gap junctions) and cascade blue (which does) into single cells, some neuropeptides decrease dye coupling: 0.1 mM GABA (P < 0.0001), 100 nM NPY (P < 0.0001), 100 nM VIP (P < 0.001), 100 nM CGRP (P < 0.001), 100 nM SP (P < 0.01), and 0.1 mM histamine (P < 0.01), whereas 0.1 mM 5‐HT, mM acetylcholine, and 1 μM isoproterenol (β‐adrenergic agonist) had no effect. Proliferation
(incorporation of tritiated thymidine) was increased by CGRP (P = 0.004) and histamine (P < 0.02), but decreased by isoproterenol (P = 0.002), 5‐HT (P = 0.003), and acetylcholine (P < 0.05). The percentage of multinucleate cells was decreased after isoproterenol (2.5%), and increased after 5‐HT (21.3%), GABA (15%), and histamine (15.1%). Compared to controls, thymulin in the supernatant was decreased after challenge with acetylcholine (52%), isoproterenol (71%), 5‐HT (73%), and histamine (84%). This study demonstrates direct effects
of neuropeptides and neurotransmitters on functional aspects of cultured thymic epithelial cells.
Maturation of B Cells in the Lamina Propria of HumanGut and Bronchi in the First Months of Human Life
Authors: El Kaissouni Jamal , Bene Marie C. , Thionnois Sophie , Monin Pierre , Vidailhet Michel , Faure Gilbert C.
Published: June 2008

Little is known of the maturation of the mucosae‐associated lymphoid tissue (MALT) in man,
because, for ethical reasons, tissues from newborns are not easy to obtain. We used the
opportunity provided by autopsies systematically performed in infants who died of Sudden Infant
Death Syndrome (SIDS) to study the maturation of the MALT after birth. Gut and bronchus
samples of 90 infants from postpartum to 90 months and who died from SIDS were collected and
studied by histological and immunofluorescence examination. Plasma cells, absent at birth,
appeared within a few hours after birth and initially were of the IgM isotype. IgA plasma cells
appeared at 12 days. These cells were first observed in gut and later in bronchi, indicating that
maturation of the gut precedes that of bronchi. The number of plasma cells increased rapidly over
time and IgA plasma cells became predominant after 3 weeks in the gut and 6 weeks in bronchi.
At birth, only small IgM bearing B‐cell foci were seen and organized germinal centers appeared
to develop over a few days, first in the gut and only later in bronchi. These results confirm that,
in man, the MALT organization at birth is still in its fetal form and that maturation depends on
intestinal challenges and evolves over several weeks before IgA becomes the predominant
isotype secreted.
Gap‐Junction Communication Pathways in Germinal Center Reactions
Authors: Krenacs Tibor , Rosendaal Martin
Published: June 2008

Intercellular channels called gap junctions enable multicellular organisms to exchange
information rapidly between cells. Though gap junctions are held to be ubiquitous in solid
tissues, we have only recently found them in the lymphoid organs. Functional direct cell‐cell
communication has now been confirmed by us and other groups in bone marrow, thymus, and
in secondary lymphoid tissues. What functions do they serve in the lymphoreticular system
where, so far, only cytokines/growth factors and adhesion molecules have been considered as
regulators? Here we show evidence for and refer to published work about functional direct cellcell
communication through gap junctions in germinal center reactions and make proposals for
their role in the immune response.

We found a large amount of the connexin43 (Cx43) gap junctions in the germinal centers of
secondary lymphoid follicles. Ultrastructurally and immunohistologically, most of the junctions
were detected on the processes of follicular dendritic cells (FDC) enveloping nondividing
centrocytes in the light zone of germinal centers where B‐cell selection is thought to take place.
Further support for this finding came by revealing the Cx43 mRNA in situ at the same location
as the protein. On antigen challenge, gap junctions appeared on the FDC as they formed
meshworks in germinal centers. In order to find out which germinal center cells communicate
directly, we separated FDC‐rich, low‐density, B‐cell fractions from human tonsil. In culture, we
injected single FDC with the low‐molecular‐weight fluorescent dye, Lucifer Yellow (Mr 457
Da), which passed between adjacent FDC and sometimes from FDC to B cells.

Based on these findings and their assigned functions in other tissues, gap junctions may
contribute to germinal center reactions in the following ways: (1) they may regulate follicle
pattern formation by controlling FDC growth, (2) they may be involved in FDC‐B‐cell signaling
contributing to the final rescue of selected B cells from apoptosis, and (3) they may enable FDC
to work as a functional syncytium providing a cellular internet for integrating germinal center
events. Data supporting these interpretations are briefly discussed.
Protective Cellular Immunity Against Influenza VirusInduced by Plasmid Inoculation of Newborn Mice
Authors: Bot Adrian , Bot Simona , García-Sastre Adolfo , Bona Constantin
Published: June 2008

Neonate organisms display an intrinsic disability to mount effective immune responses to
infectious agents or conventional vaccines. Whereas low. doses of antigens trigger a suboptimal
response, higher doses are frequently associated with tolerance induction. We investigated the
ability of a plasmid‐expressing nucleoprotein of influenza virus to prime a specific cellular
immune response when administered to newborn mice. We found that persistent exposure to
antigen following plasmid inoculation of neonates leads to a vigorous priming of specific CTLs
rather than tolerance induction. The CTLs were cross‐reactive against multiple strains of type A
influenza viruses and produced IFNγ but no IL‐4. The immunity triggered by plasmid
inoculation of neonates was protective in terms of pulmonary virus clearance as well as survival
rate following lethal challenge with influenza virus. Whereas the persistence of the plasmid at the
site of injection was readily demonstrable in adult mice at 3 months after inoculation, mice
immunized as newborns displayed no plasmid at 3 months and very little at 1 month after
injection. Thus, DNA‐based immunization of neonates may prove an effective and safe
vaccination strategy for induction of cellular immunity against microbes that cause serious
infectious diseases in the early period of life.
Thymic‐Shared Antigen‐1 (TSA‐1) A Lymphostromal Cell Membrane Ly‐6 Superfamily Molecule with a Putative Role in Cellular Adhesion
Authors: Classon Brendan J. , Boyd Richard L.
Published: June 2008

The seeding and colonization of the thymus by bone marrow stem cells and the maturation of these cells into mature T lymphocytes are dependent on cell‐surface recognition events between different cell lineages within the thymic microenvironment. Positive and negative selection processes within the thymus produce a peripheral T‐cell repertoire capable of recognizing peptides derived from foreign antigen bound to self MHC molecules. In addition to the TCR/ MHC‐peptide interaction, many other cell‐surface molecules act in concert to regulate the
kinetics of cellular interactions and intracellular signaling events during thymopoiesis. We have investigated the complexity of the thymic stroma by using monoclonal antibodies to clone cellmembrane molecules of thymic stromal cells. Thymic‐shared antigen‐1 (TSA‐1) is a molecule of interest because it is expressed by both immature thymocytes and stromal cells. We report herein the structural and evolutionary relationships between TSA‐1 and molecules of the Ly‐6 superfamily (Ly‐6SF), and present evidence that TSA‐1 functions as a cell‐surface receptor by
binding a cognate cell target molecule on the surface of a subset of thymocytes.
The Avian Transcription Factor c‐Rel is Expressed inLymphocyte Precursor Cells and Antigen‐PresentingCells During Thymus Development
Authors: Huguet C. , Bouali F. , Enrietto P. J. , Stehelin D. , Vandenbunder B. , Abbadie C.
Published: June 2008

Transcription factors of the Rel/NF‐κB family are widely involved in the immune system. In this
study, we investigate the in vivo expression of the avian protein c‐Rel in the T‐cell lineage during
thymus development. The majority of thymocytes do not express the c‐Rel protein. However,
lymphocyte precursor cells that colonize the thymus express the c‐Rel protein shortly after their
homing in the organ and before they begin to differentiate, c‐Rel is also detected in different
subsets of,antigen‐presenting cells such as epithelial cells, dendritic cells, and macrophages. In
vitro studies have shown that Rel/NF‐κB proteins are sequestered in an inactive form in the
cytoplasm by interaction with the IκBα inhibitory protein. By immunocytochemistry, we show
that in vivo c‐Rel is localized in the cytoplasm of antigen‐presenting cells but in both the
cytoplasm and nucleus of lymphocyte precursor cells. The cytoplasmic localization of c‐Rel in
antigen‐presenting cells correlates with a high expression of IκBα, whereas the nuclear
localization of c‐Rel in lymphocyte precursor cells correlates with a much lower expression of
IκBα. These results suggest that c‐Rel might be constitutively activated in lymphocyte precursor
cells.
Estrogen‐Receptor Expression and Function in Thymocytes in Relation to Gender and Age
Authors: Kohen F. , Abel L. , Sharp A. , Amir-Zaltsman Y. , Sömjen D. , Luria S. , Mor G. , Knyszynski A. , Thole H. , Globerson A.
Published: June 2008

The expression of estrogen receptor (ER) in thymocytes was studied in young, middle‐aged, and
old (2, 12, and 24 months, respectively) female and male C57BL/6J mice. Western immunoblots
prepared from the thymocytes of females of all age groups showed the presence of a 67‐kD
protein band, which has been associated with the apparent MW of denatured ER. Flow cytometry
analysis o,f cells stained with a monoclonal anti‐ER antibody (clone 13H2) disclosed ER
expression in both females and males of all age groups. In vivo treatment with estradiol (E2) led
to an increase in the specific activity of thymic creatine kinase (CK) in the female mice, whereas
the male thymocytes responded with an increase in CK activity only on treatment with
dihydrotestosterone (DHT). The data show no differences in ER expression between male and
females, but the receptor appears not to be functional in males. Interestingly, when estradiol was
applied to co‐cultures of lymphoid‐depleted fetal thymus (FT) explants and bone‐marrow cells,
or thymocytes, from young and old females, it resulted in increased cellularity of cultures
containing cells of the young, and not those of the old. The proportion of CD4/CD8 phenotypes
of the developing cells in these cultures was not affected by E2 treatment. These observations
provide a new insight into ER expression and function in T‐cell development in relation to
gender and age.
HLA Expression at the Maternal‐Fetal Interface
Authors: Hutter Heinz , Hammer Astrid , Dohr Gottfried , Hunt Joan S.
Published: June 2008

Pregancy in the human presents an “immunological paradox,” because of the unexpected willingness of mothers to accept genetically disparate tissues. The fact that the fetus can develop unharmed for nine months shows that protective mechanisms must exist to permit its survival. The conditions that permit the genetically dissimilar human fetus to evade rejection by its mother′s immune system have been the subject of intense interest for several decades. As the placental cells, which are in contact with maternal blood or tissue, are devoid of HLA class II antigens, interest has focused on the expression of HLA class molecules. Recent developments in the constitutive, transcriptional, and translational expression of HLA class I molecules on anatomically and morphologically different subpopulations of trophoblast cells will form the basis of this short review.
MHC‐Linked Syngeneic Developmental Preference inThymic Lobes Colonized with Bone Marrow Cells: A Mathematical model
Authors: Mehr Ramit , Perelson Alan S. , Sharp Ayala , Segel Lee , Globerson Amiela
Published: June 2008

Reconstitution of the T‐cell compartment after bone marrow transplantation depends on
successful colonization of the thymus by bone‐marrow‐derived progenitor cells. Recent studies
compared the development of syngeneic and allogeneic bone‐marrow‐derived cells in cocultures
with lymphoid‐depleted fetal thymus explants, leading to the discovery of MHC‐linked
syngeneic developmental preference (SDP) in the thymus. To determine the nature of cell
interactions among the bone marrow and thymic elements that might underlie SDP, we analyzed
this phenomenon by mathematical modeling. The results indicate that syngeneic mature T cells,
responsible for inducing this preference, probably interfere both with the seeding of allogeneic
bone‐marrow‐derived thymocyte progenitors in the thymic stroma and with their subsequent
proliferation. In addition, the possibility of augmented death among the developing allogeneic
thymocytes cannot be ruled out.
Development and Maintenance of the Gut‐Associated Lymphoid Tissue (Galt): the Roles of Enteric Bacteriaand Viruses
Authors: Cebra John J. , Periwal Sangeeta Bhargava , Lee Gwen , Lee Fan , Shroff Khushroo E.
Published: June 2008

GALT can be subdivided into several compartments: (a) Peyer′s patches (PP); (b) lamina propria
(LP); and (c) intraepithelial leukocyte (IEL) spaces. The B‐cell follicles of PP are quiescent in
neonatal and germ‐free (GF) adult mice. Germinal centers (GC), including sIgA+ blasts, appear
in the B follicles of formerly GF adult mice about 10‐14 days after monoassociation with various
gut commensal bacteria. The GC wax and wane over about a 3‐week period, although the
bacterial colonizers remain in the gut at high density. Neonatal mice, born of conventionally
reared (CV), immunocompetent mothers, display GC reactions in PP postweaning, although
pups of SCID mothers display precocious GC reactions at about 14 days of life. Normally, gut
colonization of neonates with segmented filamentous bacteria (SFB) leads to explosive
development of IgA plasmablasts in LP shortly after weaning. Commensal gut bacteria and the
immunocompetency of mothers also appears to control the rate of accumulation of primary B
cells from “virgin” B cells in neonates.

Enteric reovirus infection by the oral route can cause the activation of CD8+ T cells in the
interfollicular regions of PP and the appearance of virus‐specific precursor cytotoxic T
lymphocytes (pCTL) in the IEL spaces. Such oral stimulation can also lead to “activation” of
both CTL and natural killer (NK) cells in the IEL spaces. More normally, colonization of the gut
with SFB also leads to similar activations of NK cells and “constitutively” cytotoxic T cells.
The Influence of Costimulation and Regulatory Cd4+ T Cells on Intestinal Iga Immune Responses
Authors: Gärdby Eva , Kagrdic Dubrav , Kjerrulf Martin , Bromander Annakari , Vajdy Michael , Hörnquist Elisabeth , Lycke Nils
Published: June 2008

It is thought that IgA B‐cell differentiation is highly dependent on activated CD4+ T cells. In particular, cell‐cell interactions in the Peyer′s patches involving CD40 and/or CD80/CD86 have been implicated in germinal‐center formation and IgA B‐cell development. Also soluble factors, such as IL‐4, IL‐5, IL‐6, and TGFβ may be critical for IgA B‐cell differentiation in vivo. Here we report on some paradoxical findings with regard to IgA B‐cell differentiation and specific mucosal immune responses that we have recently made using gene knockout mice. More specifically, we have investigated to what extent absence of CD4+ T cells, relevant cytokines, or T‐cell‐B‐cell interactions would influence IgA B‐cell differentiation in vivo. Using CD4– or IL‐ 4‐gene knockout mice or mice made transgenic for CTLA4Ig, we found that, although specific responses were impaired, total IgA production and IgA B‐cell differentiation appeared to proceed normally. However, a poor correlation was found between, on the one hand, GC formation and IgA differentiation and, on the other hand, the ability to respond to T‐celldependent soluble protein antigens in these mice. Thus, despite the various deficiencies in CD4+ T‐cell functions seemingly intact IgA B‐cell development was observed.
Bidirectional Interactions Between Thymocytes and Thymic Epithelial Cell Lines in Vitro
Authors: Čolić Miodrag , Vučević Dragana , Popović Petar , Dujić Aleksandar
Published: June 2008

In vitro interactions of thymocytes and thymocyte hybridomas with cortical (R‐TNC.1) and medullary (TE‐R 2.5) rat thymic epithelial‐cell (TEC) lines were studied. It was found that the cortical line had better adhesion capability. It bound exclusively immature CD4+CD8+αβTCR10 thymocytes, induced apoptosis of a subset of these cells, and stimulhted proliferation of the BWRT (CD4-CD8-αβTCR-) hybridoma. The medullary line bound both immature and mature thymocytes, decreased their apoptosis, and induced apoptosis of the BWRT 8 (CD4+CD810αβTCRhi) hybridoma. Thymocyte differently modulated cytokine production by TEC lines, upregulating the secretion of IL‐1 by R‐TNC.1 and IL‐6 by TE‐R 2.5 cells. Finally, coculture of thymocytes with TEC lines resulted in different patterns of protein‐tyrosine phosphorylation in thymocytes. These results show the existence of mutual bidirectional interactions between thymocytes and TEC lines in vitro, but these processes differed depending on phenotypic characteristics and origin of TEC lines used.
Expression of Growth Hormone Receptors by Lymphocyte subpopulations in the Human tonsil
Authors: Thellin Olivier , Coumans Bernard , Zorzi Willy , Barnard Ross , Hennen Georges , Heinen Ernst , Igout Ahmed
Published: June 2008

The ability of human tonsillar lymphoid cells to express growth hormone receptor (hGH‐N‐R) was analyzed by flow cytometry. FITC‐coupled recombinant human growth hormone (hGH‐N) was used to reveal the receptors, in combination with phenotype markers.

Unlike T cells, tonsillar B cells constitutively express the hGH‐N receptor. Quiescent cells separated from activated cells by Percoll‐gradient centrifugation bear fewer receptors than activated ones. Activated T cells express hGH‐N‐R, but the typical germinal centre CD4+CD57+ T cells do not. These latter thus appear not to be fully activated.

Inside the lymph follicles, the germinal centre CD38+ B‐cell population and the mantle‐zone CD39+ B‐cell population display similar levels of hGH‐N‐R expression, but receptor density is lower on dividing dark‐zone CD38+CD10+ B cells.

Different lymphoid‐cell populations thus differ markedly in their ability to express the growth hormone receptor, in relation notably to their activation status. This highlights the link between the neuroendocrine system and the active immune defense.
Role of Prolactin in the Recovered T‐Cell Development ofEarly Partially Decapitated Chicken Embryo
Authors: Moreno J. , Varas A. , Vicente A. , Zapata A. G.
Published: June 2008

Although different experimental approaches have suggested certain regulation of the mammalian
immune system by the neuroendocrine system, the precise factors involved in the process are
largely unknown. In previous reports, we demonstrated important changes in the thymic
development of chickens deprived of the major neuroendocrine centers by the removal of
embryonic prosencephalon at 33‐38 hr of incubation (DCx embryos) (Herradón et al., 1991;
Moreno et al., 1995). In these embryos, there was a stopping of T‐cell maturation that resulted
in an accumulation of the most immature T‐cell subsets (CD4-CD8- cells and CD4-CD81o
cells) and, accordingly, in decreased numbers of DP (CD4+CD8+) thymocytes and mature
CD3+TcRαβ+ cells, but not CD3+TcRγδ lymphocytes. In the present work, we restore the
thymic histology as well as the percentage of distinct T‐cell subsets of DCx embryos by
supplying recombinant chicken prolactin, grafting of embryonic pituitary gland, or making
cephalic chick‐quail chimeras. The recovery was not, however, whole and the percentage of
CD3+TcRαβ thymocytes did not reach the normal values observed in 17‐day‐old control Sham‐DCx embryos. The results are discussed on the basis of a key role for prolactin in chicken T‐cell
maturation. This hormone could regulate the transition of DN (CD4-CD8-) thymocytes to the
DP (CD4+CD8+) cell compartment through its capacity for inducing IL‐2 receptor expression on
the former.
Differential Activation of CD8+ Tumor‐Specific Tc1 and Tc2 Cells by an IL‐10‐Producing Murine Plasmacytoma
Authors: Specht Christoph , Pauels Hans-Gerd , Becker Christian , Kölsch Eckehart
Published: June 2008

The involvement of counteractive CD8+ T‐cell subsets during tumor‐specific immune responses was analyzed in a syngeneic murine plasmacytoma model. CD8+ Tc cells against the immunogenic IL‐10‐producing BALB/c plasmacytoma ADJ‐PC‐5 can be easily induced by immunization of BALB/c mice with X‐irradiated ADJ‐PC‐5 tumor cells in vivo and in vitro. However, the failure of recipient mice to mount a protective Tc response against the tumor during early stages of a real or simulated tumor growth is not due to immunological ignorance,
but depends on the induction of tumor‐specific tolerance, involving a population of tumorinduced CD8+ T cells that are able to inhibit the generation of tumor‐specific Tc cells in a primary ADJ‐PC‐5‐specific MLTC, using IFN‐γ as a suppressive factor. Whereas most longterm cultivated CD8+ ADJ‐PC‐5‐specific Tc lines produce type‐1 cytokines on stimulation, at least two of them, which were derived from a primary MLTC, display a type‐2 cytokine spectrum. Furthermore, the primary in vitro Tc response against ADJ‐PC‐5 cells shows characteristics of a Tc2 response. The Tc response is strictly depending on tumor‐derived IL‐10. CD8+ Tc cells that are induced in a primary MLTC do not produce IFN‐γ, and the tumor‐specific Tc response is enhanced by IL‐4 but suppressed by IFN‐γ or IL‐12. In contrast, ADJ‐PC‐ 5‐specific CD8+ Tc cells from immunized mice are IFN‐γ producing Tc1 cells. Since the primary
in vitro Tc response against the tumor is suppressed even by the smallest numbers of irradiated ADJ‐PC‐5‐specific Tc1 cells via IFN‐γ these Tc1 cells behave similar to the suppressive CD8+ T cells that are induced during early stages of ADJ‐PC‐5 tumorigenesis.
The IL‐2/IL‐2‐Receptor Complex in the Maturation of Rat T‐Cell Progenitors
Authors: Varas Alberto , Romo Teresa , Jiménez Eva , Alonso Luis , Vicente Angeles , Zapata Agustín G.
Published: June 2008

On the basis of both the interleukin‐2‐receptor (IL‐2R) α‐chain expression on 16‐day‐old fetal rat thymocytes and the occurrence of interleukin‐2 (IL‐2) mRNA‐containing cells early during rat thymus ontogeny, we have investigated the possible role of IL‐2/IL‐2R complex in rat T‐cell maturation. For this purpose, we analyzed the effects of the addition of either recombinant rat IL‐ 2 or anti‐CD25 (OX‐39)‐blocking monoclonal antibodies to fetal thymus organ cultures (FTOC), established from 16‐day‐old rat embryos. IL‐2 stimulated the growth of thymocytes and, as a result, induced T‐cell differentiation, whereas OX‐39 mAb blocked the maturation of thymic‐cell progenitors. Accordingly, these results support the involvement of IL‐2/IL‐2R complex in rat Tcell
development.
A Developmental Bias in Reading Frame Usage by HumanFetal Thymic TCRBDJ Transcripts is not Present inGenomic TCRBDJ Rearrangements
Authors: George James F. , Matsuura Yasushi , Byrne Jacquelyn A. , Liu Eugene L. , Shaw Denise R. , Kearney John F.
Published: June 2008

We have previously reported that reading‐frame usage and functional diversification is developmentally
regulated, with virtually all TCRB DJ mRNA transcripts using a single reading
frame at 8 weeks of gestational age, tapering to 50% by adult life. We used the polymerase
chain reaction to create genomic libraries of DJ rearrangements in the TCRB locus from thymuses
at 7.7, 10, and 16 weeks of gestational age, and from adult thymuses. Clones were randomly
picked and sequenced to determine junctional sequences and reading‐frame
utilization. The resulting data address the hypothesis that cells bearing genomic joints in reading
frame one are preferentially selected during fetal life. This hypothesis predicts that reading‐
frame bias would also be observed among genomic DJ joints. Instead, we observed
random utilization of the three possible D‐region reading frames among genomic D1s1 =>
J1s1 joints during fetal life. Similar results were obtained at 7.7 weeks of gestational age in a
second thymus in which both RNA and DNA were simultaneously isolated and used to create
libraries of TCRBDJ transcripts or rearrangements. We conclude that reading‐frame utilization
is random among genomic D1s1‐JB1s1 rearrangements and that the preferential usage of
a single reading frame among mRNA transcripts of TCRB DJ transcripts is the result of preferential
transcription of genomic TCRB DJ joints in a single reading frame, or that TCRB DJ
transcripts have a longer half‐life than transcripts in reading frames two or three.
A Mouse with a Monoclonal Primary lmmunoglobulinRepertoire not Further Diversified by V‐GeneReplacement
Authors: Cascalho Marilia , Martin Denise A. , Wong Jamie , Lam Queenie , Wabl Matthias , Wu Gillian E.
Published: June 2008

We have generated a monoclonal B‐cell mouse by introducing homozygous, nonfunctional
RAG‐2 alleles and a λ1 light‐chain transgene into the quasi‐monoclonal (QM) mouse, which
contains a “knocked‐in” VHDJH rearrangement. Thus, this mouse, which we call MonoB, is
devoid of T cells and contains preformed heavy‐ and light‐chain genes encoding immunoglobulin
with an anti‐NP specificity. The MonoB mouse allows us to examine immunoglobulin
diversity in the absence of processes mediated by V(D)J recombination and T cells. Here we
report that not only is the MonoB′s primary immunoglobulin repertoire monoclonal, but also
that its secondary repertoire is not further diversified by V‐gene replacement or gene conversion.
Among 99 heavy‐chain and 41 λ light‐chain genes from peripheral B cells of the
MonoB mouse, there were no V‐gene replacements. When compared to the QM mouse,
which has RAG activity, and for which V‐gene replacement is the major diversifying mechanism,
these data suggest that V‐gene replacement is mediated by V(D)J recombination and
not by other recombination systems.
Identification of Thymus Specific and DevelopmentallyRegulated Genes by an Improved Version of the mRNADifferential Display Technique
Authors: Pascolo Steve , Tsoukatou Debbie , Mamalaki Clio
Published: June 2008

During embryogenesis in mouse, the thymus is seeded by waves of hematopoietic stem cells
that provide the first peripheral T lymphocytes after birth. It is known that embryo thymocytes
and adult thymocytes have different phenotypic and functional features. The identification
of genes expressed in the thymus only during embryogenesis would help to understand
the molecular basis underlying these characteristics. We used the mRNA differential display
technique to compare gene expression between thymus and kidney from embryo (171/2 days)
and adult mice. This technique is the method of choice for comparing gene expression
because it is able to display rapidly and simultaneously the mRNA complement from several
different types of cells. The major drawback of the method is that it leads to the cloning of
many false positives and therefore needs a high throughput method to screen for the truly differentially
expressed cDNAs. We combined advantages from previously described methods
in order to develop a new version of the mRNA differential display technique that is fast,
cheap, and reliable. Instead of oligo dT priming, we used random hexameres for the reverse
transcription of total RNA and 10‐mer primers for the amplification of internal parts of the
cDNAs. We obtained reproducible and clean patterns of discrete bands. We were able to easily
identify DNAs differentially amplified between embryo and adult tissues (embryo specific;
E 58.73), between thymus and kidney (thymus specific; Thy 52.54), or between embryo
and adult thymus (embryo thymus specific; E Thy 58.73) cDNA fragments. After reamplification,
cloning, and sequencing of these DNA fragments, it appeared that in most cases, one
band corresponded to a single DNA sequence. On a northern blot, each of these candidate
genes recognized a transcript that is differentially expressed as expected. Thus, we report an
optimized, reproducible, and fast mRNA differential display method that overcomes the usual
problems met with the originally described technique or its reported modifications.
Effects of the Japanese Herbal Medicine “Sho‐saiko‐to”(TJ‐9) on Interleukin‐12 Production in Patients withHCV‐Positive Liver Cirrhosis
Authors: Yamashiki Masayoshi , Nishimura Akira , Huang Xian-Xi , Nobori Tsutomu , Sakaguchi Seigo , Suzuki Hiroyuki
Published: June 2008

Interleukin‐12 (IL‐12) is an important cytokine for maintainence of normal systemic defense
and bioregulation. The Japanese herbal medicine Sho‐saiko‐to (TJ‐9) has been administered
to 1.5 million Japanese patients with chronic liver diseases. TJ‐9 is known to significantly
suppress cancer development in the liver and has macrobiotic effects. In the present study, we
examined the in vitro production of IL‐12 by circulating mononuclear cells from liver cirrhosis
patients and the effects of TJ‐9 on IL‐12 production.

The monocyte/macrophage fraction and the lymphocyte fraction of peripheral blood were
obtained from 11 HCV‐positive liver cirrhosis patients and 12 healthy subjects. Interleukin‐12
levels in the supernatants were measured using ELISA kits. The levels of IL‐12 produced by
the patients fractions were significantly lower than those produced by healthy subjects (p <
0.01, p < 0.05). However, when TJ‐9 was added to the cultures, the IL‐12 production levels in
both cell fractions increased approximately three fold, and the levels from the monocyte/macrophage
fraction were almost the same as those from healthy subjects. This effect of TJ‐9 was
attributable to two of its seven herb components, that is, scutellaria root and glycyrrhiza root.
One possible mechanism for the macrobiotic effects of TJ‐9 on liver cirrhosis patients may be
the improvement in IL‐12 production.
Uterine Cytokine Production During the Menstrual Cycle and Preimplantation Stages in Mice
Authors: Athanassakis Irene , Farmakiotis Vagia , Papadimitriou Lina
Published: June 2008

Female reproduction is the only system subjected to well defined periodic changes. The final
stage of the menstrual cycle in mammals is the maturation of the ovum and the preparation of
the female organism to support fetal development fertilization. Once pregnancy occurs, both
maternal and fetal sites emit regulatory signals to ensure embryo development and maternal
protection against a graft versus host (GvH) reaction initiated by the semi‐allogeneic fetus.
We and others have previously shown that each day of fetal development in mice is characterized
by different cytokine production, detected not only at the proximity of the feto‐placental
unit (decidua, uterus), but also in maternal lymphoid organs (spleen), as well as in the
serum. In the present study, we concentrated on the menstrual cycle and the preimplantation
stages of pregnancy and defined the levels of GM‐CSF, IL‐10, IL‐6, and IL‐3 in the murine
uterus during anoestrus, proestrus, oestrus, and second and third day of gestation. We show by
immunofluorescence and ELISA techniques that GM‐CSF is maintained at high levels during
anoestrus, proestus, oestrus, and the second day of pregnancy while dropping on the third day.
IL‐3 levels are found elevated during proestrus, second and third day of gestation, IL‐6
increases essentially during proestrus, whereas the production of IL‐10 was detected during
oestrus and the early stages of pregnancy. Immunoperoxidase staining on frozen sections of
uteri during the early gestational period localize GM‐CSF and IL‐3 production in the
endometrium, IL‐10 in the endometrium on the second day of pregnancy, and
endometrium/myometrium on the third day. Low levels of IL‐6 could be detected in the
endometrium/epithelium on the second day and endometrium/myometrium on the third day
of gestation. The role of IL‐3, IL‐10, and, to a lesser degree, IL‐6 is fortified by the embryo
itself, since these cytokines were found to be produced by blastocysts as well. These results
demonstrate the existence of a specific distribution of lymphokines within the uterine tissue,
the role of which is being discussed.
The Involvement of Laminin in Anti‐Myocardial CellAutoimmune Response in Murine Chagas Disease
Authors: Silva-Barbosa Suse Dayse , Savino Wilson
Published: June 2008

The pathogenesis of chronic chagasic cardiomyophathy associated with Chagas disease is
still controversial, although evidence indicates a T cell‐dependent autoimmune process.
Using a mouse model for chronic Chagas disease, we previously evidenced that hearts grafted
within the ears of Trypanosoma cruzi infected syngeneic recipients were rejected through a
CD4+ T cell‐dependent mechanism. Moreover, we showed that such a process was dependent
on laminin‐mediated interactions, since it could be abrogated by anti‐laminin or anti‐laminin
receptor antibodies. In this review the same passive cell transfer model is considered for discussion:
the participation of the laminin alteration in the composition of the inflammatory
infiltrate formed in response to the antimyocardial autoreactive CD4+ T cells, as well as the
presence of laminin‐binding cytokines. Finally we suggest the existence of a relationship
between the inflammatory infiltrate, the laminin contents and deposition of pro‐inflammatory
laminin‐binding cytokines, which may act in concert during the generation of Chagas disease‐
related cardiomyophathy.
“Galectin‐1 Induces Central and Peripheral Cell Death:Implications in T‐Cell Physiopathology”
Authors: Sotomayor C. E. , Rabinovich G. A.
Published: June 2008

The immune system has a remarkable capacity to maintain a state of equilibrium even as it
responds to a diverse array of foreign proteins and despite its contact exposure to self‐antigens.
Apoptosis is one of the mechanisms aimed at preserving the homeostasis after the completion
of an immune response, thus returning the immune system to a basal state and
warranting the elimination of autoagressive cells in both central and peripheral lymphoid
organs. Targeted deletions in critical genes involved in the apoptotic death machinery
together with natural spontaneous mutations have clearly shown the importance of apoptosis
in the regulation of the immune response. This complex scenario of stimulatory and inhibitory
genes has been enriched with the finding that galectin‐1, a 14.5 kDa β‐galactoside‐binding
protein, is able to induce apoptosis of immature cortical thymocytes and mature T cells by
cross‐linking cell surface glycoconjugates. Galectin‐1 is present not only in central and
peripheral lymphoid organs, but also at sites of immune privilege. In the present article we
will discuss the implications of galectin‐1‐induced apoptosis in T‐cell physiopathology in an
attempt to validate its therapeutic potential in autoimmune and inflammatory diseases.
In Vitro Studies on the Trafficking of Dendritic CellsThrough Endothelial Cells and Extra‐Cellular Matrix
Authors: Bianchi Giancarlo , D′amico Giovanna , Varone Luisella , Sozzani Silvano , Mantovania Alberto , Allavena Paola
Published: June 2008

Dendritic cells (DC) are antigen presenting cells (APC) with the unique ability to initiate an
immune response. Immature DC are localized in peripheral tissues where they exert a sentinel
function for incoming antigens (Ag). After Ag capture and exposure to inflammatory stimuli
DC undergo maturation and migrate to regional lymph nodes where the presentation of antigenic
peptides to T lymphocytes takes place. Thus their correct functioning as APC involves
localization in tissues and trafficking via the lymph or blood to lymphoid organs. In the
present study we have investigated the ability of DC to interact in vitro with human vascular
endothelial cells (EC) and extracellular matrix (ECM). DC are differentiated from monocytes
by in vitro exposure to GM‐CSF and IL‐13 for 7 days. In adhesion assays a considerable proportion
of DC binds to resting EC monolayers and this adhesion is inhibited by anti‐CD11a
and CD11b, but not anti‐CD11c mAbs. Binding to a natural ECM, derived from cultured EC
involves VLA‐4 and VLA‐5 integrins. In a transmigration assay, 10 % of input cells are able
to cross the EC monolayer in the absence of exogenous stimuli. The amount of DC transmigrated
through a monolayer of EC was increased of 2‐3 fold by C‐C chemokines RANTES,
MIP1α, and MIP‐1β. Most importantly, in view of the trafficking pattern of these cells, a significant
proportion of DC can migrate in a reverse transmigration assay, i.e. across the
endothelial basement membrane and subsequently, across endothelial cells. Upon exposure to
immune or inflammatory signals peripheral DC undergo maturation and migration to lymphoid
organs. Functional maturation is associated with loss of responsiveness to chemokines
present at sites of inflammation (e.g. MIP1α, MIP1β and RANTES) and acquisition of a
receptor repertoire which renders these cells responsive to signals which guide their localization
in lymphoid organs (e.g. MIP3β). A better understanding of the molecular basis of DC
trafficking may provide molecular and conceptual tools to direct and modulate DC localization
as a strategy to upregulate and orient specific immunity.