bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient Developmental Expression of IgY andSecretory Component like Protein in the Gut of theAxolotl (Ambystoma mexicanum )
Authors: Fellah J. S. , Iscaki S. , Vaerman J. P. , Charlemagne J.
Published: June 2008

We previously reported that a primitive vertebrate, the Mexican axolotl (Amphibian,
Urodela) synthesizes two classes of immunoglobulins. IgM are present in serum early in
the development, and represent the bulk of specific antibody synthesis after an antigenic
challenge. IgY occur in the serum later during the development, and are relatively
insensitive to immunization.
We demonstrate in the present work, using immunofluorescence with specific Mabs,
that IgY are expressed in the gut epithelium, as secretory molecules. Secretory IgY are
well expressed in the stomach and intestinal mucosae of young animals from 1 month
after hatching to the seventh month. Thereafter, IgY progressively disappear from the
gut and become readily detectable in the serum of 9‐month‐old preadult
immunologically mature animals.
Axolotl IgY are closely associated in the gut to secretory component‐like (SC)
molecules that are well‐recognized by antisera to the SC of different mammalian species.
This is the first description, in a primitive tetrapode, of an immunoglobulin class that
could be the physiological counterpart of mammalian IgA.
Thymus Ontogeny in Frogs: T‐Cell Renewal atMetamorphosis
Authors: Rollins-Smith Louise A. , Blair Patrick J. , Davis A. Tray
Published: June 2008

Metamorphosis in amphibians presents a unique problem for the developing immune
system. Because tadpoles are free‐living, they need an immune system to protect against
potential pathogens. However, at metamorphosis, they acquire a variety of new adultspecific
molecules to which the tadpole immune system must become tolerant. We
hypothesized that Xenopus laevis tadpoles may avoid potentially destructive antiself
responses by largely discarding the larval immune system at metamorphosis and
acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we
examined the influx and expansion of host T‐cell precursors in the donor thymus of
normally metamorphosing and metamorphosis‐inhibited frogs. We observed that donor
thymocytes are replaced by host‐derived cells during metamorphosis, but inhibition of
metamorphosis does not prevent this exchange of cells. The implanted thymuses export
T cells to the spleen. This donor‐derived pool of cells declines after metamorphosis in
normally developing frogs but is retained to a greater extent if metamorphosis is
inhibited. These studies confirm previous observations of a metamorphosis‐associated
wave of expansion of T cells and demonstrate that it is not dependent on the relatively
high concentrations of thyroid hormones required for metamorphosis. Although some
larval T cells persist through metamorphosis, others may be destroyed or the larval
population is significantly diluted by the expanding adult population.
Expression of GATA‐3 During Lymphocyte Differentiation and Mouse Embryogenesis
Authors: Oosterwegel Mariëtte , Timmerman Janneke , Leiden Jeffrey , Clevers Hans
Published: June 2008

The GATA family of C4 zinc‐finger transcription factors has been implicated in tissuespecific
gene regulation in birds and mammals. One of the members of this family,
GATA‐3, is reportedly expressed specifically in the T‐cell lineage, where it interacts with
GATA motifs in the TCR‐αα, TCR‐β/, and TCR‐δ enhancers, thereby controlling the T‐cell
phenotype. To evaluate the differentiation control properties of GATA‐3, we have now
documented its expression pattern during lymphoid differentiation and murine
embryogenesis.

The onset of GATA‐3 expression in the lymphoid lineage was studied in a panel of
lymphoid (precursor) cell lines by Northern blot analysis. GATA‐3 was uniquely
expressed in T‐lineage lymphocytes expressing TCR and CD3 genes; it was absent from
TCR/CD3 mRNA‐negative prothymocytes and from all B‐lineage cells.

In order to obtain information on the expression of GATA‐3 outside the immune
system, in situ hybridization was performed on mouse embryos on day 11.5‐14.5 of
gestation. GATA‐3 mRNA was detected in fetal thymus and in erythroid cells. Outside
the haemopoietic system, we detected GATA‐3 mRNA throughout the central nervous
system, in kidney, in the epidermis, lens fibers, the inner ear, whisker follicles, and in
the primary palate.

These data provide new clues about the potential role of GATA‐3 during mouse
development, and will aid the interpretation of currently ongoing gene knockout
experiments.
Changes in the Amphibian Antibody Repertoire are Correlated WithMetamorphosis and not With Age or Size
Authors: Hsu Ellen , Pasquier Louis Du
Published: June 2008

Tadpole and adult Xenopus, manipulated to be of comparable size, exhibited stagespecific
antibody expression. The production of adult‐type higher‐affinity anti‐DNP
antibodies proved to be independent of the age and size of the individual and is
concomitant with the completion of metamorphosis. The appearance of new antibody
specificities at such a time suggests that their expression occurs with the cell turnover
and renewal during a period of morphological changes.
The Acquisition of a Memory Phenotype by Murine CD4+ T Cells Is Accompanied by a Loss in Their Capacity to Increase Intracellular Calcium
Authors: Nagelkerken Lex , Hertogh-Huijbregts Anita
Published: June 2008

During the process of aging, the fraction of CD4+ T Cells with a naive phenotype, that is,
Pgp‐1- CD45RBHighMEL‐14+, decreases in favor of CD4+ T memory cells. Total CD4+ T
cells from aged mice displayed a diminished calcium response to anti‐CD3 and even
ionomycin as compared to the cells from young mice, and this was related to the
changed composition of the CD4+ T‐cell population. Regardless the age of the donor
mice, naive CD4+ T cells effectively increased intracellular calcium, whereas memory
CD4+ T cells were impaired in this regard. In addition, a heterogeneity in the
differentiation stage of the naive CD4+ T cells was shown by the observation that
calcium mobilization in naive CD4+ T cells from young mice was more profound than
that in their aged counterparts. These data thus indicate that during the acquisition of a
memory phenotype, murine CD4+ T cells lose the capacity to increase intracellular
calcium, which in turn may be responsible for the decreased level of IL‐2 production by
these cells.
Lineage Switch Macrophages Can Present Antigen
Authors: Bretz James D. , Chen Shu-Chih , Redenius Diane , Chang Hsun-Lang , Esselman Walter J. , Schwartz Richard C.
Published: June 2008

Recent reports of “lineage switching” from a lymphoid to macrophage phenotype have
left unresolved the question of whether such cells are functional macrophages or
nonfunctional products of differentiation gone awry. This study demonstrates that
several “macrophage‐like” cell lines derived from v‐Ha‐ras‐transformed pre‐B cells have
gained the capacity to effectively present antigen in MHC‐restricted fashion. Using an
assay involving the cocultivation of putative antigen‐presenting cells with chicken
ovalbumin (cOVA) and a cOVA‐specific T‐cell hybridoma, “lineage switch” cell lines
were found to present antigen as effectively as macrophage‐containing peritoneal
exudates. Neither the original pre‐B‐cell precursors nor B‐cell lymphomas derived from
them present antigen. Thus, we have demonstrated that these “lineage switch”
macrophages are capable of antigen presentation, a mature differentiated function.
While gaining macrophage characteristics, these cells have also rearranged their
kappa light‐chain immunoglobulin locus, suggesting that macrophage differentiation
and immunoglobulin rearrangement are not mutually exclusive processes. The existence
of both lymphoid and myeloid characteristics in a cell fully capable of antigen
presentation suggests greater plasticity in hematopoietic lineage commitment than
conventionally thought to be the case.
Lack of Peripherally Induced Tolerance to Established Skin Allografts in Immunologically Reconstituted Scid Mice
Authors: Rajan T. V. , Shultz Leonard D. , Greinert Dale L.
Published: June 2008

The mechanism by which the antigen‐specific immune system distinguishes between
foreign antigens (toward which it mounts an immune response) and self‐antigens (of
which it is tolerant) is not completely understood. Studies using “superantigens” and
transgenic mice have allowed investigations into some of the mechanisms of clonal
deletion, anergy, and peripheral tolerance. In the present report, we have attempted to
develop a new model system to investigate the possible mechanism(s) of peripheral
tolerance to allografts. In this system, skin grafts from C57BL/6J (B6; H‐2b mice are
grafted onto T‐ and B‐lymphocyte‐deficient C.B‐17‐scid/scid (H‐2d; hereafter referred to
as scid) mice. Because of their lack of functional lymphocytes, the scid mice readily
accept the allogeneic skin grafts. After the allografts healed, the scid mice were
reconstituted with T‐cell‐deficient fetal liver from coisogeneic C.B‐17‐∤/∤ mice or bone
marrow from weanling congenitally athymic BALB/c‐nu/nu (H‐2d; hereafter referred to
as nude) mice. Upon immunological reconstitution, the scid mice reiected the established
B6 skin allografts, suggesting that an immune system developing in the presence of an
intact peripheral skin allograft fails to develop tolerance to the peripheral allograft. This
model system may be useful for the study of the mechanisms required for the induction
of peripheral tolerance.
Phenotypic Characterization of Chicken Thymic Stromal Elements
Authors: Boyd Richard L. , Wilson Trevor J. , Bean Andrew G. , Ward Harry A. , Gershwin M. Eric
Published: June 2008

Phenotypic profiles of the thymic stromal components provide an excellent approach to
elucidating the nature of the microenvironment of this organ. To address this issue in
chickens, we have produced an extensive panel of 18 mAb to the thymic stroma. These
mAb have been extensively characterized with respect to their phenotypic specificities
and reveal that the stromal cells are equally as complex as the T cells whose maturation
they direct. They further demonstrate that, in comparison to the mammalian thymus,
there is a remarkable degree of conservation in thymic architecture between
phylogenetically diverse species. Eleven mAb reacted with thymic epithelial cells: MUI‐73 was panepithelium, MUI‐54 stained all cortical and medullary epithelium but only a
minority of the subcapsule, MUI‐52 was specific for isolated stellate cortical epithelial
cells, MUI‐62, ‐69, and ‐71 were specific for the medulla (including Hassall’s corpusclelike
structures), MUI‐51, ‐53, ‐70, and ‐75 reacted only with the type‐I epithelium, or
discrete regions therein, lining the subcapsular and perivascular regions and MUI‐58
demonstrated the antigenic similarity between the subcapsule and the medulla. Seven
other mAb identified distinct isolated stromal cells throughout the cortex and medulla.
Large thymocyte‐rich regions, which often spanned from the outer cortex to medulla,
lacked epithelial cells. These mAb should prove invaluable for determining the
functional significance of thymic stromal‐cell subsets to thymopoiesis.
A New Marker on Chicken Hematopoietic Cells isDefined by a Monoclonal Antibody Raised Against a V ßChain of the Human TCR
Authors: Lacoste-Eleaume Anne-Sophie , Bleux Christian , Corbel Catherine , Carriere Dominique , Poncelet Philippe , Kanellopoulos Jean , Kanellopoulos-Langevin Colette
Published: June 2008

In this paper, we show that a mouse monoclonal antibody, 111‐427, specific for the V ß 5.3 chain of the human T‐cell receptor (TCR) for antigen, also reacts with chicken
hematopoietic cells. Our data indicate that the majority of 111‐427 positive cells among
peripheral blood leucocytes (PBL) are thrombocytes. This antibody also recognizes two
in vitro cell lines, III‐C5, an IL‐2‐dependent T‐cell‐line and HD11, a macrophage cell line.
In addition, erythrocytes and a minor subpopulation of thymus and spleen cells are also
stained by the monoclonal antibody (mAb). No specific immunoprecipitation could be
detected from 125I radiolabeled cell lysates. By Western blotting techniques, the 111‐
427 mAb identifies a single band of apparent molecular weight 91 kD, unaffected by
reduction, from III‐C5 and HD11 cell lysates. This band is absent in negative cell control
lysates. On thrombocytes, the apparent molecular weight of the band is shifted to 87 kD.
These results indicate that the mAb does not recognize the chicken T‐cell receptor for
antigen, but a cell surface marker shared primarily between thrombocytes and
erythrocytes. This new chicken cell marker is compared to other cell surface markers in
avian or mammalian species that present some analogies in their tissue distribution.
Serum Amyloid P Component (SAP)‐Like Protein From Botryllid Ascidians Provides a Clue to Amyloid Function
Authors: Scofield V. L. , Puntambekar L. , Schluter S. F. , Coombe D. R.
Published: June 2008

The HA‐1 lectin isolated from Botrylloides leachii has an amino acid composition similar
to that of mammalian serum amyloid protein (SAP). SAP is a universal component of
mammalian amyloid deposits. Like SAP, HA‐1 has a disc ultrastructure, and antibody to
HA‐1 binds both (a) to amyloidlike fibers deposited between rejected Botrylloides
colonies and (b) to cerebral amyloid deposits in Alzheimer′s disease brains. Deposition
of protochordate amyloid within rejection sites and surrounding fouling organisms
implies that these fibers function as barriers to allogeneic and infectious challenge.
Similarly, mammalian amyloid may also function to contain inflammatory lesions and
to limit the spread of certain infections. Pathological amyloidotic conditions in humans,
such as Alzheimer′s disease, may result from unregulated expression of this primitive
encapsulation response.
Pathogenetic Significance of Fetal‐Type Acetylcholine Receptors onThymic Myoid Cells in Myasthenia Gravis
Authors: Geuder Kerstin I. , Marx Alexander , Witzemann Veit , Schalke Berthold , Toyka Klaus , Kirchner Thomas , Müller-Hermelink Hans-Konrad
Published: June 2008

To investigate the role of thymic myoid cells in the pathogenesis of myasthenia gravis
(MG), mRNA of nonneoplastic thymuses from eight MG patients was analyzed by dot
blot hybridization for the occurrence of acetylcholine receptor (AChR) subunit
transcripts, using the five AChR‐subunit cDNAs (alpha, beta, gamma, delta, and
epsilon) as probes. Attention was particularly paid to the gamma‐ and epsilon‐subunit
transcripts that specify fetal‐ or adult‐type AChR. In all eight thymuses, transcripts of
the alpha‐, beta‐, gamma‐, and delta‐subunit genes were detected. Relative
autoradiographic signal intensities correlated with the frequencies of thymic myoid cells
as determined by immunostaining with anti‐AChR monoclonal antibodies. In only one
of these thymuses were transcripts of the epsilon‐subunit gene detected in addition to
those of the other subunit genes. Four MG‐associated thymomas without myoid cells
were devoid of any AChR‐subunit mRNA. Our findings imply that fetal‐type AChR is
expressed in MG thymuses as a rule, whereas adult‐type AChR is coexpressed with it
only in a minority of cases. A similar pattern of cotranscription is known to occur at
certain stages of muscle development, and can be found in human rhabdomyosarcomas
with an intermediate stage of myogenesis. Because the serum autoantibodies of MG
patients exhibit preferential reactivity with fetal AChRs, the presence of fetal AChRs in
the thymus provides circumstantial evidence for an active involvement of thymic myoid
cells in the autoimmune process.
Analysis of Immature (CD4–CD8–) Thymic Subsets in T‐Cell Receptorαß Transgenic Mice
Authors: Wilson Anne , Pircher Hanspeter , Ohashi Pamela , Macdonald H. Robson
Published: June 2008

Introduction of a transgenic αß TCR (Vα2, Vß8.1) specific for lymphocytic
choriomeningitis virus (LCMV), in the context of H‐2Db into the genome of C57BL/6
mice, has many effects on the development and selection of T cells in both the thymus
and the periphery. These mice produce increased numbers of CD4–8+ mature T cells, all
of which express the transgenic TCR, and small numbers of CD4–8+cells using
endogenous TCRs are also produced. This study follows the intrathymic development
of T cells in these TCR αß transgenic mice, in particular the earliest CD4–8– stages. As
expected, the transgenic TCR is expressed on the cell surface at an earlier developmental
stage than endogenous TCRs in nontransgenic littermate controls. Of the three major
subsets expressing the heat–stable antigen (HSA), only the most mature, the
CD25–CD44– expresses the transgenic TCR, and the earlier CD25–CD44+ and
CD25+CD44– do not. Furthermore, in contrast to other TCRαßtransgenic lines, TCR γδ
lineage cells appear to develop normally.
Analysis by in Situ Hybridization of Cells Expressing mRNA forTumor‐Necrosis Factor in the Developing Thymus of Mice
Authors: Deman Johanne , Martin Marie-Thérèse , Delvenne Philippe , Humblet Chantal , Boniver Jacques , Defresne Marie-Paule
Published: June 2008

We have used in situ hybridization to investigate the expression of TNF‐α genes by
thymic cells during fetal development in mice. In 14‐day‐old fetal thymuses, very scarce
cells produce TNF‐α mRNA. A second phase of cytokine gene expression starts on day
16. The density of positive cells progressively increases up to day 20. Thymuses at 15
days of gestation and after birth do not express detectable cytokine mRNA. In an
attempt to identify the nature of the TNF‐α mRNA‐producing cells, acid phosphatase
activity, which is characteristic of the macrophage lineage, was studied in the same
thymuses. Acid phosphatase‐positive cells only appear on day 15. Their frequency
increases up to birth. However, no correlation can be established between acid
phosphatase—and TNFα mRNA— positive cells. The results indicate that a small subset
of thymic cells is responsible for TNF‐α mRNA production during ontogeny: These cells
are not yet identified. The possible role of TNF‐α in thymic ontogeny is discussed.
The Involvement of the Intestinal Microflora in theExpansion of CD4+ T Cells with a‐Naive Phenotype inthe Periphery
Authors: Dobber Ruud , Hertogh-Huijbregts Anita , Rozing Jan , Bottomly Kim , Nagelkerken Lex
Published: June 2008

It is well known that immune reactivity declines with age. Recently, we demonstrated
that the age‐related decrease in IL‐2 production by CD4+ T cells was accompanied by an
increased production of IL‐4 and interferon‐γ,(IFN‐γ). This age‐related shift in the profile
of lymphokine production was related to phenotypic changes within the CD4+ T‐cell
subset, that is, a decrease in the percentage of CD45RB++ CD4+ T cells and an increase in
the percentage of Pgp‐1+ CD4+ T cells. To study whether these age‐related changes were
due to previous antigenic exposure, we performed a phenotypic and functional analysis
on splenic CD4+ T cells isolated from individual, germ‐free (GF), specific pathogen‐free
(SPF), and clean conventional (CC) mice. Interestingly, the total number of splenic CD4+
T cells in GF mice was twofold lower as compared to age‐matched SPF or CC mice,
regardless whether mice were analyzed at young (10 weeks) or at advanced age (13‐14
months). Unexpectedly, the phenotypic composition of the CD4+ T‐cell subset was
comparable in the GF, SPF, and CC mice as determined by the expression of CD45RB
and Pgp‐1, indicating that CD4+ T cells with a naive phenotype (CD45RB++ Pgp‐1 –) were
not enriched in GF mice. Moreover, at an age of 13–14 months, CD4+ T cells from GF
mice frequently produced more IL‐4 and IFN‐γ, than their CC counterparts. These
lymphokine data showed, therefore, that a relatively high proportion of CD4 T cells
with a memory phenotype can also be defined in GF mice on the basis of their function.
The contamination of GF mice with a colonization resistant factor (CRF flora) resulted
in twofold higher numbers of splenic CD4+ T cells. Surprisingly, not only CD4+ T cells
with a memory phenotype (CD45RB–/+ Pgp‐1++) had expanded, but also CD4+ T cells
with a naive (CD45RB++ Pgp‐1–) phenotype. Our results, therefore, strongly suggest that
the expansion of naive CD4+ T cells in the periphery is mediated by the intestinal
microflora.
Lymphocyte Subpopulation Number and Function inInfancy
Authors: Stern Debra A. , Hicks Mary Jane , Martinez Fernando D. , Holberg Catharine J. , Wright Anne L. , Pinnas Jacob , Halonen Marilyn , Taussig Lynn M.
Published: June 2008

Normal values for percentages of lymphocyte subpopulations and functional responses
to mitogen stimulation in infancy are not well established. In the present study,
lymphocyte subpopulations were examined in umbilical cord blood samples and in
peripheral blood samples drawn before 7 and 24 months of age (mean age 10.4 months)
from a healthy population of infants born in Tucson, Arizona. Results indicate
significant increases occurred from birth to later infancy in the percentages of total T
cells (CD3), T‐cell subsets (CD4, CD8) and B cells (CD20). The CD4/CD8 ratio and the
functional responses to ConA and PWM mitogens significantly decreased from birth to
later infancy. PHA responsiveness did not show a significant change. Results from
cross‐sectional analyses (n=271) were supported in a smaller longitudinal subset (n=37).
There were no detectable ethnic‐ or gender‐related differences in cord blood or samples
obtained in later infancy. The normal values established in this study will be useful in
studies of immune‐system maturation and in the clinical evaluation of newborns,
infants, and toddlers suspected of either acquired or congenital immune‐deficiency
states.
Thymic Involution in Viable Motheaten (meυ) Mice isAssociated with a Loss of Intrathymic Precursor Activity
Authors: Hayes Sandra M. , Shultz Leonard D. , Greiner Dale L.
Published: June 2008

Mice homozygous for the viable motheaten (meυ) allele manifest abnormalities in
thymocytopoiesis, are severely immunodeficient, and develop autoimmune disorders
early in life. Premature thymic involution occurs in meυ/meυ mice, and their bone marrow
prothymocytes are unable to repopulate the thymus of adoptive recipients following
intravenous (i.v.) transfer. However, analysis of thymocytopoiesis following intrathymic
(i.t.) adoptive transfer of bone marrow from meυ/meυ mice demonstrates the presence of
normal numbers of prothymocytes. To investigate intrathymic development in meυ/meυ
mice, we determined intrathymic precursor cell number and activity. Dual labeling
analyses showed that an involuted meυ/meυ thymus is relatively enriched (fivefold) in
CD4– CD8– thymocytes (intrathymic precursor phenotype) compared with wild‐type
(+/+) thymus. However, thymocytes from meυ/meυ mice were deficient in precursor
activity when adoptively transferred i.t. into irradiated recipients. Thymocytes
recovered from the involuted thymus of aged or steroid‐treated normal mice also
displayed reduced precursor activity. However, the phenotypic profile of thymocyte
subsets from steroid‐treated mice was enriched in single positive cells (mature
phenotype) and was distinctly different from the subset distribution of thymocytes in
meυ/meυ and aged mice. These results suggest that intrathymic precursor activity in
meυ/meυ mice is decreased, and may be reflective of decreased prothymocyte seeding to
the thymus in vivo, In addition, the results suggest that the thymic involution in meυ/meυ
mice is not due solely to effects of corticosteroids.
Defects in Thymocyte Differentiation and Thymocyte‐ Stromal Interactions in the Trisomy 16 Mouse
Authors: Ewart Janet L. , Auerbach Robert
Published: June 2008

We have
examined fetal thymic development in the trisomy 16 (Ts16) mouse,
which is considered to be a model for human trisomy 21, or Down
Syndrome. The Ts16 thymus contains 10 to 20% of the number of
lymphocytes found in a normal thymus at a comparable stage.
Expression of thymocyte differentiation markers (Thy‐1, CD5, CD8,
CD4, CD3, and HSA) is severely affected in Ts16 fetuses aged
14–18 gestational days. When thymuses from 14‐day Ts16 mice were
cultured in vitro, these markers eventually
reached levels of expression comparable to those seen in normal
thymuses in culture. On the other hand, expression of CD44 appears
to be unaffected in Ts16 thymuses in vivo, but
declines in vitro relative to normal thymuses.
Reconstitution of depleted thymic stroma with thymocytes showed
evidence of defects in both developmental
compartments.
Developmental Regulation of Sialoadhesin (Sheep ErythrocyteReceptor), a Macrophage‐Cell Interaction Molecule Expressed inLymphohemopoietic Tissues
Authors: Morris Lynn , Crocker Paul R. , Hill Maxine , Gordon Siamon
Published: June 2008

Stromal macrophages in lymphohemopoietic tissues express novel macrophagerestricted
plasma membrane receptors involved in nonphagocytic interactions with
other hemopoietic cells. One such receptor with lectinlike specificity for sialylated
glycoconjugates on sheep erythrocytes and murine hemopoietic cells has been
characterized immunochemically and termed sialoadhesin. We have examined
sialoadhesin expression during mouse development to learn more about its regulation
and function. Immunocytochemical, rosetting, and Western blot studies show that
sialoadhesin is first detected on fetal liver macrophages on day 18 of development, 7
days after numerous F4/80+ macrophages are found within erythroblastic islands. In
spleen and bone marrow, sialoadhesin appears between day 18 and birth, in parallel
with myeloid development. Strongly labeled macrophages in the marginal zone of
spleen, characteristic of adult lymphoid tissues, appeared gradually between 1–4
Isolation of fetal liver macrophages at day 14 confirmed that sialoadhesin was not
involved in the binding of erythroblasts, which is mediated by a distinct cationdependent
receptor (Morris et al., 1988, p. 649). Sialoadhesin could be expressed by
isolated fetal liver macrophages after cultivation in adult mouse serum, a known source
of inducer activity, but was not dependent on the presence of this inducer, unlike adultderived
madrophages. Fetal plasma contained inducing activity on day 13, but adult
levels were not reached until 2 weeks postnatally. These studies show that sialoadhesin
is differentially regulated compared with the erythroblast receptor and F4/80 antigen,
that it is not required for fetal erythropoiesis, and that its induction on stromal
macrophages is delayed until the onset of myeloid and lymphoid development.
Sialoadhesin provides a marker to study maturation and functions of macrophages
during ontogeny of the lymphohemopoietic system.
T‐Cell‐Specific Membrane Antigens in the MexicanAxolotl (Urodele Amphibian)
Authors: Kerfourn Fabienne , Guillet Francoise , Charlemagne Jacques , Tournefier Annick
Published: June 2008

Comparative analysis of SDS‐PAGE patterns of axolotl spleen cells membrane detergent
lysates showed important discrepancies between control and thymectomized animals.
Among these, a 38‐kD protein band, which appeared as a major protein in controls, was
not or poorly expressed after thymectomy. A rabbit antiserum (L12) raised against the
38‐kD eluted band labeled in indirect immunofluorescence 80‐86% of thymocytes and
40‐46% of mIg– lymphoid cells in the spleen. The anti‐38‐kD antibodies stained in
Western blotting two antigenically related polypeptides of 38‐ and 36‐kD on splenocyte
membrane lysates. Two‐dimensional NEPHGE‐PAGE analysis indicated that the anti‐38‐kD antibodies reacted in the spleen with several gathered spots in the 7.8–8.2 pI
range, corresponding to 38–36‐kD microheterogeneous polypeptides. Most of these
spots are not further expressed in thymectomized animals. These results support
evidence that the 38‐kD surface antigens can be considered as specific surface markers
of the axolotl thymus‐derived lymphocytes.
Rat Stem‐Cell Factor Induces Splenocytes Capable Of Regenerating The Thymus
Authors: Medlock Eugene S. , Migita Russell T. , Trebasky Lisa D. , Housman Jerry M. , Elliott Gary S. , Hendren R. Wayne , Deprince Randolph B. , Greiner Dale L.
Published: June 2008

Cytokine regulation of prethymic T‐lymphoid progenitor‐cell proliferation and/or
differentiation has not been well‐defined, although much is known of cytokine
regulation of hemopoietic stem‐ and progenitor‐cell development. Here we use a
recently identified hemopoietic growth factor, stem‐cell factor (SCF) (a form of the c‐kit
ligand), and a transplant model of thymocyte regeneration to assess the effect of SCF on
the in vivo generation of prethymic, thymocyte progenitor‐cell activity. We show that
recombinant rat SCF (rrSCF164 administered to weanling rats selectively induces an
increase in thymocyte progenitor activity in the spleens of treated rats as compared to
rats treated with vehicle, polyethylene glycol (PEG)‐conjugated rat albumin, or
recombinant human granulocyte colony‐stimulating factor (rhG‐CSF). These data
demonstrate that administration of SCF in vivo affects extrathymic‐origin thymocyte
regenerating cells and may influence, directly or indirectly, early prethymic stages of T‐cell
lymphopoiesis in addition to its known effect on early stages of myelopoiesis and
erythropoiesis.
Differentiation of Mouse Embryonic Stem Cells toLympho‐Hematopoietic Lineagesin Vitro
Authors: Chen Una
Published: June 2008

Mouse embryonic stem (ES) cells can differentiate in culture to late stages of many cell
lineages. have found culture conditions that are favorable for development in vitro of
ES cells into hematopoietic cells at a stage equivalent to day 11‐14 of fetal liver
development. describe here: (1) the growth conditions necessary for maintenance of ES
cells in an undifferentiated state, and the conditions that allow differentiation of cystic
embryoid bodies that contain precursors of most hematopoietic cell lineages, including
lymphoid cells; (2) the development of lymphoid vessels from ES fetusesin vivo; (3) the
characterization of lymphoid, erythroid, megakaryoid, and myeloid cells from ES
fetuses; and (4) the cloning of cell lines representing lymphoid, myeloid lineage cells
from differentiated ES cells.
Cellular Pathway(S) of Antigen Processing and Presentation in Fish APC: Endosomal Involvement and Cell‐Free Antigen Presentation
Authors: Vallejo Abbe N. , Miller Norman W. , Harvey Nancy E. , Cuchens Marvin A. , Warr Gregory W. , Clem L. William
Published: June 2008

Studies were conducted to address further the role(s) of antigen processing and
presentation in the induction of immune responses in a phylogenetically lower
vertebrate, specifically a teleost, the channel catfish. In particular, studies were aimed at
determining the subcellular compartments involved in antigen degradation by channel
catfish antigen‐presenting cells (APC) as well as ascertaining the reexpression of
immunogenic peptides on the surfaces of APC. The results showed that exogenous
protein antigens were actively endocytosed by APC as detected by flow cytometry. Use
of radiolabeled antigen and subcellular fractionation protocols also showed that antigen
localized in endosomes/lysosomes. Furthermore, there was an apparent redistribution
of antigen between these organelles and the plasma membrane during the course of
antigen pulsing. Functional assays for the induction of in vitro antigen‐specific
proliferation of immune catfish peripheral blood leukocytes (PBL) showed that
membrane preparations from antigen‐pulsed autologous APC were highly stimulatory.
The magnitude of responses elicited with such membrane preparations was very similar
to that of PBL cultures stimulated with native antigen‐pulsed and fixed intact APC or
prefixed intact APC incubated with a peptide fragment of the nominal antigen. Current
data further corroborate our previous findings that steps akin to antigen processing and
presentation are clearly important in the induction of immune responses in lower
vertebrates like fish, in a manner similar to that seen in mammalian systems.
Consequently, it would appear that many immune functions among the diverse taxa of
vertebrates are remarkably conserved.
Self‐Reactivity and the Expression of Memory MarkersVary Independently in MRL‐Mp+/+ and MRL‐Mp‐lpr/lprMice
Authors: Smyth Lesley , Howell Michelle , Crispe I. Nicholas
Published: June 2008

MRL‐Mp‐lpr/lpr mice contain phenotypically abnormal populations of T cells, and
exhibit an SLE‐like autoimmune disease in which autoantibodies are a prominent
feature. We analyzed the phenotype and T‐cell receptor Vß expression pattern in CD4+ T
cells of this mutant mouse strain to detect abnormalities that could explain the
autoimmunity. The CD4+ T cells contain two distinct abnormal populations. One of
these expresses B220 and HSA, and in these and other respects closely resembles the
accumulating CD4–CD8– population. The other expresses a high level of CD44 (Pgp‐1),
and a high level of the 16A epitope of CD45, and so resembles post‐activation T cells.
Both of these cell types are exclusive to MRL‐Mp‐lpr/lpr. We also identified V ß5‐ and
V ß11‐positive CD4+ T cells, in both MRL‐Mp‐lpr/lpr and MRL‐Mp‐+/+ mice. We
conclude that autoimmune T cells can be detected in these mice, but that they are not the
cause of the accumulation of abnormal CD4+ and CD4–CD8–cells.
VßGene Family Usage in Spontaneous Lymphomas of AKR Mice:Evidence for Defective Clonal Deletion
Authors: de Heer Cees , de Geus Bernard , Schuurma Henk-Jan , Van Loveren Henk , Rozing Jan
Published: June 2008

T‐cell receptor (TCR) ß‐chain usage and expression of the CD3, CD4, and CD8
differentiation antigens were analyzed in 14 spontaneous AKR lymphomas. Lymphoma
cells massively infiltrated and/or proliferated in the organs analyzed (thymus, spleen,
and mesenteric lymph nodes), giving rise to a loss of organ structure. One lymphoma
occurred only in the thymus, and failed to express CD3, CD4, and CD8. All other
lymphomas expressed the CD3/TCR complex. With respect to CD4 and CD8
expression, the lymphomas were either double‐negative (DN), double‐positive (DP), or
single‐positive (SP). The frequency of DP (CD4+8+) lymphomas was low compared to the
frequency of DP thymocytes in a normal AKR thymus. A substantial heterogeneity was
seen in the intensity of CD4 and CD8 expression among various lymphomas, which was
independent of the level of CD3 expression. Considering TCR V ß gene family usage, 2
out of 14 lymphomas expressed V ß6. Normally, V ß6+ thymocytes are deleted from the
thymocyte pool at the immature DP stage of T‐cell development in AKR mice. These
data support the hypothesis that the lymphocytes in the immature DP stage of T‐cell
development are susceptible to the induction of AKR lymphomagenesis. The presence
of V ß6+ lymphoma cells indicates that the lymphomagenesis is accompanied by a
defective clonal deletion of cells expressing a possible autoreactive TCR.
A Selective Culture System for Generating TerminalDeoxynucleotidyl Transferase‐Positive Lymphoid Cells In Vitro. V. Detection of Stage‐Specific Pro‐B‐CellStimulating Activity in Medium Conditioned by Mouse Bone Marrow Stromal Cells
Authors: Mckenna Sean D. , Goldschneider Irving
Published: June 2008

The selective in vitro generation of rat, mouse, and human terminal deoxynucleotidyl
transferase‐positive (TdT+ lymphoid cells in our long‐term xenogeneic bone marrow (BM)
culture system is characterized by physical interaction between the developing lymphocytes
and mouse BM‐adherent stromal cells and macrophages. In the present study, experiments
in which micropor)us membrane culture inserts were inoculated with rat BM cells
demonstrated that although the generation of primitive B‐lineage lymphoid cells requires
the presence of a mouse BM feeder layer, cognitive recognition events are not necessary.
Similarly, cell‐free (and serum‐free) medium conditioned with mouse BM (but not thymus
or spleen) adherent cells and stromal‐cell lines therefrom supported the proliferation of
early rat lymphoid cells in a dose‐dependent manner. Double immunofluorescence for
incorporated bromo‐deoxyuridine (BrdU) and early B‐lineage markers of rat BM lymphoid
cells maintained in culture inserts or conditioned medium (CM), and studies of their in vitro
and in vivo developmental potentials, indicated that the lymphoproliferative response
resulted from the selective stimulation of lymphoid stem and/or progenitor cells. The most
primitive of these target cells had a HIS24+ HIS50- TdT- cμ- sIg-, pre‐pro‐B‐cell phenotype.
Whereas this subset normally constitutes less than 2% of B‐lineage BM cells in vivo,
it comprises more than 25% of total lymphoid cells in vitro. In addition, the number of TdT+
cells, predominantly of the early pro‐B‐cell phenotype (HIS24+ HIS50- TdT- cμ- sIg-), was
increased approximately tenfold above input levels. Based on these and previous findings,
a schematic model is proposed for the developmental pathway of early B‐lineage cells in rat
BM from the level of the committed (possibly common) lymphoid stem cell to that of the
pre‐B‐cell.
Expression of The αβ T‐Cell Receptor Is Necessary for The Generation of The Thymic Medulla
Authors: Palmer Donald B. , Viney Joanne L. , Ritter Mary A. , Hayday Adrian C. , Owen Michael J.
Published: June 2008

The architecture of the thymus of mice that congenitally fail to express the αβ T‐cell receptor
(TCRαβ) has been examined by immunohistology. In these mice, a defined mutation was
introduced into the TCRc gene by homologous recombination. By using antibodies specific
for cortical or medullary epithelium and for major histocompatibility complex antigens, the
network of cortical epithelium in these mice was shown to be essentially unaltered in
comparison with that of normal mice. In contrast, the thymic medulla was considerably
reduced in size. This analysis shows that expression of the αβ TCR but not the γδ TCR is
obligatory for establishing the thymic medulla and suggests that the growth of medullary
epithelial cells may require contact with TCRαβ‐expressing cells.
Evolution of a CD3+/CD+α/ β T‐Cell Receptor+ Mature T‐Cell Clone from CD3-CD7+ Sorted Human Bone Marrow Cells
Authors: Pohla Heike , Adibzadeh Medi , Bühring Hans-Jörg , Siegels-Hübenthal Petra , Deikeler Thomas , Owsianowsky Martin , Schenk Andrea , Rehbein Arnika , Schlotz Elke , Schaudt Kurt , Pawelec Graham
Published: June 2008

In order to study extrathymic differentiation in vitro, CD7+CD3- lymphocytes were
sorted from normal human bone marrow and cultured under conditions of limiting
dilution together with irradiated pooled allogeneic peripheral blood mononuclear cells
(PBMC) and phytohemagglutinin (PHA) in the presence of 1000 U/ml of interleukin‐2
(IL‐2). One clone was obtained that failed to react with monoclonal antibody (mAb)
TCRδ1 (TCRγ/δ‐specific) or WT31 (TCR2, α/β‐specific). From day 35 through day 74
in culture, the surface phenotype of this clone evolved into CD3+, CD4+, CD8-, TCR2+,
TCR1-, and was further characterized as CD2+, CD45RO+, CD16-, and CD56-. The presence
of mRNA for TCR α and γ but not ,and γ chains was confirmed by Northern blotting.
Accessory cell‐dependent autocrine proliferative responses to PHA (most likely
driven by IL‐2) were initially absent, but became measurable at the same time as the
TCR was acquired. However, in the absence of PHA, the clone failed to respond to a
panel of homozygous B‐cell lines representing the majority of MHC class II alleles.
Autoreactivity was also not demonstrable. Cytotoxicity was limited to MHC unrestricted
“natural killer (NK)‐like” lysis of K562 target cells, with no autocytotoxicity
detected. Tle NK‐like lysis diminished over time in parallel with the acquisition of surface
TCR. The cloned cells were not suppressive for mature lymphocyte proliferation.
After stimulation, the cells secreted tumor necrosis factor α and
granulocyte/macrophage colony‐stimulating factor (GM‐CSF) detected by immunoassays,
and T‐cell growth factors, most likely IL‐2, as detected by bioassays. Polymerase
chain‐reaction methods demonstrated the presence of mRNA for IL‐2, IL‐3, IL‐4, IL‐9,
interferon‐δ, and GM‐CSF in these cells after stimulation with PHA and B‐LCL.

These results suggest that cells with the phenotype and some functional characteristics
of mature T lymphocytes can evolve extrathymically in vitro from T‐cell precursors
sorted from normal human bone marrow.
Epithelium‐Free Area in The Thymic Cortex of Rats
Authors: Bruijntjes Joost P. , Kuper C. Frieke , Robinson Joke E. , Schuurman Henk-Jan
Published: June 2008

The histology of epithelium‐free areas in the subcapsular region of the thymus was
studied in Wistar rats. Lymphocytes in these areas were CD4/CD8 double‐positive, TCR
α/β positive in low intensity, and in CD5 labeling either negative or positive in low
intensity. There was a high proliferative activity as assessed by bromodeoxyuridine
incorporation in vivo and detected by immunohistochemistry. Various macrophage
types were observed. They were either large and round to slightly dendritic, or small
and dendritic. Most large cells were positive for MHC Class II, and labeled by the
antimacrophage antibodies ED1 and ED2. A few cells were strongly positive for Sudan
black, Oil red O, nonspecific esterase, and acid phosphatase; they resembled the large
rounded macrophages in the corticomedullary zone, although their MHC Class II and
ED2 staining was more intense. A few cells showed features of tingible body
macrophages, as they contained cellular debris.

Serial sections showed that epithelium‐free areas run from the subcapsular area to
deep in the cortex, and often border the medulla. This opens the opportunity for
immature lymphocytes to move into the medulla and corticomedullary zone without
contacting and potential selection with cortical stromal elements other than
macrophages in the epithelium‐free areas. In this case, the epithelium‐free areas may
offer a separate intrathymic pathway for T lymphocytes.
Positive and Negative Selection in Transgenic Mice Expressing a T‐Cell Receptor Specific for Influenza Nucleoprotein and Endogenous Superantigen
Authors: Mamalaki Clio , Elliott James , Norton Trisha , Yannoutsos Nicholas , Townsend Alain R. , Chandler Phillip , Simpson Elizabeth , Kioussis Dimitris
Published: June 2008

A transgenic mouse was generated expressing on most (>80%) of thymocytes and
peripheral T cells a T‐cell receptor isolated from a cytotoxic T‐cell clone (F5). This clone
is CD8+ and recognizes αα366‐374 of the nucleoprotein (NP 366‐374) of influenza virus
(A/NT/60/68), in the context of Class ,MHC Db (Townsend et al., 1986). The receptor
utilizes the Vβ11 and Vα4 gene segments for the β chain and α chain, respectively
(Palmer et al., 1989). The usage of Vβ11 makes this TcR reactive to Class II IE molecules
and an endogenous ligand recently identified as a product of the endogenous mammary
tumour viruses (Mtv) 8, 9, and 11 (Dyson et al., 1991). Here we report the development
of F5 transgenic T cells and their function in mice of the appropriate MHC (C57BL/10
H‐2b, IE-) or in mice expressing Class II MHC IE (e.g., CBA/Ca H‐2k and BALB/c H‐2d)
and the endogenous Mtv ligands. Positive selection of CD8+ T cells expressing the Vβ11
is seen in C57BL/10 transgenic mice (H‐2b). Peripheral T cells from these mice are
capable of killing target cells in an antigen‐dependent manner after a period of in vitro
culture with IL‐2. In the presence of Class II MHC IE molecules and the endogenous
Mtv ligand, most of the single‐positive cells carrying the transgenic T‐cell receptor are
absent in the thymus. Unexpectedly, CD8+ peripheral T‐cells in these (H‐2k or H‐2d) F5
mice are predominantly Vβ11 positive and also have the capacity to kill targets in an
antigen‐dependent manner. This is true even following backcrossing of the F5 TcR
transgene to H‐2d scid/scid mice, in which functional rearrangement of endogenous TcR
alpha‐ and beta‐chain genes is impaired.
CD44 in Differentiated Embryonic Stem Cells: Surface Expression and Transcripts Encoding Multiple Variants
Authors: Haegel Hélène , Dierich Andrée , Ceredig Rhodri
Published: June 2008

Expression of the surface‐adhesion molecule CD44 was investigated during the in vitro
differentiation of the embryonic stem (ES) cell line D3. By immunofluorescence analysis,
totipotent, undifferentiated ES cells did not show surface expression of CD44, although two
transcripts of approximately 1.6 and 3.3 kb were detected on Northern blots. Following 1
week of differentiation in either suspension or substrate‐attached cultures, CD44 appeared
on the surface of some D3 cells, and synthesis of an additional 4.5 kb mRNA species was
detected on Northern blots. At this stage, at least three distinct transcripts encoding CD44
variants were induced within the cultures, resulting from alternative splicing of additional
exons in the variable domains of CD44. From PCR analysis, they all appeared to contain the
variable exon v10, and two of them in addition contained v6. Taken together, these results
suggest that CD44 may play a role in cell migration and adhesion in the early development
of the mouse embryo.
The Accessory Molecule Lgp55 Plays a Role Early in Murine Fetal Thymocyte Differentiation
Authors: Mcduffie Marcia , Golde William T.
Published: June 2008

A rat IgM monoclonal antibody, PA3‐795, inhibits the antigen‐specific responses of mouse
T‐cell hybridomas. It recognizes a heavily glycosylated cell‐surface protein, designated
Lgp55, that is detectable after activation on mature T cells. During fetal life, Lgp55 is found
at high levels on newly immigrant thymic T‐cell precursors prior to surface expression of
other T‐lineage molecules. High levels of expression are also found on thymocytes in the
outer cortex of adult mice. Thymocytes at later stages of differentiation bear decreasing
amounts of surface Lgp55, and none is detectable on “single‐positive” thymocytes in the
thymic medulla or on resting mature T cells from the periphery. Addition of monoclonal
anti‐Lgp55 to fetal thymus organ culture decreases the output of “mature” CD4 singlepositive
thymocytes when it is begun before fetal day 13.5. These findings suggest that
Lgp55 contributes to cell‐cell interactions that regulate very early steps in T‐cell development
in the mouse.
Strain‐Dependent Migration of CD4 and CD8 Lymphocyte Subsets to Lymph Nodes in NOD (Nonobese Diabetic) and Control Mice
Authors: Faveeuw Christelle , Gagnerault Marie-Claude , Lepault Françoise
Published: June 2008

Subpopulations of lymphoid cells were compared with respect to their ability to migrate into
peripheral lymphoid organs of nonobese diabetic (NOD) mice and various strains of control
mice. In short‐term, in vivo homing studies, no major differences in the pattern of homing
of B and T cells were observed among all mouse strains studied. On the other hand, CD4
cells localized consistently more efficiently than CD8 cells in both PP and LN of adult NOD
and BALB/c mice, whereas both populations migrated roughly equivalently in LN of adult
DBA/2, CBA, and C57BL/6 mice. No age‐dependent differences in the homing of CD4 and
CD8 cells were observed in BALB/c mice. On the contrary, in 2‐week‐old NOD mice, CD4
and CD8 cells migrated equally well. The preferential entry of CD4 cells in adult NOD and
BALB/c did not result from increased blood transit time of CD8 cells. On the other hand,
the preferential migration of CD8 cells was observed in the liver, whereas the two T‐cell
subsets migrated equally well in the lungs. The differences in the homing characteristics of
CD4 and CD8 cells among NOD, BALB/c, and C57BL/6 mice were not related to
modifications in the level of expression of adhesion molecules such as MEL‐14, LFA‐1, and
Pgp‐1.