Recall antigen activation induces prompt release of CCR5 ligands from PBMC: implication in memory responses and immunization

CCR5 ligands RANTES, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta are potent and specific inhibitors of strains of human immunodeficiency virus (HIV) that use CCR5 as a receptor, which are the strains most involved in primary infection. Recently, we observed that release of CCR5 ligands is a consistent and reproducible parameter of response to antigen activation in studies using PBMC. In this study, we show that CCR5 ligands are released upon antigen [Fragment C of tetanus toxin (TTC)] stimulation in 81% (n = 16) of subjects tested, as detected by a standard ELISA in tissue culture supernatants of antigen-activated cells. In contrast, ELISA for other cytokines from the same supernatants revealed that IFN-gamma release could be detected only in 31% of subjects, IL-2 could be detected only in 12% of the subjects and IL-4 was not detectable in any of the subjects tested. Similarly, proliferative responses to TTC, as measured by a standard tritiated thymidine incorporation assay, were detectable in only 56% of the subjects. Similar observations have been reported in flow cytometric studies, and resonate with previous findings emphasizing the role of CCR5 in T cell responses. In addition, the levels of CCR5 ligands in supernatants from antigen-activated cells were sufficient to inhibit infection of R5 HIV. Thus, CCR5 ligands might play a role in controlling HIV in vivo. Taken together, these observations suggest that CCR5 ligands, and in particular MIP-1alpha and MIP-1beta, released in the course of memory responses may play a role in protecting CD4(+) memory T cells from infection.     

WIP and WASP play complementary roles in T cell homing and chemotaxis to SDF-1alpha

Homing of lymphocytes to tissues is a biologically important multistep process that involves selectin-dependent rolling, integrin-dependent adhesion and chemokine-directed chemotaxis. The actin cytoskeleton plays a central role in lymphocyte adhesion and motility. Wiskott-Aldrich syndrome protein (WASP), the product of the gene mutated in Wiskott-Aldrich syndrome, and its partner, the Wiskott-Aldrich syndrome protein-interacting protein (WIP), play important roles in actin re-organization in T lymphocytes. We used mice with disruption of the WASP and WIP genes to examine the role of WASP and WIP in T cell homing. T cell homing to spleen and lymph nodes in vivo was deficient in WASP-/- and WIP-/- mice and severely impaired in WASP-/-WIP-/- double knockout (DKO) mice. Deficiency of WASP, WIP or both did not interfere with selectin-dependent rolling or integrin-dependent adhesion of T cells in vitro. Chemotaxis to stromal cell-derived factor-1alpha (SDF-1alpha) in vitro was mildly reduced in T cells from WASP-/- mice. In contrast, it was significantly impaired in T cells from WIP-/- mice and severely reduced in T cells from DKO mice. Cellular F-actin increase following SDF-1alpha stimulation was normal in WASP-/- and WIP-/- T cells, but severely reduced in T cells from DKO mice. Actin re-organization and polarization in response to SDF-1alpha was abnormal in T cells from all knockout mice. Early biochemical events following SDF-1alpha stimulation that are important for chemotaxis and that included phosphorylation of Lck, cofilin, PAK1 and extracellular regulated kinase (Erk) and GTP loading of Rac-1 were examined in T cells from DKO mice and found to be normal. These results suggest that WASP and WIP are not essential for T lymphocyte rolling and adhesion, but play important and partially redundant roles in T cell chemotaxis in vitro and homing in vivo and function downstream of small GTPases.     

Comprehensive phenotypic analysis of the gut intra-epithelial lymphocyte compartment: perturbations induced by acute reovirus 1/L infection of the gastrointestinal tract

Intestinal intra-epithelial lymphocytes (IELs) form a highly specialized lymphoid compartment. IELs consist primarily of T cells that are dispersed as single cells within the epithelial cell layer that surrounds the intestinal lumen. These lymphocytes along with lamina propria lymphocytes are considered to play an important role in the regulation of immune responses. IELs are heterogeneous with regard to phenotype, and they contain sub-populations with diverse functions. In our most recent study, we found that intra-duodenal inoculation of mice with reovirus serotype 1/strain Lang (reovirus 1/L) induced expression of both germinal center and T cell antigen and CD11c on IELs suggesting these cells to be the recently stimulated cells in gut mucosal tissue. We also demonstrated that IELs from these mice when cultured in vitro in the presence of reovirus 1/L-pulsed antigen-presenting cells generated reovirus 1/L-specific MHC-restricted CTL whose function was mediated utilizing perforin, Fas-FasL and TRAIL mechanisms. This present study provides a comprehensive analysis of the diverse subsets of IELs, which function with other mucosal cells to provide a strong, protective immunity in a highly regulated fashion inside the microenvironment of the intestinal epithelium. We demonstrated that the IEL population contains both thymus-dependent (TD) and thymus-independent (TI) lymphocytes in mice and that a complex phenotype is present when sub-populations are analyzed for TCR, Thy-1, CD4, CD8 and B220 expression in a comprehensive manner. In reovirus 1/L-inoculated mice, we found a decrease in the TI population and an increase in the TD population characterized by significant alterations in various sub-populations. This increase was largely due to an increase in CD4(+), CD8(+) and CD4/CD8 double-positive sub-populations of TD IELs. Intracellular cytokine analysis demonstrated induction of IFN-gamma and an increase in effector/cytotoxic CD8 and CD4 cells after reovirus 1/L infection. These results suggest that TD IELs may play an important role in the clearance of reovirus 1/L infection from gut.     

Activation of Vgamma9Vdelta2 T cells by non-peptidic antigens induces the inhibition of subgenomic HCV replication

Hepatitis C virus (HCV) has evolved complex strategies to evade host immune responses and establish chronic infection. Since human Vgamma9Vdelta2 T lymphocytes play a critical role in the immune response against viruses, we analyzed their antiviral functions on Huh7 hepatoma cells carrying the subgenomic HCV replicon (Rep60 cells). In a transwell culture system, Rep60 cells were co-cultured with either PBMCs or highly purified gammadelta T cells stimulated by non-peptidic antigens. Vgamma9Vdelta2 T cell activation was associated with a dramatic reduction of HCV RNA levels. Neutralizing antibodies targeting IFN-gamma revealed a critical role for this cytokine in the inhibition of HCV replication. Interestingly, drugs already in clinical use, such as Phosphostim and Zoledronate, known to activate gammadelta T cells, were shown to induce the inhibition of HCV replication mediated by Vgamma9Vdelta2 T cells of HCV patients. Our data suggest that the therapeutic activation of Vgamma9Vdelta2 T lymphocytes may represent an additional strategy to inhibit HCV replication and to restore a Th1-oriented immune response in HCV-infected patients.     

Thymic stroma is required for the development of human T cell lineages in vitro

Development of the T cell lineage is characterized by the homingof hematopoietic precursors to thymus, followed by their acquisitionof receptors for antigen. T cell receptors are ß or heterodimers associated with CD3 (TCR-CD3). Very early T cellprecursors in humans have been characterized as CD7+45+ cellswhich lack the T cell differentiation antigens CD1, CD2, CD3,CD4, and CD8. A phenotypically equivalent early thymocyte populationalso occurs in postnatal life, and we have previously shownthat interleukin 2 (IL2) promotes the development in vitro ofboth the ß and the T cells from these early thymocytes.Here we have analyzed the requirements of the induction of theIL2 pathway in early thymocytes, and their developmental potential.We show that: (I) thymic stromal cells, which are present inthymocyte suspensions, are necessary to induce the IL2 pathwayand the development of ß or T cell lineages fromearly thymocytes in vitro; and (II) when removed from the invivo environment, early thymocytes can develop in vitro intoTCR-CD3^– cells of the natural killer (NK) lineage. Weconclude that CD7+45+, CD1–2–3–4–8–early thymocytes are multipotential progenitors that, at least,have the capacity to develop into ß or T cell andNK lineages. The analysis of the mechanisms of generation andselection of human T and NK cell diversity, not feasible inbone marrow cultures, is now possible.     

Ligand-induced autoregulation of IL-2 receptor {alpha} chain expression in murine T cell lines

The IL-2 receptor (IL-2R) is composed of three chains a, ßand . In mice, contrary to the human system, we have previouslydemonstrated that the IL-2Rß complex does not bindIL-2. Therefore, mouse IL-2 response is completely dependenton the expression of the IL-2R gene product. T cell clones expressingmouse IL-2Rß and the human IL-2R transgene have beenstudied. When cells are grown in IL-4, mouse IL-2R is not expressed.However, exposure to IL-2 leads to the expression of the endogenousmurine IL-2R subunit. The T cell line expressing mouse IL-2Rand human IL-2Rß can grow in IL-2 but does not expressendogenous murine IL-2 R. Transfection of these cells with thehuman IL-2R gene restores the capacity to induce murine IL-2R.This result demonstrates that IL-2-IL-2R interactions are requiredfor induction of IL-2R. The kinetics of induction and deinductionof murine IL-2R have been studied using clone 18.III. From negativecells, expression of murine IL-2R is a very slow phenomenon.From cells fully expressing IL-2R, deinduction is a two-stepprocess: after a rapid decrease of IL-2R the cells continueto express, for a long period of time, basal levels of murineIL-2R. When cells expressing basal levels of IL-2R are exposedto IL-2, induction of IL-2R is a very rapid phenomenon. Theautoregulatory loop formed by IL-2-IL-2R therefore displaysdifferent levels of functioning.     

Maternal serum levels of interferon-gamma and interleukin-2 soluble receptor-alpha predict the outcome of early IVF pregnancies

BACKGROUND: Elevated maternal serum levels of interleukin-2 soluble receptor-alpha (IL-2 sRalpha), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) have been associated with pregnancy loss. The aim of our study was to evaluate the predictive value of these cytokines in the outcome of early IVF pregnancies. METHODS: One hundred and fifty-nine consecutive IVF patients who were subsequently diagnosed to have a biochemical pregnancy (n = 23), a first-trimester miscarriage (n = 19) or a normal term delivery (n = 117) were included in this study. Serum was collected from the initial pregnancy test, 11 days after a day 3 embryo transfer, and all samples were analysed for IL-2 sRalpha, TNF-alpha and IFN-gamma by commercially available enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: IL-2 sRalpha levels were significantly higher in patients with an early pregnancy loss compared with patients with a normal term delivery (849.5 +/- 69.6 versus 693.5 +/- 31.2 pg/ml, P = 0.02), and a cut-off point of IL-2 sRalpha >1000 pg/ml predicted a poor pregnancy outcome (44.4 versus 22.7% pregnancy loss, IL-2 sRalpha >or=1000 versus IL-2 sRalpha <1000 pg/ml; P = 0.02). IFN-gamma-positive patients had twice the risk for poor IVF pregnancy outcome compared with IFN-gamma-negative subjects (40.8 versus 20.0%, respectively; P < 0.02), including a significantly lower implantation rate (37.6 +/- 0.05 versus 50.0 +/- 0.03%, respectively; P = 0.02). There was no difference in pregnancy outcome based upon serum levels, or the ability to detect the presence of TNF-alpha. No differences in levels of these cytokines were found based on the aetiology of the patients' infertility. CONCLUSIONS: Elevated maternal serum levels of IL-2 sRalpha and IFN-gamma as early as 11 days after embryo transfer are associated with poor IVF pregnancy outcome.     

Induction of Ly-6A/E expression by murine lymphocytes after in vivo immunization is strictly dependent upon the action of IFN-alpha/beta and/or IFN-gamma

Ly-6A/E is a phosphatidylinositol-linked membrane protein which mediates murine T and B cell signalling. IFN-gamma, IFB-alpha/beta, LPS, and IL-4 have all been reported to induce or upregulate Ly-6A/E by normal lymphocytes. Since no systematic study has addressed the stimulant selectivity of Ly-6A/E expression by murine lymphocytes nor investigated its induction and regulation during primary in vivo immune responses we analyzed in vitro Ly-6A/E expression after murine stimuli and during a number of distinct in vivo immunizations. We show that LPS induces B cell Ly-6A/E in vitro by stimulating the release of IFN-alpha/beta by 'contaminating' adherent cells. In the presence of anti-IFN-gamma + anti-IFN-alpha/beta antibodies, no Ly-6A/E was induced upon addition of multiple cytokines, including IL-4, or mitogenic doses of anti-Ig antibody. Furthermore, IFN-gamma-containing, CD4+ T cell (Th1) supernatants potently induced Ly-6A/E by murine B cells whereas IL-4-containing (Th2) supernatants were either weak or ineffective; anti-IFN-gamma + anti-IFN-alpha/beta inhibited Ly-6A/E induction by both Th1 and Th2 supernatants. Immunization of mice with Brucella abortus or poly (I).poly (C) resulted in induction of Ly-6A/E expression by virtually all B and T cells, whereas injection of G alpha M delta led to peak induction of Ly-6A/E by approximately 50% of both B and T cells. Lymphocytes from mice infected with the nematode parasites Nippostrongylus brasiliensis or Heligmosomoides polygyrus expressed no Ly-6A/E.(ABSTRACT TRUNCATED AT 250 WORDS)     

Involvement of {alpha}1 and {alpha}4 integrins in gut mucosal injury of graft-versus-host disease

We have investigated the involvement of adhesion molecules inthe lymphocyte infiltration associated with acute intestinalgraft-versus-host disease (GVHD) induced by injection of C3Hlymph node cells into irradiated (C3H x DBA/2)F₁ mice. Firstwe analyzed the expression profile of adhesion molecules including1, 2, 4, 5, 6, L and ß7 integrins, CD44 and L-selectinof lymphocytes from lymph nodes and gut mucosa in normal mice.In normal mice, intraepithelial lymphocytes (IEL) and laminapropria lymphocytes (LPL) uniquely showed increased expressionof 1, 2 and ß7 integrins, and decreased expressionof L-selectin compared with that of lymphocytes of the lymphnodes and Peyer's patches. In mice with GVHD, IEL and LPL ofdonor lymph node cells origin underwent phenotyplc changes characterizedby the increased expression of 1, L and ß7 integrins,and the loss of L-selectin. The expression profile of adhesionmolecules on IEL and LPL of GVHD mice resembled that of normalmice except for the lack of 2 integrin. Treatment of GVHD micewith anti-1,-4 or-ß7 integrin antibody alone partiallyprevented the mucosal pathology of intestinal GVHD, whereasonly mice treated with anti-1 showed reduced donor lymphocyticinfiltration into the intestinal mucosa. In contrast, treatmentwith anti-L or anti-CD44 antibody did not affect the intestinalGVHD. Furthermore, dual blockade of both 1 and 4 integrins completelyinhibited the mucosal pathology and donor lymphocyte infiltrationof intestinal GVHD. These results indicate that 1 and 4 integrinsplay an important role in the pathology of intestinal GVHD.     

Transient hypogonadotrophic hypogonadism in males with acute toxoplasmosis: suppressive effect of interleukin-1 beta on the secretion of GnRH

BACKGROUND: In September 2002, an outbreak of toxoplasmosis was noted in a male boarding high school on the Aegean coast of Turkey. We have focused our efforts to investigate the sex hormones in this population. METHODS: Blood samples were collected from 40 male patients, 17-18 years old, who also had positive titres of antibody to Toxoplasma gondii. Serum FSH, LH, free testosterone (FT), total testosterone (TT), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta) and macrophage-inflammatory protein-1alpha (MIP-1alpha) concentrations were measured in all patients and 20 control subjects. Initially, the patients were divided on the basis of the levels of sex hormones into the following groups: patients who had normal sex hormone levels (n = 31) as group A and patients with low sex hormone levels (n = 9) as group B. RESULTS: IL-1beta levels were found to be higher in group B patients than group A. The levels of IL-1beta correlated significantly in a negative manner with FSH, LH, FT and TT in all patients with acute toxoplasmosis (n = 40). CONCLUSIONS: Acute toxoplasma infection may cause temporary hypogonadotrophic gonadal insufficiency regardless of the course of the disease.     

Polymorphism of the human T cell receptor alpha chain variable genes: identification of a highly polymorphic V gene probe

In this study, we report the RFLP of the human T cell receptor (TCR) alpha chain variable gene segments. Using DNA samples from 20 individuals and three restriction endonucleases (BamHI, EcoRI and HindIII), the degree of RFLP of a number of different V gene segments was defined. Half of the V alpha subfamilies (6/12) were characterized by a predominant hybridization pattern, with only a few individuals displaying a second pattern. However, one particular V gene family, V alpha 6, has at least five allelic forms that segregated consistently in familial studies. The V alpha polymorphisms revealed in this study, together with those exhibited by V beta gene subfamilies, should prove useful in studying possible associations between TCR gene usage and disorders of the immune system.     

Individual plasmacytoid dendritic cells are major contributors to the production of multiple innate cytokines in an organ-specific manner during viral infection

Plasmacytoid dendritic cells (pDCs) are an important source of IFN-alpha/beta in response to a variety of viruses in vivo, including murine cytomegalovirus (MCMV). However, the respective contributions of various infected organs, and within these of pDCs, conventional dendritic cells and other cells, to the systemic production of IFN-alpha/beta or other innate cytokines during viral infections in vivo is largely unknown. Whether a specialization of pDC subsets in the production of different patterns of innate cytokines exists in vivo in response to a viral infection has not been investigated. Here, by analyzing for the first time directly ex vivo, at the single-cell level, the simultaneous production of up to three cytokines in pDCs isolated from MCMV-infected mice, we show that (i) pDCs are the quasi-exclusive source of IFN-alpha/beta, IL-12 and tumor necrosis factor (TNF)-alpha, early during MCMV infection, in two immunocompetent mouse lines and with two viral strains, (ii) pDC activation for IFN-alpha/beta production is organ specific and (iii) a significant proportion of pDCs simultaneously produce IFN-alpha/beta, TNF-alpha and IL-12, although TNF-alpha and IFN-alpha/beta appear more often co-expressed with one another than each of them with IL-12. Altogether, these results show a broad and non-redundant role of pDCs in early innate detection of, and defense against, viral infection. The data also show differences in the responsiveness of pDCs from different tissues and suggest distinct molecular requirements for pDC production of various cytokines. These observations must be taken into account when designing new antiviral vaccination strategies aimed at harnessing pDC responses.     

Monoclonal antibody against murine T cell receptor V alpha 14 cross-reacts with human CD3 epsilon and detects disulfide-linked dimeric form.

A monoclonal antibody against V14+ alpha-chain of murine T cell receptor (TCR) was established by fusing spleen cells from a rat immunized with a soluble chimeric TCR/IgG3 protein containing murine TCR V alpha 14J alpha 281 in place of the VHDHJH of an IgG3. lambda 1, and subjected to screening on a human transfectant (Jurkat variant) expressing the murine V14J281 alpha-chain. The anti-mouse V alpha 14 antibody precipitated TCR alpha beta molecules from Triton X-100-solubilized extracts of 125I-labeled murine thymocytes and spleen cells. Unexpectedly, the antibody showed cross-reactivity to the human CD3 epsilon molecule and detected a disulfide-linked 20 kDa dimeric form of human CD3 epsilon, which is a novel family component of the CD3 complex and is associated closely with the CD3 zeta-zeta homodimer as well as TCR alpha beta or TCR gamma delta.     

Stimulation of prostaglandin (PG) F2{alpha} and PGE2 release by tumour necrosis factor-{alpha} and interleukin-1{alpha} in cultured human luteal phase endometrial cells

Tumour necrosis factor- (TNF-) and interleukin-1 (IL-1) areimportant mediators of cell signalling in the uterus. Prostaglandins(PG) have been implicated in the increase of endometrial vascularpermeability which occurs during the implantation process. Thisstudy evaluates the effect of these two pleiotropic cytokineson PGF₂ and PGE₂ release from human luteal phase endometrialglandular epithelial cells (GEC) and stromal cells (STC) inculture. Basal PGF and PGE release did not differ significantlyfrom each other or among cell types, and declined significantlywith increasing number of days in culture. On day 3, basal PGrelease had decreased to half of that on day 1 of culture. However,both cell types were still able to respond to the addition ofexogenous arachidonic acid (5 µM) on day 3 of culture,with PG release by GEC being elevated 7- to 10-fold and by STCmoderately, but still significantly, on day 4. The permissiveeffect of arachidonic acid on the stimulation of PG releasemay indicate the down-regulation of phospholipase A₂ with continuedtime in culture. However, the addition of arachidonic acid (5µM) on day 0 of culture, while able to cause significantlyincreased PG release from GEC, had no effect on STC. In contrast,the addition of a combination of arachidonic acid (5 µM),and either recombinant human TNF- (10 µg rhTNF-/I) or10 µg rhlL-1/I, had a synergistic action and caused thesignificantly increased release of PGF and PGE from both celltypes, compared with that achieved with either arachidonic acidor the cytokine alone (although GEC responded more than STC).During the first 24 h after the addition of rhTNF- or rhlL-1,both cytokines stimulated PG release from both cell types ina dose- and time-dependent fashion. Neither cycloheximide (10µM) nor actinomycin D (10 µM) affected basal PGrelease, but both blocked cytokine-induced PG release from bothcell types. These results suggest that there is a differentialcontrol of human endometrial cell PG biosynthesis, and thatPG release may be regulated through gene activation.     

IL-1 is required for allergen-specific Th2 cell activation and the development of airway hypersensitivity response

IL-1 is a pro-inflammatory cytokine consisted of two molecular species, IL-1alpha and IL-1beta, and the IL-1 receptor antagonist (IL-1Ra) is a natural inhibitor of both molecules. Although it is suggested that IL-1 potentiates immune responses mediated by T(h)2 cells, the role of IL-1 in asthma still remains unclear. In this study, we demonstrate that the ovalbumin (OVA)-induced airway hypersensitivity response (AHR) in IL-1alpha/beta-deficient (IL-1alpha/beta(-/-)) mice was significantly reduced from the levels seen in wild-type mice, whereas the responses seen in IL-1Ra(-/-) mice were profoundly exacerbated, suggesting that IL-1 is required for T(h)2 cell activation during AHR. OVA-specific T cell proliferation, IL-4 and IL-5 production by T cells, and IgG1 and IgE production by B cells in IL-1alpha/beta(-/-) mice were markedly reduced compared with these responses in wild-type mice; such responses were enhanced in IL-1Ra(-/-) mice. Using IL-1alpha(-/-) and IL-1beta(-/-) mice, we determined that both IL-1alpha and IL-1beta are involved in this reaction. Both IgG1 and IgE levels were reduced in IL-1beta(-/-) mice, while only IgE levels were affected in IL-1alpha(-/-) mice, indicating a functional difference between IL-1alpha and IL-1beta. These observations indicate that IL-1 plays important roles in the development of AHR.     

PYNOD, a novel Apaf-1/CED4-like protein is an inhibitor of ASC and caspase-1

Recently, a large subfamily of nucleotide-binding and oligomerization domain-containing proteins that have an N-terminal pyrin-like domain and C-terminal leucine-rich repeats has been described. In this study, we identified PYNOD, a novel member of this family that lacks the leucine-rich repeats. We found that human PYNOD mRNA is expressed in various tissues and at high levels in heart, skeletal muscle and brain. It is also expressed in various cell lines, including haematopoietic cell lines. PYNOD oligomerizes and binds to ASC, an adaptor protein that plays a role in apoptotic and inflammatory signal transduction, and to caspase-1 and IL-1beta. PYNOD inhibits apoptosis-associated speck-like protein containing a CARD (ASC)-mediated NF-kappaB activation and apoptosis, and caspase-1-mediated IL-1beta maturation, and it does so in the presence and absence of constitutively active mutants of CARD12 and PYPAF1, which are enhancers of these processes. Thus, PYNOD is a novel regulator of apoptosis and inflammation.     

Induction of human hsp60 expression in monocytic cell lines.

Both bacterial and mammalian heat shock proteins (HSP) are recognized by some T cells, and hsp60 recognition has been implicated in rheumatoid arthritis. We have developed a model to study the induction of hsp60 in human monocytic cell lines. An anti-mycobacterial hsp65 mAb (ML30), cross-reacting with human hsp60 was used to screen 21 human tumor cell lines in Western blot analysis. All T cell and B cell lymphomas constitutively expressed hsp60 protein at moderate to high levels, while little or no hsp60 protein was detected in two monocytic leukemia lines. Moderate to high levels of hsp60 mRNA and protein could be induced in the THP-I monocytic leukemia cell line by heat shock, retinoic acid, interferon (IFN)-gamma or tumor necrosis factor (TNF)-alpha treatment, the highest levels obtained with a combination of IFN-gamma/TNF-alpha. This was also seen using two rabbit anti-hsp60 antisera directed against the N-terminal or C-terminal part of the human hsp60 protein. The determinants detected by the ML30 mAb or the two rabbit anti-hsp60 antisera were not cell surface expressed, as measured with immunofluorescence (FACS) analysis on control cultured or cytokine treated cell lines. This could be a useful model for studies related to the induction of hsp60 in human cells.     

A large proportion of bovine T cells express the gamma delta T cell receptor and show a distinct tissue distribution and surface phenotype

The numbers, phenotype, and tissue distribution of gamma delta T cells in cattle were studied using two monoclonal antibodies (mAbs) which react with the bovine gamma delta T cell receptor (TCR). Both mAbs stained 20-40% of T cells in peripheral blood, and immunoprecipitated molecules of 44 and 36 kd (reduced) and 70-80 kd (non-reduced). In cattle the majority of circulating gamma delta T cells showed a distinct surface phenotype; they expressed T19, a 215 kd molecule described in sheep and cattle which marks only gamma delta T cells. Bovine gamma delta T cells were also CD2-, CD4-, and mostly CD8-, and failed to express CD6, a molecule possibly involved in T cell activation. The distribution of gamma delta T cells in cattle lymphoid tissues differed markedly from that in humans, in that bovine gamma delta T cells were concentrated around lymph node trabeculae and were usually sparse or absent from the B cell and T cell domains of lymph nodes. Like most other species studied, gamma delta T cells in cattle were localized to epithelial surfaces, particularly within the skin and intestine, indicating that it was at these sites where gamma delta T cells functioned. Our results provide further evidence for the unusual localization, recirculation pattern, and phenotype of gamma delta T cells, and also show that some features of gamma delta T cells can differ quite markedly from species to species.     

Molecular control of the implantation window

Human endometrium is the end organ of the hypothalamic-pituitary-ovarian axis. Therefore, endometrium is susceptible to changes in the cases of infertility that originate from disturbances in the normal functioning of this axis. In addition, some cases of unexplained infertility may be due to altered endometrial function. This disturbed endometrial function may originate from lesions in the molecular repertoire that are crucial to implantation. Human endometrium becomes receptive to implantation by the blastocyst within a defined period during the menstrual cycle. The duration of this so-called 'endometrial receptivity' or 'implantation' period seems to span from few days after ovulation to several days prior to menstruation. Successful implantation results from a co-ordinated series of events that would allow establishment of a timely dialogue between a receptive endometrium and an intrusive blastocyst. The members of the molecular repertoire that make endometrium receptive to implantation are gradually being recognized. Among these are the cytokines, integrins, heat shock proteins, tastin and trophinin. In addition, the expression of a second set of genes including tumour necrosis factor alpha (TNF-alpha) and ebaf, may be the appropriate signal for the closure of the 'implantation window', for making the endometrium refractory to implantation and for preparing it for the menstrual shedding.