Restricting IL-2 availability may be one means by which Treg can constrain Th17 establishment 25. Our data support this hypothesis and demonstrate a reciprocal
development of Treg and Th17 in the skin C57BL/6 mice vaccinated with Lm/CpG, indicating that IL-2, and perhaps other cytokines (rather than IL-23) may be implicated in the regulation of Th17 cells in our model. This needs to be confirmed with more experiments to define the role that multiple cytokines (i.e. IL-2, IL-12, IL-27, IL-15, IL-21, IRF4) may have in the generation and expansion of Th17 cells in our vaccination model. Our experiments intend to begin to unravel the reciprocal role of Th17 and Th1 in the Lm/CpG-vaccinated animals, and demonstrate that IL-17 is required for vaccine-associated Navitoclax cell line Ruxolitinib purchase parasite killing. IFN-γ neutralization also has a negative effect on parasite containment. Interestingly, the secretion of both IL-17 and IFN-γ appears to be linked as elimination of IL-17 decreased the expression of IFN-γ and vice versa. Although IFN-γ has proposed as a negative regulator of Th17 development, recent evidence has revealed can act synergistically to promote inflammation and disease control 18, 26–29. In any case, the fact that both IL-17 and IFN-γ are produced by
different CD4+ T-cell populations and that neutralization of the two cytokines did not result in an additive effect suggests that that their production may be sequential, or may be regulated by a shared factor (e.g. IL-27 23). The relationship of Th1 and Th17 during protective immunity remains controversial. Defining the trends that direct their interplay is impaired by the variation in inoculation routes, infection dosages, and sites of infection. New evidence further complicates this picture and points towards plasticity of Th17 and Th1 subpopulations: recent observations reveal that differentiated Th17 cells may become Th1 effectors and that Th17 cells Coproporphyrinogen III oxidase may be enhanced by the Th1 factors IFN-γ and T-bet (reviewed in 30). We intend to continue to
decipher the interplay between T-cell effector populations in our system as well as other models of leishmaniasis. The question remains on how Th17 cells control parasite growth in vaccinated animals. IL-17 is highly proinflammatory and induces expression of other inflammatory cytokines and of matrix metalloproteases important in facilitating the tissue entry of attracted leukocytes. IL-17 mediates recruitment, activation, and proliferation of neutrophils. Our data demonstrate that neutrophils migrate to the site of Lm/CpG infection concomitant with the Th17 cell expansion. It has been described that neutrophils protect C57BL/6 mice against infection, inducing killing by a mechanism that requires macrophage activation by neutrophil elastase 31.
Splenocytes were cultured in anti-CD3 coated flat-bottom 96-well plates (0.5 × 106 cells/well) in the presence of increasing concentrations (0–1000 ng/mL) of the immunosuppressive drug MP . For MOG35-55 stimulation, splenocytes were harvested from EAE mice, cultured at 0.5 × 106 cells/well in a U-shape 96-well plates and stimulated with 10 μg/mL MOG35-55. Culture plates were incubated at 37°C in a 5% CO2 atmosphere. After 48 h incubation, supernatants were harvested and stored at −80°C until cytokine analysis. Levels
of IL-2, IFN-γ, IL-4, IL-6, IL-10, IL-1, TNF-α, MCP1, and IL-17A were measured either with a multiplex ELISA kit (Quansys Biosciences, Logan, Utah) or with individual cytokine sandwich ELISA kits (Biolegend, San Diego, CA) as indicated in figure legends and according to manufacturer’s instructions. The immunosuppressive effect of MP is presented as percent of cytokine production without Kinase Inhibitor Library supplier MP. Mice were immunized by subcutaneous injection
into flanks of 100 μg MOG35-55 emulsified in CFA (Difco, Detroit, MI). Pertussis toxin (List Biological Laboratories, Campbell, CA) was injected intraperitoneally (500 ng/mouse) KPT-330 manufacturer immediately following MOG35-55 injection and again 48 hours later. From day 9 postimmunization, mice were examined daily for clinical signs of the disease and the manifestation of the disease was graded on a 0–5 scale according to the following parameters: 0 = no clinical signs; 0.5 = loss of tail tonus; 1 = tail paralysis; 2 = partial hind-limb paralysis; 3 = hind-limb paralysis; 4 = complete paralysis; 5 = death. All statistical analyses were performed with
GraphPad Prism version 5.02 for Windows (GraphPad Software, San Diego, CA). All variables are expressed as mean ± SEM. p-values were calculated with Student’s t-test or ANOVA test as indicated in figure legends. We thank Dr. Tali Brunner and Prof. Marta Weinstock-Rosin for their valuable comments. We thank Dr. Irit Solodkin for graphical editing the manuscript figures. The Israel Science Foundation and Israel Ministry of Health supported this study. The authors declare no financial or commercial conflict of interest. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized Farnesyltransferase for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Fig. 1. CVS induces anxiety-like behaviors. Anxiety levels were quantified following 24 days of CVS or nonstress conditions. The elevated plus maze (A–B) and open field tests (C) were performed as described in Materials and methods. Bar graphs represent means ± SEM of 20–21 mice in each group, pooled from three independent experiments. p-values were calculated by Student’s t-test. **p < 0.01; ***p < 0.001.
None of the participants consulted an occupational health physician for treatment of adverse events after vaccination selleck compound with either the pandemic H1N1 2009 vaccine or the seasonal trivalent vaccine. Most adverse events after vaccination with the pandemic
H1N1 2009 vaccine were mild and occurred on the day of, or the day after, the first and second vaccinations and most disappeared within three days. The frequency of local reactions was greater in Group 2 than in Group 1. One participant in Group 2 had erythema or swelling of ≥ 5 cm after the first dose of the pandemic H1N1 2009 vaccine, this resolved the following day. Local reactions in each arm of the participants after the simultaneous vaccination of the seasonal trivalent influenza vaccine and the pandemic H1N1 2009 vaccine were comparable. Local pain was evaluated on the basis of median VAS scores. Compared with male participants, female participants tended to have more severe pain at the injection site for all of the vaccination time points. The frequency of systemic reactions after the second vaccination of the
pandemic H1N1 2009 vaccine was also greater in Group 2. Fatigue occurred more frequently (13.6%) after the second pandemic H1N1 2009 vaccination compared with other vaccination time points. The major finding of this study is that antibody responses to the pandemic H1N1 2009 vaccine are inhibited by pre-vaccination with the seasonal trivalent
influenza vaccine. However, since no booster effect from vaccination with the second dose of the pandemic H1N1 Erlotinib 2009 influenza vaccine was observed in either study group, one vaccination may be enough to induce an adequate HI antibody response. Slight increases dipyridamole in GMT, SCR and SPR were observed after the second dose of the vaccine in Group 2, but these differences were not significant (GMT: P= 0.4902, SCR: P= 0.6875 and SPR: P= 0.4531). Because stratified randomization had ensured that the factors affecting the post-vaccination antibody response were well-balanced between the study groups, the results suggest that the antibody response to the second dose of the pandemic H1N1 2009 influenza vaccine was inhibited by the seasonal trivalent influenza vaccination. This result was unexpected because it was assumed that priming with the seasonal trivalent vaccine would expand the common memory to H1N1 viruses and facilitate the response to the subsequent pandemic H1N1 2009 vaccine. The inhibitory effect however was reminiscent of a peculiar immunological phenomenon seen in cases of natural infection with seasonal influenza viruses known as “original antigenic sin” in which an antibody response to a new variant is inhibited when individuals immunologically primed with other strains are re-infected with a related but different new variant. As to the mechanism of OAS, Kim et al.
As both neutrophils and monocytes buy PD98059 are versatile innate immune cells, DC functions may be either over- or underestimated in CD11c.DTR and CD11c.DOG mice, depending on the experimental setup. In this light, it is essential to determine whether other inducible DC-depletion models (e.g. zDC.DTR, Langerin.DTR, BDCA2.DTR, SiglecH.DTR, Clec9a.DTR, and CD205.DTR mice) also exhibit neutrophilia and monocytosis upon DT injection. Of note, zDC.DTR mice have been reported to possess increased neutrophil counts in the spleen upon DT treatment . Our understanding of DC biology would greatly benefit from a mouse model that combines specific
depletion of DCs without the induction of neutrophilia and monocytosis. Work at the London Research Institute
is funded by Cancer Research UK. C.R.S. acknowledges additional support in the form of a prize from Fondation Bettencourt-Schueller and a grant from the European Research Council. J. v B. is supported by the Boehringer Ingelheim Fonds. B.U.S. was supported by an EMBO long-term Fellowship. The authors declare no financial or commercial conflict of interest. small molecule library screening “
“Subunit vaccines have the potential advantage to boost Mycobacterium bovis Bacillus Calmette-Guérin (BCG)-primed immunity in adults. However, most candidates are antigens highly expressed in replicating bacilli but not in dormant or persisting bacilli, which exist during Mycobacterium tuberculosis infection. We constructed M. tuberculosis fusion protein Ag85B-Mpt64190–198-HspX (AMH) and Ag85B-Mpt64190–198-Mtb8.4 (AMM), which consist
of Ag85B, the Adenosine triphosphate 190–198 peptide of Mpt64, HspX (Rv2031c) and Mtb8.4 (Rv1174c), respectively. AMH and/or AMM were mixed with adjuvants composed of dimethyl-dioctyldecyl ammonium bromide and BCG polysaccharide nucleic acid (DDA-BCG PSN) to construct subunit vaccines. Mice were immunized thrice with Ag85B, AMH and AMM vaccines and the immunogenicity of the fusion protein vaccines was determined. Then, mice were primed with BCG and boosted twice with Ag85B, AMH, AMM and AMM + AMH vaccines, respectively, followed by challenging with M. tuberculosis virulent strain H37Rv, and the immune responses and protective effects were measured. It was found that mice immunized with AMH vaccine generated high levels of antigen-specific cell-mediated responses. Compared with the group injected only with BCG, the mice boosted with AMM, AMH and AMM + AMH produced higher levels of Ag85B-specific IgG1 and IgG2a and IFN-γ-secreting T cells upon Ag85B and Mycobacterium tuberculosis purified protein derivative (PPD) stimulation. It is interesting that only mice boosted with AMM + AMH had significantly lower bacterial count in the lungs than those receiving BCG, whereas mice boosted with AMH or AMM did not.
Furthermore, three other cytokines, namely IFN-γ, IL-12 and IL-18, led Idasanutlin to bystander activation of MP CD8+ T cells; the bystander activation effect of the latter two cytokines was likely mediated via induction of IFN-γ 3. Subsequently, it was shown that none of these cytokines were able to directly stimulate T cells in vitro, suggesting that these cytokines induced production of another, possibly common, effector cytokine that is able to activate T cells. This cytokine was shown
to be IL-15, which is produced and presented to T cells by APC upon stimulation with IFN-α/β and IFN-γ 4, 5 (Fig. 1). IL-15 preferentially stimulates MP CD8+ T cells – a consequence of MP CD8+ T cells expressing very high levels of CD122 4–7. CD122 is the common IL-2/IL-15 receptor β subunit, which together with the common γ chain (γc), is necessary for signal transduction upon IL-15 or IL-2 binding. Notably, heterologous CD44low naïve CD8+ T cells are also activated following virus infection 1,
8, although to a much lower extent than MP CD8+ T cells, which is possibly due to weaker IL-15-responsiveness conferred by intermediate expression levels of CD122 4. In contrast to the wealth of data available for the CD8+ compartment, CD4+ T-cell bystander activation has not been LDK378 in vivo as well characterized, at least until now. Bystander activation of CD4+ T cells Staurosporine cell line is less efficient as compared with that of CD8+ T cells; however, unrelated CD44high MP CD4+ T cells have been reported to undergo a low degree of bystander proliferation upon virus infection and following administration of poly(I:C) or LPS 1, 2, 9. This low degree of bystander activation found in MP CD4+ T cells may be a result of the cells’ intermediate
CD122 expression, which is comparable to CD122 levels on naïve CD8+ cells 4, 7. Bystander activation of MP CD4+ T cells has also been observed in mice receiving injection of the synthetic NKT cell ligand α-GalCer; this bystander effect was independent of IFN-α/β but required (at least partially) IFN-γ 9. Moreover, infection of mice with the parasite Leishmania donovani also led to proliferation of heterologous memory CD4+ T cells 10. In humans, Di Genova et al. 11 have previously shown that tetanus toxoid (TT)-booster vaccination of individuals induced not only the expansion of TT-specific memory CD4+ T cells but also the expansion of memory (but not naïve) CD4+ T cells specific for the purified protein derivative of tuberculin and Candida albicans, thus suggesting bystander activation of the non-TT-specific cells. In this issue of the European Journal of Immunology, Di Genova et al. revisit the issue of bystander activation in CD4+ T cells 12 using a mouse model to better understand the underlying mechanism involved.
05). There were no significant differences between outcomes after end-to-end repair or nerve grafting (P > 0.05) and between outcomes from repair of injuries in different zone (P > 0.05). Early DNA Damage inhibitor diagnosis and surgical treatment with careful dissection of the ulnar nerve branches within the canal is very important. Adequate exposure is usually required to repair the nerve in the Guyon canal. Nerve grafting in this level could give analogous results as the end-to-end repair. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012. “
“In microsurgical breast reconstruction, an adequate selection of recipient vessels is crucial for a successful
outcome. Although the internal mammary (IM) vessels offer an attractive option, the internal mammary perforator (IMP) vessels are becoming a reliable alternative. The purpose of this study is to investigate the external diameters, lumen area, and atherosclerotic lesions changes of the IMP, IM, and deep inferior epigastric (DIE) vessels through quantitative and qualitative histomorphometric analysis. Ninety-six vessels of bilateral IM, IMP, and DIE vessels from 16 fresh female cadavers were evaluated. Mean age was 54.06 ± 5.7 years. External diameters, lumen area, and degenerative changes of the tunica Ixazomib in vitro intimae and media were analyzed by qualitative histomorphometric analysis. Seventy-one vessels (20 IM, 31
IMP, and 20 DIE vessels) were included in the final histological analysis. A statistically lower external diameters and lumen area were presented by the IMP. The DIE vessels showed a lower incidence (10%) of moderate and severe intimal layer degenerative changes (P = 0.0589). The IMP and DIE vessels showed a lower incidence (9.4 and 25%, respectively) of major media layer degenerative changes (P = 0.0001). No major arterial degenerative lesions were observed in the IMP arteries. Although the IMP external diameters and lumen area were lower than the IM, the results others of this study indicated that the tunica media layer in the IMP is less damaged than the other recipient vessels.
The results of the comparative histological study permitted to describe additional advantages and disadvantages of using IMP as a recipient vessel for free flap breast reconstruction. © 2013 Wiley Periodicals, Inc. Microsurgery 34:217–223, 2014. “
“Although never exceeding a few square centimeters, finger pulp defects are reconstructive challenges due to their special requirements and lack of neighboring tissue reserve. Local flaps are the common choice in the management of this injury. However, the development of microsurgery and clinical practice have greatly boosted the application of different free flaps for finger pulp reconstruction with excellent results, especially when local flaps are unsuitable or impossible for the coverage of large pulp defects.
). Expression of the anti-apoptotic genes Bcl-2 and Bcl-xL was markedly decreased in the T-cell-specific Stat3-deleted group compared with the control group (Fig. 6a). Stat3, Bcl-2 and Bcl-xL protein levels were reduced; accordingly, the expression of cleaved caspase-3 was enhanced in purified T cells from T-cell-specific Stat3-deficient mice (Fig. 6b). Furthermore,
expression of both Bcl-2 and Bcl-xL in splenic T cells was considerably reduced in Stat3-deficient mice, as shown by flow cytometry analyses and immunofluorescence assays (Fig. 6c,d). These data collectively suggest that Stat3 plays a crucial role in maintenance of the T-cell population by inducing Bcl-2 and Bcl-xL expression. We demonstrated that Stat3 contributes to T-cell homeostasis by inducing the expression of Bcl-2 family genes. Stat3 deficiency may
enhance the susceptibility of check details T cells to apoptosis by attenuating the expression of Bcl-2 and Bcl-xL, resulting in the breakdown find more of T-cell homeostasis in lymphoid organs. In the present study, we successfully generated T-cell-specific Stat3-deficient mice, as described previously (Fig. 1). These mice were born healthy and presented no obvious abnormalities. The study in which T-cell-specific Stat3-deficient mice were first generated showed that these mice had no abnormalities in T-cell development. Instead, it demonstrated that Stat3-deficient T lymphocytes have impaired proliferation in response to IL-6 treatment and defective IL-2-mediated Endonuclease IL-2 receptor α chain expression.[16, 17] However, a recent study reported that the spleen and lymph nodes of T-cell-specific Stat3-deficient mice were smaller than those of wild-type littermates. We also found that the spleens of T-cell-specific Stat3-deficient mice were considerably smaller and that their cell numbers were reduced (Figs 1c,d, and 2b). These findings were attributable to the deficiency of T lymphocytes, rather than non-T
cells, in Stat3-knockout mice (Fig. 2a,c). We demonstrated that both the per cent population and absolute numbers of CD4+ and CD8+ T cells were reduced in Stat3-deficient mice (Fig. 2d–f). The maintenance of Foxp3+ regulatory T cells has also been reported to be attributable to the common γ chain cytokine signalling in which Stat3 and Stat5 are involved.[24, 25] Consistently, the population and the number of cells of CD4+ Foxp3+ T cells were notably decreased in Stat3-deficient mice when compared with the control group (Fig. 2g,h). Next, we investigated whether the reduction of CD4+ or CD8+ T lymphocytes was mainly a result of the decrease of naive or memory/effector T cells. The population of CD44low CD62Lhigh naive cells in both CD4+ and CD8+ T lymphocytes was significantly reduced in splenocytes and lymph node cells from Stat3-deficient mice, whereas that of CD44high CD62Llow effector/memory cells was unchanged (Fig. 3a–c).
IL-17 has been implicated in many inflammatory diseases, including rheumatoid arthritis, multiple sclerosis, asthma and systemic lupus erythematosus [12–14]. The role of Th17 cytokines in tuberculosis has recently been investigated. MLN0128 solubility dmso IL-17 plays a key role in early neutrophil-mediated pulmonary inflammatory responses, T cell-mediated IFN-γ production and granuloma formation in the lung in response to infection with bacillus Calmette–Guérin (BCG) [15,16]. Studies in IL-23- and IL-12/23-deficient mice have highlighted the importance of the role played by the IL-23/Th17 pathway in immune responses against mycobacterial infection [2,17]. Furthermore, IL-17 accelerates memory Th1 responses in vaccinated mice infected
subsequently with Mycobacterium tuberculosis. IL-22, a member of the IL-10 family of cytokines, is also produced by Th17 cells [13,18]. It acts primarily on non-immune buy IWR-1 cells, as IL-22R is not expressed on immune cells . IL-22 plays a protective role during inflammation of various tissues, including liver, intestine and heart [20–22], perhaps by inducing the release of anti-microbial agents such as β-defensin-2 and proinflammatory molecules belonging to the S100 family of calcium-binding proteins . In contrast to IL-17, the role of IL-22 in tuberculosis is not well defined; however, in patients with active tuberculosis (TB), elevated levels of IL-22
in bronchoalveolar lavage specimens have been reported . IL-17 has also been shown to mobilize, recruit and activate neutrophils  which appear early during mycobacterial infection. The role of granulocytes in tuberculosis is not clear, but reports suggest that they release chemokines to recruit monocytes and contribute to granuloma formation [25,26]. The lack of neutrophils during the early stages of infection increases bacterial burden in infected tissues because of decreased production of TNF-α, Vasopressin Receptor IL-1 and IL-12 . Moreover, neutrophils directly affect mycobacterial killing activity by releasing anti-microbial peptides such as cathelicidin LL-37
and lipocalin-2 . In addition to a protective response, neutrophils may be involved in the destructive immune responses in active tuberculosis [29,30]. Mice infected with the virulent strains of M. tuberculosis exhibited formation of granulomas with lymphopenic and granulocytic lesions which resulted ultimately in the death of the host . Furthermore, IL-27-deficient mice infected with mycobacteria succumbed to death due to hyperinflammatory responses when granulomatous lesions have abundant neutrophils . To gain insight into the involvement of Th17 cells, we measured basal levels of IL-17/IL-22 expressing lymphocytes and granulocytes and secretion of proinflammatory cytokines including IL-17 and IL-22 in circulation as well as following peripheral blood mononuclear cell (PBMC) stimulation with mycobacterial antigens in individuals with both latent and active stages of disease.
Subsequently, cells were allowed to adhere to poly-L-lysine-coated glass slides, mounted with anti-bleach reagent and analyzed by confocal microscopy (Leica AOBS SP2 confocal laser scanning microscope system containing a DM-IRE2 microscope with glycerol objective lens (PL APO 63×/NA1.30) was used; images were acquired using Leica confocal software (version 2.61)). We thank the staff of our animal facility for the care of the animals used in this study. We also thank Dr. B. J. Appelmelk
for kindly providing us the PAA-biotinylated glycans and Dr. S. van Vliet for critically reading the manuscript. S. K. S. was supported by NWO Mozaïek grant 017.001.136 from the Dutch Scientific Research program, E. S. by grant of the AICR 07-0163 and W. W. U. by grant SII071030 of SenterNovem. Conflict of interest: The authors declare no financial or commercial conflict of interest. Detailed facts of importance to specialist readers are published as ”Supporting BTK inhibitor Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made
available as submitted by the authors. “
“Common variable immunodeficiency disorders (CVIDs) are the most frequent symptomatic primary immunodeficiencies in adults. They comprise a heterogeneous group of pathologies, with frequent non-infectious complications in addition to the bacterial infections INCB018424 supplier that usually characterize their presentation. Complications include a high risk of malignancy, especially lymphoma and gastric cancer. Helicobacter pylori infection and pernicious anaemia are risk predictors for gastric cancer in the general population and probably in patients with CVIDs. Screening for gastric cancer in a high-risk
population appears to improve survival. Given the increased risk of gastric cancer in patients with CVIDs and prompted by a case of advanced gastric malignancy in a patient with a CVID and concomitant pernicious anaemia, we performed a review of the literature for gastric cancer and conducted a cohort study of gastric pathology in 116 patients with CVIDs under long-term follow-up in Oxford. Regardless of the presence of pernicious anaemia or H. pylori infection, patients with CVIDs have a 10-fold increased risk of gastric cancer Dehydratase and are therefore a high-risk population. Although endoscopic screening of all patients with CVIDs could be considered, a more selective approach is appropriate and we propose a surveillance protocol that should reduce modifiable risk factors such as H. pylori, in order to improve the management of patients with CVIDs at risk of gastric malignancy. The common variable immunodeficiency disorders (CVIDs) are a heterogeneous group of diseases characterized by primary antibody failure, although many patients with CVIDs also exhibit defects in cell-mediated immunity suggesting immune dysregulation . Such a diagnosis requires the exclusion of other known causes of hypogammaglobulinaemia .
is expressed in the pregnant endometrium in primates,58 rodents,60 and ruminants.61 However, the conceptus signal(s) inducing these changes in humans has not been defined, but it does not appear to be as a direct effect of hCG production. In addition, ISG15 is increased in PBL in cattle during early pregnancy.62,63 Ixazomib Whether similar increases in ISG15 in peripheral immune cells are induced during human pregnancy is not known. Nonetheless, hCG clearly alters circulating immune cell function in ways expected to result in immunosuppression. Komorowski et al.64 showed that hCG reduced IL-2 and increased sIL-2 receptor secretion by human PBMC. These two together would result in reduced peripheral T-cell activation in response to paternal alloantigens. In rodents treated with hCG peptides, there was evidence of reduced neutrophil migration to sites of Listeria monocytogenes replication associated with reduced chemokine production.65 These results are consistent with the observations that pregnant humans exhibit
increased susceptibility to this pathogen.66 T cells treated with recombinant hCG showed reduced proliferation, decreased IFN-γ secretion and increased IL-10 production.30 Furthermore, hCG reduced the ability of in vitro-matured dendritic cells to stimulate T cells, potentially contributing to peripheral tolerance during pregnancy.67,68 In addition, hCG stimulated PBMC to increase IL-8 production which would support embryo implantation.43 GSI-IX cost Taken together these studies provide strong support for a systemic, non-luteal
action for hCG targeting specific components of the circulating immune system. With the discovery and characterization of the systemic role for CG from the primate conceptus,1 numerous investigations were launched to determine if similar systemic actions were involved in pregnancy recognition in ruminants.69 These studies identified an early conceptus protein that, when introduced into the uterus in purified eltoprazine form, rescued the CL. This protein, first called ovine trophoblast protein-1 or trophoblastin, and later IFN-τ, blocked development of the uterine luteolytic mechanism through paracrine actions on the uterine endometrium.6 These studies all led to the conclusion that there was little evidence for a systemic effect of the ruminant conceptus on the CL. For example, Godkin et al.7 injected iodinated IFN-τ into the uterus and assayed various tissues, including blood, for radioactivity and found that only very small amounts of label escaped the uterus (<1%). There was no evidence of significant accumulation of labeled IFN-τ in the ovary, nor were they able to demonstrate that IFN-τ could enhance progesterone production by luteal cells in vitro even though luteal membrane preparations specifically bound labeled IFN-τ. Numerous attempts to detect IFN-τ in uterine venous blood by radioimmunoassay were unsuccessful.