Sperm donation: an alternative to improve post-ICSI live birth rates in advanced maternal age patients.

STUDY QUESTION: Can sperm donation increase live birth rates following ICSI in advanced maternal age (AMA) patients? SUMMARY ANSWER: Sperm donation increases the live birth rate in AMA ICSI cycles. WHAT IS KNOWN ALREADY: In ICSI practice, sperm donation has been predominantly applied to overcome male infertility. The involvement of paternal age and lower sperm quality in the severe reduction in fertility observed in AMA patients remains to be clarified. STUDY DESIGN, SIZE, DURATION: Retrospective multicenter cohort study including data generated between 2015 and 2019 from 755 ICSI cycles achieving a fresh embryo transfer, of which 337 were first homologous cycles (normozoospermic partner sperm and homologous oocytes) and 418 were first sperm donation cycles (donor sperm and homologous oocytes). The association of sperm origin (partner vs donor) with live birth was assessed by multivariate analysis in non-AMA (<37 years, n = 278) and AMA (≥37 years, n = 477) patients, separately, including in the model all variables previously found to be associated with live birth in a univariate analysis (number of MII oocytes recovered, number of embryos transferred, and maternal age). ICSI outcomes were compared between sperm donation and homologous cycles in overall, non-AMA and AMA patients. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was conducted in three fertility clinics and included 755 Caucasian patients aged 24-42 years undergoing their first homologous or sperm donation ICSI cycle achieving a fresh embryo transfer. MAIN RESULTS AND THE ROLE OF CHANCE: The multivariate analysis revealed that sperm donation was positively associated with the likelihood of a live birth independently of all other variables tested in AMA (P = 0.02), but not in non-AMA patients. Live birth, delivery, and miscarriage rates differed substantially between sperm donation and homologous AMA cycles; live birth and delivery rates were 70-75% higher (25.4% vs 14.5% and 22.5% vs 13.5%, respectively; P < 0.01), while miscarriage occurrence was less than half (18.0% vs 39.5%; P < 0.01) in sperm donation compared to homologous AMA cycles. LIMITATIONS, REASONS FOR CAUTION: This study is limited by its retrospective nature, differences in patients profiles between sperm donation and homologous-control groups and varying proportion of donor cycles between fertility centers, although these variations have been controlled for in the statistical analysis. WIDER IMPLICATIONS OF THE FINDINGS: The findings suggest that sperm donation increases live birth rates while reducing miscarriage occurrence in AMA patients, and thus may be a valid strategy to improve ICSI outcomes in this growing and challenging patient group. STUDY FUNDING/COMPETING INTEREST(S): N/A. TRIAL REGISTRATION NUMBER: N/A.

A novel transnational fresh oocyte donation (TOD) program based on transport of frozen sperm and embryos.

STUDY QUESTION: What is the clinical efficacy of an oocyte donation program based on the transportation of frozen semen and embryos between two countries? SUMMARY ANSWER: The transnational oocyte donation program is efficient and reliable and it could provide a first-line strategy to overcome the lack of donors in some countries. WHAT IS KNOWN ALREADY: While there is increasing need for donated oocytes, in many countries the availability of donors is still insufficient to cover the therapeutic demands, and patients are referred abroad for treatment. Since embryo cryopreservation is reliable and efficient, we propose a strategy based on frozen embryos instead of frozen oocytes to satisfy the increasing demand for cross border oocyte donation. STUDY DESIGN, SIZE, DURATION: This is a retrospective cohort study including 630 patients treated from December 2015 to July 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Infertile women were treated with elective vitrified-thawed embryo shipping and embryo transfer (ET) between two IVF clinics, one in Spain and one in Italy. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 2617 embryos were created for the 630 patients and the survival rate after warming was 98.5%. After the first ET the live birth rate (LBR) was 30.6%. In 476 patients (75.5%), embryos were transferred at the cleavage stage (Day 2 or 3) and the LBR was 29.2%. Vitrified blastocysts were available for 154 patients (24.5%) and the LBR was 35%. Among patients who did not achieve a pregnancy after the first frozen ET (FET), 92.5% had at least one frozen embryo for successive procedures. 213 patients underwent a second FET. The LBR at the second FET was 30%. The cumulative LBR at the end of the observation period was 39.3%. LIMITATIONS, REASONS FOR CAUTION: The study design was retrospective. A direct comparison with vitrified oocyte donors cycle and subsequent fresh ET would have permitted to compare this strategy versus the current standard based on vitrified gametes. WIDER IMPLICATIONS OF THE FINDINGS: The LBR found in our study is more than acceptable and seems to be higher than what reported with vitrified oocytes. The transnational fresh oocyte donation program may have several advantages over the shipment of vitrified oocytes: similarly to the fresh oocyte donation program it allows for personalized care in oocyte recipient, which is provided by assigning a flexible number of oocytes, and at the same time it maintains the benefit of a frozen ART program permitting scheduling flexibility. The TOD program is efficient and may be proposed as a first-line strategy for distance and inter-countries oocyte donation programs. STUDY FUNDING, COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER: NA.

Focused time-lapse analysis reveals novel aspects of human fertilization and suggests new parameters of embryo viability.

STUDY QUESTION: Can focused application of time-lapse microscopy (TLM) lead to a more detailed map of the morphokinetics of human fertilization, revealing novel or neglected aspects of this process? SUMMARY ANSWER: Intensive harnessing of TLM reveals novel or previously poorly characterised phenomena of fertilization, such as a cytoplasmic wave (CW) preceding pronuclear formation and kinetics of pronuclear chromatin polarization, thereby suggesting novel non-invasive biomarkers of embryo quality. WHAT IS KNOWN ALREADY: In recent years, human preimplantation development has been the object of TLM studies with the intent to develop morphokinetic algorithms able to predict blastocyst formation and implantation. Regardless, our appreciation of the morphokinetics of fertilization remains rather scarce, currently including only times of polar body II (PBII) emission, pronuclear appearance and fading, and first cleavage. This is not consistent with the complexity and importance of this process, calling for further TLM studies aimed at describing previously unrecognized or undetected morphokinetic events and identifying novel developmental biomarkers. STUDY DESIGN, SIZE, DURATION: The study involved a retrospective observation by TLM of the fertilization process in 500 oocytes utilized in consecutive ICSI cycles carried out in 2016. A maximum of five fertilized oocytes per patients were included in the analysis to reduce possible patient-specific biases. Oocytes of patients with different diagnoses of infertility where included in the analysis, while cases involving cryopreserved gametes or surgically retrieved sperm were excluded. PARTICIPANTS/MATERIALS, SETTINGS, METHODS: Microinjected oocytes where assessed by a combined TLM-culture system (Embryoscope). Oocytes that were not amenable to TLM assessment, due to excess of residual corona cells or inadequate orientation for the observation of PBII emission, were not analysed. We identified and monitored 28 parameters relevant to meiotic resumption, pronuclear dynamics, chromatin organization, and cytoplasmic/cortical modifications. Times (T) were expressed as mean ± SD hours post-insemination (p.i.) and analysed, where appropriate, by Paired T Student or Fisher's exact tests. MAIN RESULTS AND ROLE OF CHANCE: PBII emission was occasionally followed (4.3% of cases) by the transient appearance of a protrusion of the cell surface, the fertilization cone (FC), probably resulting from interaction of the male chromatin with the oocyte cortex. Pronuclear formation was always preceded by a radial CW originating from the initial position of the male pronucleus (PN) and extending towards the oocyte periphery. The appearance of the CW followed a precise sequence, occurring always 2-3 h after PBII emission and shortly before PN appearance. Male and female PN appeared virtually simultaneously at approximately 6.2 h p.i. However, while the female PN always formed cortically and near the site of emission of the PBII, the initial position of the male PN was cortical, intermediate, or central (15.2%, 31.2% and 53.6%, respectively). PN juxtaposition involved rapid and straight movement of the female PN towards the male PN. In addition, the initial position of male PN formation was predictive of the position of PN juxtaposition. It was also observed that nucleolar precursor bodies (NPBs) aligned along the juxtaposition area and this happened considerably earlier for the female PN (8.2 ± 2.6 vs.11.2 ± 4.1 h, P = 0.0001). Although it occurred rarely, displacement of juxtaposed PN to the cortex was strongly associated (P < 0.0001) with direct cleavage into three blastomeres at the first cell division. The times of PN breakdown and first cleavage showed a very consistent trend, occurring earlier or progressively later depending on whether initial male PN positioning was central, intermediate or cortical, respectively. Finally, time intervals between discrete fertilization events were strongly associated with embryo quality on Day 3. For example, longer intervals between disappearance of the cytoplasmic halo and PN breakdown were highly predictive of reduced blastomere number and increased fragmentation (P = 0.0001). LARGE SCALE DATA: N/A. LIMITATIONS, REASON FOR CAUTION: Some of the morphokinetic parameters assessed in this study may require better definition to reduce inter-operator annotation variability. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, overall, these data represent the most detailed morphokinetic description of human fertilization. Many of the illustrated parameters are novel and may be amenable to further elaboration into algorithms able to predict embryo quality, as suggested by the findings presented in this study. STUDY FUNDING/COMPETING INTERESTS: None.

Characterization of the human cumulus cell transcriptome during final follicular maturation and ovulation.

Cumulus expansion and oocyte maturation are central processes in ovulation. Knowledge gained from rodent and other mammalian models has revealed some of the molecular pathways associated with these processes. However, the equivalent pathways in humans have not been thoroughly studied and remain unidentified. Compact cumulus cells (CCs) from germinal vesicle cumulus oocyte complexes (COCs) were obtained from patients undergoing in vitro maturation (IVM) procedures. Expanded CCs from metaphase 2 COC were obtained from patients undergoing IVF/ICSI. Global transcriptome profiles of the samples were obtained using state-of-the-art RNA sequencing techniques. We identified 1746 differentially expressed (DE) genes between compact and expanded CCs. Most of these genes were involved in cellular growth and proliferation, cellular movement, cell cycle, cell-to-cell signaling and interaction, extracellular matrix and steroidogenesis. Out of the DE genes, we found 89 long noncoding RNAs, of which 12 are encoded within introns of genes known to be involved in granulosa cell processes. This suggests that unique noncoding RNA transcripts may contribute to the regulation of cumulus expansion and oocyte maturation. Using global transcriptome sequencing, we were able to generate a library of genes regulated during cumulus expansion and oocyte maturation processes. Analysis of these genes allowed us to identify important new genes and noncoding RNAs potentially involved in COC maturation and cumulus expansion. These results may increase our understanding of the process of oocyte maturation and could ultimately improve the efficacy of IVM treatment.

Anti-Müllerian hormone remains highly expressed in human cumulus cells during the final stages of folliculogenesis.

This study evaluated whether anti-Müllerian hormone (AMH) was differentially expressed in cumulus (CC) and granulosa (GC) cells from large antral and pre-ovulatory follicles collected from individual follicles in women undergoing in-vitro maturation (IVM) or IVF treatment. Expression studies of AMH, AMH receptor 2, FSH receptor, aromatase and androgen receptor were performed in CC in IVM patients where cumulus-oocyte-complex had expanded, CC in IVM patients where cumulus-oocyte-complex remained compacted, GC from immature follicles and CC and GC from IVF patients. Microarray data on corresponding GC and CC from follicles from IVF patients was included. AMH expression was significantly higher in CC than in GC from both mature and immature follicles and in CC from immature follicles than in CC from pre-ovulatory follicles from IVF patients (P < 0.05). AMH expression was significantly higher in CC that remained compacted compared with those that had expanded (P < 0.008). AMH was correlated to the expression of FSH receptor, androgen receptor and AMH receptor 2 but not to aromatase expression. The expression pattern of AMH receptor 2 reflected that of AMH. AMH may exert intrafollicular functions even in human large antral and pre-ovulatory follicles and may be related to follicular health.

Functional evidence for epitope spreading in the relapsing pathology of experimental autoimmune encephalomyelitis.

The role of epitope spreading in the pathology of relapsing-remitting experimental autoimmune encephalomyelitis (R-EAE) was examined. Using peripherally induced immunologic tolerance as a probe to analyze the neuropathologic T cell repertoire, we show that the majority of the immunopathologic reactivity during the acute phase of R-EAE in SJL/J mice induced by active immunization with the intact proteolipid (PLP) molecule is directed at the PLP139-151 epitope and that responses to secondary encephalitogenic PLP epitopes may contribute to the later relapsing phases of disease. Intermolecular epitope spreading was demonstrated by showing the development of T cell responses to PLP139-151 after acute disease in mice in which R-EAE was initiated by the transfer of T cells specific for the non-cross-reactive MBP84-104 determinant. Intramolecular epitope spreading was demonstrated by showing that endogenous host T cells specific for a secondary encephalitogenic PLP epitope (PLP178-191) are demonstrable by both splenic T cell proliferative and in vivo delayed-type hypersensitivity responses in mice in which acute central nervous system damage was initiated by T cells reactive with the immunodominant, non-cross-reactive PLP139-151 sequence. The PLP178-191-specific responses are activated as a result of and correlate with the degree of acute tissue damage, since they do not develop in mice tolerized to the initiating epitope before expression of acute disease. Most importantly, we show that the PLP178-191-specific responses are capable of mediating R-EAE upon adoptive secondary transfer to naive recipient mice. Furthermore, induction of tolerance to intact PLP (which inhibits responses to both the initiating PLP139-151 epitope and to the PLP178-191 epitope) after the acute disease episode is sufficient to prevent relapsing disease. These results strongly support a contributory role of T cell responses to epitopes released as a result of acute tissue damage to the immunopathogenesis of relapsing clinical episodes and have important implications for the design of antigen-specific immunotherapies for the treatment of chronic autoimmune disorders in humans.

Exploring the pros and cons of new approaches for gamete cross-border donation based on fresh and vitrified oocytes.

As highlighted by European statistics, the employment of donor oocytes is a growing option for women who cannot make use of their own gametes. As the potential recipients are continuously increasing in number, a donor programme which satisfies this demand is mandatory. Improvements in cryopreservation techniques, like oocyte and embryo vitrification, have led to the overcoming of the sequence of stimulation-retrieval-transfer both from a spatial and a temporal point of view, with the development of cryobanks of oocytes permitting crossborder donation. However, while some studies report comparable success when using vitrified and fresh oocytes we still need to investigate whether the use of fresh oocytes give higher live birth rate than cryopreserved ones, when the same number of oocytes are given. The performance of embryo cryopreservation, conversely, seems to be more reliable. A novel approach based on the shipment of frozen sperm from the recipient's country to the oocyte donor's one, where fresh oocytes are inseminated and the resulting embryos frozen and transported back to the referring IVF centre to perform a frozen embryo transfer may be a good strategy. We believe that the use of frozen embryos from fresh oocytes could be associated with a higher cumulative live birth rate per cycle, while favouring personalised oocyte recipient care with a flexible number of oocytes assigned and limiting the burden of travelling abroad.

Theiler's virus-induced demyelination: prevention by immunosuppression.

The effect of immunosuppression with cyclophosphamide and rabbit antiserum to mouse thymocytes on demyelination induced by Theiler's virus in SJL/J mice was ascertained from Epon-embedded sections (1 micrometer) of the central nervous system. Immunosuppression not only eliminated mononuclear cell infiltrates in the spinal cord white matter, but it also prevented the occurrence of demyelination. These results suggest that demyelination in this infection is immune-mediated.

Detection of AIDS virus in macrophages in brain tissue from AIDS patients with encephalopathy.

One of the common neurological complications in patients with the acquired immune deficiency syndrome (AIDS) is a subacute encephalopathy with progressive dementia. By using the techniques of cocultivation for virus isolation, in situ hybridization, immunocytochemistry, and transmission electron microscopy, the identity of an important cell type that supports replication of the AIDS retrovirus in brain tissue was determined in two affected individuals. These cells were mononucleated and multinucleated macrophages that actively synthesized viral RNA and produced progeny virions in the brains of the patients. Infected brain macrophages may serve as a reservoir for virus and as a vehicle for viral dissemination in the infected host.

Motor neuron degeneration in mice that express a human Cu,Zn superoxide dismutase mutation.

Mutations of human Cu,Zn superoxide dismutase (SOD) are found in about 20 percent of patients with familial amyotrophic lateral sclerosis (ALS). Expression of high levels of human SOD containing a substitution of glycine to alanine at position 93--a change that has little effect on enzyme activity--caused motor neuron disease in transgenic mice. The mice became paralyzed in one or more limbs as a result of motor neuron loss from the spinal cord and died by 5 to 6 months of age. The results show that dominant, gain-of-function mutations in SOD contribute to the pathogenesis of familial ALS.

Predictive factors in in-vitro maturation in unstimulated women with normal ovaries.

The in-vitro maturation protocol (IVM) is an intriguing tool in assisted reproduction since it omits the side-effects of drug stimulation and reduces the cost of the entire procedure, both in terms of time and patient/society costs. In the Biogenesi Reproductive Medicine Centre, the IVM technique has been applied for more than 3 years, obtaining successful results in terms of maturation and fertilization rates, number of pregnancies and healthy babies born. At present, IVM is widely accepted in polycystic ovary and polycystic ovarian syndrome patients but its application in other women is still controversial. This study has been carried out in order to determine the efficiency of unstimulated IVM in women with morphologically and endocrinologically normal ovaries. Body mass index, basal FSH and oestradiol concentrations, antral follicle count, endometrial thickness and lead follicle size were correlated with the outcome of the procedure so as to obtain useful criteria to select women with regular cycles for an IVM technique. It was found that basal oestradiol concentration, FSH concentration and antral follicle count are useful criteria in deciding whether to start and continue the procedure, while lead follicle size and endometrial thickness are important criteria in deciding the timing of oocyte retrieval.

Human oocyte cryopreservation: comparison between slow and ultrarapid methods.

The success of reproductive technologies is facilitated by the cryopreservation of embryos and gametes. In Italy, where legislation prohibits zygote and embryo cryopreservation, clinics have extensively introduced oocyte cryopreservation. Two different strategies of oocyte cryopreservation are available: slow freezing or ultrarapid cooling (vitrification). Although the results are very encouraging with both methods, there is still controversy regarding both the procedure itself and the most suitable method to use. This study reports the routine application of the two different oocyte cryopreservation methods in programmes running in two consecutive periods. The study centre carried out 286 thawing cycles for a total of 1348 thawed oocytes cryopreserved by the slow-freezing method and 59 warming cycles for a total of 285 warmed oocytes cryopreserved by vitrification. Comparison of the outcomes obtained with the slow-freezing method versus vitrification in women who underwent IVF for infertility showed survival, fertilization, pregnancy and implantation rates of 57.9% versus 78.9% (P < 0.0001), 64.6% versus 72.8% (P = 0.027), 7.6% versus 18.2% (P = 0.021) and 4.3% versus 9.3% (P = 0.043) respectively. These results suggest that oocyte vitrification is associated with a better outcome than the slow-freezing method.

Effect of different gonadotrophin priming on IVM of oocytes from women with normal ovaries: a prospective randomized study.

This study was designed to determine if the efficiency of in-vitro maturation (IVM) in women with normal ovaries can be improved by gonadotrophin administration. 400 women were randomly allocated in four groups: group A, non-primed cycles; group B, human chorionic gonadotrophin (HCG)-primed cycles; group C, FSH-primed cycles; and group D, FSH- plus HCG-primed cycles. There were significant differences in the IVM rate among the groups. In groups where HCG was used, the overall maturation rate was higher (57.9% in group B and 77.4% in group D; 48.4% in group A and 50.8% in group C) and the percentage of total available metaphase II-stage oocytes was higher (60.4% in group B and 82.1% in group D; 48.4% in group A and 50.8% in group C). The overall clinical pregnancy rate per transfer (CPR) was 18.3% and the implantation rate (IR) was 10.6%. There was a difference in CPR among the groups: group D (29.9%) versus group A (15.3%), P = 0.023; group D versus group B (7.6%), P < 0.0001; group D versus group C (17.3%), P = 0.046. The results of this study are clearly in favour of FSH plus HCG priming. FSH priming and HCG priming alone showed no significant effects on clinical outcome.

Characterization of the miRNA regulators of the human ovulatory cascade.

Ovarian follicular development and ovulation are complex and tightly regulated processes that involve regulation by microRNAs (miRNAs). We previously identified differentially expressed mRNAs between human cumulus granulosa cells (CGCs) from immature early antral follicles (germinal vesicle - GV) and mature preovulatory follicles (metaphase II - M2). In this study, we performed an integrated analysis of the transcriptome and miRNome in CGCs obtained from the GV cumulus-oocyte complex (COC) obtained from IVM and M2 COC obtained from IVF. A total of 43 differentially expressed miRNAs were identified. Using Ingenuity IPA analysis, we identified 7288 potential miRNA-regulated target genes. Two hundred thirty-four of these target genes were also found in our previously generated ovulatory gene library while exhibiting anti-correlated expression to the identified miRNAs. IPA pathway analysis suggested that miR-21 and FOXM1 cooperatively inhibit CDC25A, TOP2A and PRC1. We identified a mechanism for the temporary inhibition of VEGF during ovulation by TGFB1, miR-16-5p and miR-34a-5p. The linkage bioinformatics analysis between the libraries of the coding genes from our preliminary study with the newly generated library of regulatory miRNAs provides us a comprehensive, integrated overview of the miRNA-mRNA co-regulatory networks that may play a key role in controlling post-transcriptomic regulation of the ovulatory process.

Fas-mediated apoptosis in clinical remissions of relapsing experimental autoimmune encephalomyelitis.

PLP139-51-induced experimental autoimmune encephalomyelitis (R-EAE) displays a relapsing-remitting paralytic course in female SJL mice. We investigated the role of apoptosis/activation-induced cell death (AICD) in the spontaneous recovery from acute disease. Clinical EAE was significantly enhanced in Fas (CD95/APO-1)-deficient SJL lpr/lpr mice, which displayed significantly increased mean peak clinical scores, reduced remission rates, and increased mortality when compared with their SJL +/lpr littermates. PLP139-151-specific proliferative responses were fairly equivalent in the 2 groups, but draining lymph node T cells from SJL lpr/lpr mice produced dramatically increased levels of IFN-gamma. Central nervous system (CNS) Fas and FasL mRNA levels in wild-type SJL (H-2(s)) mice peaked just before spontaneous disease remission and gradually declined as disease remitted. We applied the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay to detect apoptosis in situ in spinal cords of mice at various clinical stages of EAE. Most TUNEL(+) cells were found during active periods of inflammation: the acute, peak, and relapse time points. Significantly fewer apoptotic cells were observed at preclinical and remission time points. Collectively, these findings indicate that Fas-mediated apoptosis/AICD plays a major role in the spontaneous remission after the initial acute inflammatory episode and represents an important intrinsic mechanism in regulation of autoimmune responses.

A virus-induced molecular mimicry model of multiple sclerosis.

Molecular mimicry is the process by which virus infection activates T cells that are cross-reactive with self antigens. Infection of SJL/J mice with the neurotropic picornavirus Theiler's murine encephalomyelitis virus (TMEV) leads to a progressive CD4(+) T cell-mediated demyelinating disease similar to multiple sclerosis. To study the potential of virus-induced molecular mimicry to initiate autoimmune demyelination, a nonpathogenic TMEV variant was engineered to encode a 30-mer peptide encompassing the immunodominant encephalitogenic myelin proteolipid protein (PLP139-151) epitope. Infection with the PLP139-151-encoding TMEV led within 10-14 days to a rapid-onset paralytic demyelinating disease characterized by PLP139-151-specific CD4(+) Th1 responses; insertion of a non-self ovalbumin sequence led to restoration of the normal late-onset disease. Early-onset disease was also observed in mice infected with a TMEV encoding PLP139-151 with an amino acid substitution at the secondary T cell receptor (TCR) contact residue (H147A), but not in mice infected with TMEV encoding a PLP139-151 substitution at the primary TCR contact (W144A). Most significantly, mice infected with TMEV encoding a Haemophilus influenzae mimic peptide, sharing only 6 of 13 amino acids with PLP139-151, displayed rapid-onset disease and developed cross-reactive PLP139-151-specific CD4(+) Th1 responses. To our knowledge, this is the first study showing that a naturally infectious virus encoding a myelin epitope mimic can directly initiate organ-specific T cell-mediated autoimmunity.

Mechanisms of immunotherapeutic intervention by anti-CD40L (CD154) antibody in an animal model of multiple sclerosis.

Relapsing experimental autoimmune encephalomyelitis (R-EAE) in the SJL mouse is a Th1-mediated autoimmune demyelinating disease model for human multiple sclerosis and is characterized by infiltration of the central nervous system (CNS) by Th1 cells and macrophages. Disease relapses are mediated by T cells specific for endogenous myelin epitopes released during acute disease, reflecting a critical role for epitope spreading in the perpetuation of chronic central CNS pathology. We asked whether blockade of the CD40-CD154 (CD40L) costimulatory pathway could suppress relapses in mice with established R-EAE. Anti-CD154 antibody treatment at either the peak of acute disease or during remission effectively blocked clinical disease progression and CNS inflammation. This treatment blocked Th1 differentiation and effector function rather than expansion of myelin-specific T cells. Although T-cell proliferation and production of interleukin (IL)-2, IL-4, IL-5, and IL-10 were normal, antibody treatment severely inhibited interferon-gamma production, myelin peptide-specific delayed-type hypersensitivity responses, and induction of encephalitogenic effector cells. Anti-CD154 antibody treatment also impaired the expression of clinical disease in adoptive recipients of encephalitogenic T cells, suggesting that CD40-CD154 interactions may be involved in directing the CNS migration of these cells and/or in their effector ability to activate CNS macrophages/microglia. Thus, blockade of CD154-CD40 interactions is a promising immunotherapeutic strategy for treatment of ongoing T cell-mediated autoimmune diseases.

Ultrastructural immunohistochemical localization of poliovirus during virulent infection of mice.

Ultrastructural immunohistochemistry was used to localize type 2 human poliovirus (HPV 2) during virulent infection of mice caused by the Lansing strain. In the spinal cord, immune-reaction product was exclusively localized within neurons and their processes. The absence of viral antigen in glial, endothelial and inflammatory cells further supports the strict neuronotropicity of HPV. In addition, viral antigen and virus-like particles were localized in synaptic complexes and axons, including preterminal axons. This clear demonstration of HPV in neuronal cell bodies, their axons, and synaptic elements strongly supports the hypothesis of HPV dissemination in the central nervous system via axonal transport.