Correction: Cross-presentation of a spread-defective MCMV is sufficient to prime the majority of virus-specific CD8+ T cells.

[This corrects the article DOI: 10.1371/journal.pone.0009681.].

Secondary hyperalgesia in the rat first degree burn model is independent of spinal cyclooxygenase and nitric oxide synthase.

Various animal models of pain are dependent on activation of different glutamate receptor subtypes. First degree burn of the paw elicits a secondary hyperalgesia that is dependent on Ca2+ permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), but not N-methyl-D-aspartate (NMDA) receptors. The present study takes advantage of that specificity by examining the effects of spinal pretreatments of agents on this secondary hyperalgesia. Rats with indwelling intrathecal catheters were pretreated with agents prior to paw injury. Mechanical withdrawal thresholds were measured before, and for three h after the injury. Spinal pretreatment with cyclooxygenase (10 and 30 microg (S)-(+)-ibuprofen; and 3 and 30 microg ketorolac) and nitric oxide synthase (33 and 100 microg N(G) Nitro-L-arginine methyl ester hydrochloride (L-NAME) and 10 microg thiocitrulline) inhibitors resulted in no specific anti-allodynia. In contrast, ziconotide (0.3, 1.0 and 3 microg), the N-type voltage gated calcium channel antagonist was very effective in blocking burn-induced sensitivity at all doses used. l-type (Diltiazam 230 microg) and P-type (Agatoxin IVA 0.3 microg) calcium channel blockers produced intermediate effects. Thus, cyclooxygenase and nitric oxide synthase are assumed not to be downstream of Ca2+ permeable AMPA receptors. Voltage gated calcium channels blockers could exert their effects either pre- or post-synaptically.

Pain experienced using two different methods of endometrial biopsy: a randomized controlled trial.

OBJECTIVE: To compare patient-reported pain, provider- reported ease of use, and tissue sampling adequacy between endometrial biopsy instruments. METHODS: Women presenting for endometrial biopsy were randomized to either Pipelle or Explora curette. The primary outcome was patient-reported pain with biopsy as measured by a 100-mm visual analog scale. Secondary outcomes included the adequacy of biopsy sample and provider-reported ease of instrument use. RESULTS: Groups were similar in respect to age, parity, ethnicity, level of dysmenorrhea, menopausal status, and biopsy indication. The most common indication for biopsy was abnormal uterine bleeding. Subject reported pain with biopsy was similar between groups (Pipelle, 6.21 ± 2.41 cm; Explora, 6.91 ± 2.88 cm; P=.14), as was provider-reported ease of use. Although procedure length was significantly shorter for patients in the Pipelle group (4.05 ± 1.48 minutes compared with 5.27 ± 2.53 minutes; P=.007), 38% of Pipelle procedures required two or more passes to obtain a sample compared with only 9% using the Explora (P=.004). The Explora group had a higher proportion of adequate samples (97% compared with 91%; P=.33). CONCLUSION: Women's pain during endometrial biopsy does not differ by type of biopsy instrument used. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov NCT00613925.

Cross-presentation of a spread-defective MCMV is sufficient to prime the majority of virus-specific CD8+ T cells.

CD8+ T cells can be primed by peptides derived from endogenous proteins (direct presentation), or exogenously acquired protein (cross-presentation). However, the relative ability of these two pathways to prime CD8+ T cells during a viral infection remains controversial. Cytomegaloviruses (CMVs) can infect professional antigen presenting cells (APCs), including dendritic cells, thus providing peptides for direct presentation. However, the viral immune evasion genes profoundly impair recognition of infected cells by CD8+ T cells. Nevertheless, CMV infection elicits a very strong CD8+ T cell response, prompting its recent use as a vaccine vector. We have shown previously that deleting the immune evasion genes from murine cytomegalovirus (MCMV) that target class I MHC presentation, has no impact on the size or breadth of the CD8+ T cell response elicited by infection, suggesting that the majority of MCMV-specific CD8+ T cells in vivo are not directly primed by infected professional APCs. Here we use a novel spread-defective mutant of MCMV, lacking the essential glycoprotein gL, to show that cross-presentation alone can account for the majority of MCMV-specific CD8+ T cell responses to the virus. Our data support the conclusion that cross-presentation is the primary mode of antigen presentation by which CD8+ T cells are primed during MCMV infection.

Investigation of the impact of the common animal facility contaminant murine norovirus on experimental murine cytomegalovirus infection.

Murine norovirus (MNV) is a recently discovered pathogen that has become a common contaminant of specific pathogen-free mouse colonies. MNV-1 induces a robust interferon-beta response and causes histopathology in some mouse strains, suggesting that it may impact other mouse models of infection. Despite many concerns about MNV-1 contamination, there is little information about its impact on immune responses to other infections. This study addresses whether MNV-1 infection has an effect on a model of murine cytomegalovirus (MCMV) infection. Exposure to MNV-1 resulted in a decreased CD8 T cell response to immunodominant MCMV epitopes in both BALB/c and C57BL/6 mice. However, MNV-1 did not impact MCMV titers in either mouse strain, nor did it stimulate reactivation of latent MCMV. These data suggest that while MNV-1 has a mild impact on the immune response to MCMV, it is not likely to affect most experimental outcomes in immunocompetent mice in the MCMV model.

MHC class I immune evasion in MCMV infection.

Murine cytomegalovirus (MCMV) is a well-studied model of natural beta-herpesvirus infection. However, many questions remain regarding its control by and evasion of the immune response it generates. CD8 and CD4 T cells have both unique and redundant roles in control of the virus that differ based on the immunocompetence of the infected mice. MCMV encodes major histocompatibility complex (MHC) class I immune evasion genes that can have an impact in vitro, but their role in infection of immunocompetent mice has been difficult to identify. This review addresses the evidence for their in vivo function and suggests why they may be evolutionarily conserved.

Viral interference with antigen presentation does not alter acute or chronic CD8 T cell immunodominance in murine cytomegalovirus infection.

Both human CMV and murine CMV (MCMV) elicit large CD8 T cell responses, despite the potent effects of viral genes that interfere with the MHC class I (MHC I) pathway of Ag presentation. To investigate the impact of immune evasion on CD8 T cell priming, we infected mice with wild-type (wt) MCMV or a mutant lacking its MHC I immune evasion genes, Deltam4+m6+m152 MCMV. In acute infection, the two viruses elicited a CD8 T cell response to 26 peptide epitopes that was virtually identical in total size, kinetics, and immunodominance hierarchy. This occurred despite results demonstrating that primary DCs are susceptible to the effects of MCMV's MHC I immune evasion genes. Eight months later, responses to both wt and mutant MCMV displayed the same CD8 T cell "memory inflation" and altered immunodominance that characterize the transition to chronic MCMV infection in C57BL/6 mice. Taken together, these findings suggest either that cross-priming dominates over direct CD8 T cell priming in both acute and chronic MCMV infection, or else that the MHC I immune evasion genes of MCMV are unable to alter direct CD8 T cell priming in vivo. At 2 years postinfection, differences in CD8 T cell immunodominance emerged between individual mice, but on average there were only slight differences between wt and mutant virus infections. Overall, the data indicate that the presence or absence of MHC I immune evasion genes has remarkably little impact on the size or specificity of the MCMV-specific CD8 T cell response over an entire lifetime of infection.

Genome-wide analysis reveals a highly diverse CD8 T cell response to murine cytomegalovirus.

Human CMV establishes a lifelong latent infection in the majority of people worldwide. Although most infections are asymptomatic, immunocompetent hosts devote an extraordinary amount of immune resources to virus control. To increase our understanding of CMV immunobiology in an animal model, we used a genomic approach to comprehensively map the C57BL/6 CD8 T cell response to murine CMV (MCMV). Responses to 27 viral proteins were detectable directly ex vivo, the most diverse CD8 T cell response yet described within an individual animal. Twenty-four peptide epitopes were mapped from 18 Ags, which together account for most of the MCMV-specific response. Most Ags were from genes expressed at early times, after viral genes that interfere with Ag presentation are expressed, consistent with the hypothesis that the CD8 T cell response to MCMV is largely driven by cross-presented Ag. Titration of peptide epitopes in a direct ex vivo intracellular cytokine staining assay revealed a wide range of functional avidities, with no obvious correlation between functional avidity and the strength of the response. The immunodominance hierarchy varied only slightly between mice and between experiments. However, H-2(b)-expressing mice with different genetic backgrounds responded preferentially to different epitopes, indicating that non-MHC-encoded factors contribute to immunodominance in the CD8 T cell response to MCMV.