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Mycoplasma contamination of cell lines is a common occurrence and may affect the cell line behaviour in a variety of ways. Contamination with mycoplasma is usually not obvious so cell lines should be frequently tested. Several commercially available kits for mycoplasma detection exist, however the Ph. Eur. culture method which can take several weeks to yield results is still considered to be the ‘gold standard’ method. There is therefore a need for rapid alternative methods with comparable sensitivity, specificity and species range. Here, we describe an internally-controlled Taqman-based real-time PCR assay for cell culture medium without the need for DNA extraction. The assay can detect less than 10 CFU of the most frequently encountered mycoplasma contaminants in mammalian cell cultures. The validated assay has the potential to be used as a routine test in the production of cell culture-based Biologicals.

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Mortality rates associated with C. gattii infections are estimated to be between 13% and 33%, depending on an individual’s predisposition, and C. gattii has caused at least 39 deaths in the PNW region. There have been four other international travel cases reported in patients from Europe and Asia with travel history to the PNW, but this report describes the first North American traveler who acquired C. deuterogattii infection presenting within the United States and the first case of a C. deuterogattii outbreak infection associated with anti-GM-CSF autoantibodies. Early and accurate diagnoses are important for disease prevention and treatment and for control of infectious diseases. Continual reporting of C. deuterogattii infections is necessary to raise awareness of the ongoing outbreak in the PNW and to alert travelers and physicians to the areas of endemicity with potential risks., The region encompassing the Pacific Northwest (PNW), Vancouver Island, Oregon, and Washington has been the location of an ongoing Cryptococcus gattii outbreak since the 1990s, and there is evidence that the outbreak is expanding along the West Coast into California. Here we report a clinical case of a 69-year-old, HIV-negative man from North Carolina who was diagnosed with a fungal brain mass by magnetic resonance imaging (MRI) and pathology. He had traveled to Seattle and Vancouver 3 years earlier and to Costa Rica 4 months prior to presentation. Phenotypic evidence showed that the fungal mass isolated from the patient’s brain represented C. gattii. In agreement with the phenotypic results, multilocus sequence typing (MLST) provided genotypic evidence that assigned the infecting organism within the C. gattii species complex and to the C. deuterogattii VGIIa clade. Whole-genome sequencing revealed >99.99% identity with the C. deuterogattii reference strain R265, indicating that the infecting strain is derived from the highly clonal outbreak strains in the PNW. We conclude that the patient acquired the C. gattii infection during his travel to the region 3 years prior and that the infection was dormant for an extended period of time before causing disease. The patient tested positive for anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, supporting earlier reports that implicate these autoantibodies as a risk factor associated with C. gattii infection.

TMEM16F is a Ca2+ -gated ion channel that is required for Ca2+ -activated phosphatidylserine exposure on the surface of many eukaryotic cells. TMEM16F is widely expressed and has roles in platelet activation during blood clotting, bone formation and T cell activation. By combining microscopy and patch clamp recording we demonstrate that activation of TMEM16F by Ca2+ ionophores in Jurkat T cells triggers large-scale surface membrane expansion in parallel with phospholipid scrambling. With continued ionophore application,TMEM16F-expressing cells then undergo extensive shedding of ectosomes. The T cell co-receptor PD-1 is selectively incorporated into ectosomes. This selectivity depends on its transmembrane sequence. Surprisingly, cells lacking TMEM16F not only fail to expand surface membrane in response to elevated cytoplasmic Ca2+, but instead undergo rapid massive endocytosis with PD-1 internalisation. These results establish a new role for TMEM16F as a regulator of Ca2+ activated membrane trafficking.

The Pacific Northwest (PNW), Vancouver Island, Oregon, and Washington have been the location of an ongoing Cryptococcus gattii outbreak since the 1990s, and there is evidence that the outbreak is expanding along the West Coast into California. Here we report a clinical case of a 69-year-old, HIV-negative man from North Carolina who was diagnosed with a fungal brain mass by magnetic resonance imaging (MRI) and pathology. He had traveled to Seattle and Vancouver three years earlier and Costa Rica four months prior to presentation. Phenotypic evidence shows the fungal mass isolated from the patient’s brain is C. gattii. In agreement with the phenotypic results, MLST provides genotypic evidence that assigns the infecting organism within in the C. gattii species complex and belonging to the C. deuterogattii VGIIa clade. Whole genome sequencing revealed >99.99% identity to the C. deuterogattii reference strain R265, indicating that the infecting strain is derived from the highly clonal outbreak strains in the PNW. We conclude the patient acquired the C. gattii infection during his travel to region three years prior and the infection was dormant for an extended period of time before causing disease. The patient tested positive for anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, supporting earlier reports that implicate these autoantibodies as a risk factor a risk factor associated with C. gattii infection.ImportanceMortality rates associated with C. gattii infections are estimated to be between 13% and 33% depending on an individual’s predisposition, and C. gattii has caused more at least 39 deaths in the PNW region. There have been four other international travel cases reported in patients from Europe and Asia with travel history to the PNW, but this study describes the first North American travel who acquired C. deuterogattii infection presenting within the United States, and the first case of a C. deuterogattii outbreak infection associated with anti-GM-CSF autoantibodies. Early and accurate diagnoses are important for disease prevention, treatment, and control of infectious diseases. Continual reporting of C. deuterogattii infections is necessary to raise awareness of the ongoing outbreak in the PNW and alert travelers and physicians to the endemic areas with potential risks.

TMEM16F, an ion channel gated by high cytoplasmic Ca2+, is required for cell surface phosphatidylserine exposure during platelet aggregation and T cell activation. Here we demonstrate in Jurkat T cells and HEK293 cells that TMEM16F activation triggers large-scale surface membrane expansion in parallel with lipid scrambling. Following TMEM16F mediated scrambling and surface expansion, cells undergo extensive membrane shedding. The membrane compartment that expands the cell surface does not recycle, nor does it involve endoplasmic reticulum or acidified lysosomes. Surprisingly, T cells lacking TMEM16F expression not only fail to scramble lipid and expand surface membrane, but instead undergo a rapid membrane internalization known as massive endocytosis (MEND) in response to the same Ca2+ stimulus as their parental cells. TMEM16F dependent membrane shedding and MEND traffic similar sets of membrane receptors from the cell surface. The selective participation of the T cell co-receptor PD-1 in this trafficking is determined by its single transmembrane domain, establishing a fundamental role for TMEM16F as a regulator of Ca2+-activated membrane trafficking.

There is no cure for HIV, largely because HIV establishes a small but sustained pool of latently infected cells that are not cleared by antiretroviral therapy (ART). Current strategies include firstly reactivating the latent HIV reservoir and then using T cell immunotherapy to clear reactivated cells. However, pre-ART CD8 T cell escape variants have been reported in the HIV reservoir, which may limit CD8 T cell recognition and clearance of HIV-infected cells. The extent of virus escape from T cells in the latent reservoir is unclear. HIV-specific T cell responses were comprehensively mapped across the Clade B HIV proteome by IFN-g ELISpot in 25 ART-suppressed participants. In parallel, replication competent viruses derived from supernatants of autologous resting CD4 T cells following mitogenic reactivation were sequenced. Peptides spanning virus variants within reactive T cell epitopes were synthesized and examined by ELISpot for evidence of escape, defined as ≥50% difference in T cell magnitude between peptide variants. No correlations were observed between the size of the latent HIV reservoir and either HIV-specific T cell breadth (1–19 epitopes) or magnitude (156–2855 SFU/M PBMCs). T cell escape was assessed in 17 participants. 39% of reactive T cell epitopes (48/124) harbored ≥1 amino acid variants in the sequenced latent reservoir. Of those 48, 20 afforded T cell escape, providing an overall escape frequency in the reservoir of 16% (20/124). These data show that the majority of replication competent latent HIV viruses do not harbor CD8 T cell escape mutants, suggesting that immunotherapy approaches that boost CD8 T cell responses can successfully target the latent reservoir in HIV curative and or remission strategies.

Antiretroviral therapy (ART) is unable to eradicate human immunodeficiency virus type 1 (HIV-1) infection. Therefore, there is an urgent need to develop novel therapies for this disease to augment anti-HIV immunity. T cell therapy is appealing in this regard as T cells have the ability to proliferate, migrate, and their antigen specificity reduces the possibility of off-target effects. However, past human studies in HIV-1 infection that administered T cells with limited specificity failed to provide ART-independent, long-term viral control. In this study, we sought to expand functional, broadly-specific cytotoxic T cells (HXTCs) from HIV-infected patients on suppressive ART as a first step toward developing cellular therapies for implementation in future HIV eradication protocols. Blood samples from seven HIV+ patients on suppressive ART were used to derive HXTCs. Multiantigen specificity was achieved by coculturing T cells with antigen-presenting cells pulsed with peptides representing Gag, Pol, and Nef. All but two lines were multispecific for all three antigens. HXTCs demonstrated efficacy as shown by release of proinflammatory cytokines, specific lysis of antigen-pulsed targets, and the ability to suppress HIV replication in vitro. In conclusion, we are able to generate broadly-specific cytotoxic T cell lines that simultaneously target multiple HIV antigens and show robust antiviral function.

Mycoplasma is a prokaryotic organism that is a frequent and occult contaminant of cell cultures. This organism can modify many aspects of cell physiology, rendering experiments that are conducted with contaminated cells worthless. Because of their small size, Mycoplasmas can pass through filters used to prevent bacterial and fungal contamination and potentially spread to all the cultures in a laboratory. It is essential that all new cell cultures entering a laboratory and all cell banks are tested for the presence of Mycoplasma. It is recommended that two techniques be used, selected from a PCR-based method, indirect staining and an agar and broth culture. This protocol describes these three tests for detecting Mycoplasma, which take from 1 d to 3-4 weeks, and such tests should be an obligatory component of quality control in every tissue culture laboratory.

Objectives The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and the possible relatedness between human and animal isolates were investigated among veterinary staff and hospitalized animals in a referral small animal hospital in the UK. Methods A total of 300 swab samples were taken from nasal and oral mucosae of 78 veterinary staff, 45 dogs, 12 cats and from 30 environmental surfaces. Staphylococci were isolated by selective enrichment and characterized by biochemical tests and antimicrobial disc susceptibility testing. MRSA isolates were genotypically confirmed by PCR and typed by PFGE. Results MRSA was isolated from 14 staff (17.9%), four dogs (9%), and three environmental sites (10%) yielding a total of 28 MRSA isolates. PFGE analysis revealed that most MRSA isolates were indistinguishable (56%) or closely related (26%) to EMRSA-15, one of the two epidemic MRSA strains dominant in UK hospitals. Like EMRSA-15, the predominant strain isolated from staff, dogs and environmental sites was resistant to fluoroquinolones in addition to all beta-lactams. Conclusions The study provides evidence of EMRSA-15 mucosal carriage in veterinary staff and hospitalized dogs, with the risk of MRSA carriage in veterinary staff being significantly higher than reported for the UK healthy community. EMRSA-15 was predominant in the hospital environment, including humans, dogs, and inanimate objects, but the mode by which the strain was introduced and spread remains uncertain.