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Influenza A virus infects many animal species. Zoonotic transmission allows for the introduction of novel influenza A virus strains to the human population, which has the potential to cause the [...]

Normal human skin was maintained in organ cultures for several days in Ham's F-10 medium with good preservation of the epidermal cells. When the partially purified IgG fraction from the pooled sera of patients with pemphigus vulgaris or pemphigus foliaceous was added to this culture system, after 24 hr some evidence of epidermal acantholysis was seen. By 72 hr, extensive suprabasilar epidermal acantholysis had occurred in which the acantholytic cells were indistinguishable histologically from the acantholytic cells in biopsies from skin lesions of patients with pemphigus vulgaris. In the control cultures (i.e., F-10 medium or F-10 medium + normal human serum IgG), none of these changes was seen. Direct immunofluorescent staining of these explants using fluorescein-labeled goat antihuman IgG showed that by 6 hr binding of the pemphigus IgG had occurred in the intercellular cement substance of the epidermis. The staining intensity was maximal by 18 to 20 hr. When the pemphigus serum was fractionated by DEAE-cellulose column chromatography, three major IgG-containing peaks (presumably IgG subclasses) were eluted which bound to the epidermal intercellular substance and caused acantholysis in culture. The complement system did not play a role in the antibody-induced acantholysis since complement was not included in this system and heating the reconstituted F-10 + pemphigus IgG for 1 hr at 58°C did not destroy the acantholytic activity. Autoradiographic experiments showed that after about 2 days in culture the rates of incorporation of RNA and protein precursors in the suprabasilar cells in the presence of pemphigus IgG were reduced to less than 10% of the normal IgG controls, whereas these synthetic activities of the basal cells were only slightly affected. These observations lead to the proposal that it is the interaction of the pemphigus autoantibody(s) with the suprabasilar epidermal cell which initiates and possibly sustains the process(es) of acantholysis. [ABSTRACT FROM AUTHOR]

Hydrocortisone, triamcinolone acetonide, aurothioglucose and soybean trypsin inhibitor were added to normal human skin explants cultured with IgG from pemphigus serum to determine if acantholysis could be prevented. At the therapeutic concentrations used none of these compounds prevented binding of the autoantibody to the epidermal target cells, and none prevented acantholysis. These experiments support the concepts that the pemphigus antibody alone is responsible for producing the acantholytic lesions of pemphigus, that the therapeutic effectiveness of steroids and gold salts is probably due to their ability to reduce serum autoantibody titres and that pemphigus acantholysis is probably not caused by a serine proteinase. [ABSTRACT FROM AUTHOR]

Human-to-swine transmission of seasonal influenza viruses has led to sustained human-like influenza viruses circulating in the U.S. swine population. While some reverse zoonotic-origin viruses adapt and become enzootic in swine, nascent reverse zoonoses may result in virus detections that are difficult to classify as "swine-origin" or "human-origin" due to the genetic similarity of circulating viruses. This is the case for human-origin influenza A(H1N1) pandemic 2009 (pdm09) viruses detected in pigs following numerous reverse zoonosis events since the 2009 pandemic. We report the identification of two human infections with A(H1N1)pdm09 viruses originating from swine hosts and classify them as "swine-origin" variant influenza viruses based on phylogenetic analysis and sequence comparison methods. Phylogenetic analyses of viral genomes from two cases revealed these viruses were reassortants containing A(H1N1)pdm09 hemagglutinin (HA) and neuraminidase (NA) genes with genetic combinations derived from the triple reassortant internal gene cassette. Follow-up investigations determined that one individual had direct exposure to swine in the week preceding illness onset, while another did not report swine exposure. The swine-origin A(H1N1) variant cases were resolved by full genome sequence comparison of the variant viruses to swine influenza genomes. However, if reassortment does not result in the acquisition of swine-associated genes and swine virus genomic sequences are not available from the exposure source, future cases may not be discernible. We have developed a pipeline that performs maximum likelihood analyses, a k-mer-based set difference algorithm, and random forest algorithms to identify swine-associated sequences in the hemagglutinin gene to differentiate between human-origin and swine-origin A(H1N1)pdm09 viruses. [ABSTRACT FROM AUTHOR]

On August 3, 2016, the Ohio Department of Health Laboratory reported to CDC that a respiratory specimen collected on July 28 from a male aged 13 years who attended an agricultural fair in Ohio during July 22-29, 2016, and subsequently developed a respiratory illness, tested positive by real-time reverse transcription-polymerase chain reaction (rRT-PCR) for influenza A(H3N2) variant* (H3N2v). The respiratory specimen was collected as part of routine influenza surveillance activities. The next day, CDC was notified of a child aged 9 years who was a swine exhibitor at an agricultural fair in Michigan who became ill on July 29, 2016, and tested positive for H3N2v virus at the Michigan Department of Health and Human Services Laboratory. Investigations by Michigan and Ohio health authorities identified 18 human infections linked to swine exhibits at agricultural fairs. To minimize transmission of influenza viruses from infected swine to visitors, agricultural fair organizers should consider prevention measures such as shortening the time swine are on the fairgrounds, isolating ill swine, maintaining a veterinarian on call, providing handwashing stations, and prohibiting food and beverages in animal barns. Persons at high risk for influenza-associated complications should be discouraged from entering swine barns.

The architectural factor HMGI-C is of considerable interest for its recognized roles in mammalian development and tumorigenesis. As a result, the identification of downstream target genes of HMGI-C is the present focus of active research. In vitro evidence from macrophage cell lines has previously suggested that Hmgi-c is necessary for the inducible activation of MuRantes expression. To attempt to verify this hypothesis, an in vivo analysis was performed that took advantage of the existence of the Hmgi-c null mouse strain. The ability of cells and tissues extracted from Hmgi-c null mice to express the inflammatory chemokine MuRantes was investigated. The investigation examined MuRantes expression in primary embryonic fibroblasts and fresh peritoneal macrophages after Newcastle disease virus induction and whole organs after lipopolysaccharide induction. Each of these systems clearly demonstrates that Hmgi-c is not required for the activation of MuRantes expression.