The use of Random Homozygous Gene Perturbation to identify novel host-oriented targets for influenza.

Conventional approaches for therapeutic targeting of viral pathogens have consistently faced obstacles arising from the development of resistant strains and a lack of broad-spectrum application. Influenza represents a particularly problematic therapeutic challenge since high viral mutation rates have often confounded many conventional antivirals. Newly emerging or engineered strains of influenza represent an even greater threat as typified by recent interest in avian subtypes of influenza. Based on the limitations associated with targeting virally-encoded molecules, we have taken an orthogonal approach of targeting host pathways in a manner that prevents viral propagation or spares the host from virus-mediated pathogenicity. To this end, we report herein the application of an improved technology for target discovery, Random Homozygous Gene Perturbation (RHGP), to identify host-oriented targets that are well-tolerated in normal cells but that prevent influenza-mediated killing of host cells. Improvements in RHGP facilitated a thorough screening of the entire genome, both for overexpression or loss of expression, to identify targets that render host cells resistant to influenza infection. We identify a set of host-oriented targets that prevent influenza killing of host cells and validate these targets using multiple approaches. These studies provide further support for a new paradigm to combat viral disease and demonstrate the power of RHGP to identify novel targets and mechanisms.

Anti-ganglioside antibody induction by swine (A/NJ/1976/H1N1) and other influenza vaccines: insights into vaccine-associated Guillain-Barré syndrome.

BACKGROUND: Receipt of an A/NJ/1976/H1N1 "swine flu" vaccine in 1976, unlike receipt of influenza vaccines used in subsequent years, was strongly associated with the development of the neurologic disorder Guillain-Barré syndrome (GBS). Anti-ganglioside antibodies (e.g., anti-GM(1)) are associated with the development of GBS, and we hypothesized that the swine flu vaccine contained contaminating moieties (such as Campylobacter jejuni antigens that mimic human gangliosides or other vaccine components) that elicited an anti-GM(1) antibody response in susceptible recipients. METHODS: Surviving samples of monovalent and bivalent 1976 vaccine, comprising those from 3 manufacturers and 11 lot numbers, along with several contemporary vaccines were tested for hemagglutinin (HA) activity, the presence of Campylobacter DNA, and the ability to induce anti-Campylobacter and anti-GM(1) antibodies after inoculation into C3H/HeN mice. RESULTS: We found that, although C. jejuni was not detected in 1976 swine flu vaccines, these vaccines induced anti-GM(1) antibodies in mice, as did vaccines from 1991-1992 and 2004-2005. Preliminary studies suggest that the influenza HA induces anti-GM(1) antibodies. CONCLUSIONS: Influenza vaccines contain structures that can induce anti-GM(1) antibodies after inoculation into mice. Further research into influenza vaccine components that elicit anti-ganglioside responses and the role played by these antibodies (if any) in vaccine-associated GBS is warranted.

Patterns of Guillain-Barre syndrome in children: results from a Mexican population.

BACKGROUND: Guillain-Barré syndrome (GBS) is an acute, immune-mediated flaccid paralysis frequently associated with Campylobacter infection. Of two predominant GBS subtypes, a demyelinating subtype (acute inflammatory demyelinative polyneuropathy [AIDP]) predominates in the United States and Europe, and axonal subtype (acute motor axonal neuropathy [AMAN]) is the predominant form in China. Previous clinical studies suggested that AMAN also occurs in Mexican children. The purpose of this study was to describe the subtypes of GBS in children from Mexico City. METHODS: We prospectively studied 121 children admitted to two pediatric hospitals in Mexico City from 1996 to 2002. Clinical histories were obtained, electrophysiologic studies were performed to determine GBS subtype, and microbiologic studies were performed. RESULTS: Of the 121 children, 46 had AMAN and 32 had AIDP. The male to female ratio was 1.3 for AMAN cases (mean age = 6.3) and 3.0 for AIDP cases (mean age = 7.0). There was a strong seasonal distribution of AMAN cases in July to September. Children with AMAN, but not AIDP, had worsening of illness during hospitalization as judged by peak severity scores. Vomiting was more likely in AIDP (28.1%) vs AMAN (6.5%) (p = 0.012) and diarrhea was more common in AMAN (32.6%) than AIDP (12.5%) (p = 0.06). IgG anti-GM1 antibody titers were higher in patients with AMAN vs AIDP (p = 0.067). Anti-GD1a antibodies were equally present in both groups. Anti GQ1b titers were higher in AMAN vs AIDP (p = 0.009). Campylobacter antibody responses were positive in 44.1% of patients with AMAN and 37.0% of patients with AIDP. Twenty patients (14 = AMAN, 6 = AIDP) had positive stool cultures for C jejuni. Two serotypes, HS:19 and HS:41, accounted for 6 of 10 Campylobacter isolates available for serotyping from these cases. CONCLUSIONS: This study confirms that acute motor axonal neuropathy is an important Guillain-Barré syndrome subtype in Mexican children, is associated with diarrhea, and occurs seasonally.

Molecular mimicry in Campylobacter jejuni: role of the lipo-oligosaccharide core oligosaccharide in inducing anti-ganglioside antibodies.

Campylobacter jejuni is recognized as the most common identifiable pathogen associated with the development of Guillain-Barré syndrome (GBS), an acute autoimmune-mediated disease affecting the peripheral nervous system. The immune response to ganglioside-like structures in lipo-oligosaccharides (LOSs) of certain C. jejuni strains is thought to cross-react with human nerve gangliosides and induce GBS. To study the involvement of LOSs in the pathogenesis of Campylobacter-induced GBS, we created truncated LOS molecules by inactivating the waaF gene in a GBS-associated isolate of C. jejuni. Gas Chromatography-MS analysis of the waaF mutant LOSs revealed a marked reduction in sugar content, including sialic acid and galactose. GM1 and GD1a-like mimicry was not detected in the waaF mutant by Western blot analysis with cholera toxin B and anti-GD1a antibodies. Mice immunized with the waaF mutant failed to develop anti-GM1 or anti-GD1a antibodies. The waaF mutant also showed reduced adherence to and invasion of INT-407 cells. The results indicate that the LOS of C. jejuni HB93-13 is essential for adherence and invasion as well as for anti-ganglioside antibody induction.

Increasing fluoroquinolone resistance in Campylobacter jejuni, Pennsylvania, USA,1982-2001.

Fluoroquinolone-resistant Campylobacter jejuni has been observed worldwide and is now being seen in the United States. Among patients in our health-care system in Pennsylvania, fluoroquinolone-resistant C. jejuni were not observed from 1982 to 1992; however, resistance increased to 40.5% in 2001. Resistance to erythromycin remains at a low level (<5%).

Campylobacter jejuni from patients with Guillain-Barré syndrome preferentially expresses a GD(1a)-like epitope.

GM(1)- and GD(1a)-like ganglioside mimicry in Campylobacter jejuni lipooligosaccharide (LOS) is considered to be involved in the pathogenesis of Campylobacter-induced Guillain-Barré syndrome (GBS). Compared with gastroenteritis-related isolates, GBS-related C. jejuni isolates were strongly associated with the expression of GD(1a)-like mimicry. The presence of a few genes involved in LOS ganglioside mimicry, cst-II, cgtA, and cgtB, was also associated with GBS-related strains. GD(1a)-like epitope expression may be an important virulence phenotype associated with the risk of developing GBS following campylobacter infection.