Maternal Antibiotic Treatment Impacts Development of the Neonatal Intestinal Microbiome and Antiviral Immunity.

Microbial colonization of the infant gastrointestinal tract (GIT) begins at birth, is shaped by the maternal microbiota, and is profoundly altered by antibiotic treatment. Antibiotic treatment of mothers during pregnancy influences colonization of the GIT microbiota of their infants. The role of the GIT microbiota in regulating adaptive immune function against systemic viral infections during infancy remains undefined. We used a mouse model of perinatal antibiotic exposure to examine the effect of GIT microbial dysbiosis on infant CD8(+) T cell-mediated antiviral immunity. Maternal antibiotic treatment/treated (MAT) during pregnancy and lactation resulted in profound alterations in the composition of the GIT microbiota in mothers and infants. Streptococcus spp. dominated the GIT microbiota of MAT mothers, whereas Enterococcus faecalis predominated within the MAT infant GIT. MAT infant mice subsequently exhibited increased and accelerated mortality following vaccinia virus infection. Ag-specific IFN-γ-producing CD8(+) T cells were reduced in sublethally infected MAT infant mice. MAT CD8(+) T cells from uninfected infant mice also demonstrated a reduced capacity to sustain IFN-γ production following in vitro activation. We additionally determined that control infant mice became more susceptible to infection if they were born in an animal facility using stricter standards of hygiene. These data indicate that undisturbed colonization and progression of the GIT microbiota during infancy are necessary to promote robust adaptive antiviral immune responses.

2-Methylpropyl ester of 3-(adenin-9-yl)-2-hydroxypropanoic acid. Mechanism of antiviral action in vaccinia virus-infected L929 cells.

Alkyl esters of (RS)-3-(adenin-9-yl)-2-hydroxypropanoic acid (AHPA) were shown recently to be broad spectrum antiviral agents (De Clercq E and Holy A, J Med Chem 28: 282-287, 1985). It was postulated that these alkyl esters function as prodrugs by undergoing hydrolysis catalyzed by cellular esters to AHPA, a known inhibitor of S-adenosyl-L-homocysteine (AdoHcy) hydrolase. In this study, we describe the metabolic fate of the 2-methylpropyl ester of AHPA (AHPA-iBu) in murine L929 cells. When AHPA-iBu was included in the culture medium, it was taken up rapidly by murine L929 cells. The uptake was time- and concentration-dependent, resulting in the intracellular accumulation of the free acid, AHPA. Treatment with AHPA-iBu caused inhibition of cellular AdoHcy hydrolase in both a time- and a dose-dependent manner. Complete inhibition of the enzyme was achieved after a 1-hr incubation in culture medium containing 50 microM AHPA-iBu. The inhibition of the enzyme caused cellular accumulation of AdoHcy and a significant increase in the ratio of AdoHcy/S-adenosyl-L-methionine (AdoMet). Partial recovery of the AdoHcy hydrolase activity in L929 cells treated with 50 microM AHPA-iBu was observed after 24 hr. This recovery of enzyme activity was paralleled by a significant decrease in the cellular levels of AdoHcy and the ratio of AdoHcy/AdoMet. AHPA-iBu also exerted an inhibition (IC50 = 0.17 microM) of vaccinia virus plaque formation in monolayers of L929 cells. A 1 microM concentration of AHPA-iBu, which caused 80% inhibition of plaque formation, produced a 17-fold increase in AdoHcy content in drug-treated, virus-infected cells versus non-drug-treated, virus-infected cells and a 15% undermethylation of the poly(A)+ RNA. These data show that AHPA-iBu is a prodrug for AHPA which inhibits cellular AdoHcy hydrolase. The inhibition of this enzyme elevates cellular levels of AdoHcy, creating an unfavorable environment which suppresses replication of vaccinia virus.

Mechanisms in the pathogenesis of post-infectious vaccinia virus encephalomyelitis in the mouse.

After intracranial replication of a neurotropic strain of vaccinia in mouse brain, analysis of the purified virus preparation reveals the presence of at least one host protein on the virus which was identified as the myelin basic protein. Vaccinia virus Elstree, a dermotropic virus may substitute for complete Freund's adjuvant (CFA) in inducing experimental allergic encephalomyelitis (EAE). Guinea pigs challenged with virus-myelin emulsions without CFA developed clinical and histological signs of EAE.

Vaccinia keratouveitis manifesting as a masquerade syndrome.

A patient who used contact lenses and had a history of blunt trauma developed vaccinia keratouveitis after accidental ocular autoinoculation from a recent vaccination site. Corneal and conjunctival cultures were taken for bacteria, fungi, Acanthamoeba, and viruses. Viral-like cytopathic effects became evident in tissue culture within three days. Immunofluorescence studies were negative for varicella-zoster virus, herpes simplex virus, adenovirus, measles, mumps, parainfluenza, and influenza. Pox viral particles were identified in the infected tissue cultures by electron microscopy. The Hind III restriction endonuclease profile of the viral DNA isolate was similar to the Lister strain of vaccinia virus. Ocular vaccinia may manifest as a masquerade syndrome and may mimic signs of herpes simplex virus, varicella-zoster virus, and Acanthamoeba infection. Although vaccination with vaccinia is currently limited to a few populations throughout the world, vaccinia must still be considered in the differential diagnosis of infectious keratouveitis.

[Morphological proof of vaccinia virus multiplication in enucleated cells]. / Morfologicheskie dokazatel'stva razmnozheniia virusa ospovaktsiny v énukleirovannykh kletkakh.

Primary monkey kidney cells were enucleated by the combined effect of cytochalasin B and ultracentrifugation. The effectiveness of enucleation in the experiments was 96-99%. Cytoplasts after 1-hour restoration were inoculated with the WR strain of vaccinia virus at a multiplicity of 0.1, 1.0, 10, and 50 PFU/cell. Within 20-21 h postinoculation when a marked cytopathic effect of the virus was evident, the material was fixed for electron microscopy. Serial ultrathin sections of the infected material were examined. Careful examination of the infected cytoplasts revealed all the usual stages of the morphogenetic cycle of vaccinia virus, from virion absorption by the host cell to clumps of mature virus particles in the cytoplasm and extracellularly. Vaccinia virus is thought to have morphologically complete replication cycle in the cytoplasts.

[Results of a study of the pathogenesis of postvaccinal encephalitis]. / Nekotorye itogi izucheniia patogeneza postvaktsinal'nykh éntsefalitov.

The results of 10-year virological and immunological studies in patients with postvaccination encephalitis (PVE) developing after smallpox vaccination are analysed. Vaccinia virus was isolated from 23 (59%) out of 39 children in the acute stage of PVE and for a long period in the protracted course of the disease in 14 out of 24 from the cerebrospinal fluid in 15 out of 33 from the blood, in 8 out of 24 from the throat and in 4 out of 5 from the brain or spinal cord tissue. Examinations of 56 serum specimens from 36 children with PVE revealed considerable variations in the levels of virus-neutralizing antibodies (VNA): 6 had no VNA, while 10 children showed low titres (10-20). No cases of agammaglobulinemia were observed. Instances of defective immune response were found which was manifested by a delay in increasing levels of IgM and IgG in response to vaccination. Two children were shown to have a defective cellular immunity. It is concluded that vaccinia virus participates in the pathogenesis of PVE; realization of the pathogenic properties of the virus requires the proper conditions, the main of which appears to consist in the immunodeficient state. The analysis of the appurtenance of 342 children to blood groups of the ABO system did not confirm the dependence of the development of postvaccination complications upon the presence in the blood of the vaccinees of the A antigen or immunological advantages of persons having alpha-isoantibodies.

[Effect of phosphonoacetic acid on experimental vaccinia infection]. / Vliianie fosfonouksusnoi kisloty na eksperimental'nuiu ospovaktsinal'nuiu infektsiiu.

The effect of phosphonoacetic acid (PAA) on reproduction of vaccinia virus in chick embryo fibroblast cultures and on the development of vaccinia virus infection in rabbits was studied. In vitro the preparation was tested as a solution, in vivo as a solution and ointment. In rabbits, the preparation was applied epicutaneously and inoculated subcutaneously and intravenously. All these routes were found to be effective. A single application conferred a much lower protective effect than daily administration for 4 days. Poly (I).poly (C) administered subcutaneously was found to be more effective than PAA. The latter in tissue culture exerted a marked inhibiting effect when used in a dose of 100 microgram/ml.

[Laboratory-confirmed case of human infection with ratpox (cowpox)]. / Laboratorno podtverzhdennyi sluchai zarazheniia cheloveka ospoi krys (ospoi korov).

The present work describes a case of human disease resulting from the bite of a white rat and caused by a biological variant of cowpox virus. The isolates obtained from the sick man and the white rats which had been the source of this infection proved to be identical and did not differ from the biological variants of cowpox virus, isolated earlier from white rats and carnivorous animals of the family Felidae. Thus, the possibility of ratpox (cowpox) transmission from sick rodents to man was established.

[Participation of vaccinia virus in the pathogenesis of different clinical forms of postvaccinal complications. I. Frequency of vaccinia virus detection in the vaccinted who have usual and complicated reactions to vaccination]. / Ob uchastii virusa vaktsiny v patogeneze razlichnykh klinicheskikh form postvaktsinal 'nykh oslozhnenii. Soobshchenie I. Chastota obnaruzheniia virusa vaktsiny u privitykh s obychnoi i oslozhnennoi reaktsiei na vaktsinatsiiu.

The virological examination of 1365 samples taken from 469 children vaccinated against smallpox revealed considerable differences in the frequency and the time of vaccinia virus detection in different clinical forms of postvaccinal pathology as compared with uncomplicated vaccinal process. During the postvaccinal period taking its normal course vaccinia virus was isolated from 7.3% of children only from the pharynx till day 8 following vaccination. In generalized and creeping vaccinia the virus was isolated from 71.4% of children, in postvaccinal encephalitis from 57.1% of children, in vaccinal angina frove-mentioned complications vaccinia virus was detected in the samples obtained from the patients till days 24, 35, 15 and 24 respectively. The etiopathogenetic role of vaccinia virus in a number of postvaccinal complications is discussed.

Characterisation of poxviruses from sporadic human infections.

An orthopoxvirus was isolated from the vesicular rash of a man in Natal who died in coma and who had not been vaccinated. Analysis of the viral DNA showed that it was a vaccinia virus, more closely related to the virus of South African smallpox vaccine than to other vaccinia viruses. DNA analysis also showed that an orthopoxvirus isolated from a sporadic case of severe pustular rash in Nigeria was a vaccinia virus closely related to the smallpox vaccine virus used there. Minor biological differences between the viruses isolated and the corresponding vaccine strains suggested that some natural transmission of the virus had occurred, but the results of DNA analysis implied that they originated from the use of smallpox vaccine. No similar cases have been detected since smallpox vaccination was discontinued.

Extracellular release of enveloped vaccinia virus from mouse nasal epithelial cells in vivo.

The release of vaccinia virus from mouse nasal epithelial cells infected in vivo was studied by electron microscopy. Intracellular naked vaccinia virus was enwrapped by Golgi membranes to form a double membrane intermediate. The outer membrane of the intermediate presumably fused with the plasma membrane, releasing extracellular enveloped virus. No signs of simple naked virus budding at the plasma membrane were observed. The majority of extracellular virus was enveloped and not naked.