In vivo and in vitro activity of Streptococcus faecium extract on Herpes simplex virus

The effects of substance or substance extracted from Str. faecium SF 68 on HSV-1 are evaluated. The "in vivo" assay show that bacterial extract introduced i.p. in mice simultaneously with HSV-1 brought about 100% of survival, but bacterial extract after virus challenge brought about complete mortality of mice. "In vitro" assays show that bacterial extract reduce significantly PFU number. It seemed that Str. faecium extract affected the virus at the stage of adsorption on the host cells.     

单纯疱疹病毒致病模型的研究

对单纯疱疹病毒（HSV）感染小白鼠致病特点进行了观察。小白鼠感染HSV第4天后开始发病,感染后2h血液内可分离出病毒,第48小时病毒血症水平和病毒检出率较高。不同组织病毒分布不同,脑、神经节在感染后第72小时病毒滴度较高,心、肝组织在第5天达到高峰。结果说明所建立的HSV致病模型可用于评价抗HSV药物。     

Studies on the Neutralization of Herpes Simplex Virus

Millipore-filtered herpes virus and a hyperimmune rabbit serum were reacted to analyze the unneutralizable persistent fraction (PF). When the PF was serially diluted with antibody-containing diluent, the plaque-formers reduced in number. When the serial dilutions were made with antibody-free diluent, plaque numbers were disproportionately smaller in lower dilutions. The PF filtered through a 0.22μ Millipore membrane showed only a slight loss of infectivity, but a further incubation of the filtrate at 37 C resulted in a marked reduction of titer. This effect was less pronounced when the membrane porosity was larger. Additional virus given to the PF was quickly neutralized by excess antibody. On the other hand, dilution of the virus–serum mixture followed by incubation at 37 C or sonication did not further reactivate the virus. When neutral complexes were sedimented by ultra-centrifugation and resuspended in antibody-free diluent, a partial reactivation slightly exceeding the usual PF level occurred with a concomitant release of antibody. It is proposed that the PF may be free virus resulting from reversible virus-antibody reaction.     

Studies on the Neutralization of Herpes Simplex Virus

Herpes virus was reacted with an early rabbit antiserum containing predominantly complement-requiring neutralizing (CRN) antibody to produce CRN-antibody-sensitized virus (SV), and the action of complement (C') upon SV was studied. Reduction of infectivity due to C' was about equal with undiluted and 1000-fold diluted SV. Even higher dilutions which contained about 10 to 100 infectious units per 0.05 ml were also completely inactivated by C'. Kinetic experiments revealed that the velocity of titer reduction in the presence of C' of 100-fold diluted SV was not slower than that of undiluted SV. When SV was first treated with C' and then diluted 100-fold, the surviving virus showed but a slightly reduced efficiency of filtration through the 0.45 μ Millipore membrane as compared with SV first diluted 1: 100 and then treated with C'. The titer reduction of SV–C'1 complexes in the presence of C'4 followed a one-hit curve. These results indicated that the reduction of infectivity of SV due to C' was not a result of immunoaggregation of infectious SV. Alternative possible mechanisms of the action of C' are discussed.     

Studies on the Neutralization of Herpes Simplex Virus

A portion of the seed virus remained active even in the presence of excess antibody. With an early serum or relatively low concentrations of a hyperimmune serum, the presence of such unneutralizable virus was uncovered by the addition of complement. This unneutralizable persistent fraction (PF) was distinguished from sensitized virus surviving in insufficient antibody, because the latter was inactivated by a high concentration of antibody as quickly as the control virus. The level of the PF was constant regardless of the serum species, serum lot, dilution of serum, antibody class and complement requirement of antibody, being approximately 0.1% of the seed virus. Millipore filtration of the seed virus lowered this PF level to varying degrees depending upon the porosity. However, when filtered virus-serum mixtures were incubated at 37 C for a sufficient time and then filtered again, a portion of the unneutralized virus did pass a 0.22 μ membrane. Furthermore, virus sensitized with insufficient antibody showed no increase in resistance to complement after 10 hr incubation at 4 C. These results proved that viral aggregation was not the essential cause of the PF. It was confirmed, on the other hand, that the neutralization of virus by hyperimmune IgG followed a one-hit curve. Analysis of these data appeared to support Rappaport's postulation that the PF represented antibody-coated virus whose critical antigenic sites were all left unbound.     

In vitro Anti-viral Activity of the Total Alkaloids from Tripterygium hypoglaucum against Herpes Simplex Virus Type 1

Herpes simplex virus type 1 (HSV-1) is a commonly occurring human pathogen worldwide. There is an urgent need to discover and develop new alternative agents for the management of HSV-1 infection. Tripterygium hypoglaucum (level) Hutch (Celastraceae) is a traditional Chinese medicine plant with many pharmacological activities such as anti-inflammation, anti-tumor and antifertility. The usual medicinal part is the roots which contain about a 1% yield of alkaloids. A crude total alkaloids extract was prepared ...     

Herpes Simplex Virus Type 1 Glycoprotein gC Mediates Immune Evasion In Vivo

Many microorganisms encode proteins that interact with molecules involved in host immunity; however, few of these molecules have been proven to promote immune evasion in vivo. Herpes simplex virus type 1 (HSV-1) glycoprotein C (gC) binds complement component C3 and inhibits complement-mediated virus neutralization and lysis of infected cells in vitro. To investigate the importance of the interaction between gC and C3 in vivo, we studied the virulence of a gC-null strain in complement-intact and C3-deficient animals. Using a vaginal infection model in complement-intact guinea pigs, we showed that gC-null virus grows to lower titers and produces less severe vaginitis than wild-type or gC rescued virus, indicating a role for gC in virulence. To determine the importance of complement, studies were performed with C3-deficient guinea pigs; the results demonstrated significant increases in vaginal titers of gC-null virus, while wild-type and gC rescued viruses showed nonsignificant changes in titers. Similar findings were observed for mice where gC null virus produced significantly less disease than gC rescued virus at the skin inoculation site. Proof that C3 is important was provided by studies of C3 knockout mice, where disease scores of gC-null virus were significantly higher than in complement-intact mice. The results indicate that gC-null virus is approximately 100-fold (2 log₁₀) less virulent that wild-type virus in animals and that gC-C3 interactions are involved in pathogenesis.     

Evolution and Diversity in Human Herpes Simplex Virus Genomes

Herpes simplex virus 1 (HSV-1) causes a chronic, lifelong infection in >60% of adults. Multiple recent vaccine trials have failed, with viral diversity likely contributing to these failures. To understand HSV-1 diversity better, we comprehensively compared 20 newly sequenced viral genomes from China, Japan, Kenya, and South Korea with six previously sequenced genomes from the United States, Europe, and Japan. In this diverse collection of passaged strains, we found that one-fifth of the newly sequenced members share a gene deletion and one-third exhibit homopolymeric frameshift mutations (HFMs). Individual strains exhibit genotypic and potential phenotypic variation via HFMs, deletions, short sequence repeats, and single-nucleotide polymorphisms, although the protein sequence identity between strains exceeds 90% on average. In the first genome-scale analysis of positive selection in HSV-1, we found signs of selection in specific proteins and residues, including the fusion protein glycoprotein H. We also confirmed previous results suggesting that recombination has occurred with high frequency throughout the HSV-1 genome. Despite this, the HSV-1 strains analyzed clustered by geographic origin during whole-genome distance analysis. These data shed light on likely routes of HSV-1 adaptation to changing environments and will aid in the selection of vaccine antigens that are invariant worldwide.     

Studies on the Neutralizing Antibody to Herpes Simplex Virus

The type-specific antibody responses in rabbits immunized with both types of herpes simplex virus (HSV), measured by complement-requiring neutralizing (CRN) and slow-reacting CRN (s-CRN) antibody assays were compared. Titers of type-specific antibody measured by s-CRN antibody assay were always markedly higher than those measured by CRN antibody assay. The s-CRN antibody assay was so sensitive that even an undetectable level of CRN antibody could be readily detected by this method. The detection of type-specific antibody by s-CRN antibody assay may be useful when attempting to analyze human HSV infection.     

Early Events in Herpes Simplex Virus Infection: a Radioautographic Study

The early events in herpes simplex virus infection were studied by means of radio-autography. The virus was rapidly taken up by the host cells and uncoated. Viral deoxyribonucleic acid (DNA) reached the nuclear sites of replication in 15 to 30 min after infection. The viral DNA occasionally associated with chromosomes or condensed chromatin but was more frequently found to be randomly distributed. Viral progeny appeared 3 hr after infection. These particles did not show any particular spatial relationship to the parental DNA. The morphological latent period lasted 2.5 hr.     

Inactivation of Herpes Simplex Virus by Concanavalin A

The infectivity of herpes simplex virus type 1 (HSV-1) was inactivated after treatment with either concanavalin A (ConA) or periodate. Phytohemagglutinin, wheat germ agglutinin, pokeweed mitogen, and neuraminidase failed to inactivate the virus. The effect of ConA could be specifically inhibited or reversed by the addition of α-methyl-d-glucoside or α-methyl-d-mannoside. Evidence was obtained that HSV-1 inactivated by ConA could adsorb to host cells. Viral aggregation was not a major mechanism in the inactivation of HSV-1 by ConA. Under the experimental conditions employed, inactivation of HSV-1 was faster by ConA than by antiserum and less temperature dependent. A ConA-resistant fraction was detected which appeared to adsorb less quickly than untreated virus, and penetration of ConA-resistant fraction was strikingly slow. The presence of aggregates in the virus preparation did not appear to account for the ConA-resistant fraction. Inactivation of viral infectivity by ConA was obtained only with enveloped viruses, since HSV-1, HSV-2, pseudorabies, and vesicular stomatitis virus were inactivated and vaccinia and echovirus type 6 were not.     

Persistent Herpes Simplex Virus Infection In Vitro with Cycles of Cell Destruction and Regrowth.

Hampar, Berge (National Institute of Dental Research, Bethesda, Md.), and Mary Lou Copeland. Persistent herpes simplex virus infection in vitro with cycles of cell destruction and regrowth. J. Bacteriol. 90:205-212. 1965.-The susceptibility of two Chinese hamster cell lines to herpes simplex virus (HSV) was studied from the time of their initiation through successive subcultures. The cells' susceptibility to the cytocidal effects of HSV decreased as the number of cell passages increased. During the early cell passages, the decrease in cell susceptibility to HSV was characterized by an increased time after infection for complete cell destruction to occur, with a concomitant increase in the period when virus could be recovered from supernatant fluids. This was followed by a number of cell passages during which persistent HSV infections were established. The persistent infections were characterized by (i) cycles of virus synthesis and cell destruction followed by regrowth of the cells, (ii) initiation and maintenance under conditions optimal for cell growth in the absence of antibody, (iii) the cells' ability to be passaged while still maintaining their cycling patterns, (iv) a relationship between virus synthesis and cell proliferation, and (v) inability of long-term treatment with antibody to "cure" the persistent infections. The unique characteristics of this HSV infection were compared with other persistent in vitro viral infections.