Betsy C. Herold

Glycoprotein C-independent binding of herpes simplex virus to cells requires cell surface heparan sulphate and glycoprotein B

Previous studies have shown that the initial interaction of herpes simplex virus (HSV) with cells is binding to heparan sulphate and that HSV-1 glycoprotein C (gC) is principally responsible for this binding. Although gC-negative viral mutants are impaired for binding and entry, they retain significant infectivity. The purpose of the studies reported here was to explore the requirements for infectivity of gC-negative HSV-1 mutants. We found that absence or alteration of cell surface heparan sulphate significantly reduced the binding of gC-negative mutant virus and rendered cells resistant to infection, as shown previously for the wild-type virus. We isolated a recombinant double-mutated HSV strain that produces virions devoid of both of the known heparin-binding glycoproteins, gB and gC. The drastically impaired binding of these mutant virions to cells, relative to gC-negative and wild-type virions, indicates that gB mediates the binding of gC-negative virions to cells. Thus at least two HSV glycoproteins can independently mediate the binding of HSV to cell surface heparan sulphate to start the process of viral entry into cells.

Heparan Sulfate Glycosaminoglycans as Primary Cell Surface Receptors for Herpes Simplex Virus

Our current incomplete picture of the earliest events in HSV infection may be summarized as follows. The initial interaction of virus with cells is the binding of virion gC to heparan sulfate moieties of cell surface proteoglycans. Stable binding of virus to cells may require the interaction of other virion glycoproteins with other cell surface receptors as well (including the interaction of gB with heparan sulfate). Penetration of virus into the cell is mediated by fusion of the virion envelope with the cell plasma membrane. Events leading up to this fusion require the action of at least three viral glycoproteins (gB, gD and gH), one or more of which may interact with specific cell surface components. It seems likely that binding of gB to cell surface heparan sulfate may occur and may be important in the activation of some event required for virus penetration. Heparan sulfate is present not only as a constituent of cell surface proteoglycans but also as a component of the extracellular matrix and basement membranes in organized tissues. In addition, body fluids contain both heparin and heparin-binding proteins, either of which can prevent the binding of HSV to cells (WuDunn and Spear, 1989). As a consequence, the spread of HSV infection is probably influenced, not only by immune responses to the virus, but also by the probability that virus will be entrapped or inhibited from binding to cells by extracellular forms of heparin or heparan sulfate.

Cryoprecipitates in kawasaki syndrome: Association with coronary artery aneurysms

Cryoprecipitates are postulated to play a role in the pathogenesis of several vasculitic illnesses and infectious diseases. To investigate the presence of cryoprecipitates in Kawasaki syndrome, we studied sera from 25 children with acute Kawasaki syndrome. None of the subjects was treated with intravenous gamma-globulin. Cryoprecipitates were detectable in sera of 11 of 25 (44%) children studied. The mean (±SE protein concentration of the cryoprecipitates was 88.0 (±20.2) Mg/ml serum. Cryoprecipitates consisted primarily of IgG and IgM; no complement components were detected but highly sensitive methods were not used. The presence of cryoprecipitates in the serum of children with acute Kawasaki syndrome was associated with the subsequent development of coronary artery aneurysms detected by echocardiogram (P <0.05). There was no association between detectable cryoprecipitates and either peak platelet count or erythrocyte sedimentation rate. In one patient, measurement of cryoprecipitates in serial samples showed a reduction in concentrations that paralleled subsidence of disease activity. We speculate that cryoprecipitates may be a marker for increased risk of coronary aneurysm formation and may play a role in the pathogenesis of the cardiac disease in Kawasaki syndrome.

Polystyrene Sulfonate Is a Safe and Effective Candidate Topical Antimicrobial for the Prevention of Sexually Transmitted Diseases

Polystyrene Sulfonate Is a Safe and Effective Candidate Topical Antimicrobial for the Prevention of Sexually Transmitted Diseases

DRAMATIC INCREASE IN COMMUNITY-ACQUIRED METHICILLIN-RESISTANTSTAPHYLOCOCCUS AUREUS (MRSA) IN CHILDREN WITH NO PREDISPOSING RISK.|[dagger]| 1028

Background: MRSA is typically acquired nosocomially by patients with predisposing risks. Community-acquired (CA) infections are infrequent. Having observed several children hospitalized with CA MRSA infection, we sought to define the scope of the problem by reviewing medical records of all children with Staphylococcus aureus (SA) isolated from any site in 1993-5. For comparison, we reviewed charts of all those who had MRSA isolated in 1988-90. Methods: An isolate was defined as CA if the culture was obtained ≤ 72 h after hospitalization and the patient did not have risk factors for MRSA including prior hospitaization or antimicrobial therapy within the last 6 mo. Each SA isolate was determined to be colonizing or associated with clinical disease. Susceptibility testing was done by Vitek Auto Microbic System and/or disc diffusion. Available MRSA blood isolates in 1993-5 were characterized by pulse field gel electrophoresis (PFGE).Results: For 1993-5, 298 charts were reviewed, (57 and 241 charts from patients with MRSA and methicillin susceptible (MSSA) isolates, respectively); for 1988-90 30 charts were reviewed from patients with MRSA. The percentage of CA MRSA isolates increased from 3.3% in 1988-90 to 46.4% in 1993-5 (p=0.001). 74% of MRSA and 60% of MSSA isolates in 1993-5 were associated with disease. Among the CA disease isolates, the disease spectrum was not different when stratified by methicillin resistance. Cellulitis accounted for 48% and 43% of patients with MRSA and MSSA, respectively; abscesses accounted for 30% and 28% and pneumonia accounted for 13% and 9%, respectively. Irrespective of methicillin resistance, the disease spectrum among the nosocomially acquired SA infections differed from the CA disease spectrum; for example, bacteremia was most frequent, accounting for 21% and 37% of MRSA and MSSA disease isolates, respectively. Nosocomial MRSA had higher rates of resistance to clinda, TMP-SMX, erythro, and gent (p≤ 0.02) than did CA MRSA. Among 7 isolates subjected to PFGE, there were three patterns suggesting that a single MRSA clone was not responsible for the increased prevalence. Conclusion: The prevalence of CA MRSA infections has increased dramatically in our pediatric population. The disease spectrum of CA MRSA infection is similar to CA MSSA infection. CA MRSA were less often multiply resistant than nosocomial MRSA isolates.

REQUIREMENTS FOR ENTRY OF HERPES SIMPLEX VIRUSES (HSV) INTO PRIMARY HUMAN VAGINAL/CERVICAL CELLS. |[dagger]| 715

Genital HSV infection is a major health problem that impacts both on sexually active individuals and neonates who become infected perinatally. To develop new strategies for the prevention of HSV, determination of the requirements for establishment of genital infection is imperative. The aims of these studies are to identify requirements for entry of HSV into cervical cells. Primary cultures were established using fragments of vagina, ectocervix and endocervix from specimens obtained from patients who had undergone hysterectomies for conditions such as endometriosis. Pts. ranged in age from 30-54, mean 43±7 years. We found that both HSV-1 and HSV-2 form plaques on primary cells within 24 h of infection; at the same m.o.i., virus plaques on cell lines in 48-72 h. Endocervix (columnar epithelium) was more susceptible to infection than ectocervix (squamous epithelium). Susceptibility of HSV infection increased if cells were cultured in the presence of 10-8-10-10 m/L of 17-beta-estradiol. We found that heparan sulfate serves as a receptor for binding of HSV to the cells. Heparin, an analog of HS, but not other glycosaminoglycans inhibited viral binding. The antiviral activity of heparin for both serotypes was independent of anticoagulant activity. N-sulfated regions of heparin were key for interactions of HSV with the cell surfaces since N-desulfation, but not N-deacetylation, abolished the antiviral activity. To assess the role of the heparin-binding glycoprotein, gC, in viral entry, we compared infection of wild-type (WT) and gC-deletion (gC-) viruses. We found a significant impairment in ability of HSV-1 gC- virus to infect primary human ectocervix. In contrast, deletion of gC from HSV-2 had no deleterious effect on HSV-2 infection of primary cells. These observations may reflect serotype differences in the role of gC in binding and entry for HSV-1 and HSV-2. In conclusion: 1) Primary human cervical and vaginal cells are susceptible to HSV infection in vitro and are a model system for study of genital tract infection; 2) HS is a receptor for viral binding; 3) for HSV-1, but not HSV-2, gC plays a key role in mediating viral entry into primary human cells; 4) serotype differences in gC may contribute to serotype differences in cell tropism.

GLYCOPROTEIN C(gC) of HERPES SIMPLEX VIRUS (HSV) TYPE 1 BINDS TWO DISTINCT POLYSACCHARIDE POPULATIONS WITHIN HEPARIN. † 704

GLYCOPROTEIN C(gC) of HERPES SIMPLEX VIRUS (HSV) TYPE 1 BINDS TWO DISTINCT POLYSACCHARIDE POPULATIONS WITHIN HEPARIN. † 704

HERPES SIMPLEX VIRUS TYPE 1(HSV) GLYCOPROTEIN C(gC) PLAYS DIFFERENT ROLES IN EPITHELIAL AND NEURONAL CELL ENTRY. † 1027

HERPES SIMPLEX VIRUS TYPE 1(HSV) GLYCOPROTEIN C(gC) PLAYS DIFFERENT ROLES IN EPITHELIAL AND NEURONAL CELL ENTRY. † 1027

GLYCOPROTEIN C OF HERPES SIMPLEX VIRUS TYPE 1 BINDS TO SPECIFIC POLYSACCHARIDES WITHIN HEPARIN. 1016

GLYCOPROTEIN C OF HERPES SIMPLEX VIRUS TYPE 1 BINDS TO SPECIFIC POLYSACCHARIDES WITHIN HEPARIN. 1016

Cell Surface Receptors Required for Herpes simplex Virus Infection Include Heparan Sulfate Glycosaminoglycans

Herpes simplex virus (HSV) is one of the several biologically distinct herpes viruses that cause disease in humans. The most common manifestations of HSV disease include keratitis and cutaneous lesions, such as cold sores and fever blisters, and similar lesions on genital organs. Rarely, the virus can induce more serious disease such as encephalitis and disseminated infections affecting several organ systems. HSV is not eliminated following the healing of lesions but persists as latent virus in the neurons of sensory or autonomic ganglia connecting with sites of viral inoculation or replication. Reactivation of latent virus is responsible for the recurrences of lesions that afflict many people. There are two serotypes of HSV, designated HSV-1 and HSV-2. HSV-1 is most commonly associated with facial lesions, keratitis and encephalitis in adults whereas HSV-2 is most commonly associated with genital lesions and neonatal infections (Corey et al, 1988).