A sensitive assay for anti-HIV-1 drug discovery in a biological safety level-2 laboratory.

Studies involving infectious, wild type HIV-1 must be performed under strict BSL-3 practice. We have employed a defective (deltaTat/Rev)MC99 and cloned 1A2 line, ie, mutated HIV-1 and Tat/Rev transfected cells to verify anti-HIV-1 activity in a BSL-2 laboratory. A number of extracts from various parts of 11 species of plants were studied. Results were correlated with those of an anti-HIV-1 reverse transcriptase (RT) assay.

Encapsidation defectiveness of herpes simplex virus type 2 during replication at acid pH condition.

The maximal yield of herpes simplex virus type 2 (HSV-2) grown at pH 6.5 decreased 10(2)-10(3) fold compared to that recovered at pH 7.5. Electron microscopic observation of the infected cells maintained at these 2 pH conditions indicated that approximately equal amounts of immature virions were synthesized 6 hours after infection. However, at 18 hours post infection the majority of viruses present in the nucleus of infected cells maintained at pH 6.5 were empty or partially cored capsids with some particles enveloped and present in the cytoplasm, whereas at pH 7.5 mature virions already appeared at the cytoplasmic membrane. Analysis of viral polypeptides by radioimmunoprecipitation indicated that the synthesis of p40, a family of polypeptides closely involved in viral DNA encapsidation, was significantly impaired in infected cells maintained at pH 6.5.

Recovery frequencies of herpes simplex virus types 1 and 2 from symptomatic and asymptomatic genital herpes cases and antiviral sensitivities of isolates.

Herpes simplex viruses were isolated from 40.8 to 56.0 per cent of the patients with genital herpes. The frequency of recovery seemed to be higher in females than in males, particularly during the first episode of infection. Asymptomatic shedding of the virus from female genitalias was approximately 0.7 per cent. Herpes simplex virus type 2 represented 98.4 per cent of all isolates and the remaining isolates were type 1. These isolates exhibited a wide range of sensitiveness to 9-(2-hydroxyethoxymethyl) guanine (acyclovir) as demonstrated by antiviral inhibition assay and no single strain exhibited high in vitro drug ID50 value.

Epidemiological study of enteric coronavirus excretion by an enzyme-linked immunosorbent assay.

The enzyme-linked immunosorbent assay with a blocking test was used to determine the prevalence of enteric coronavirus excretion among the population of Bangkok and Khon Kaen province. The results indicated that coronaviruses were present in fecal samples from both children and adults with or without diarrhea. It is interesting that the viruses were more frequently observed in the apparently healthy individuals in Bangkok than in the patients with diarrhea whereas the excretion rates were approximately alike in both groups in Khon Kaen province. Among children aged less than 5 years (with or without diarrhea) the viruses were more frequently observed in stools from young children (1-5 years old) than from the newborn (less than 1-year-old) particularly those living in the Bang Khen slum area and in the rural Khon Kaen community. The rate of coronavirus excretion did not increase with age and some apparently healthy individuals continued to excrete the viruses for several months. The results also suggested that chronic parasitic infection associated with low socioeconomic status might influence the excretion of enteric coronaviruses in the feces.

Evaluation of biotin-streptavidin enzyme-linked immunosorbent assay for detection of genital herpes simplex virus infection.

A biotin-streptavidin enzyme-linked immunosorbent assay (B-SA ELISA) was evaluated for detection of herpes simplex virus (HSV) in clinical specimens which were cervico-vaginal swabs from 205 asymptomatic women and swabs from the genital lesions of 163 suspected patients. All specimens were also subjected to a conventional virus isolation in cell culture. A blocking B-SA ELISA had 100% specificity and 98% sensitivity compared with viral isolation from patients, but had only 40% sensitivity using specimens from asymptomatics. The conventional B-SA ELISA might also be used; it gave results corresponding to B-SA ELISA blocking test except for a single specimen which was considered a false positive.