J. Van Der Veen

Establishment of two human cell strains from kidney and reticulosarcoma of lung

Two strains of human epithelial-like cells derived from normal kidney and from reticulosarcoma of lung are described; the cells are called T-1 and T-4 cells, respectively. The T-1 cell strain has been propagated in continuous culture for more than 21/2 years, the T-4 cell strain for more than one year. Both cell strains have been grown in media containing 40 per cent human serum, 5 per cent horse serum and 5 per cent calf serum, respectively. The cell strains have been found to propagate a number of viruses.

Patterns of infections with adenovirus types 4, 7 and 21 in military recruits during a 9-year survey

Numerous studies have shown the importance of adenoviruses as a cause of acute respiratory disease in military recruits. However, there are few reports on surveys of respiratory infections in military populations conducted for a period of years in order to obtain reliable and detailed data on the epidemiological pattern of adenovirus infection (Bloom et al. 1964; Rosenbaum et al. 1965). Such data are required to provide a well-founded base for the control of adenovirus illness. The present study was established for this purpose. This paper summarizes the results of a survey of respiratory infection in military recruits over a 9-year period. It was designed primarily to acquire information on the behaviour of adenovirus infections. From 1963 to 1967 additional studies were

Enzyme-linked immunosorbent assay for measurement of antibody against cytomegalovirus and rubella virus in a single serum dilution.

Enzyme-linked immunosorbent assays (ELISA) were developed for quantifying cytomegalovirus (CMV) and rubella antibodies using a single serum dilution (1/800) in conjunction with a standard curve. A near linear relation was found between the logarithms of absorbance values of sera at a dilution of 1/800 and the titres as determined by an end point dilution ELISA. The reproducibility of the single dilution ELISA was good; the within-test coefficients of variation averaged 7.5% for CMV antibody and 12.4% for rubella antibody. A close correlation was found between ELISA and complement-fixing (CF) antibody titres to CMV and between ELISA and haemagglutination-inhibition (HI) antibody titres to rubella virus. The titres in ELISA were 200 to 1000 times higher than in CF for CMV and 50 to 100 times higher than in HI for rubella virus.

Enzyme-linked immunosorbent assay for quantitation of toxoplasma antibodies in human sera.

An enzyme-linked immunosorbent assay(ELISA) was developed for the detection of toxoplasma antibodies using a single serum dilution (1:800) in conjunction with a standard curve Antigen was prepared from Toxoplasma gondii cultivated in human cell cultures. A nearly linear relationship was found between the logarithms of the absorbance values of 120 human sera at a dilution of 1/800 and the titres as determined by an end point dilution ELISA. The reproducibility of the single dilution ELISA was excellent; the coefficients of variation for within-day and day-to-day tests were less than 15%. A close correlation was found between the results obtained with ELISA, indirect immunofluorescence (IF), and complement fixation (CF). The titres in ELISA were 20 to 40 times higher than in IF and 200 to 1000 times higher than in CF.

Prevalence of toxoplasma antibodies according to age with comments on the risk of prenatal infection.

Sera from 1661 persons in 12 age groups from 0 to 79 years were titrated for toxoplasma antibodies in the indirect immunofluorescence test. The sera were collected from patients with symptoms suggestive of acute, mainly respiratory, viral infections. After the first year of life, the prevalence of antibodies started to rise, reaching 59% between 40 and 79 years of age. From the prevalence of antibodies in different age groups the annual infection risk, i.e, the risk of a non-immune person acquiring toxoplasma infection, was estimated for successive age periods. The estimated annual infection risk increased from 0 . 5% in early childhood to 3% during adolescence and early adult life. Approximately 70--80% of females entered the age of reproduction without evidence of seroimmunity to toxoplasma. The risk of primary infection during pregnancy was estimated from the age distribution of parturient women in The Netherlands in 1975 and the age-specific incidence of primary infections, i.e. the incidence in the total population of susceptible and immune persons. This incidence of primary infection decreased from 1 . 62% per 9 months at the age of 17 1/2--20 years to 0 . 37% at the age of 37--45 years. The incidence of primary infections in pregnant women was estimated to be 1 . 25%.

Experimental infection with Sendai virus in mice.

Less than one plaque-forming unit (PFU) of Sendai virus was required to produce a serologically demonstrable infection when inoculated intranasally into mice of a specific pathogen-free colony showing no evidence of previous infection. No difference in susceptibility to serologically demonstrable infection and fatal disease was observed between male and female mice or between 4-week-old and 12-week-old mice. The distribution of virus and the antibody response were studied in 4-week-old and 12-week-old mice inoculated with 50 PFU of Sendai virus. Virus was recovered from the lungs and nasal washings from 24 hours after inoculation to at least 10 days later. Virus titers reached maximum levels at 4 to 6 days. No virus was recovered from the blood, intestines, kidneys and urine. Complement-fixing (CF), hemagglutination-inhibiting (HI) and neutralizing antibodies were demonstrable from the 8th day. Neutralizing antibody persisted at a higher level than did CF and HI antibodies.

A new serological technique for identification of adenovirus infections.

Summary Titers of antibodies against a group-specific antigenic component of vertex capsomers of human adenoviruses have been determined in sera from healthy and adenovirus-infected individuals. For this purpose a hemagglutination-enhancement (HE) test based on the capacity of antibodies to convert penton incomplete hemagglutinins of types 3 and 11 into hemagglutinating aggregates, was employed. Penton HE antibodies had been acquired in about 75% of all individuals before the age of 5 years and the percentage approached 100 at the age of 15 years. After the primary adenovirus infection, penton HE antibodies appeared to remain at a titer of 40 or higher. Renewed adenovirus infections caused booster increases of the base line HE titers. These rises of antibody titers can be practically employed for serological diagnosis of adenovirus infections. The relative usefulness of the penton HE test as compared to the group-specific complement fixation test is discussed.

Effect of relative humidity on experimental transmission of Sendai virus in mice.

Summary The effect of relative humidity on airborne transmission of Sendai virus infection in mice was studied. Greater rates of transmission were observed at higher RH than at a lower one. The rate of transmission was reduced by increased ventilation. A viral strain recovered after serial airborne transmissions showed no evidence of increased transmissibility.

Secondary antibody response of guinea pigs to parainfluenza and mumps viruses

1. The antibody response in guinea pigs infected successively with the same virus or with two different viruses (parainfluenza 1 or 3, Sendai, or mumps) was studied at different times after inoculation by complementfixation and hemagglutination-inhibition techniques. 2. On first infection the response was type-specific. On second infection with the same virus, heterotypic as well as homologous antibody was found soon after inoculation. Successive infections with parainfluenza 3 and Sendai viruses or vice versa resulted in a recall of antibody to the first infecting virus. 3. The results confirm the close antigenic relationship between parainfluenza 1 and Sendai viruses and the antigenic relations between different types of parainfluenza viruses, and in addition suggest that mumps and parainfluenza 2 viruses share antigen. The antibody response in guinea pigs infected successively with the same virus or with two different viruses (parainfluenza 1 or 3, Sendai, or mumps) was studied at different times after inoculation by complementfixation and hemagglutination-inhibition techniques. On first infection the response was type-specific. On second infection with the same virus, heterotypic as well as homologous antibody was found soon after inoculation. Successive infections with parainfluenza 3 and Sendai viruses or vice versa resulted in a recall of antibody to the first infecting virus. The results confirm the close antigenic relationship between parainfluenza 1 and Sendai viruses and the antigenic relations between different types of parainfluenza viruses, and in addition suggest that mumps and parainfluenza 2 viruses share antigen.

Viral replication in mouse macrophages.

Cultures of mouse peritoneal macrophages were capable of supporting the growth of vesicular stomatitis virus (VSV), mengovirus, mouse hepatitis virus (MHV-3 and MHV-S), and reovirus type 3. Age of the cultures and peritoneal stimulation of macrophages appeared to influence this capacity. Increased viral replication was found in cultures one or more days old and in cultures of stimulated macrophages. Phytohemagglutinin (PHA)-stimulated mouse lymphocytes were relatively resistant; only VSV and mengovirus were capable of replicating in these cells.