Margrét Gudnadóttir

Virus isolated from the brain of a patient with multiple sclerosis

Abstract In search for a virus as a possible cause of multiple sclerosis thirteen brains from patients with multiple sclerosis and four brains from persons with other conditions were tested by various tissue culture methods during a period of 4 years. Isolation of a herpeslike virus from a brain of a patient with a 27-year history of multiple sclerosis is described and neutralizing antibodies against the virus in sera from groups of patients with MS and groups of healthy adults are compared. A statistically significant difference was observed in the number of positive sera from Icelandic MS patients as compared with two groups of healthy Icelandic adults.

Comparison of immunoblots with neutralizing and complement fixing antibodies in experimental and natural cases of visna-maedi.

SummaryIn this study the humoral antibody response in visna-maedi virus disease in sheep during long-term infection was analyzed utilizing immunoblot assays, neutralization tests and complement fixation tests. In immunoblot assays antibodies to several virus specific protein bands were detected, both against the viral envelope glycoproteins and internal proteins of the virus. The immunoblot reaction pattern resembled that found in HIV-1 infection in humans, consistent with reported similar molecular weight of the major proteins of these two viruses. The immunoblot band pattern was compared with the pattern of complement fixing and neutralizing antibodies through the preclinical and clinical course in natural and experimental cases of visna-maedi. Of six immunoblot bands identified as virus specific, the antibody response against threegag products and the majorenv glycoprotein appeared early in infection, at a similar time as the complement fixing antibodies. The response against two proteins, one presumably the transmembrane protein and the other possibly agag precursor, was delayed.

Vaccination delays Maedi-Visna lentivirus infection in a naturally-infected sheep flock.

BackgroundThe Maedi-Visna (MV) lentivirus causes two slowly progressive eventually fatal diseases of sheep, Maedi, a progressive interstitial pneumonia, and Visna, a progressive demyelinating disease of the central nervous system. Other lentiviruses also cause fatal slow infections in their natural hosts, e.g. the HIV virus in humans. Results of experimental vaccination against any lentivirus where vaccinees are challenged by natural routes, may therefore be of general interest. From 1991–1998 experiments with formalin-inactivated whole Maedi-Visna virus vaccine were carried out in the Department of Microbiology at the University of Iceland. Western Blot tests showed good immune response to all major proteins of the virus. When aluminium hydroxide was added to the vaccine all vaccinees developed neutralizing antibodies to the vaccine strain at titers 1/8 – 1/256. After housing 5 twin pairs, one twin in each pair vaccinated, the other unvaccinated, with infected sheep for 4 years, all the unvaccinated twins became infected, but only 2 of their vaccinated siblings as confirmed by virus cultivation experiments on tissues from their lungs spleens lymph nodes and choroid plexuses.ResultsOne twin in each of 40 female twin pairs, born into a Maedi-Visna-infected sheep flock and kept under natural farming conditions in Cyprus, was vaccinated at birth, 3 weeks and 3 months, with formalin-inactivated whole Maedi-Visna lentivirus vaccine adjuvanted with aluminium hydroxide. 17 mothers of the twins were seronegative, 13 seroconverting and 10 had old infection. Of 17 vaccinees born to seronegative mothers 9 were uninfected at 28 months, but only 2 of their unvaccinated siblings. Of 13 unvaccinated twins born to seroconverting mothers, 12 caught infection during their first 10 weeks, but only 4 of their vaccinated siblings. Vaccination had no effects on 10 vaccinees born to mothers with long-standing Maedi-Visna infections and broad andibody response at birth of their lambs.ConclusionCompared with their unvaccinated siblings, natural infection was delayed in significant number of vaccinated twins born by seronegative and seroconverting mothers and vaccinated at birth, 3 weeks and 3 months with formalin inactivated whole MV vaccine adjuvanted with aluminium hydroxide. Maternal antibodies interfered with vaccination so early in life if the mother had old infection.

Experiments with inactivated visna-maedi vaccine.

Sixteen Icelandic sheep were vaccinated against Visna-Maedi infection with formalin inactivated whole virus vaccine to which alun was added as an adjuvant. Western Blots showed that all the vaccinees responded to the major proteins of the virus. They all developed neutralizing antibodies ranging in titers from 1/8-1/256 at maximum for individual sheep. Passive transfer of antibodies and neutralizing activity from vaccinated ewes to their lambs was demonstrated. Exposure of the 16 vaccinees and their 16 unvaccinated control sheep to natural infection is attempted by housing them with heavily infected sheep. After 9 months of exposure there is no seroconversion in the unvaccinated group. Only time can tell, whether or not such conventional vaccination with inactivated vaccine protects the vaccinees.

MEASLES VACCINATION IN ADULTS WITH AND WITHOUT COMPLICATING CONDITIONS.

Measles has had particularly serious effects when epidemics have occurred in isolated susceptible adult populations. The newly developed measles vaccines may therefore be of special importance to these groups and such data as are available m a y be of interest to personel responsible for the medical care of such populations. This repor~ summarizes briefly the experience obtained with live a t tenuated measles vaccine (Edmonston B level) when over 700 susceptible persons, most ly adults, were vaccinated in rural areas of Iceland in 1962. The age distribution of the subjects is given in Table 1. The trial was one of several carried out at tha t t ime in various parts of the world under the auspices of the World Heal th Organization. Detailed analyses of the results appear elsewhere (1, 2) but the most important findings may be summarized as follows: