Virus-induced diabetes mellitus. I. Hyperglycemia and hypoinsulinemia in mice infected with encephalomyocarditis virus.

Infection of DBA/2N male mice with encephalomyocarditis virus resulted in a diabeteslike syndrome characterized by hyperglycemia, glycosuria, hypoinsulinemia, polydipsia, and polyphagia. Blood glucose levels were elevated within 4 days after infection and reached a maximum mean level of 320 mg/100 ml within 12 days. Approximately 60-80% of the animals developed a transient hyperglycemia while 10-15% of the animals remained hyperglycemic for well over 6 mo. The remaining animals failed to become hyperglycemic but many had abnormal glucose tolerance curves. Hyperglycemia was most pronounced when animals were allowed free access to food, and the incidence of byperglycemia was related both to the strain and sex of the animals, with few females developing hyperglycemia. The amount of immunoreactive insulin in the plasma of infected hyperglycemic mice was significantly lower than in appropriate controls, and injection of exogenous insulin resulted in a rapid drop in the blood glucose levels. Despite the fact that certain animals were hyperglycemic for many months, virus could not be recovered from the pancreas after the first 10 days of the infection.

Nonencapsidated infectious DNA of adeno-satellite virus in cells coinfected with herpesvirus.

Adeno-associated satellite viruses produce antigen detectable by immunofluorescence but not infectious virus in tissue culture cells coinfected with herpes simplex virus. Analysis of DNA extracts from these infected cells shows that large amounts of infectious satellite virus DNA are produced but not encapsidated in the system. This result indicates that satellite virus may be defective at the maturation step.

Measles antibodies as related to HL-A types in multiple sclerosis.

One hundred thirty-six patients with multiple sclerosis and several control groups were studied for measles antibodies using several different antigens. Measles antibodies were higher in the multiple sclerosis population, but siblings also had higher titers than matched and random controls. The elevation in antibody titers (complement fixation) was found in female multiple sclerosis patients and male patients with HL-A types 3, 7, and W-18. Male patients not carrying these HL-A antigens had, as a group, relatively normal antibody levels. These data confirm a familial factor in elevated measles antibody titers. We suggest that HL-A antigens are linked to one of the factors that determines measles antibody titers in multiple sclerosis patients.

HLA in multiple sclerosis. Relationship to measles antibody, mitogen responsiveness and clinical course.

In our study of multiple sclerosis (MS) patients we have found significant increases in the A3, B7, and DW2 antigens. We have also studied immune responses in these same patients. There was elevation of measles antibodies in MS patients positive for A3, B7, and B18 as compared to MS patients without those antigens. The first study of mitogen responsiveness (31 patients) showed a decreased response in A3, and B7 positive patients. Study of a second and a larger group (62 patients), at a different time, failed to confirm this deficiency. We propose that there is a genetically linked (HLA) T cell deficiency in some MS patients and that this deficiency results in high humoral responses to measles antigens and an evanescent (or cyclical) reduced T cell response to mitogen.

Antigenic variants of rabies virus.

The authors studied nineteen street virus isolates from different regions of Canada using either anti-nucleocapsid and anti-glycoprotein monoclonal antibodies or cross-protection tests. This study only allowed us to recognize three groups of viruses with different nucleocapsid patterns, and no difference, as far as protection with a Pitmann-Moore vaccine is concerned, between four of these strains.

HLA-D typing with an association of Dw2 and absent immune responses towards herpes simplex (type i) antigen in multiple sclerosis.

We have confirmed that HLA-Dw2 is increased in MS patients to 47% (normals 20%). Lymphocyte transformation and antibody studies with herpes simplex antigen show that many of the DW2-positive MS patients have low or absent responses. The association of low responses to HSV and the presence of Dw2 is statistically significant at a p value less than 0.01.

Regulatory control of blood products in Canada.

Blood products are considered as biological drugs in Canada and are regulated under The Food and Drugs Act. Before a biological drug may be sold, the manufacturer must file a new drug submission with the Bureau of Biologics and receive a notice that the submission complies with the regulations. In addition the manufacturer must comply with the requirements for a license, including the detailed description of manufacturing facilities, qualifications of personnel, and standard operating procedures of all manufacturing steps. To verify the information provided by the manufacturer, senior scientists of the Bureau conduct an inspection of the manufacturing premises. In order to ensure the safety and potency of the product, the Bureau authorizes the sale of the product on a lot by lot basis. Samples of each lot are submitted to the Bureau laboratories for testing. In November 1984 the Bureau required manufacturers to treat coagulation products by a method proven to inactivate HTLV-III/LAV. While immune globulin preparations have not been associated with virus transmission in recipients, the Bureau tested 22 lots of various immune globulin products for HTLV-III/LAV antibodies. Using the Western Blot assay 9 lots were found antibody positive. Although these lots are not considered infectious, further studies are required from manufacturers to demonstrate by virus isolation attempts and virus "spiking" studies that the fractionation procedure eliminates potentially infectious virus.

The potency of tissue-type plasminogen activator (TPA) determined with chromogen and clot-lysis assays.

An assessment was made of two methods for determining the potency of tissue-type plasminogen activator (TPA). A chromogenic microtitre plate assay was established which contained TPA, plasminogen, a synthetic plasmin substrate (H-D-valyl-L-leucyl-L-lysyl-p-nitroaniline dihydrochloride, S2251) and any one of the following stimulators: native fibrinogen, enzymatic and chemical digests of fibrinogen, poly-D-lysine (PDL) and chemical derivatives of the latter. The chromogen assay was compared with an automated clot-lysis (turbidimetric) assay for sensitivity, reproducibility and validity for potency determination. Reference preparations of TPA were titrated in both assays: in the chromogen assay the dose-response curves were non-parallel, whereas parallelism was observed in the clot-lysis assay. Thus, the chromogen assay was restricted in its applicability and disqualified from any routine regulatory use. The potency of individual lots of recombinant (r)TPA could only be estimated in International Units (IU) of TPA activity with the automated clot-lysis assay and the potency values obtained (IU/vial) were in remarkably close agreement with the manufacturers' values.

Persistence of influenza serum antibodies in humans following immunization with a bivalent A/Victoria and A/New Jersey vaccine.

The persistence of serum antibodies 1 year after immunization with a bivalent vaccine containing recombinant viruses that were antigenically identical with A/Victoria/3/75 (H3N2) and A/New Jersey/8/76 (Hsw1N1) viruses was measured in 128 persons aged 18 to 65 years. Serum samples were tested with the hemagglutination inhibition assay against the two vaccine antigens and against A/Texas/1/77 (H3N2) and A/USSR/90/77 (H1N1) viruses. Prior to vaccination 56% and 79% of the participants had been found to be seronegative to A/Victoria and A/New Jersey antigens respectively; the geometric mean antibody titres were low (1:5 to 1:11) except in persons aged 51 to 65 years, whose mean titre of antibody to the A/New Jersey antigen was 1:23, and persons aged 26 to 35 years, whose mean titre of antibody to the A/USSR antigen was 1:25. By 3 weeks after vaccination 85% of the seronegative persons had a fourfold or greater rise in titres of antibodies to the viruses in the vaccine, and 70% had a fourfold increase in titre of antibody to the A/Texas antigen. Of the persons aged 26 to 35 years (seronegative and seropositive) 68% had a fourfold or greater increase in titre of antibody to the A/USSR antigen. There was no change in the mean titres of 19 unvaccinated control subjects during the observation period. At 6 and 12 months after vaccination the titres of antibodies to the A/Victoria and A/New Jersey antigens had declined moderately in all age groups from those observed 3 weeks after vaccination. The rate of decline was similar for the various antibodies except that to the A/USSR antigen in persons 26 to 35 years of age, in whom the decline was much slower.

Virus-induced diabetes mellitus. II. Relationship between beta cell damage and hyperglycemia in mice infected with encephalomyocarditis virus.

Infection of DBA 2 male mice with the M variant of encephalomyocarditis virus resulted in a diabetes-like syndrome. Histologic examination of the pancreas revealed damage to the beta cells with little involvement of the acinar cells. The severity of the hyperglycemia correlated closely with the degree of beta cell damage. By immunofluorescence, viral antigens could be detected in the beta cells during the first 10 days of the infection. In contrast to the response found in male DBA 2 mice, infection of DBA 2 female mice and male mice of several other strains resulted in little if any elevation of blood glucose concentration. Histologic examination of the pancreas of these animals revealed only minimal damage to the beta cells. It is concluded that differences in the severity of the hyperglycemia between DBA 2 males and females and among the different strains of male mice tested are directly related to the degree of beta cell damage produced by the viral infection.

Use of monoclonal antibodies prepared with Sabin vaccine viruses for the characterization of poliovirus strains isolated in Canada.

Eleven of 90 hybridomas that secreted neutralizing antibodies to various types of poliovirus, were cloned and their monoclonal antibodies tested for the intratypic differentiation of poliovirus isolates. All monoclonal antibodies (MAs) prepared with three types of Sabin vaccine viruses were specific with their homologous viruses but only one of three Saukett MAs was found suitable for intratypic serodifferentiation. A total of 112 poliovirus strains isolated from specimens of human or sewage origin in Canada from 1962 to 1981 were tested with these MAs. Approximately 90% of the virus isolates tested confirmed the findings previously obtained in the antigenic marker assays. Either pools or panels of individual MAs are suitable for the characterization of poliovirus isolates. Preliminary results of experiments conducted with pools of MAs and with single MAs added in various sequences, demonstrated that the location of the virus epitopes played an important role in the neutralization process.

Virus-induced diabetes mellitus. III. Influence of the sex and strain of the host.

Nineteen inbred strains of male mice were infected with encephalomyocarditis virus. Five strains became hyperglycemic and had abnormal values in glucose tolerance tests; three strains remained normoglycemic but had abnormal values in glucose tolerance tests; and the remaining strains showed no abnormalities in blood glucose levels or glucose tolerance tests. Female mice from three of five strains tested also developed hyperglycemia, but in one strain (DBA/2) the hyperglycemia was less severe in females than in males. Castrated DBA/2 males developed less severe hyperglycemia than uncastrated males, even though the degree of damage to beta cells appeared to be similar in the two groups. Host factors apparently influence both the development and expression of virus-induced diabetes mellitus.

Seroepidemiological and ecological studies of the adenovirus-associated satellite viruses.

The seroepidemiology of the defective adenovirus-associated satellite viruses was studied by use of a neutralization test that has been shown to be much more sensitive than the complement-fixation (CF) test. Less than 25% of the subjects in any age group were positive for any type of satellite virus CF antibody. The neutralization test revealed serological evidence of satellite infection in almost 80% of the subjects in some age groups. Studies of geometric mean antibody titers by neutralization showed that antibody against type 1 and the type 2-3 complex reached peak levels at 2 to 3 years of age; antibody against types 2 and 3 reached mean titers of 500 to 800, whereas mean antibody levels of only 200 were found for type 1. Type 4 antibodies were rarely noted in human sera. In a companion study in monkeys, monospecific responses to types 1 and 4 were found only in rhesus and green monkey sera, respectively. These data suggest that the type 2-3 complex may be the only naturally occurring satellite serotype which infects man and that antibodies noted against types 1 and 4 may be the result of cross-reactions. No satellite viruses were isolated from throat or rectal swabs of 100 children between 6 months and 3 years of age. However, the patterns of adenovirus and enterovirus isolations from these specimens were typical of previous studies in this laboratory.