Serologic evidence of an association between enteroviruses and the onset of type 1 diabetes mellitus. Pittsburgh Diabetes Research Group.

Serum was collected from 128 patients < or = 18 years of age admitted to the Children's Hospital of Pittsburgh with new-onset insulin-dependent diabetes mellitus (IDDM) and from 120 control-patients who were frequency-matched to case-patients for age, sex, and date of bleed. Serum was tested for IgM against 14 enterovirus serotypes: coxsackieviruses B1-B6 and A9, echoviruses 4, 6, 9, 11, 30, and 34, and enterovirus 71. Case-children 13-18 years of age were more likely than control-patients to be IgM-positive for 9 of 14 serotypes (P < or = .05 for each). In contrast, case-children 10-12 years of age and 1-9 years of age were each more likely than age-matched control-children to be IgM positive for 1 serotype (P < or = .05 for each). In addition, the association between IgM positivity and IDDM occurred earlier in girls than in boys. These data support an association between IDDM and enterovirus IgM positivity in older children.

Inactivation and stability of viral diagnostic reagents treated by gamma radiation.

The objective of this study was to apply the pertinent findings from gamma inactivation of virus infectivity to the production of high quality diagnostic reagents. A Gammacell 220 (Atomic Energy of Canada, Ltd., Ottawa, Canada) was used to subject 38 viruses grown in either susceptible tissue cultures or embryonated chicken eggs to various doses of gamma radiation from a cobalt-60 source. The radiation required to reduce viral infectivity was 0.42 to 3.7 megarads (Mrad). The effect of gamma treatment on the antigenic reactivity of reagents for the complement fixation (CF), hemagglutination (HA) and neuraminadase assays was determined. Influenza antigens inactivated with 1.7 Mrad displayed comparable potency, sensitivity, specificity and stability to those inactivated by standard procedures with beta-propiolactone (BPL). Significant inactivation of influenza N1 and B neuraminidase occurred with greater than 2.4 Mrad radiation at temperatures above 4 degrees C. All 38 viruses were inactivated, and CF or HA antigens were prepared successfully. Antigenic potency remained stable with all antigens for 3 years and with 83% after 5 years storage. Influenza HA antigens evaluated after 9 years of storage demonstrated 86% stability. Gamma radiation is safer than chemical inactivation procedures and is reliable and effective replacement for BPL in preparing diagnostic reagents.

In vitro effect of ascorbic acid on infectivity of herpesviruses and paramyxoviruses.

Suspensions of herpes simplex virus types 1 and 2, cytomegalovirus, and parainfluenzavirus type 2 were inactivated within 24 h when treated at 37 degrees C with 1 mg (5.05 mM) of copper-catalyzed sodium ascorbate per ml. The infectivity titer of respiratory syncytial virus was reduced substantially after 24 h but required 48 h for inactivation. Under these conditions, inactivation of these viruses was also successfully achieved with 5.68 mM catalyzed ascorbic acid. Copper (Cu2+), when added with the ascorbate solution at 5 micrograms/ml (0.022 mM), exhibited a catalytic effect on the inactivation of these viruses. The rate of inactivation was affected by the incubation temperature, time of exposure, and the virus concentration. Ascorbate concentrations as high as 10 mg/ml (50.5 mM) demonstrated only a minimum increase in effect on viral inactivation. The loss of infectivity did not alter either the hemagglutination or complement fixation qualities of the antigens.