Mussel-associated viral hepatitis, type A: serological confirmation

7 members of a family of 14 developed acute viral hepatitis approximately one month after a family outing. Epidemiological investigation incriminated incompletely cooked mussels (Mytilus edulis) as the vehicle of infection and revealed a statistically significant difference in attack-rates between mussel-ingesters (70%) and non-ingesters (0%) (P=0-035). The aetiological role of hepatitis-A virus, suspected on epidemiological grounds, was serologically confirmed by the demonstration of rises in titres of serum-antibody to hepatitis-A antigen (serologically related to the MS-1 strain of hepatitis-A virus), determined by immune adherence haemagglutination.

Purification of hepatitis A antigen from feces and detection of antigen and antibody by immune adherence hemagglutination

Hepatitis A antigen (HA Ag) was purified from feces collected during acute illness from patients with naturally occurring viral hepatitis, type A. Positive fecal specimens were identified by immune electron microscopy, but for detection of HA Agduring purification immune adherence hemagglutination (IAHA) and microtiter solid-phase radioimmunoassay were used. Isopycnic banding in cesium chloride, rate-zonal separation in sucrose, and preparative zonal electrophoresis were used in various combinations for successive purification, and the purified antigen was successfully used in a test for antibody by IAHA. Seronconversions to HA Ag were demonstrated by IAHA in 20 instances of hepatitis A virus infection, but in none of six cases of type B hepatitis or three cases of post-transfusion hepatitis unrelated to heaptitis A or B viruses, nor in two individuals without hepatitis. In addition, the temporal pattern of antibody development during type A hepatitis was studied in serial sera from an experimentally infected chimpanzee. Antibody titers by IAHA correlated well with antibody ratings determined by immune electron microscopy.

A microtiter solid-phase radioimmunoassay for hepatitis A antigen and antibody

A microtiter solid phase radioimmunoassy for hepatitis A antigen (HA Ag) and antibody (anti-HA) was developed. The test was more sensitive than immune adherence hemagglutination for detecting HA Ag and almost as sensitive for detecting anti-HA. The specificity and sensitivity of reagents were examined and optimum conditions for the test were determined. Radioimmunoassay, immune adherence hemagglutination, and immune electron microscopy were compared for detecting anti-HA. A serologic response to HA Ag was detected in paired sera from patients with type A hepatitis but not from patients with type B or non-A, non-B hepatitis by all three techniques.

Microtiter solid-phase radioimmunoassay for hepatitis B antigen

A micro-solid-phase radioimmunoassay (micro-SPRIA) for hepatitis B antigen (HB Ag) was developed for use with microtiter serological equipment. Radiolabeled immunoglobulin G was prepared from human and animal sera containing hepatitis B antibody (HB Ab); it was not necessary to isolate specific HB Ab by immunochemical means. A micro-SPRIA prepared with guinea pig reagents was approximately as sensitive as the AusRIA radioimmunoassay, but, like the AusRIA test, yielded false positive results. A micro-SPRIA prepared with human reagents was slightly less sensitive but did not yield false positive results. These micro-SPRIA tests offer several advantages, including conservation of reagents, adaptability to other antigen-antibody systems, ease of performance (especially when testing large numbers of specimens), and economy.

A colour test for the measurement of antibody to certain mycoplasma species based upon the inhibition of acid production

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