A population screening test for antibody to XXXX .

@entity1 @entity805 @entity9031 @entity465
In areas where sporadic cases of measles continue to occur in spite of vaccination programs, the availability of a simple screening test for determination of seropositivity to @entity805 is desirable. A sensitive radioimmunoassay (RIA) screening test (ST) for the detection of IgG antibody to @entity805 , based on a solid phase RIA, is described. The assays were performed on @entity9031 microtiter plates for which the RIAST requires only 5 microliters of serum per subject. Antigen consisted of a sonicated extract of @entity805 -infected Vero cells. Rabbit antihuman IgG specific for the Fc-segment of human IgG, labeled with 125I, was used to detect human IgG bound to viral antigen. The basic RIA method was characterized by carrying out full titrations of sera of 53 healthy adults, 10 @entity1 , and 13 @entity1 with measles-associated illness. These sera were also tested by the hemagglutination inhibition (HI) technique; most of the measles sera were also tested by @entity465 ( @entity465 ). RIAST results (expressed as binding ratios) obtained for 52 healthy adults are compared with their RIA serum titers. Of the 200 sera of @entity1 of various ages tested by the RIAST, 63 borderline sera were also tested by HI. The RIAST, which does not require serum treatment other than inactivation, proved to be more sensitive as an indicator of seropositivity than HI. Implications of the results and practical applications of the screening test are discussed.
