IgM antibodies against enterovirus
antigen were determined by solid-phase reverse
immunosorbent test (SPRIST). The 145 sera studied were sampled from cases of
enterovirus infections diagnosed by virus isolation and/or
complement fixation. In 91 sera from
enterovirus infections diagnosed by virus isolation 11/40, 16/28 and 9/23 were positive in SPRIST against ECHO 3 and/or Coxsackie B3
antigen during the first, during the second and third, and after 3 weeks of illness, respectively. The corresponding figures for 85 sera from
enterovirus infections diagnosed by a greater than or equal to 4-fold rise in
complement fixing (CF) antibody titre against
antigen from ECHO 18 and/or Coxsackie
B5 antigen were 10/39, 12/20 and 9/26. None out of 22 sera with
rheumatoid factor reacted in SPRIST, but 1/92 and 1/154 sera from blood donors was positive in SPRIST with Coxsackie B3 and ECHO 3
antigen, respectively.
IgM antibodies against ECHO 3
antigen as determined by SPRIST were found to be cross-reactive over a broad range of enterovirus types and positive results were recorded with sera from
infections with Coxsackie A9, B3, B4, B5, ECHO 3, 9, 17, 18, 25 and 30. Heterotypic titres in SPRIST were of the same magnitude (up to 25,600) as recorded against the homotypic virus, 12,800 and 1,600, in two sera from one patient with an ECHO 3
infection. SPRIST was found to be a rapid convenient, cross-reactive and a cheap mu-capture assay for enteroviruses with more than 50% sensitivity during the second and third weeks after onset of illness.