Dot-ELISA for serodiagnosis of human infections due to Western equine encephalitis virus

A standard dot-ELISA (enzyme-linked immunosorbent assay) was modified for use in detecting IgM and IgG class antibodies to Western equine encephalitis (WEE) virus in serum samples from humans infected with this virus. Nitrocellulose membranes were soaked in supernatant fluid from WEE virus-infected cell cultures, air dried, and blocked with bovine protein. Serum samples were pipetted onto sections of the nitrocellulose, incubated, and washed. Addition of antibody to human immunoglobulin conjugated to alkaline phosphatase and enzyme substrate were used to detect the antibodies. Of 13 samples positive for IgM antibody to WEE virus by IgM antibody capture ELISA, 12 were positive by IgM dot-ELISA. IgG antibody to WEE virus was detected by dot-ELISA in 7/8, 10/14 and 7/10 samples with neutralizing, hemagglutination-inhibiting, or complement-fixing antibodies, respectively.