Application of immunoperoxidase staining to more rapid detection and identification of rubella virus isolates.

Efforts were made to shorten the time required for detection of rubella virus in clinical materials through the use of immunoperoxidase (IP) staining. Comparative studies were performed in which specimens were inoculated in parallel into BHK-21 hamster kidney cells, which were examined by IP staining at 5 days, and into BK-13 and BS-C-1 cells, which were examined in two ways, viz., by subpassage at 7 days into BHK-21 cells and IP staining 3 days later and by subpassage at 7 days into BS-C-1 cells followed by interference testing and immunofluorescence (IF) staining on positive materials (standard method). Direct inoculation into BHK-21 cells with IP staining at 5 days permitted detection and identification of 59% of the 63 positive specimens. Toxicity of some specimens preserved with sorbitol and of certain tissue specimens reduced the number of satisfactory examinations which could be performed in this system. Virus detection and identification by IP staining on subpassaged RK-13 and BS-C-1 materials, requiring a total of 18 days, was comparable to the longer interference-IF method, requiring 17 days. Results obtained by IP staining and interference-IF showed 98% correlation on RK-13 materials and 97% correlation on BS-C-1 materials. IP staining on inoculated BHK-21 cells can be a useful method for rapid identification of a relatively high proportion of rubella-positive specimens, particularly if sorbitol-preserved specimens are avoided, and IP staining on subpassaged RK-13 and BS-C-1 materials is a highly satisfactory alternative to the longer interference-IF method.