Isolation of rubella virus from brain in chronic progressive panencephalitis

Rubella virus was isolated from the brain of a congenitally-infected, 12-year-old child in whom progressive mental and motor deterioration became evident at age 8 and 11 years respectively. The virus was initially isolated in a co-culture of CV-I cells with the trypsinized brain tissue; subsequently the culture of the brain tissue also showed evidence of rubella virus infection recognized by indirect fluorescent antibody technique (IFA) using anti-rubella virus antibody prepared in rabbits as intermediate serum. Both isolates interfered with infection of BSC-I cell lines by echovirus type II. The interfering virus was identified as rubella virus by IFA with the specific antiserum, and it is designated as the NTr strain of rubella virus. The complement fixing antibody titre to rubella virus in serum was I:256. The spinal fluid was anticomplementary. Rubella virus haemagglutinating antibody titre (HI) in serum was I:8196 and in the spinal fluid I:128. The HI antibody was of the IgG class. The corresponding HI titres to rubeola virus in serum and spinal fluid were I:8 and less than I:2 respectively.